V17.0 BSS (Access) Parameters User Guide - bPUG
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V17.0 BSS Parameter User Guide (BPUG) Document number: Document issue: Document status: Date: PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 External document Copyright© 2008 Nortel Networks, All Rights Reserved Printed in France NORTEL CONFIDENTIAL The information contained in this document is the property of Nortel Networks. Except as specifically authorized in writing by Nortel Networks, the holder of this document shall keep the information contained herein confidential and shall protect same in whole or in part from disclosure and dissemination to third parties and use same for evaluation, operation and maintenance purposes only. The content of this document is provided for information purposes only and is subject to modification. It does not constitute any representation or warranty from Nortel Networks as to the content or accuracy of the information contained herein, including but not limited to the suitability and performances of the product or its intended application. This is the Way. This is Nortel, Nortel, the Nortel logo, and the Globemark are trademarks of Nortel Networks. All other trademarks are the property of their owners. V17.0 BSS Parameter User Guide (BPUG) PUBLICATION HISTORY System release: GSM/BSS V17 March 2008 Issue 17.03/EN Update for v17 Channel Readiness. Update of Enhanced Measurement Reporting Parameters (§4.8.24); update of GSM to UMTS handovers parameters (§4.5.8); clarification on msTxPwrMax2ndBand on Power Control Parameters section (§ 5.16) October 2007 Issue 17.02/EN Update for v17 Customer Readiness. Update of GSM to UMTS handover with normal measurement reporting (§4.8.24); update of legacy measurement reporting to include UTRAN neighbours (§4.5.8); update of reporting priority criteria used in EMR (§4.6.5); summary of differences between MR and EMR (§4.6.8); new section on eMLPP Preemption (§4.12); clarification of types of TDMA priorities (§6.27.2); new recommendation for trafficPCMAllocationPriority; new range for hoMarginBeg; clarification of bscHopReconfUse; diversity mandatory for ICA (§4.18); end of support of PCM Error Correction (§4.20); list of Railway parameters (§3.3); update of handover decision table for AMR TCH (§4.8.4); clarification of Downlink DTX activation (§4.11.10). July 2007 Issue 17.01/EN Update for v17 Business Readiness + 21 weeks: Legacy measurement report (§4.5); Enhanced Measurement Report (§4.6); Downlink FER (§4.6.11); GSM to UMTS Handover (§4.8.24, §7.7); Single BCCH Multizone Enhancement (§4.8.2, §4.8.6, §4.10.6, §6.30); AMR-HR on preempted pDTCH (§4.25.6, impact on AboT §4.25.8); A5/3 Encryption (§4.30); Smart BTS Power management (§4.31); Novel adaptive receiver (§4.29); BSS CS Paging Coordination (§4.13.8); H3 impact on BTS cabinet power setting (§4.16); new recommended values for modeModifyMandatory (§5.18); addition of RxQual criteria for interzone handovers (§4.8.6); removal of reference to gsmProtocol in ICA (§5.30); Sysinfo broadcast cycle (§4.17.3). Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 2/629 V17.0 BSS Parameter User Guide (BPUG) System release: GSM/BSS V16 March 2007 Issue 16.04/EN Update for V16 ChR + 8 Weeks: Update of Network Synchronization (§ 4.34); Update of TX Power Offset for signalling Channels parameters (§ 5.34); Update of network Synchronization Impacts (§ 6.36); Addition of Network Synchronization Engineering planning (§ 6.37) and Network Synchronization First Trial Results (§ 6.38) November 2006 Issue 16.03/EN Update for V16 ChR after review: Update of CellAllocation (§ 5.21); update PCM error correction (§ 4.17.3); update of AMR based on traffic parameters (§ 5.34) October 2006 Issue 16.02/EN Update for V16 ChR: Update of TEPMOS for AMR and not EFR calls (§ 6.32.2 and § 6.32.6) I Multipaging command message (§ 4.10.5); UI Multipaging command message (§ 4.10.6); Tx Power Offset for signalling Channels (§ 4.23.9); update coderPoolConfiguration (§ 5.34); update PCM error correction (§ 4.17.3); update rescue Handover (§ 4.6.1) and PBGT formula (§ 4.5.1); PCM priority (§ 6.27.5); update Cabinet power description (§ 4.13.1) May 2006 Issue 16.01/EN Update for V16 CuR: 6.16 Frequency Spacing Between Two TRXs of the Same Area March 2006 Issue 16.0/EN Update for V16. CuR: Repeated Downlink FACCH (§ 4.23.8); Tx Power Offset for signalling Channels (§ 4.23.9); Directed Retry Handover and queuing (§ 4.5.5, § 4.23.5 removed from WPS description); updates on CellAllocation and mobileAllocation description (§ 5.21);updates on AMR mechanism (§ 4.23.2, §4.23.4);updates on TCH allocation management (§ 4.9.1, §4.9.2); updates on interference cancellation (§ 4.15, 6.22); update on lRxQualDLH and lRxQualULH description (§ 5.10);update on dARPPh1Priority description (§ 5.36); update coderPoolConfiguration (§ 5.34); update on extended cell description (§ 5.12) Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 3/629 V17.0 BSS Parameter User Guide (BPUG) System release: GSM/BSS V15 October 2005 Issue 15.10/EN Update for V15.1.1 CuR: AMR based on traffic (§ 4.22.7, § 6.35); AMR improvements (amr adaptation table : § 4.22.2, § 4.22.3, § 6.32.3, § 5.34); Network Synchronization (§ 3.2.46, § 4.25, § 5.36, § 6.36); Automatic Handover Adaptation (§ 4.5.22 frequency hopping, §6.33.2 Fine Tuning); NMO I (§ 4.9.5, § 5.37); list of possible dual band network (§ 6.20.3); update of cell models (§ 6.27.4); update on concentricCell with HePA (§ 4.5.6 and § 5.16 bizonePowerOffset and concentricCell, § 6.6.1 bizonePowerOffset, § 6.6.2 ZoneTxPowerMaxReduction); update CellAllocation and mobileAllocation description (§ 5.21) September 2005 Issue 15.09/EN Update for V15.1 ChR + 8 weeks: overhaul of Concentric Cell matter (§ 4.5.6 Concentric/DualCoupling/DualBand Cell Handover, § 5.16 Concentric Cell Parameters and § 6.6 Concentric Cell) and Microcell matter (§ 6.21 Microcell Benefits) based on recent field feedback, add of a guideline for traffic HO (§ 6.34 Handover for traffic reasons activation guideline), update on the appendix B: Erlang table, add of § 4.5.10 Ad-Hoc Frequency plan, update on amrReserved2 and uMTSAccessMinLevel parameters. July 2005 Issue 15.08/EN Update for V15.1 ChR: add of Satellite Abis Interface description, Automatic Handover Adpatation field field feedback March 2005 Issue 15.07/EN Update for V15.1 CuR: update of existing features on BSC12000 (Automatic Handover Adaptation, support of S18000, configure sending SI2Quater & SI13 on NORM or EXT BCCH), update on Cell Group Management and Load Balancing, Changed microCellCaptureTimer parameter range of values April 2005 Issue 15.06/EN Update for V15.0.1 ChR: correction for noOfBlocksForAccessGrant parameter (it is greater than zero if the SysInfo 2Q and/or SysInfo 13 on extended BCCH features are activated) November 2004 Issue 15.05/EN Update for V15.0.1 CuR: AMR field feedback and GSM products update Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 4/629 V17.0 BSS Parameter User Guide (BPUG) September 2004 Issue 15.04/EN Update for V15.0 ChR June 2004 Issue 15.03/EN Update for AMR December 2003 Issue 15.00/EN Update for Wireless Priority Service System release: GSM/BSS V14 June 2004 Issue 14.05/EN Update for AMR December 2003 Issue 14.04/EN Update for V14.3 ChR December 2002 Issue 14.03/EN September 2002 Issue 14.02/EN Update with V14 System release: GSM/BSS V13 September 2002 Issue 13.02/EN Update with V13 Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 5/629 V17.0 BSS Parameter User Guide (BPUG) System release: GSM/BSS V12 May 2001 Issue 12.02/EN Update with V12 (Chapters 1 to 4 except the counters and GSM fields in Chapter 3 “Algorithms Parameters”). January 2000 Issue 12.01/EN Modifications after Review. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 6/629 V17.0 BSS Parameter User Guide (BPUG) CONTENTS 1. ABOUT THIS DOCUMENT .........................................................................................................16 1.1. 1.2. 1.3. 1.4. 1.5. 1.6. OBJECT ..................................................................................................................................16 SCOPE ...................................................................................................................................16 AUDIENCE FOR THIS DOCUMENT ..............................................................................................16 DISCLAIMER ...........................................................................................................................16 DOCUMENT STRUCTURE ..........................................................................................................17 UPDATES TO PREVIOUS RECOMMENDATIONS ............................................................................18 between V16 and V17...................................................................................................18 between V15.1.1 and V16.............................................................................................18 between V15.1 and V15.1.1..........................................................................................19 between V15.0 and V15.1.............................................................................................20 1.6.1 1.6.2 1.6.3 1.6.4 2. RELATED DOCUMENTS ............................................................................................................22 2.1. 2.2. APPLICABLE DOCUMENTS ........................................................................................................22 REFERENCE DOCUMENTS .......................................................................................................22 3. CLASSIFICATION OF BSS PARAMETERS ..............................................................................25 3.1. 3.2. 3.3. 3.4. PARAMETER LIST ....................................................................................................................25 GSM UNUSED PARAMETERS ....................................................................................................34 RAILWAY-SPECIFIC PARAMETERS (GSM-R)..............................................................................34 PARAMETERS VERSUS BSS FEATURES AND PROCEDURES .......................................................36 2G Cell Selection and Reselection ...............................................................................36 2G-3G Cell Reselection ................................................................................................36 Legacy Measurement Reporting ...................................................................................36 Enhanced Measurement Reporting ..............................................................................36 Level averaging.............................................................................................................36 Quality averaging ..........................................................................................................36 Distance averaging .......................................................................................................36 Cell eligibility..................................................................................................................36 Radio Link Failure .........................................................................................................37 Interference management .............................................................................................37 PCH and RACH control parameters .............................................................................37 Concentric Cell ..............................................................................................................37 Extended cell.................................................................................................................37 Queuing and priority management................................................................................37 eMLPP Preemption .......................................................................................................37 SMS-CB ........................................................................................................................37 Frequency Hopping.......................................................................................................37 Dynamic barring of access class ..................................................................................38 DTX ...............................................................................................................................38 Uplink Power control .....................................................................................................38 Downlink Power control.................................................................................................38 Directed retry handover.................................................................................................38 Uplink intracell handover...............................................................................................38 Downlink intracell handover ..........................................................................................38 Intercell handover on bad uplink quality criterion..........................................................38 Intercell handover on bad downlink quality criterion .....................................................38 Intercell handover on bad uplink level criterion.............................................................39 Intercell handover on bad downlink level criterion ........................................................39 Intercell handover on power budget criterion................................................................39 Nortel confidential 3.4.1 3.4.2 3.4.3 3.4.4 3.4.5 3.4.6 3.4.7 3.4.8 3.4.9 3.4.10 3.4.11 3.4.12 3.4.13 3.4.14 3.4.15 3.4.16 3.4.17 3.4.18 3.4.19 3.4.20 3.4.21 3.4.22 3.4.23 3.4.24 3.4.25 3.4.26 3.4.27 3.4.28 3.4.29 PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 7/629 V17.0 BSS Parameter User Guide (BPUG) 3.4.30 3.4.31 3.4.32 3.4.33 3.4.34 3.4.35 3.4.36 3.4.37 3.4.38 3.4.39 3.4.40 3.4.41 3.4.42 3.4.43 3.4.44 3.4.45 3.4.46 3.4.47 3.4.48 3.4.49 3.4.50 3.4.51 3.4.52 3.4.53 3.4.54 3.4.55 4. Microcellular algorithm ..................................................................................................39 Intercell handover on distance criterion ........................................................................39 Handover for traffic reasons..........................................................................................39 Handover decision according to adjacent cell (V12).....................................................39 General protection against HO PingPong.....................................................................39 Call clearing...................................................................................................................39 Frequency Band favouring ............................................................................................39 Minimum Time between Handover (before V12) ..........................................................40 Radio resource control at cell level ...............................................................................40 Pre-synchronised Handover..........................................................................................40 Interferer cancellation....................................................................................................40 Early HO decision .........................................................................................................40 Maximum RxLev for PBGT ...........................................................................................40 Cell Tiering ....................................................................................................................40 TTY support on BSC/TCU 3000....................................................................................40 Protection against intracell HO Ping-pong ....................................................................40 Automatic Handover adaptation....................................................................................40 GSM to UMTS Handover ..............................................................................................41 Adaptative Full/Half Rate ..............................................................................................41 Wireless Priority Service ...............................................................................................41 Network Synchronization ..............................................................................................41 Repeated Downlink FACCH..........................................................................................41 Tx Power Offset for Signalling.......................................................................................41 Novel adaptive Receiver ...............................................................................................41 A5/3 Encryption Algorithm.............................................................................................42 BTS Smart Power Management ...................................................................................42 ALGORITHMS .............................................................................................................................43 4.1. 4.2. INTRODUCTION .......................................................................................................................43 CONVENTIONS AND UNITS .......................................................................................................43 Unit ................................................................................................................................43 Phase 2 BTS and MS maximum transmitting output powers .......................................44 GSM Products sensitivity and power ............................................................................46 Conversion rules ...........................................................................................................47 Accuracy related to measurements ..............................................................................47 Frequency band ............................................................................................................48 Overview .......................................................................................................................49 Selection or reselection between cells of current Location Area ..................................50 Reselection to a cell of a different Location Area..........................................................50 Additional reselection criterion (for phase 2).................................................................50 UE algorithm in GSM circuit mode................................................................................54 3G neighbouring cell information in SI2quater..............................................................55 Control Information in SI2Quater ..................................................................................56 Principle.........................................................................................................................57 Neighbour cell Monitoring .............................................................................................57 Serving cell monitoring..................................................................................................58 Reporting Period ...........................................................................................................58 Neighbour Cell Lists ......................................................................................................58 Measurement Report Content.......................................................................................59 Multiband reporting (V10)..............................................................................................60 UTRAN cell reporting using legacy measurement reports (V17)..................................60 Note on powerControlIndicator parameter....................................................................63 Nortel confidential 4.2.1 4.2.2 4.2.3 4.2.4 4.2.5 4.2.6 4.3. 4.3.1 4.3.2 4.3.3 4.3.4 4.4. 4.4.1 4.4.2 4.4.3 4.5. 4.5.1 4.5.2 4.5.3 4.5.4 4.5.5 4.5.6 4.5.7 4.5.8 4.5.9 2G CELL SELECTION AND RESELECTION ..................................................................................49 2G - 3G CELL RESELECTION ...................................................................................................54 LEGACY MEASUREMENT REPORTING .......................................................................................57 PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 8/629 V17.0 BSS Parameter User Guide (BPUG) 4.5.10 4.6. 4.6.1 4.6.2 4.6.3 4.6.4 4.6.5 4.6.6 4.6.7 4.6.8 4.6.9 4.6.10 4.6.11 4.7. 4.7.1 4.7.2 4.7.3 4.7.4 4.8. 4.8.1 4.8.2 4.8.3 4.8.4 4.8.5 4.8.6 4.8.7 4.8.8 4.8.9 4.8.10 4.8.11 4.8.12 4.8.13 4.8.14 4.8.15 4.8.16 4.8.17 4.8.18 4.8.19 4.8.20 4.8.21 4.8.22 4.8.23 4.8.24 4.9. 4.10. Note on Rxlev Uplink/Downlink difference ....................................................................64 Principle.........................................................................................................................65 Reporting period............................................................................................................65 Enhanced Measurement Report content ......................................................................65 Neighbour Cell lists .......................................................................................................66 Order of reporting priority of neighbour cells.................................................................67 Measurement Information message .............................................................................67 MI/SACCH scheduling ..................................................................................................69 Main differences between Normal and Enhanced Measurement Reporting ................70 New BSS parameters....................................................................................................70 Impact of EMR on Interference Matrix ..........................................................................71 Impact of EMR on Radio Measurement Distribution (RMD) .........................................72 Principle.........................................................................................................................73 Averaging process ........................................................................................................74 Rescaling.......................................................................................................................75 Missing downlink measurements ..................................................................................75 General formulas...........................................................................................................78 Direct TCH Allocation....................................................................................................81 Handovers .....................................................................................................................85 Handovers decision priority...........................................................................................87 Directed Retry Handover...............................................................................................89 Concentric/DualCoupling/DualBand Cell Handover .....................................................92 Rescue Handover .........................................................................................................98 Power Budget Handover ............................................................................................ 100 Handover for traffic reasons (from V12)..................................................................... 100 Handover decision according to adjacent cell priorities and load (from V12)............ 103 Automatic cell tiering (from V12) ................................................................................ 104 Microcellular Handover .............................................................................................. 109 Forced Handover ....................................................................................................... 112 Early HandOver Decision........................................................................................... 113 Maximum RxLev for Power Budget ........................................................................... 114 Pre-synchronized HO................................................................................................. 115 Radio channel allocation ............................................................................................ 115 Define eligible neighbor cells for intercell handover (except directed retry) .............. 116 Handover to 2nd best candidate when return to old channel .................................... 117 Protection against RunHandover=1 ........................................................................... 117 General protection against HO ping-pong (from V12) ............................................... 118 Automatic handover adaptation ................................................................................. 120 Protection against Intracell HO Ping-Pong ................................................................ 123 GSM to UMTS handover............................................................................................ 126 ENHANCED MEASUREMENT REPORTING (EMR) .......................................................................65 UPLINK MEASUREMENT PROCESSING ......................................................................................73 DIRECT TCH ALLOCATION AND HANDOVER ALGORITHMS .........................................................78 HANDOVER ALGORITHMS ON THE MOBILE SIDE ..................................................................... 137 POWER CONTROL ALGORITHMS ........................................................................................... 138 Step by step Power Control ....................................................................................... 138 One shot Power Control............................................................................................. 139 Fast Power Control at TCH assignment .................................................................... 141 Power Control on mobile side .................................................................................... 142 AMR Power Control ................................................................................................... 142 Power adaptation after an interzone ho ..................................................................... 143 TCH Allocation and Priority ........................................................................................ 146 Queuing...................................................................................................................... 150 Nortel confidential 4.10.1 4.10.2 4.10.3 4.10.4 4.10.5 4.10.6 4.11. 4.11.1 4.11.2 TCH ALLOCATION MANAGEMENT ......................................................................................... 146 PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 9/629 V17.0 BSS Parameter User Guide (BPUG) 4.11.3 4.11.4 4.11.5 4.11.6 4.11.7 4.11.8 4.11.9 4.11.10 4.12. 4.12.1 4.12.2 4.12.3 4.12.4 4.12.5 4.12.6 4.12.7 4.12.8 4.13. 4.13.1 4.13.2 4.13.3 4.13.4 4.13.5 4.13.6 4.13.7 4.13.8 4.14. 4.14.1 4.14.2 4.14.3 4.14.4 4.14.5 4.15. 4.15.1 4.15.2 4.15.3 4.15.4 4.16. 4.16.1 4.16.2 4.16.3 4.17. 4.17.1 4.17.2 4.17.3 4.18. 4.19. Barring of access class .............................................................................................. 154 Radio link failure process (run by the MS) ................................................................. 159 Radio link failure process (run by the BTS) ............................................................... 159 Call reestablishment procedure ................................................................................. 160 Call Clearing Process (run by BTS) ........................................................................... 161 Interference Management (BTS and BSC) ................................................................ 161 Uplink DTX ................................................................................................................. 161 Downlink DTX......................................................................................................... 163 .......................................................................................................... 165 Principle of eMLPP..................................................................................................... 165 End-to-end perspective .............................................................................................. 166 Preemption attributes ................................................................................................. 168 BSS Radio Resource preemption algorithm .............................................................. 169 Activation parameter .................................................................................................. 172 eMLPP preemption versus PDTCH preemption ........................................................ 172 Interworking................................................................................................................ 173 Restrictions................................................................................................................. 174 Paging command Process ......................................................................................... 175 Paging command repetition process (run by BTS) .................................................... 177 Request access command process ........................................................................... 179 Request access command repetition process ........................................................... 179 I Multipaging command message .............................................................................. 180 UI Multipaging command message............................................................................ 182 Network Mode of Operation I support in BSS ............................................................ 184 BSS CS Paging Coordination .................................................................................... 186 Frequency hopping principles .................................................................................... 188 Main benefits of frequency hopping ........................................................................... 189 Synthesised frequency hopping................................................................................. 191 Baseband frequency Hopping.................................................................................... 192 Ad-Hoc frequency plan............................................................................................... 194 BSC12000 Overload Management ............................................................................ 195 BSC3000 Overload Management .............................................................................. 198 Load Balancing .......................................................................................................... 200 V15.1 Evolution of Load Balancing ............................................................................ 200 Cabinet power description.......................................................................................... 202 Pr computation ........................................................................................................... 203 Ps computation .......................................................................................................... 205 Dual Band Handling ................................................................................................... 207 SI2Quater & SI13 on Extended or Normal BCCH...................................................... 210 Summary of SYSINFO Scheduling ............................................................................ 211 EMLPP PREEMPTION PCH AND RACH CHANNEL CONTROL ................................................................................... 175 FREQUENCY HOPPING ......................................................................................................... 188 BSC OVERLOAD MANAGEMENT MECHANISMS....................................................................... 195 CABINET OUTPUT POWER SETTING ...................................................................................... 202 SYSTEM INFORMATION MESSAGES RELATED FEATURES ........................................................ 207 INTERFERENCE CANCELLATION ............................................................................................ 213 EXTENDED CCCH ............................................................................................................... 215 Customer/service provider benefits ........................................................................... 215 Feature functional description .................................................................................... 215 Feature principle ........................................................................................................ 216 Nortel confidential 4.19.1 4.19.2 4.20. 4.20.1 PCM ERROR CORRECTION .................................................................................................. 216 PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 10/629 V17.0 BSS Parameter User Guide (BPUG) 4.20.2 4.20.3 4.21. 4.21.1 4.21.2 4.22. 4.22.1 4.22.2 4.23. 4.23.1 4.23.2 4.24. 4.25. Feature benefits ......................................................................................................... 217 Feature activation....................................................................................................... 217 TTY principle .............................................................................................................. 218 TTY impact ................................................................................................................. 219 Principle...................................................................................................................... 221 Performances ............................................................................................................. 221 Principle...................................................................................................................... 222 Performances ............................................................................................................. 223 CELLULAR TELEPHONE TEXT MODEM (TTY) ......................................................................... 218 LOCATION SERVICES............................................................................................................ 221 SMS-CELL BROADCAST....................................................................................................... 222 BSC/TCU 3000 INTRODUCTION ........................................................................................... 225 AMR - ADAPTATIVE MULTI RATE FR/HR .............................................................................. 226 Basics and specific terminology................................................................................. 226 AMR mechanisms ...................................................................................................... 228 Traffic Management mechanisms.............................................................................. 231 AMR L1m ................................................................................................................... 235 Legacy L1M................................................................................................................ 245 pDTCH Preemption by AMR FR or HR calls ............................................................. 245 Engineering rules ....................................................................................................... 247 AMR based on traffic.................................................................................................. 249 Repeated Downlink FACCH....................................................................................... 254 Tx Power Offset for Signaling Channels ................................................................ 257 Principle...................................................................................................................... 262 WPS – Queuing management ................................................................................... 262 WPS – Access class barring with class periodic rotation .......................................... 265 WPS – Public access bandwith protection................................................................. 266 Principle...................................................................................................................... 268 Feature activation....................................................................................................... 269 Feature Interworking .................................................................................................. 269 Global description ...................................................................................................... 270 Feature activation....................................................................................................... 272 Feature impacts expectations .................................................................................... 273 Principle...................................................................................................................... 274 HW/SW dependence.................................................................................................. 274 Activation Guidelines.................................................................................................. 274 Principle...................................................................................................................... 276 Hardware dependence............................................................................................... 276 Ciphering activation rules........................................................................................... 276 Performance impact ................................................................................................... 278 Definitions................................................................................................................... 279 Principle...................................................................................................................... 279 Pre V17 Behaviour ..................................................................................................... 279 Nortel confidential 4.25.1 4.25.2 4.25.3 4.25.4 4.25.5 4.25.6 4.25.7 4.25.8 4.25.9 4.25.10 4.26. 4.26.1 4.26.2 4.26.3 4.26.4 4.27. 4.27.1 4.27.2 4.27.3 4.28. 4.28.1 4.28.2 4.28.3 4.29. 4.29.1 4.29.2 4.29.3 4.30. 4.30.1 4.30.2 4.30.3 4.30.4 4.31. 4.31.1 4.31.2 4.31.3 WPS - WIRELESS PRIORITY SERVICE ................................................................................... 262 SATELLITE ABIS INTERFACE .................................................................................................. 268 NETWORK SYNCHRONIZATION .............................................................................................. 270 NOVEL ADAPTIVE RECEIVER................................................................................................. 274 A5/3 ENCRYPTION ALGORITHM ............................................................................................. 276 BTS SMART POWER MANAGEMENT ...................................................................................... 279 PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 11/629 V17.0 BSS Parameter User Guide (BPUG) 4.31.4 4.31.5 4.31.6 5. Post V17 Behaviour ................................................................................................... 280 Hardware dependence............................................................................................... 281 Activation Guidelines.................................................................................................. 281 ALGORITHM PARAMETERS .................................................................................................. 284 5.1. 5.2. 5.3. 5.4. 5.5. 5.6. 5.7. 5.8. 5.9. 5.10. 5.11. 5.12. 5.13. 5.14. 5.15. 5.16. 5.17. 5.18. 5.19. 5.20. 5.21. 5.22. 5.23. 5.24. 5.25. 5.26. 5.27. 5.28. 5.29. 5.30. 5.31. 5.32. 5.33. 5.34. 5.35. 5.36. 5.37. 5.38. 5.39. 5.40. 5.41. 5.42. 5.43. 5.44. 5.45. INTRODUCTION .................................................................................................................... 284 2G CELL SELECTION AND RESELECTION PARAMETERS .......................................................... 285 2G-3G CELL RESELECTION PARAMETERS ............................................................................. 290 LEGACY MEASUREMENT REPORTING PARAMETERS ............................................................... 292 ENHANCED MEASUREMENT REPORTING PARAMETERS .......................................................... 293 RADIO LINK FAILURE PARAMETERS ....................................................................................... 297 SIGNAL QUALITY AVERAGING PARAMETERS .......................................................................... 300 SIGNAL STRENGTH AVERAGING PARAMETERS....................................................................... 302 NEIGHBOR CELL AVERAGING PARAMETERS .......................................................................... 305 DISTANCE AVERAGING PARAMETERS .................................................................................... 307 HANDOVER (GLOBAL) PARAMETERS ..................................................................................... 309 INTRACELL HANDOVER PARAMETERS.................................................................................... 322 INTERCELL HANDOVER THRESHOLD PARAMETERS ................................................................ 325 HANDOVER FOR MICROCELLULAR NETWORK PARAMETERS ................................................... 329 DISTANCE MANAGEMENT PARAMETERS ................................................................................ 331 POWER CONTROL PARAMETERS........................................................................................... 335 TCH ALLOCATION MANAGEMENT PARAMETERS .................................................................... 343 EMLPP RADIO RESOURCE PREEMPTION PARAMETER ........................................................... 357 DIRECTED RETRY HANDOVER PARAMETERS ......................................................................... 358 CONCENTRIC CELL PARAMETERS ......................................................................................... 362 INTERFERENCE LEVEL PARAMETERS .................................................................................... 370 RADIO RESSOURCES CONTROL AT CELL LEVEL .................................................................... 373 BSS TIMERS ....................................................................................................................... 374 PAGING PARAMETERS .......................................................................................................... 381 FREQUENCY HOPPING PARAMETERS .................................................................................... 386 BSC LOAD MANAGEMENT PARAMETERS ............................................................................... 393 DUALBAND CELL PARAMETERS ............................................................................................ 394 DTX PARAMETERS .............................................................................................................. 401 MISCELLANEOUS ................................................................................................................. 402 INTERFERENCE CANCELLATION PARAMETERS ....................................................................... 405 PCM ERROR CORRECTION PARAMETERS ............................................................................. 407 CELL TIERING PARAMETERS ................................................................................................. 408 ENCODING PARAMETERS ..................................................................................................... 411 SMS-CELL BROADCAST PARAMETERS ................................................................................. 412 PROTECTION AGAINST INTRACELL HO PING-PONG PARAMETERS .......................................... 413 AUTOMATIC HANDOVER ADAPTATION PARAMETERS .............................................................. 414 GSM TO UMTS HANDOVER PARAMETERS............................................................................. 416 AMR - ADAPTATIVE MULTI RATE FR/HR PARAMETERS ......................................................... 424 WPS - WIRELESS PRIORITY SERVICES PARAMETERS ............................................................ 442 NETWORK SYNCHRONIZATION PARAMETERS ......................................................................... 443 NETWORK MODE OF OPERATION PARAMETERS ..................................................................... 445 BSS CS PAGING COORDINATION PARAMETER ...................................................................... 445 NOVEL ADAPTIVE RECEIVER PARAMETER .............................................................................. 446 A5/3 ENCRYPTION ALGORITHM PARAMETERS ........................................................................ 447 BTS SMART POWER MANAGEMENT PARAMETERS................................................................. 450 6. ENGINEERING ISSUES........................................................................................................... 451 6.1. GSM/GPRS TS SHARING: PRIORITY HANDLING AND QUEUING ............................................. 451 Resources reserved for priority 0 and preemption..................................................... 451 GSM/GPRS TS sharing and queuing: ....................................................................... 452 Resources strategy .................................................................................................... 453 Nortel confidential 6.1.1 6.1.2 6.1.3 PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 12/629 V17.0 BSS Parameter User Guide (BPUG) 6.2. LAYER 1 MANAGEMENT: CHANGES BETWEEN V1 AND V2 ...................................................... 454 Main differences......................................................................................................... 454 Benefit ........................................................................................................................ 462 Change in Handover performance after L1mV2 implementation............................... 462 6.2.1 6.2.2 6.2.3 6.3. 6.4. ONE-SHOT POWER CONTROL .............................................................................................. 463 MINIMUM TIME BETWEEN HANDOVER.................................................................................... 464 Micro-cellular network ................................................................................................ 464 Non micro-cellular network......................................................................................... 466 Benefit of feature on mono-layer structure................................................................. 467 Benefit of feature on multi-layers structure ................................................................ 468 Concentric Cell Parameter Definition......................................................................... 472 Concentric Cell Field Experience ............................................................................... 475 6.4.1 6.4.2 6.5. 6.5.1 6.5.2 6.6. 6.6.1 6.6.2 DIRECTED RETRY HANDOVER BENEFIT ................................................................................. 467 CONCENTRIC CELLS ............................................................................................................ 471 6.7. IMPACT OF DTX ON AVERAGING ........................................................................................... 479 6.8. BEST NEIGHBOUR CELLS STABILITY ..................................................................................... 480 6.9. TCH ALLOCATION GENERAL RULES ..................................................................................... 481 6.10. GENERAL RADIO FREQUENCY RULES ................................................................................... 482 6.11. DIFFERENCE BETWEEN UPLINK AND DOWNLINK LEVELS ........................................................ 483 6.12. EFFECTS OF “NOOFMULTIFRAMESBETWEENPAGING” ON MOBILE BATTERIES AND RESELECTION REACTIVITY ...................................................................................................................................... 484 6.13. EFFECTS OF SMS-CELL BROADCAST USE ON “NOOFBLOCKSFORACCESSGRANT”................. 486 6.14. IMPACT OF THE AVERAGING ON THE HANDOVERS .................................................................. 487 6.14.1 6.14.2 6.14.3 6.15. 6.15.1 6.15.2 6.16. 6.16.1 6.16.2 6.16.3 6.17. 6.17.1 6.17.2 6.17.3 6.17.4 6.18. 6.18.1 6.18.2 6.18.3 6.19. 6.19.1 6.19.2 6.19.3 6.19.4 6.19.5 6.20. Global statistics .......................................................................................................... 487 Study of reactivity....................................................................................................... 488 Ping pong vs Reactivity.............................................................................................. 488 Impact on capacity ..................................................................................................... 489 Impact on call drops ................................................................................................... 489 Intra_cell..................................................................................................................... 490 Intra_site..................................................................................................................... 490 Inter_site..................................................................................................................... 490 Gains and losses........................................................................................................ 491 Designs margins ........................................................................................................ 492 Environmental factors margins................................................................................... 492 Link budget balance or disbalance (∆)....................................................................... 493 Broadband noise ........................................................................................................ 495 Blocking...................................................................................................................... 495 How to improve the MCL............................................................................................ 496 Nortel choice between Baseband and Synthesised Frequency hopping .................. 497 Fractional load............................................................................................................ 499 Maximum TRX configuration (homogeneous sites of configuration Sxxx) ................ 500 SFH parameter setting for 1X1 pattern: strategy 1 .................................................... 501 SFH parameter setting for 1X3 pattern: Strategy 2 ................................................... 506 IMPACT OF CALL RE-ESTABLISHMENT ON THE NETWORK ....................................................... 489 FREQUENCY SPACING BETWEEN TWO TRXS OF THE SAME AREA .......................................... 490 LINK BUDGET (LB)............................................................................................................... 491 MINIMUM COUPLING LOSS (MCL)......................................................................................... 495 GENERAL RULES FOR SYNTHESISED FREQUENCY HOPPING .................................................. 497 DUALBAND NETWORKS ........................................................................................................ 512 Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 13/629 V17.0 BSS Parameter User Guide (BPUG) 6.20.1 6.20.2 6.20.3 6.21. 6.21.1 6.21.2 6.21.3 6.21.4 6.22. 6.23. Frequency band favouring ......................................................................................... 512 Frequency band defavouring ..................................................................................... 514 Possible dualband network ........................................................................................ 515 Frequency super reuse .............................................................................................. 516 Traffic Homogenization .............................................................................................. 516 Radio conditions improvement................................................................................... 516 Microcell Field Experience ......................................................................................... 517 MICROCELL BENEFITS .......................................................................................................... 516 INTERFERENCE CANCELLATION USAGE ................................................................................. 518 SET UP PRINCIPLES OF A NEIGHBORING LIST AND A BCC PLAN ............................................. 519 Introduction................................................................................................................. 519 4/12 reuses pattern .................................................................................................... 519 1X3 and 1X1 Fractional reuse pattern specific case ................................................. 521 Set-up principles of a BSIC plan ................................................................................ 523 Description ................................................................................................................. 524 Case A: Mobile moving straight ................................................................................. 525 Case B: Mobile turning at the cross road................................................................... 526 Introduction................................................................................................................. 527 OMC-R Parameter settings........................................................................................ 527 Timing HO .................................................................................................................. 528 Definition of sensitivity................................................................................................ 532 Static and dynamic sensitivity .................................................................................... 533 Typical / guaranteed sensitivity .................................................................................. 533 Space diversity gains ................................................................................................. 533 Cross-polarization antenna use ................................................................................. 534 Circular polarization and crosspolar antennas........................................................... 535 SDCCH Dimensioning................................................................................................ 537 TDMA priorities .......................................................................................................... 538 BSS prerequisite ........................................................................................................ 540 BSS: Suggestions for parameters to be modified for the special event .................... 541 NSS level.................................................................................................................... 542 “CPU Engineering limit” meaning............................................................................... 545 “CPU Call Processing limit” meaning......................................................................... 546 Important note ............................................................................................................ 547 Dualband cell ............................................................................................................. 547 Concentric cell............................................................................................................ 550 Dualcoupling cell ........................................................................................................ 550 Paging parameters..................................................................................................... 552 Field examples: BSS paging repetition tuning ........................................................... 553 Field examples: NSS paging repetition tuning ........................................................... 554 Nortel confidential 6.23.1 6.23.2 6.23.3 6.23.4 6.24. 6.24.1 6.24.2 6.24.3 6.25. 6.25.1 6.25.2 6.25.3 6.26. 6.26.1 6.26.2 6.26.3 6.26.4 6.26.5 6.26.6 6.27. 6.27.1 6.27.2 6.28. 6.28.1 6.28.2 6.28.3 6.29. 6.29.1 6.29.2 6.30. 6.30.1 6.30.2 6.30.3 6.30.4 6.31. 6.31.1 6.31.2 6.31.3 STREET CORNER ENVIRONMENT .......................................................................................... 524 SYNCHRONIZED HO VERSUS NOT SYNCHRONIZED HO .......................................................... 527 BTS SENSITIVITY ................................................................................................................. 532 SDCCH DIMENSIONING AND TDMA PRIORITIES .................................................................... 537 ENGINEERING GUIDELINES FOR EXCEPTIONAL EVENTS .......................................................... 540 ENGINEERING LIMITS WITH BSC OVERLOAD CONTROL MECHANISM ....................................... 545 POWER CONTROL COMPENSATION IN INTERZONE HANDOVER ................................................ 547 GSM PAGING REPETITION PROCESS TUNING ....................................................................... 552 PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 14/629 V17.0 BSS Parameter User Guide (BPUG) 6.32. AMR FIELD FEEDBACK ........................................................................................................ 555 NSS Interaction .......................................................................................................... 555 AMR Theoretical Performances ................................................................................. 556 AMR Engineering Studies .......................................................................................... 559 Half Rate Penetration Analysis .................................................................................. 565 AMR User Behaviour Effect ....................................................................................... 568 Voice Quality Analysis................................................................................................ 570 AMR Monitoring ......................................................................................................... 572 Related parameters.................................................................................................... 578 Deployment Optimization and Monitoring .................................................................. 579 Algorithms and Parameters Definition ....................................................................... 583 Expected effects and recommended parameters ...................................................... 585 6.32.1 6.32.2 6.32.3 6.32.4 6.32.5 6.32.6 6.32.7 6.33. 6.33.1 6.33.2 6.34. 6.34.1 6.34.2 6.35. 6.36. IMPACT OF AUTOMATIC HANDOVER ADAPTATION ACTIVATION ................................................. 578 HANDOVER FOR TRAFFIC REASONS ACTIVATION GUIDELINE .................................................. 583 DISABLING AMR BASED ON TRAFFIC IN V15.1.1 .................................................................... 589 NETWORK SYNCHRONIZATION IMPACTS ................................................................................. 590 Collision Probability.................................................................................................... 590 TSC Impacts............................................................................................................... 592 FN Offset Impacts ...................................................................................................... 593 Interference Cancellation ........................................................................................... 595 TSC Planning ............................................................................................................. 598 FN Offset Planning..................................................................................................... 598 TN Offset Planning..................................................................................................... 599 Synchronization Strategies ........................................................................................ 600 6.36.1 6.36.2 6.36.3 6.36.4 6.37. 6.37.1 6.37.2 6.37.3 6.37.4 6.38. 7. NETWORK SYNCHRONIZATION ENGINEERING PLANNING ........................................................ 598 NETWORK SYNCHRONIZATION FIRST TRIAL RESULTS ............................................................. 601 APPENDIX A: MAIN EXCHANGE PROCEDURES AT BSC LEVEL...................................... 604 7.1. 7.2. 7.3. 7.4. 7.5. 7.6. 7.7. 7.8. 7.9. 7.10. 7.11. ESTABLISHMENT PROCEDURE .............................................................................................. 604 CHANNEL MODE PROCEDURE .............................................................................................. 605 DEDICATED CHANNEL ASSIGNMENT ...................................................................................... 606 INTRACELL HANDOVER PROCEDURE ..................................................................................... 607 INTRABSS HANDOVER PROCEDURE ..................................................................................... 608 INTERBSS HANDOVER PROCEDURE ..................................................................................... 609 2G-3G HANDOVER PROCEDURE ........................................................................................... 610 RESOURCE RELEASE PROCEDURE (EXAMPLE)...................................................................... 611 SACCH DEACTIVATION PROCEDURE ................................................................................... 612 MOBILE TERMINATING CALL ................................................................................................. 613 MOBILE ORIGINATING CALL .................................................................................................. 614 8. 9. APPENDIX B: ERLANG TABLE.............................................................................................. 615 ABBREVIATIONS & DEFINITIONS ......................................................................................... 618 9.1. 9.2. ABBREVIATIONS ................................................................................................................... 618 DEFINITIONS ........................................................................................................................ 624 10. INDEX ....................................................................................................................................... 627 Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 15/629 V17.0 BSS Parameter User Guide (BPUG) 1. 1.1. ABOUT THIS DOCUMENT OBJECT This document describes BSS GSM and Nortel algorithms and parameters from an engineering point of view. This document is written by Nortel BSS experts and contains extensive Nortel BSS parameters setting know-how. Informations coming from experiments, studies, simulations are also related in the document. The parameters are called by the name used in the features and algorithms. For their corresponding name (when different) at the OMC, refer to [R6]. The parameters described in this document are the ones used in the features and algorithms. Refer to [R2] to have a description of all BSS parameters. 1.2. SCOPE This version is issued for the ChR milestone of the V17 BSS GSM release. 1.3. AUDIENCE FOR THIS DOCUMENT Draft and preliminary: Nortel R&D, PLM and Eng' Standard: customers and Nortel R&D, Product Line Management and Engineering teams.' 1.4. DISCLAIMER Depending on particular objective, call profile and network characteristics, a parameter setting can never be judged as being universally optimized. The recommended setting presented in this document should result in good network performance; however several iterations and improvements may be required in order to be optimal according to customer specificities. Every effort is made to incorporate suggestions and feedback received from customers. PRELIMINARY VERSION The recommended setting has been validated with product and system tests in lab. This document will be updated and adjusted after the first results from VO site or new Product Test/End-to-end labs if available. STANDARD VERSION This is a living document and the contents will be modified based on feedback received from R&D, Engineering and customers. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 16/629 V17.0 BSS Parameter User Guide (BPUG) 1.5. DOCUMENT STRUCTURE In chapter §3 CLASSIFICATION OF BSS PARAMETERS, BSS algorithm parameters are presented in alphabetic order according to their group. Process and related objects are also provided. Chapter §4 ALGORITHMS describes the GSM Nortel BSS algorithms and recommends ways to use them efficiently. BSS parameters used in the algorithms are described in chapter §5 ALGORITHM PARAMETERS. For each parameter, a recommended value and a default value are given. Engineering rules explain how to select the parameter value. In chapter §6 ENGINEERING ISSUE, engineering issues resulting from studies on parameter setting and on products, simulations and experiments are developped. Chapter §7 APPENDIX A: MAIN EXCHANGE PROCEDURES AT BSC LEVEL gives the main exchange procedures at BSC level. In chapter §8 APPENDIX B: ERLANG TABLE, an Erlang table presents the maximum offered load according to the number of channels and the blocking rate. In chapter §9 ABBREVIATIONS & DEFINITIONS, the signification of all the abbrevations used in this document and some key-definitions are explained. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 17/629 V17.0 BSS Parameter User Guide (BPUG) 1.6. UPDATES TO PREVIOUS RECOMMENDATIONS 1.6.1 BETWEEN V16 AND V17 modeModifyMandatory: New recommended value set to “not used”. This parameter is no longer useful but setting to “used” may yield undesirable side-effects in particular circumstances. enhancedTRAUframeIndication : This parameter is no longer useful in V17 due to the end of support of the PCM Error Correction feature. pcmErrorCorrection : This parameter is no longer useful in V17 duie to the end of support of the PCM Error Correction feature. bscHopReconfUse : New recommended value for BSC that manage only BTS with hybrid coupling. Old recommendation : “false (mandatory for hybrid coupling).” New recommendation : “the value (true or false) is indifferent for a BSC that manages only BTS with hybrid coupling”. trafficPCMAllocationPriority : New recommended value for BCCH TDMA. Old recommendation : highest priority (0) for BCCH TDMA. New recommendation : lowest priority (255) for BCCH TDMA. 1.6.2 BETWEEN V15.1.1 AND V16 amrReserved1: This new parameter was introduced to enable/disable RATSCCH procedure for AMR FR. Recommended value set to 0 (enable RATSCCH procedure) hrCellLoadEnd New recommended value set to 60, instead of 5 or 10 in urban areas and 50 or 60 in rural areas. Now the value depends on the number of DRXs on the cell. hrCellLoadStart New recommended value set to 80, instead of 70 or 80 in rural areas, and 20 or 30 in urban areas. Now the value depends on the number of DRXs on the cell. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 18/629 V17.0 BSS Parameter User Guide (BPUG) 1.6.3 BETWEEN V15.1 AND V15.1.1 hrCellLoadEnd: New recommended value set to 5 -10 in urban areas and 50 - 60 in rural areas, instead of 0 hrCellLoadStart: New recommended value set to a fix value i.e 20-30 in urban areas and 70-80 in rural areas instead of a value greater than 0 hoMarginTrafficOffset: New recommended value set to 6 instead of 2; HoMarginTrafficOffset should be tune such as the resulting margin should be equivalent to the one for rescue HO. early classmark sending: New recommended value set this value to Allowed even if dual band network is not used. This parameter allows MS to send its capacity downlink Advanced Receiver performance. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 19/629 V17.0 BSS Parameter User Guide (BPUG) 1.6.4 BETWEEN V15.0 AND V15.1. RadioLinkTimeOut: New recommended value set to 32 instead of 20. when AMR is activated RLT drop calls contribution is usually much higher in coverage limited or rural areas because calls are being dragged at cell edges and the overlap between neighboring sites is less important than in urban areas. This recommendation helps to reduce the contribution of RLT drop Rlf1: New recommended value set to 7 instead of 4. This new recommendation is linked to RLT one when AMR is activated HoMarginBeg: New recommended value set to 2dB instead of 4 when Automatic Handover Adaptation is activated. This new setting helps to get effective margin of 6 dB AllocPriorityTimer: New recommended value set to [5 0 5 5 0 0 0 0 28 28 28 28 28 28] instead of [0 0 3 0 0 0 0 0 28 28 28 28 28 28]. AllocWaitThreshold: New recommended value set to [n 0 n n 0 0 0 0 5 5 5 5 5] instead of [0 0 n 0 0 0 0 0 5 5 5 5 5]. CallReestablishmentPriority: New recommended value set to 15 instead of 16. IntraCellHOIntPriority: New recommended value set to 14 instead of 17. DirectedRetryPrio: New recommended value set to 17 instead of no recommended value. biZonePowerOffset: New recommended value depends on the engineering rules, in v15.0 it was 63 dB for monozone and 3 dB otherwise. ConcentAlgoMsRange: New recommended value set to 34 instead of depending on the radius of the site. Small to large HO priority New recommended value set to 14 instead of 17. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 20/629 V17.0 BSS Parameter User Guide (BPUG) T3103 New recommended value set to 9 seconds instead of 5. From a handover perspective it is recommended to use 9s in order to offer a wider window of good completion of the procedure at cell edge where the quality might be poorer. noOfBlocksForAccessGrant Addition of a recommended value for SI2Quater or/and SI13 on ext BCCH. Data non transparent mode New recommended value set to TBD instead of 9.6kb/s Serving factor offset New recommended value set to 0 instead of -2. It means it will actually favor the server or disfavor in order word the neighbor greatly. amrReserved2 New recommended values will depend of in what is base AMR alarm handovers and AMR power control. Old value was 3. amrFRIntercellCodecMThresh New recommended value set to 10k2 instead of 6k7. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 21/629 V17.0 BSS Parameter User Guide (BPUG) 2. 2.1. RELATED DOCUMENTS APPLICABLE DOCUMENTS [A1] PE/DCL/DD/000136 Access (EGPRS) Parameter User Guide 2.2. REFERENCE DOCUMENTS [R1] [R2] [R3] [R4] [R5] [R6] [R7] [R8] [R9] [R10] [R11] [R12] [R13] [R14] [R15] [R16] [R17] [R18] [R19] [R20] [R21] [R22] [R23] [R24] PE/SYS/DD/000065 PE/DCL/DD/000007 PE/DCL/DD/000000 PE/DCL/DD/0124 PE/DCL/DD/0125 PE/MD/DD/000008 PE/DCL/DD/000138 PE/BTS/DD/1514 PE/SYS/DD/0272 PE/SYS/INF/0225 PE/SYS/DD/6293 PE/SYS/INF/0140 PE/SYS/INF/0190 PE/SYS/DD/279 PE/BTS/DD/0421 PE/SYS/DD/0291 PE/SYS/DD/0330 PE/SYS/DD/0331 PE/SYS/DD/0482 PE/SYS/DD/010888 PE/SYS/INF/0242 PE/SYS/DD/0356 PE/SYS/DD/0432 UMT/SYS/DD/29 Configuration parameters for BSS BSS Operating Principles BSS Product Documentation Overview BSS Parameter Dictionary Observation Counter Dictionary GDMO Configuration Management GSM/GPRS/EDGE BSS Engineering Rules SFS of Layer 1 Management TF875: Dual band cells management Concentric cell improvements (CM888/TF889) FN for stepped coupling Handover for traffic reasons: TF132 Handover decision according to adjacent cell priorities and load TF716 TF 995: Automatic Cell Tiering TF809: Early handover decision TF821: General protection against HO Ping-pong TF1216: Automatic handover adaptation TF1217: Protection against intra-cell HO Pingpong 22464: WPS - Access class barring with class periodic rotation 27318 Configure sending of SI2Quater and SI13 on Ext or Norm BCCH TF184: Extended CCCH SV1322: TTY on BSC/TCU e3 AR1526 - SMS-CB Usability improvement GSM to UMTS mobility Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 22/629 V17.0 BSS Parameter User Guide (BPUG) [R25] [R26] [R27] [R28] [R29] [R30] [R31] [R32] [R33] [R34] [R35] [R36] [R37] [R38] [R39] [R40] [R41] [R42] [R43] [R44] [R45] [R46] [R47] [R48] [R49] [R50] [R51] [R52] [R53] [R54] [R55] PE/SYS/DD343 PE/SYS/DD/486 PE/SYS/DD/487 PE/SYS/DD/005776 PE/BSS/APP/012435 PE/SYS/DD/005321 PE/SYS/DD/0231 PE/IRC/APP/014199 PE/BSS/APP/0115 PE/IRC/APP/021006 PE/SYS/DD/016451 PE/SYS/DD/016458 PE/DCL/DD/018141 PE/SYS/DD/012303 PE/SYS/DD/005337 PE/SYS/DD/16945 PE/SYS/DD/16359 PE/SYS/DD/21289 PE/SYS/DD/11409 PE/SYS/DD/021592 PE/SYS/DD/012171 PE/SYS/DD/019402 PE/DCL/DD/014271 PE/DCL/DD/014272 PE/DCL/DD/014273 PE/DCL/DD/014274 PE/DCL/DD/014275 PE/DCL/DD/014276 PE/DCL/DD/014277 PE/DCL/DD/014278 PE/DCL/DD/014289 SV713 : AMR Full Rate; SV885 AMR Half Rate 22463: WPS - Queuing management 22465 : WPS - Public access bandwidth protection 24394 : Directed retry without queuing activation AMR Engineering Handbook Advanced Speech Call Items Evolutions PM990 Satellite ABIS interface Satellite Abis Interface - Engineering Guideline Reference Manual for BSC data configuration Network Synchronisation Handbook 30296 – Repeated Downlink FACCH 30293 – Tx Offset for Signalling Channels Lb Interface Engineering Rules 21531 - Enhanced Measurement Report (EMR) 2473 - GSM to UMTS handover 30169 - AMR-HR on preempted PDTCH 27392 - Support of A5/3 Encryption Algorithm 28703 - Multi-zone cell enhancement Distributions on Radio measurements 34208 - BTS6k/18k Smart Power Management 27288 - Novel Adaptive Receiver 32280 - Joint Diversity BTS S2000L Engineering Rules BTS S2000H Engineering Rules BTS S4000 Outdoor Engineering Rules BTS S4000 Indoor Engineering Rules BTS eCell Engineering Rules BTS S8000-S8003 Indoor & S8000 Outdoor Engineering Rules BTS S12000 Indoor & Outdoor Engineering Rules BTS 18000 Indoor & Outdoor Engineering Rules BTS 18000 GSM-UMTS Indoor & Outdoor Engineering Rules Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 23/629 V17.0 BSS Parameter User Guide (BPUG) [R56] [R57] [R58] PE/DCL/DD/018541 PE/SYS/DD/21412 PE/DCL/DD/14283 BTS 6000 GSM Indoor & Outdoor Engineering Rules 34160 - BSS Paging Coordination Radio Interface Engineering Rules Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 24/629 V17.0 BSS Parameter User Guide (BPUG) 3. 3.1. CLASSIFICATION OF BSS PARAMETERS PARAMETER LIST The following table gives a classification of the main BSS tunable parameters sorted by alphabetical order, the object they are associated to at the OMC-R (as they are described in [R1]) and the main features using those parameters. Parameter name BSS Object- Feature(s) using this parameter accessClassCongestion adaptiveReceiver adjacent_cell_umbrella_ref allocPriorityTable V9 V17 V9 V7 bts transceiver bts bts Barring of access class Novel Adaptive Receiver Directed Retry Handover TCH Allocation and Priority Queuing WPS – Queuing management allocPriorityThreshold allocPriorityTimers allocWaitThreshold allOtherCasesPriority amrUlFrAdaptationSet amrUlHrAdaptationSet amrDlFrAdaptationSet amrUlHrAdaptationSet amrDirectAllocIntRxLevDL amrDirectAllocIntRxLevUL amrDirectAllocRxLevDL amrDirectAllocRxLevUL amrFRIntercellCodecMThresh amrFRIntracellCodecMThresh amrHRIntercellCodecMThresh amrHRtoFRIntracellCodecMThresh amriRxLevDLH amriRxLevULH amrReserved1 amrReserved2 answerPagingPriority V7 V7 V7 V7 V15 V15 V15 V15 V14 V14 V14 V14 V14 V14 V14 V14 V14 V14 V16 V14 V7 bts bts bts bts bts bts bts bts bts bts bts bts handOverControl handOverControl handOverControl handOverControl handOverControl handOverControl handOverControl handOverControl bts TCH Allocation and Priority Queuing Queuing WPS – Queuing management Queuing WPS – Queuing management TCH Allocation and Priority Queuing AMR Codec mode adaptation AMR Codec mode adaptation AMR Codec mode adaptation AMR Codec mode adaptation AMR Handover mechanisms Direct TCH Allocation AMR Handover mechanisms Direct TCH Allocation AMR Handover mechanisms Direct TCH Allocation AMR Handover mechanisms Direct TCH Allocation AMR Handover mechanisms AMR Handover mechanisms AMR Handover mechanisms AMR Handover mechanisms AMR Handover mechanisms AMR Handover mechanisms AMR RATSCCH Proceudre AMR Legacy L1M TCH Allocation and Priority Queuing Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 25/629 V17.0 BSS Parameter User Guide (BPUG) assignRequestPriority averagingPeriod baseColourCode bCCHFrequency bCCHFrequency bCCHFrequency biZonePowerOffset V7 V7 V7 V7 V7 V7 V12 bts handOverControl bts adjacentCellHandover adjacentCellReselecti on bts adjacentCellHandover General formulas Direct TCH Allocation Concentric/DualCoupling/DualBand Cell Handover biZonePowerOffset V12 handoverControl General formulas Direct TCH Allocation Concentric/DualCoupling/DualBand Cell Handover bscHopReconfUse bscMSAccessClassBarringFunction bscQueuingOption bsMsmtProcessingMode bsPowerControl bssMapT1 bssMapT12 bssMapT13 bssMapT19 bssMapT20 bssMapT4 bssMapT7 bssMapT8 bssMapTchoke bssPagingCoordination bssSccpConnEst bsTxPwrMax btsSMSynchroMode bts Time Between HO configuration btsHopReconfRestart btsIsHopping btsMSAccessClassBarringFunction btsThresholdHopReconf callClearing callReestablishment callReestablishmentPriority capacityTimeRejection V8 V9 V7 V7 V7 V7 V7 V7 V8 V8 V7 V7 V7 V7 V17 V7 V7 V15 V9 V12 V8 V7 V9 V8 V7 V7 V7 V14 bts bts bts bts bts bts bts handOverControl bsc bsc signallingPoint bts powerControl bsc bsc bsc bsc bsc bsc bsc bsc bsc bts signallingPoint powerControl btsSiteManager bts General formulas Cabinet Output Power Setting Network Synchronization Minimum time between Handover General protection against HO ping-pong Reconfiguration procedure Frequency Hopping Barring of access class Reconfiguration procedure Call Clearing Process Radio link failure process, Call reestablishment procedure TCH Allocation and Priority Queuing Protection against Intracell HO Ping-Pong AMR Handover mechanisms Nortel confidential TCH Allocation and Priority Queuing Radio channel allocation Interference Management Network Synchronization Reconfiguration procedure Barring of access class Queuing WPS – Queuing management Measurement Processing Power Control Algorithms AMR Power Control BSS CS Paging Coordination PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 26/629 V17.0 BSS Parameter User Guide (BPUG) cellAllocation cellBarQualify cellBarred cellDeletionCount cellDtxDownLink cellReselectHysteresis cellReselectOffset cellReselInd cellType cellType channelType cId V7 V8 V7 V7 V7 V8 V7 V8 V7 V7 V7 V17 bts bts bts bts bts bts bts bts adjacentCellHandOver bts channel adjacentCellUTRAN GSM to UMTS handover Frequency Hopping Selection, Reselection Algorithms Selection, Reselection Algorithms Measurement Processing Handovers screening DTX Selection, Reselection Algorithms Selection, Reselection Algorithms Selection, Reselection Algorithms Microcellular Algo Microcellular Algo coderPoolConfiguration V14 transcoder AMR Channel allocation Cellular Telephone Text Modem (TTY) compressedModeUTRAN concentAlgoExtMsRange V17 V9 bts handOverControl GSM to UMTS handover Direct TCH Allocation Concentric/DualCoupling/DualBand Cell Handover concentAlgoExtRxLev V9 handOverControl Direct TCH Allocation Concentric/DualCoupling/DualBand Cell Handover concentAlgoIntMsRange concentAlgoIntRxLev concentric_cell cpueNumber cypherModeReject dARPPh1Priority Data14_4OnNoHoppingTs data mode 14.4 kbit/s data non transparent mode data non transparent mode data transparent mode data transparent mode delayBetweenRetrans directedRetry directedRetryModeUsed directedRetryPrio distHreqt distWtsList diversity diversityUTRAN dtxMode V9 V9 V9 V12 V12 V8 V15 V12 V11 V11 V11 V11 V11 V8 V9 V9 V12 V7 V7 V7 V17 V7 V14 handOverControl handOverControl bts btsSiteManager signallingPoint transceiver bts transcoder board bts signallingPoint bts signallingPoint bts adjacentCellHandOver bts bts handOverControl handOverControl bts adjacentCellUTRAN bts Concentric/DualCoupling/DualBand Cell Handover Concentric/DualCoupling/DualBand Cell Handover Concentric/DualCoupling/DualBand Cell Handover Cell Group Management CPU/BIFP LOAD SHARING A5/3 Encryption algorithm Network Synchronization PCM Error Correction PCM Error Correction PCM Error Correction PCM Error Correction PCM Error Correction PCM Error Correction Paging command repetition process Directed Retry Handover Directed Retry Handover Directed Retry Handover Measurement Processing Measurement Processing Interference Cancellation GSM to UMTS handover DTX Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 27/629 V17.0 BSS Parameter User Guide (BPUG) early classmark sending earlyClassmarkSendingUTRAN emergencyCallPriority enableRepeatedFacchFr encrypAlgoAssComp encrypAlgoCiphModComp encrypAlgoHoPerf encrypAlgoHoReq encryptionAlgorSupported enhancedTRAUFrameIndication enhCellTieringConfiguration estimatedSiteLoad extended cell facchPowerOffset fDDARFCN fDDMultiratReporting V10 V17 V7 V16 V8 V8 V8 V8 V7 V12 V14 V15 V9 V16 V17 V17 bts bts bts bts signallingPoint signallingPoint signallingPoint signallingPoint bsc bsc handOverControl btsSiteManager bts bts adjacentCellUTRAN bts Tx Power Offset for Signalling GSM to UMTS handover Enhanced Measurement Reporting GSM to UMTS handover UTRAN cell reporting using legacy measurement reports (V17) fDDreportingThreshold fDDreportingThreshold2 V17 V17 handOverControl handOverControl Enhanced Measurement Reporting GSM to UMTS handover Enhanced Measurement Reporting GSM to UMTS handover UTRAN cell reporting using legacy measurement reports (V17) fhsRef filteredTrafficCoefficient fnOffset forced handover algo frAMRPriority frPowerControlTargetMode frPowerControlTargetModeDl gprsNetworkModeOperation gprsPreemptionForHR gsmToUmtsReselection gsmToUMTSServiceHo handOver from signalling channel hoMargin V7 V15 V15 V9 V14 V14 V16 V15 V17 V14 V17 V7 V7 channel bts btsSiteManager adjacentCellHandOver transceiver transceiver powerControl bts bsc bts bsc handOverControl adjacentCellHandOver Frequency Hopping AMR based on traffic Network Synchronization Forced Handover AMR Channel allocation AMR Power Control AMR Power Control Network Mode of Operation I support in BSS pDTCH Preemption by AMR HR calls 2G - 3G Cell Reselection GSM to UMTS handover Direct TCH Allocation and Handover Algorithms Handovers Power budget formula Handover for traffic reasons Define eligible neighbor cells for intercell handover Automatic handover adaptation hoMarginAMR hoMarginAMRUTRAN V14 V17 adjacentCellHandOver adjacentCellUTRAN AMR Handover mechanisms Handovers GSM to UMTS handover Modified SYS INFO 3 Location Services GSM to UMTS handover TCH Allocation and Priority Queuing Repeated Downlink FACCH A5/3 Encryption algorithm A5/3 Encryption algorithm A5/3 Encryption algorithm A5/3 Encryption algorithm A5/3 Encryption algorithm PCM Error Correction Cell Tiering Parameters V15.1 Evolution of Load Balancing Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 28/629 V17.0 BSS Parameter User Guide (BPUG) hoMarginBeg V11 bts Handovers Early HandOver Decision Automatic handover adaptation Direct TCH Allocation hoMarginDist V8 adjacentCellHandOver Handover condition for leaving a cell on distance Define eligible neighbor cells for intercell handover hoMarginDistUTRAN hoMarginRxLev V17 V8 adjacentCellUTRAN adjacentCellHandOver GSM to UMTS handover Handovers Define eligible neighbor cells for intercell handover hoMarginRxLevUTRAN hoMarginRxQual V17 V8 adjacentCellUTRAN adjacentCellHandOver GSM to UMTS handover Handovers Define eligible neighbor cells for intercell handover hoMarginRxQualUTRAN hoMarginTiering hoMarginTrafficOffset hoMarginTrafficOffsetUTRAN hoMarginUTRAN hoPingpongCombination hoPingpongCombinationUTRAN hoPingpongTimeRejection hoPingpongTimeRejectionUTRAN hoppingSequenceNumber hoRejectionTimeOverloadUTRAN hoSecondBestCellConfiguration hoTraffic hoTraffic hrAMRPriority hrCellLoadEnd hrCellLoadStart hrPowerControlTargetMode hrPowerControlTargetModeDl incomingHandOver interBscDirectedRetry interBscDirectedRetryFromCell interCellHOExtPriority V17 V14 V12 V17 V17 V12 V14 V17 V12 V17 V7 V17 V9 V12 V12 V14 V14 V14 V14 V16 V7 V9 V9 V7 adjacentCellUTRAN adjacentCellHandOver adjacentCellUTRAN frequencyHopSystem adjacentCellUTRAN bsc bsc bts transceiver bts bts powerControl powerControl handOverControl bsc bts bts GSM to UMTS handover General protection against HO ping-pong GSM to UMTS handover Synthesised frequency hopping GSM to UMTS handover Handover to 2nd best candidate when return to old channel Handover for traffic reasons Handover for traffic reasons AMR Channel allocation AMR Channel allocation AMR Channel allocation AMR Power Control AMR Power Control Handovers Directed Retry Handover Directed Retry Handover TCH Allocation and Priority Queuing interCellHOIntPriority interferenceType interferer cancel algo usage intraBscDirectedRetry intraBscDirectedRetryFromCell intraCell V7 V12 V10 V9 V9 V7 V12 Nortel confidential adjacentCellUTRAN handOverControl adjacentCellHandOver adjacentCellUTRAN adjacentCellUTRAN adjacentCellHandOver GSM to UMTS handover Automatic cell tiering Handover for traffic reasons GSM to UMTS handover GSM to UMTS handover General protection against HO ping-pong bts adjacentCellHandover bts bsc bts handOverControl TCH Allocation and Priority Queuing Automatic cell tiering Interference Cancellation Directed Retry Handover Directed Retry Handover Intracell Handover decision for signal quality PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 29/629 V17.0 BSS Parameter User Guide (BPUG) intraCellHOIntPriority intraCellQueuing intraCellSDCCH layer3MsgCyphModComp locationAreaCodeUTRAN lRxLevDLH V7 V8 V8 V8 V17 V7 bts bts handOverControl signallingPoint adjacentCellUTRAN handOverControl TCH Allocation and Priority Queuing Queuing Intracell Handover decision for signal quality A5/3 Encryption algorithm GSM to UMTS handover Handover condition for leaving a cell on rxlev Define eligible neighbor cells for intercell handover lRxLevDLP lRxLevULH lRxLevULP lRxQualDLH lRxQualDLP lRxQualULH lRxQualULP maio masterBtsSmId maxNumberRetransmission measurementProcAlgorithm V7 V7 V7 V7 V7 V7 V7 V7 V15 V8 V12 powerControl handOverControl powerControl handOverControl powerControl handOverControl powerControl channel btsSiteManager bts bts Power Control Algorithms AMR Power Control Handover condition for leaving a cell on rxlev Power Control Algorithms AMR Power Control Handover condition for leaving a cell on rxqual Power Control Algorithms AMR Power Control Handover condition for leaving a cell on rxqual Power Control Algorithms AMR Power Control Synthesised frequency hopping Network Synchronization Request access command repetition process Measurement Processing Direct TCH Allocation and Handover Algorithms microCellCaptureTimer microCellStability minNbOfTDMA missDistWt missRxLevWt missRxQualWt mobileCountryCodeUTRAN mobileNetworkCodeUTRAN mobileAllocation modeModifyMandatory msBtsDistanceInterCell V8 V8 V7 V7 V7 V7 V17 V17 V7 V9 V7 adjacentCellHandOver adjacentCellHandOver bts handOverControl handOverControl handOverControl adjacentCellUTRAN adjacentCellUTRAN frequencyHopSystem bsc handOverControl Measurement Processing Measurement Processing Measurement Processing GSM to UMTS handover GSM to UMTS handover Synthesised frequency hopping Baseband Frequency Hopping Directed Retry Handover Handovers screening Handover condition for leaving a cell on distance msRangeMax msTxPwrMax V7 V7 handOverControl bts Handover condition for leaving a cell on distance Accuracy related to measurements General formulas Forced Handover Power Control Algorithms msTxPwrMax2ndBand msTxPwrMaxCCH msTxPwrMaxCell V12 V7 V7 bts bts adjacentCellHandOver Concentric/DualCoupling/DualBand Cell Handove Selection, Reselection Algorithms General formulas Handovers screening Nortel confidential Microcellular Algo Microcellular Algo PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 30/629 V17.0 BSS Parameter User Guide (BPUG) Directed Retry Handover: BTS Forced Handover Define eligible neighbor cells for intercell handover Power Control Algorithms multi band reporting V10 bts Multiband reporting Enhanced Measurement Reporting GSM to UMTS handover nbLargeReuseDataChannels nbOfRepeat nCapacityFRRequestedCodec neighDisfavorOffset new power control algorithm nFRRequestedCodec nHRRequestedCodec noOfBlocksForAccessGrant noOfMultiframesBetweenPaging notAllowedAccessClasses numberOfPwciSamples numberOfSlotsSpreadTrans numberOfTCHFreeBeforeCongestion numberOfTCHFreeToEndCongestion numberOfTCHQueuedBeforeCongestion numberOfTCHQueuedToEndCongestion offsetLoad offsetPriority offsetPriorityUTRAN otherServicesPriority pagingOnCell pcmErrorCorrection penaltyTime powerBudgetInterCell V14 V8 V14 V14 V9 V12 V14 V14 V7 V7 V7 V14 V7 V9 V9 V9 V9 V12 V12 V17 V7 V9 V12 V8 V7 handOverControl handOverControl bts bts bts handOverControl bts bts bts bts bts adjacentCellHandover adjacentCellHandover adjacentCellUTRAN bts bts bts bts handOverControl AMR Handover mechanisms AMR Handover mechanisms Paging command Process Paging command Process Barring of access class Automatic cell tiering Request access command repetition process Barring of access class Handover for traffic reasons Barring of access class Handover for traffic reasons Barring of access class Handover for traffic reasons Barring of access class Handover for traffic reasons Handover decision according to adjacent cell priorities ans load Handover decision according to adjacent cell priorities ans load GSM to UMTS handover TCH Allocation and Priority Queuing PCH and RACH channel control PCM Error Correction Selection, Reselection Algorithms Handovers screening Power budget formula Handover for traffic reasons powerControlIndicator powerIncrStepSizeDL powerIncrStepSizeUL powerRedStepSizeDL powerRedStepSizeUL preemptionAuthor pRequestedCodec preSynchroTimingAdvance priority V7 V14 V14 V14 V14 V15 V14 V10 V7 bts powerControl powerControl powerControl powerControl signallingPoint handOverControl adjacentCellHandOver transceiver Nortel confidential bts bts handOverControl handOverControl powerControl Automatic cell tiering Paging command repetition process AMR Handover mechanisms Automatic handover adaptation Power Control Algorithms Power Control Algorithms Power Control Algorithms Power Control Algorithms Power Control Algorithms Power Control Algorithms eMLPP Preemption AMR Handover mechanisms Pre-synchronized HO PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 31/629 V17.0 BSS Parameter User Guide (BPUG) processorLoadSupConf pwciHreqave minTimeQualityIntraCellHO qsearchC V8 V12 V14 V14 V17 handOverControl handOverControl handOverControl Automatic cell tiering Protection against Intracell HO Ping-Pong AMR Handover mechanisms Enhanced Measurement Reporting GSM to UMTS handover UTRAN cell reporting using legacy measurement reports (V17) radChanSelIntThreshold radioAllocator radioLinkTimeout radResSupBusyTimer radResSupervision radResSupFreeTimer reportTypeMeasurement retransDuration rlf1 rlf2 rlf3 rNCId rndAccTimAdvThreshold runCallClear runHandOver V8 V12 V7 V8 V8 V8 V17 V8 V8 V8 V8 V17 V8 V7 V7 handOverControl bts bts bsc bts bsc bts bts bts bts bts adjacentCellUTRAN bts bts bts Radio link failure process Radio link failure process Radio link failure process GSM to UMTS handover Request access command process Call Clearing Process Handovers Microcellular Algo Protection against RunHandover=1 runPwrControl rxLevAccessMin rxLevDLIH rxLevDLPBGT rxLevDLPbgtUTRAN rxLevHreqave rxLevHreqaveBeg V7 V7 V7 V11 V17 V7 V11 bts bts handOverControl adjacentCellHandOver adjacentCellUTRAN handOverControl handOverControl Power Control Algorithms AMR Power Control Selection, Reselection Algorithms Intracell Handover decision for signal quality Handovers screening Maximum RxLev for Power Budget GSM to UMTS handover Measurement Processing Early HandOver Decision Automatic handover adaptation Fast power control at TCH assignment rxLevHreqt rxLevMinCell V7 V7 handOverControl adjacentCellHandOver Measurement Processing General formulas Handovers screening Define eligible neighbor cells for intercell handover rxLevMinCellUTRAN rxLevNCellHreqaveBeg V17 V11 adjacentCellUTRAN handOverControl GSM to UMTS handover Early HandOver Decision Automatic handover adaptation Fast power control at TCH assignment rxLevULIH rxLevWtsList rxNCellHreqave V7 V7 V7 handOverControl handOverControl handOverControl Nortel confidential bsc BSC Overload Management Mechanisms Interference Management Radio link failure process Enhanced Measurement Reporting GSM to UMTS handover Intracell Handover decision for signal quality Measurement Processing Measurement Processing Early HandOver Decision PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 32/629 V17.0 BSS Parameter User Guide (BPUG) Automatic handover adaptation rxQualAveBeg rxQualDLIH rxQualHreqave rxQualHreqt rxQualULIH rxQualWtsList sacchPowerOffset sacchPowerOffsetSelection scramblingCode selfAdaptActivation selfTuningObs servingBandReporting servingBandReportingOffset servingfactorOffset siteGsmFctList small to large zone HO priority smartPowerManagementConfig smartPowerSwitchOffTimer smsCB speechMode speechMode standard indicator AdjC standard indicator AdjC standardIndicator synchronized t3101 t3103 t3107 t3109 t3111 t3121 t3122 temporaryOffset thresholdInterference timeBetweenHOConfiguration timerPeriodicUpdateMS tnOffset trafficPCMAllocationPriority V14 V7 V7 V7 V12 V12 V16 V16 V17 V14 V12 V17 V17 V14 V7 V9 V17 V17 V7 V8 V14 V8 V14 V10 V12 V10 V12 V12 V7 V9 V9 V9 V9 V9 V17 V9 V8 V7 V9 V12 V7 V15 V9 bts btsSiteManager transceiver Nortel confidential handOverControl handOverControl handOverControl handOverControl handOverControl handOverControl bts bts adjacentCellUTRAN bts handOverControl bts handOverControl handOverControl btsSiteManager handOverControl PowerControl PowerControl bts bts signallingPoint adjacentCellHandover adjacentCellReselect bts adjacentCellHandOver bts bts bts bts bts bts bts bts handOverControl bsc Automatic handover adaptation Intracell Handover decision for signal quality Measurement Processing Measurement Processing Intracell Handover decision for signal quality Measurement Processing Tx Power Offset for Signalling Tx Power Offset for Signalling GSM to UMTS handover Automatic handover adaptation Automatic cell tiering Enhanced Measurement Reporting GSM to UMTS handover Enhanced Measurement Reporting GSM to UMTS handover Automatic handover adaptation TCH Allocation and Priority Queuing BTS Smart Power Management BTS Smart Power Management SMS-Cell Broadcast AMR - Adaptative Multi Rate FR/HR AMR - Adaptative Multi Rate FR/HR Dual Band Handling Dual Band Handling Concentric/DualCoupling/DualBand Cell Handover Pre-synchronized HO Handover Algorithms on the Mobile Side GSM to UMTS handover Selection, Reselection Algorithms Radio channel allocation Interference Management Power Budget Handover General protection against HO ping-pong Network Synchronization PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 33/629 V17.0 BSS Parameter User Guide (BPUG) transceiver equipment class transceiver equipment class transceiverZone uMTSAccessMinLevel uMTSReselectionARFCN uMTSReselectionOffset uMTSSearchLevel uplinkPowerControl uRxLevDLP uRxLevULP uRxQualDLP uRxQualULP wPSManagement wPSQueueStepRotation zone Tx power max reduction zoneFrequencyHopping zoneFrequencyThreshold V9 V9 V9 V14 V14 V14 V14 V8 V7 V7 V7 V7 V15 V15 V9 V9 V9 transceiverEquipment transceiverZone transceiver bts bts bts bts powerControl powerControl powerControl powerControl powerControl bsc bts transceiverZone transceiverZone transceiverZone Concentric/DualCoupling/DualBand Cell Handover Concentric/DualCoupling/DualBand Cell Handover Concentric/DualCoupling/DualBand Cell Handover 2G - 3G Cell Reselection 2G - 3G Cell Reselection 2G - 3G Cell Reselection 2G - 3G Cell Reselection Power Control Algorithms AMR Power Control Power Control Algorithms Power Control Algorithms Power Control Algorithms Power Control Algorithms WPS - Wireless Priority Service WPS - Wireless Priority Service Concentric/DualCoupling/DualBand Cell Handover Concentric/DualCoupling/DualBand Cell Handover Concentric/DualCoupling/DualBand Cell Handover 3.2. GSM UNUSED PARAMETERS The table presented below summarizes the GSM parameter still “reserved for future use”. Parameter name BSS Object- Feature(s) using this parameter sigPowerOverboost extendedTimingAdvanceWindow highSpeedUplinkDistortionRemoval V16 V16 V16 bts bts bts Tx Power Overboost for Signalling Channels Extended TA Window (GSM-R only, RM2 only) High Speed Distorsion removal (GSM-R only, RM2 only) 3.3. RAILWAY-SPECIFIC PARAMETERS (GSM-R) Before V16, the GSM-R specific parameters did not appear on the OMC-R MMI of GSM customers. Starting in v16, the MMI is common between GSM and GSM-R. It means that public GSM customers have visibility on GSM-R specific parameters that are of no use for public GSM. This list is provided in this section for information only : GSM customers must not change the default values for these parameters. The definition and use of these parameters is explained in a separate Railway-specific Parameter User Guide document that is provided to GSM-R customers only. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 34/629 V17.0 BSS Parameter User Guide (BPUG) Parameter name BSS Object- GSM-R Feature(s) using this parameter batteryRemoteControllerPresence emergencyThreshold eMLPPThreshold msPowerClassToggle nCHPosition preemptionAuthor (*) timerGCCHNotif uplinkReply uplinkReplyTimer voiceBroadcastService voiceGroupCallService V15.1R V15.1R V12.4d V15.1R V12.4d V12.4d V15.1R V15.1R V15.1R V12.4d V12.4d btssitemanager signallingPoint signallingPoint bts bts signallingPoint signallingPoint bsc bts signallingPoint signallingPoint BTS Battery Remote Monitoring ASCI Evolutions Enhanced Multilevel Precedence and Preemption Mobile class sensiticity counters Advanced Speech Call Items Enhanced Multilevel Precedence and Preemption ASCI Evolutions ASCI Evolutions ASCI Evolutions Advanced Speech Call Items Advanced Speech Call Items (*) Since v15.1, this parameter is also used in GSM for activation of eMLPP radio resource preemption in the BSS. Other eMLPP parameters are useful only in GSM-R for group calls (emergencyThreshold and eMLPPThreshold). Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 35/629 V17.0 BSS Parameter User Guide (BPUG) 3.4. PARAMETERS VERSUS BSS FEATURES AND PROCEDURES Here is the list of the main BSS tunable parameters sorted by procedure or feature. 3.4.1 2G CELL SELECTION AND RESELECTION cellBarQualify, cellBarred, rxLevAccessMin, msTxPwrMaxCCH, cellReselInd, cellReselectHysteresis, cellReselectOffset, temporaryOffset, penaltyTime, rndAccTimAdvThreshold. 3.4.2 2G-3G CELL RESELECTION uMTSAccessMinLevel, uMTSReselectionARFCN, uMTSReselectionOffset, uMTSSearchLevel. 3.4.3 LEGACY MEASUREMENT REPORTING multiBandReporting, powerControlIndicator, fDDMultiratReporting, fDDreportingThreshold2, qsearchC 3.4.4 ENHANCED MEASUREMENT REPORTING multiBandReporting, reportTypeMeasurement, servingBandReportingOffset, servingBandReporting, fDDMultiratReporting, fDDreportingThreshold, fDDreportingThreshold2, qsearchC 3.4.5 LEVEL AVERAGING rxLevHreqave, rxLevHreqt, rxLevWtsList, missRxLevWt, rxLevHreqaveBeg. 3.4.6 QUALITY AVERAGING rxQualHreqave, rxQualHreqt, rxQualWtsList, missRxQualWt. 3.4.7 DISTANCE AVERAGING distHreqt, distWtsList, missDistWt. 3.4.8 CELL ELIGIBILITY rxLevMinCell, rxNCellHreqave, cellDeletionCount, rxLevHreqave, missRxLevWt, msTxPwrMaxCell, msTxPwrMax, hoSecondBestCellConfiguration, rxLevNCellHreqaveBeg. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 36/629 V17.0 BSS Parameter User Guide (BPUG) 3.4.9 RADIO LINK FAILURE radioLinkTimeOut, rlf1, rlf2, rlf3, t3111, t3109. 3.4.10 INTERFERENCE MANAGEMENT averagingPeriod, thresholdInterference, radChanSelIntThreshold. 3.4.11 PCH AND RACH CONTROL PARAMETERS delayBetweenRetrans, maxNumberRetransmission, nbOfRepeat, noOfBlocksForAccessGrant, noOfMultiframesBetweenPaging, numberOfSlotsSpreadTrans, pagingOnCell, retransDuration, t3122, gprsNetworkModeOperation, bssPagingCoordination. 3.4.12 CONCENTRIC CELL concentric cell, concentAlgoExtMsRange, concentAlgoExtRxLev, concentAlgoIntMsRange, concentAlgoIntRxLev, transceiverEquipmentClass, transceiverZone, zoneFrequencyHopping, zoneFrequencyThreshold, small to large zone HO Priority, zone Tx power max reduction, biZonePowerOffset, biZonePowerOffset(n), rxLevMinCell(n). 3.4.13 EXTENDED CELL extended cell, rndAccTimAdvThreshold, msRangeMax, callClearing, channelType. 3.4.14 QUEUING AND PRIORITY MANAGEMENT allocPriorityTable, allocPriorityTimers, allocPriorityThreshold, allocWaitThreshold, allOtherCasesPriority, answerPagingPriority, assignRequestPriority, bscQueuingOption, callReestablishmentPriority, emergencyCallPriority, interCellHOExtPriority, interCellHOIntPriority, intraCellHOIntPriority, otherServicesPriority, small to large zone HO Priority, directedRetryPrio, intraCellQueuing. 3.4.15 EMLPP PREEMPTION preemptionAuthor. 3.4.16 SMS-CB smsCB, noOfBlocksForAccessGrant, channelType. 3.4.17 FREQUENCY HOPPING btsIsHopping, hoppingSequenceNumber, maio, siteGsmFctList, cellAllocation, mobileAllocation, fhsRef, bscHopReconfUse, btsHopReconfRestart, btsThresholdHopReconf, zoneFrequencyHopping, zoneFrequencyThreshold. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 37/629 V17.0 BSS Parameter User Guide (BPUG) 3.4.18 DYNAMIC BARRING OF ACCESS CLASS bscMsAccessClassBarringFunction, btsMsAccessClassBarringFunction, accessClassCongestion, numberOfTCHFreeBeforeCongestion, numberOfTCHFreeToEndCongestion, numberOfTCHQueuedBeforeCongestion, numberOfTCHQueuedToEndCongestion, notAllowedAccessClasses. 3.4.19 DTX dtxMode, cellDtxDowlink. 3.4.20 UPLINK POWER CONTROL uplinkPowerControl, new power control algorithm, runPowerControl, , powerIncrStepSizeUL, powerRedStepSizeUL, lRxQualULP, uRxQualULP, lRxLevULP, uRxLevULP, msTxPwrMax, msTxPwrMax2ndBand. 3.4.21 DOWNLINK POWER CONTROL bsPowerControl, new power control algorithm, runPwrControl, powerIncrStepSizeDL, powerRedStepSizeDL, lRxQualDLP, uRxQualDLP, lRxLevDLP, uRxLevDLP. 3.4.22 DIRECTED RETRY HANDOVER interBscDirectedRetry, intraBscDirectedRetry, interBscDirectedRetryFromCell, intraBscDirectedRetryFromCell, modeModifyMandatory, directedRetryModeUsed, msTxPwrMaxCell, msTxPwrMax, directedRetry, adjacent cell umbrella ref, directedRetryPrio. 3.4.23 UPLINK INTRACELL HANDOVER intraCell, intraCellSDCCH, runHandOver, rxLevULIH, lrxQualULH, rxQualULIH. 3.4.24 DOWNLINK INTRACELL HANDOVER intraCell, intraCellSDCCH, runHandOver, rxLevDLIH, lRxQualDLH, rxQualDLIH. 3.4.25 INTERCELL HANDOVER ON BAD UPLINK QUALITY CRITERION handOver from signalling channel, runHandOver, lrxQualULH, hoMarginRxQual. 3.4.26 INTERCELL HANDOVER ON BAD DOWNLINK QUALITY CRITERION handOver from signalling channel, runHandOver, lRxQualDLH, hoMarginRxQual. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 38/629 V17.0 BSS Parameter User Guide (BPUG) 3.4.27 INTERCELL HANDOVER ON BAD UPLINK LEVEL CRITERION handOver from signalling channel, runHandOver, lRxLevULH, hoMarginRxLev. 3.4.28 INTERCELL HANDOVER ON BAD DOWNLINK LEVEL CRITERION handOver from signalling channel, runHandOver, lRxLevDLH, hoMarginRxLev. 3.4.29 INTERCELL HANDOVER ON POWER BUDGET CRITERION handOver from signalling channel, runHandOver, powerBudgetInterCell, hoMargin, rxLevDLPBGT. 3.4.30 MICROCELLULAR ALGORITHM handOver from signalling channel, runHandOver, cellType, microCellCaptureTimer, microCellStability, rxNCellHreqave. 3.4.31 INTERCELL HANDOVER ON DISTANCE CRITERION msBtsDistanceInterCell, handOver from signalling channel, runHandOver,hoMarginDist. 3.4.32 HANDOVER FOR TRAFFIC REASONS handOver from signalling channel, runHandOver, hoTraffic, hoMarginTrafficOffset. 3.4.33 HANDOVER DECISION ACCORDING TO ADJACENT CELL (V12) handOver from signalling channel, runHandOver, offsetLoad, offsetPriority. 3.4.34 GENERAL PROTECTION AGAINST HO PINGPONG hoPingpongCombination, hoPingpongTimeRejection. 3.4.35 CALL CLEARING callClearing, runCallClear. 3.4.36 FREQUENCY BAND FAVOURING early classmark sending, multi band reporting, cellBarred, cellBarQualify, hoMargin, hoMarginDist, hoMarginRxQual, hoMarginRxLev, offsetPriority. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 39/629 V17.0 BSS Parameter User Guide (BPUG) 3.4.37 MINIMUM TIME BETWEEN HANDOVER (BEFORE V12) timeBetweenHOConfiguration, bts Time Between HO configuration. 3.4.38 RADIO RESOURCE CONTROL AT CELL LEVEL radResSupervision, radResSupBusyTimer, radResSupFreeTimer. 3.4.39 PRE-SYNCHRONISED HANDOVER synchronised, preSynchroTimingAdvance. 3.4.40 INTERFERER CANCELLATION interferer cancel algo usage, diversity 3.4.41 EARLY HO DECISION hoMarginBeg, rxLevHreqaveBeg, rxLevNCellHreqaveBeg. 3.4.42 MAXIMUM RXLEV FOR PBGT rxLevDLPBGT. 3.4.43 CELL TIERING interferenceType, intraCell, measurementProcAlgorithm, nbLargeReuseDataChannels, hoMarginTiering, pwciHreqave, numberOfPwciSamples, selfTuningObs. 3.4.44 TTY SUPPORT ON BSC/TCU 3000 coderPoolConfiguration. 3.4.45 PROTECTION AGAINST INTRACELL HO PING-PONG capacityTimeRejection, minTimeQualityIntraCellHO. 3.4.46 AUTOMATIC HANDOVER ADAPTATION selfAdaptActivation, servingfactorOffset, neighDisvaforOffset, rxQualAveBeg. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 40/629 V17.0 BSS Parameter User Guide (BPUG) 3.4.47 GSM TO UMTS HANDOVER gsmToUMTSServiceHO, earlyClassmarkSendingUTRAN, compressedModeUTRAN, mobileCountryCodeUTRAN, mobileNetworkCodeUTRAN, locationAreaCodeUTRAN, rNCId, cId, fDDARFCN, scramblingCode, diversityUTRAN, t3121, rxLevMinCellUTRAN, rxLevDLPbgtUTRAN, hoMarginUTRAN, hoMarginAMRUTRAN, hoMarginRxLevUTRAN, hoMarginRxQualUTRAN, hoMarginDistUTRAN, hoMarginTrafficOffsetUTRAN, offsetpriorityUTRAN, hoPingpongCombinationUTRAN, hoPingpongTimeRejectionUTRAN, hoRejectionTimeOverloadUTRAN 3.4.48 ADAPTATIVE FULL/HALF RATE amrDlFrAdaptationSet, amrDlHrAdaptationSet, amrUlFrAdaptationSet, amrUlHrAdaptationSet, coderPoolConfiguration, speechMode, HRCellLoadStart, HRCellLoadEnd, frAMRPriority, hrAMRPriority, hrPowerControlTargetMode, hrPowerControlTargetModeDl, frPowerControlTargetMode, frPowerControlTargetModeDl, bsPowerControl, uplinkPowerControl, pRequestedCodec, nHRRequestedCodec, nFRRequestedCodec, amrFRIntercellCodecMThresh, amrFRIntracellCodecMThresh, amrHRIntercellCodecMThresh, amrHRtoFRIntracellCodecMThresh, hoMarginAMR, amriRxLevDLH, amriRxLevULH, nCapacityFRRequestedCodec, amrDirectAllocIntRxLevDL, amrDirectAllocIntRxLevUL, amrDirectAllocRxLevDL, amrDirectAllocRxLevUL, filteredTrafficCoefficient, gprsPreemptionForHR. 3.4.49 WIRELESS PRIORITY SERVICE allocPriorityTable, allocPriorityTimers, allocWaitThreshold, bscQueuingOption, wPSManagement, wPSQueueStepRotation. 3.4.50 NETWORK SYNCHRONIZATION btsSMSynchroMode, tnOffset, fnOffset, dARPPh1Priority, masterBtsSmId, baseColourCode 3.4.51 REPEATED DOWNLINK FACCH enableRepeatedFacchFr 3.4.52 TX POWER OFFSET FOR SIGNALLING facchPowerOffset, sacchPowerOffset, sacchPowerOffsetSelection 3.4.53 NOVEL ADAPTIVE RECEIVER adaptiveReceiver Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 41/629 V17.0 BSS Parameter User Guide (BPUG) 3.4.54 A5/3 ENCRYPTION ALGORITHM cypherModeReject, encrypAlgoAssComp, encrypAlgoCiphModComp, encrypAlgoHoPerf, encrypAlgoHoReq, encryptionAlgorSupported, layer3MsgCyphModComp 3.4.55 BTS SMART POWER MANAGEMENT smartPowerManagementConfig, smartPowerSwitchOffTimer Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 42/629 V17.0 BSS Parameter User Guide (BPUG) 4. 4.1. ALGORITHMS INTRODUCTION This chapter describes major BSS GSM algorithms using OMC-R algorithm parameters, both on the BTS and the MS side. 4.2. CONVENTIONS AND UNITS In this chapter, the following abbreviations are used: • • • • • • RXQUAL_DL: weighted average for DL signal quality (MS measurements) RXQUAL_UL: weighted average for UL signal quality (BTS measurements) RXLEV_DL: weighted average for DL signal strength (MS measurements) RXLEV_UL: weighted average for UL signal strength (BTS measurements) MS_BS_Dist: weighted average of MS distance from BTS (MS timing advance) RXLEV_NCELL(n): arithmetic average for signal strength on neighbor cell (reported by the MS) 4.2.1 UNIT Thresholds on signal quality are given in RXQUAL values. Samples measurements are also reported in RXQUAL values. When internal calculations are performed, RXQUAL values are converted into bit error rates (BER) using mean values and compared to thresholds which are also converted into bit error rate. From the V9 BSS release, the comparison is done with the upper or the lower limit of the BER range. RxQual value 0 1 2 3 4 5 6 7 BER range value BER < 0.2% 0.2% < BER < 0.4% 0.4% < BER < 0.8% 0.8% < BER < 1.6% 1.6% < BER < 3.2% 3.2% < BER < 6.4% 6.4% < BER < 12.8% 12.8% < BER Mean BER value 0.14% 0.28% 0.57% 1.13% 2.26% 4.53% 9.05% 18.10% Signal strength thresholds are given in dBm (from -110 dBm to -47 dBm). Signal strength measurements reported by the mobiles and the BTS are given in the rxlev format (from 0 to 63). The average signal strength measurement values, which are compared to the rxlev thresholds, are the integer part of the average result. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 43/629 V17.0 BSS Parameter User Guide (BPUG) 4.2.2 PHASE 2 BTS AND MS MAXIMUM TRANSMITTING OUTPUT POWERS MOBILE PHASE 2 MAXIMUM TRANSMITTING OUTPUT POWER Power Class GSM 850 / GSM 900 Nominal Maximum Output Power restricted MS Phase 1 8W (39 dBm) 5W (37 dBm) 2W (33 dBm) 0,8W (29 dBm) DCS 1800 Nominal Maximum Output Power 1W (30 dBm) 0,25W (24 dBm) 4W (36 dBm) PCS 1900 Nominal Maximum Output Power 1W (30 dBm) 0,25W (24 dBm) 2W (33 dBm) Tolerance for condition Normal 1 2 3 4 5 +/- 2 dB +/- 2 dB +/- 2 dB +/- 2 dB +/- 2 dB Extreme +/- 2,5 dB +/- 2,5 dB +/- 2,5 dB +/- 2,5 dB +/- 2,5 dB ASSOCIATED POWER CONTROL LEVELS GSM 850 / GSM 900 Power control level Nominal Output power (dBm) 39 37 35 33 31 29 27 25 23 21 19 17 15 13 11 9 7 5 Tolerance (dB) for conditions N 0-2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19-31 ±2 ±3 ±3 ±3 ±3 ±3 ±3 ±3 ±3 ±3 ±3 ±3 ±3 ±3 ±5 ±5 ±5 ±5 E ± 2,5 ±4 ±4 ±4 ±4 ±4 ±4 ±4 ±4 ±4 ±4 ±4 ±4 ±4 ±6 ±6 ±6 ±6 29 30 31 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15-28 Power control level DCS 1800 Nominal Output power (dBm) N 36 34 32 30 28 26 24 22 20 18 16 14 12 10 8 6 4 2 0 ±2 ±3 ±3 ±3 ±3 ±3 ±3 ±3 ±3 ±3 ±3 ±3 ±4 ±4 ±4 ±4 ±4 ±5 ±5 Tolerance (dB) for conditions E ± 2,5 ±4 ±4 ±4 ±4 ±4 ±4 ±4 ±4 ±4 ±4 ±4 ±5 ±5 ±5 ±5 ±5 ±6 ±6 22-29 30 31 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16-21 Power control level PCS 1900 Nominal Output power (dBm) Reserved 33 32 30 28 26 24 22 20 18 16 14 12 10 8 6 4 2 0 Reserved ±3 ±3 ±3 ±3 ±3 ±3 ±3 ±3 ±3 ±3 ±3 ±4 ±4 ±4 ±4 ±4 ±5 ±5 ±4 ±4 ±4 ±4 ±4 ±4 ±4 ±4 ±4 ±4 ±4 ±5 ±5 ±5 ±5 ±5 ±6 ±6 Tolerance (dB) for conditions N E Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 44/629 V17.0 BSS Parameter User Guide (BPUG) BASE STATION PHASE 2 MAXIMUM TRANSMITTING OUTPUT POWERS GSM 850 / GSM 900 CLASS 1: [320 - 640[ W [55 - 58[ dBm CLASS 2: [160 - 320[ W [55 - 58[ dBm CLASS 3: [80 -160[ W [49 - 52[ dBm CLASS 4: [40 - 80[W [46 - 49[ dBm CLASS 5: [20 - 40[ W [43 - 46[dBm CLASS 6: [10 - 20[ W [40 - 43[ dBm CLASS 7: [5 - 10[ W [37 - 40[ dBm CLASS 8: [2.5 - 5[ W [34 - 37[ dBm GSM 1800 / GSM 1900 CLASS 1: [20 - 40[ W [43 - 46[ dBm CLASS 2: [10 - 20[ W [40 - 43[ dBm CLASS 3: [5 - 10[ W [37 - 40[ dBm CLASS 4: [2.5 - 5[ W [34 - 37[ dBm Tolerance for condition Normal +/- 2 dB +/- 2 dB +/- 2 dB +/- 2 dB +/- 2 dB +/- 2 dB +/- 2 dB +/- 2 dB Extreme +/- 2,5 dB +/- 2,5 dB +/- 2,5 dB +/- 2,5 dB +/- 2,5 dB +/- 2,5 dB +/- 2,5 dB +/- 2,5 dB Settings will be provided to allow output power to be reduced from its maximum level to at least six steps of nominally 2 dB with an accuracy of ≈1 dB to allow a fine adjustment of the coverage by the network operator. In addition, the actual absolute output power at each static RF power step (N) shall be 2*N dB below the absolute output power at static RF power step 0 with a tolerance of ≈3 dB under normal conditions and ≈4dB under extreme conditions. The static RF power step 0 will be the actual output power according to the TRX power class. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 45/629 V17.0 BSS Parameter User Guide (BPUG) 4.2.3 GSM PRODUCTS SENSITIVITY AND POWER Please refer to the following documents for information on main RF characteristics of the Nortel BTS portfolio : BTS S2000L Engineering Rules : [R47] BTS S2000H Engineering Rules : [R48] BTS S4000 Outdoor Engineering Rules : [R49] BTS S4000 Indoor Engineering Rules : [R50] BTS eCell Engineering Rules : [R51] BTS S8000-S8003 Indoor & S8000 Outdoor Engineering Rules : [R52] BTS S12000 Indoor & Outdoor Engineering Rules : [R53] BTS 18000 Indoor & Outdoor Engineering Rules : [R54] BTS 18000 GSM-UMTS Indoor & Outdoor Engineering Rules : [R55] BTS 6000 GSM Indoor & Outdoor Engineering Rules : [R56] Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 46/629 V17.0 BSS Parameter User Guide (BPUG) 4.2.4 CONVERSION RULES POWER CONVERSION The main power conversion rules are provided below. P (dB) = P (dBW) = 10 log (PW) P (dBm) = P (dBmW) = 10 log (PmW) P (dB) = P (dBm) - 30 E (dBV / m) = P (dBm) + 20 log FHz + 77,2 DISTANCE - TIMING ADVANCE CONVERSION The table below gives the conversion rules of the timing advance versus the distance. One bit corresponds to 554 m and the accuracy is 0.25 bit (i.e 138.5 m) Timing Advance 0 1 2 3 … 63 [34 902..35456[ 0.4 % Distance (m) [0..554[ [554..1108[ [1108..1662[ [1662.. Recommendation accuracy 25 % 12.5 % 6.1 % 3.1 % Due to multipath and to MS synchronization accuracy, the gap of timing advances between two different MS for a given distance can reach 3 bits (i.e. 1,6 km). The value of the timing advance has an impact on decision taking for handover and call clearing. The timing advance is calculated by taking into account all the rays coming from a same signal. The timing advance must be used carefully as a handover and call clearing criteria, especially in a microcellular configuration. 4.2.5 ACCURACY RELATED TO MEASUREMENTS The GSM recommendation specifies the absolute and relative accuracy of the MS and BTS measurements (Rec. GSM 05.08 § 8.1.2). The table below provides the GSM absolute accuracy recommendation. MS and BTS absolute measurement accuracy from - 110 dBm to - 70 dBm under normal conditions from - 110 dBm to - 48 dBm under normal conditions from - 110 dBm to - 48 dBm under extreme conditions +/- 4 dB +/- 6 dB +/- 6 dB Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 47/629 V17.0 BSS Parameter User Guide (BPUG) The overlap between the different ranges (see above normal condition cases) are specified in the recommendation. This recommendation is not restrictive and most of the BTS and MS may provide better results. However, these figures show that the threshold accuracy handover and power control field strength may be off by a few dB. The relative accuracy depends on the gap between measurement levels and sensivity levels. The table below provides the GSM relative accuracy recommendation of a difference between two measurements lower than 20 dB. MS and BTS absolute measurement accuracy lower measured level > sensitivity + 14 dB sensitivity + 14 dB> lower measured level > sensitivity + 1 dB sensitivity + 1 dB > lower measured level + 2 / - 2 dB + 2 / - 3 dB + 2 / - 4 dB For example, the level difference between two field strengths, which are higher than the sensivity + 14 dBm, must be within the range of [-2 dB to +2 dB]. Output power tolerance must also be considered in the parameters setting because the parameters bsTxPwrMax and msTxPwrMax are used in the algorithms. 4.2.6 FREQUENCY BAND Frequency band P-GSM 900 E-GSM 900 R-GSM 900 DCS 1800 PCS 1900 GSM 450 GSM 480 GSM 850 GSM 750 Fl(n) [lower band] Fl(n) = 890 + 0,2 * n Fl(n) = 890 + 0,2 * n Fl(n) = 890 + 0,2 * (n - 1024) Fl(n) = 890 + 0,2 * n Fl(n) = 890 + 0,2 * (n - 1024) Fl(n) = 1710,2 + 0,2 * (n - 512) Fl(n) = 1850,2 + 0,2 * (n - 512) Fl(n) = 450,6 + 0,2 * (n - 259) Fl(n) = 479 + 0,2 * (n - 306) Fl(n) = 824,2 + 0,2 * (n - 128) Fl(n) = 747,2 + 0,2 * (n - 438) n range 1 ≤ n ≤ 124 0 ≤ n ≤ 124 975 ≤ n ≤ 1023 0 ≤ n ≤ 124 955 ≤ n ≤ 1023 512 ≤ n ≤ 885 512 ≤ n ≤ 810 259 ≤ n ≤ 293 306 ≤ n ≤ 340 128 ≤ n ≤ 251 438 ≤ n ≤ 511 Fu(n) [upper band] Fu(n) = Fl(n) + 45 Fu(n) = Fl(n) + 45 Fu(n) = Fl(n) + 45 Fu(n) = Fl(n) + 95 Fu(n) = Fl(n) + 80 Fu(n) = Fl(n) + 10 Fu(n) = Fl(n) + 10 Fu(n) = Fl(n) + 45 Fu(n) = Fl(n) + 30 Frequencies are in MHz. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 48/629 V17.0 BSS Parameter User Guide (BPUG) 4.3. 2G CELL SELECTION AND RESELECTION 4.3.1 OVERVIEW NETWORK SELECTION At switch-on, the mobile is required to select, among a set of PLMNs that is further defined below, the highest priority PLMN that is both : • • "available" and "allowable" An available PLMN is a PLMN on which a cell has been found that is not barred and where Rxlev > rxLevAccessMin An allowable PLMN is a PLMN which is not in the list of "forbidden PLMNs" in the MS. The set of possible PLMNs and their decreasing order of priority is : • • • the last PLMN on which the MS performed a successful registration (Location area update); the Home PLMN (this is the PLMN where the MCC and MNC of the PLMN identity match the MCC and MNC of the IMSI); other PLMNs, in the order explicitely defined in the SIM. This order of priority is valid, whether the MS is a roamer or not. CELL SELECTION PROCEDURE: • The selection process begins with a signal strength measurement averaging on the whole frequency band lasting approximately three seconds in order to sort channels according to their strength. Then, for the most powerful channel, the MS tries to detect the FCH channel, then decodes the SCH channel, and if the MNC and MCC are not forbidden, it listens to SYSTEM INFORMATION 1 to 4 to get full information on that cell and possibly select it depending on the selection criterion. If one of the steps fails, the next powerful channel is tried and so on. • • CELL RESELECTION PROCEDURE: • Reselection criteria are calculated every 5 to 60 seconds period (depending on the number of cells for which BCCH is in BCCH Allocation and number of multiframes between paging) because MS must perform at least 5 measurements on every cell listed in the BCCH Allocation before averaging is allowed. For phase 1 MS, C1 path loss criterion is used whereas for phase 2 MS, the C2 criterion is used. Then, for the most powerful channel, the MS attempts to detect the FCH channel, then decodes the SCH channel, and if the NCC and BCC are not forbidden, it will Nortel confidential • PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 49/629 V17.0 BSS Parameter User Guide (BPUG) listen to SYSTEM INFORMATION 1 to 4 to get full information on that cell and possibly select it depending on the selection criterion. 4.3.2 SELECTION OR RESELECTION BETWEEN CELLS OF CURRENT LOCATION AREA In Phase 1, MS checks that cellBarred flag is not set to “barred” before sorting eligible cells. In Phase 2, MS checks cellBarred and cellBarQualify flags in order to define the cell’s access (normal,low,barred). C1 is the path loss criterion for unbarred cells of allowed PLMN. To be selected, a cell must have a positive C1: C1 = RXLEV - rxLevAccessMin - Max (B,0) >0 with B = msTxPwrMaxCCH - P P = maximum RF output power of the MS Received levels must be higher than rxlevAccessMin and if a mobile state has a classmark lower than msTxPwrMaxCCH, it must get closer to the cell to have access to it. 4.3.3 RESELECTION TO A CELL OF A DIFFERENT LOCATION AREA This is an additionnal criteria for reselection towards a “y” cell having a different Location Area from the current one. A choice must be made between C1 values for cell having a different Location Area: C1(x) < C1(y) - cellReselectHysteresis The value used for the parameter cellReselectHysteresis is the-one set in the current serving cell. 4.3.4 ADDITIONAL RESELECTION CRITERION (FOR PHASE 2) In Phase 2, MS checks cellBarred and cellBarQualify flags in order to define the cell’s access (normal, low, barred). To activate this feature, the cellReselInd parameter will be set to “true”. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 50/629 V17.0 BSS Parameter User Guide (BPUG) The C1 criterion did not provide a way of preventing a fast moving mobile station from reselecting a “fugitive cell” nor avoiding ping-pong reselection. The idea is to give a cell a tunable access for reselection and to prevent mobiles from reselecting a cell if that cell is new to the mobile or if it was recently the serving cell: C2 = C1 + cellReselectOffset - temporaryOffset * H (penaltyTime - t) for penaltyTime ≠ 640 C2 = C1 - cellReselectOffset for penaltyTime = 640 where t is a timer started as soon as a cell enters the mobile best cell list: • • t = penaltyTime if the new cell in the list is the previous serving cell t = 0 otherwise and H(x) is a function: • • H(penaltyTime - t) = 0 if t ≥ penaltyTime H(penaltyTime - t) = 1 if t < penaltyTime temporaryOffset is a negative offset. By adding an offset (cellReselectOffset) it is possible to give different priorities, for example, to different types of cells in case of a multilayer network or to different bands when multiband operation is used. The timer penaltyTime ensures that the mobile will reselect a cell which has been received with a sufficient level for a sufficient time. Some microcellular handover algorithms are based on this C2 reselection principle. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 51/629 V17.0 BSS Parameter User Guide (BPUG) Priority of access: cellBarred and cellBarQualify parameters. The parameters are used to give each cell the authorization to be selected or reselected, and for all of them a priority of access is given. The selection procedure is mainly concerned by this priority introduction. SELECTION For the server cell and the neighboring cells, the C1 algorithm is computed. The C2 algorithm is computed only if cell reselection is used (cellReselInd = true). A priority is affected to each eligible cell and is only applied to Phase II MS. IF cellBarQualify = TRUE THEN the cell priority is “low”, whatever the “cellBarred” value is. IF cellBarQualify = FALSE AND IF the cell is barred (cellBarred set to “barred”) THEN the cell priority is null (the cell can not be reselected in idle mode). IF cellBarQualify = FALSE AND IF the cell is not barred THEN the priority is “normal”. For a mobile Phase II: if no cell with NORMAL priority is eligible (cell contained in the eligible list constituted using the C1 algorithm), then the cells with LOW priority are scanned. So even if a cell is barred, a phase II mobile is able to select this cell, but it will not be able to perform a call on it. For a mobile Phase I: it is not possible to reselect a cell that is barred. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 52/629 V17.0 BSS Parameter User Guide (BPUG) cellBarred barred barred not barred not barred false true false true cellBarQualify low normal low Priority no selection possible Note: To forbid the access of a cell to a MS, the cellBarred set to “not barred” and incomingHandover set to ”disabled”, is not sufficient. Care must be taken with the cellBarQualify that gives the priority. RESELECTION There is only one kind of priority which is NORMAL. IF the cell is barred AND IF cellBarQualify is false THEN the reselection is not authorized. cellBarred barred barred not barred not barred false true false true cellBarQualify normal normal normal Priority no selection possible Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 53/629 V17.0 BSS Parameter User Guide (BPUG) 4.4. 2G - 3G CELL RESELECTION In v14.2, GSM to UMTS mobility is only provided to mobiles in Idle Mode using the cell reselection algorithm with BSC12000 and BSC3000. The 2G-3G mobility in connected mode is addressed by the 2G-3G Handover feature (V17). This part only considers reselection from a GSM cell to a UMTS FDD cell. As UMTS is deployed, if GSM access network does not provide "GSM to UMTS mobility" for mobiles in idle mode, all the dual-mode mobiles (e.g. mobile supporting both GSM and UTRAN/FDD radio access technologies) will be stuck on GSM cells: • • • • when leaving UMTS coverage the mobile will reselect a GSM cell when on a GSM cell a dual-mode mobile will only reselect a GSM cell switching off-on the mobile will not make the mobile reselect UMTS, since the mobile is first looking for its last "Registered technology" at power on using a different PLMN for UMTS (being the mutimode subscriber HPLMN) and GSM layers can help, but this will not work for the operators not taking this option 4.4.1 UE ALGORITHM IN GSM CIRCUIT MODE Instead of the C2 criterion used in GSM only network, the dual-mode cell reselection uses a criteria based on RLA_C (Received Level Averages for Circuit services), which is an unweighted average of the received signal levels measured in dBm. The UE starts measuring 3G cells when RLA_C in serving cell is below or above Qsearch_I (depending on the value of Qsearch_I). Main reason is to save mobile battery. The UTRAN/FDD neighbouring cell n is reselected by the UE if the 2 following conditions are met: (CPICH_RSCP(n) > RLA_Cserving + FDD_Qoffset) during 5 seconds (CPICH Ec/No)(n) > FDD_Qmin • • CPICH_RSCP(n): is the Received Signal Code Power on one code measured on the Primary CPICH (CPICH Ec/No)(n): is the received energy per chip on the Primary CPICH divided by the power density in the band The 1st condition ensures a minimum signal level is available from cell n. The 2nd condition ensures the quality (level of interference) of cell n is acceptable. The parameters used by the mobile to perform intersystem cell reselection are the following. Nortel Parameter Name uMTSSearchLevel uMTSReselectionOffset uMTSAccessMinLevel 3GPP Parameter Name Qsearch_I FDD_Qoffset FDD_Qmin Description Search for 3G cells if signal level is bellow Applies an offset to C2 to cell re-selection to access technology FDD UMTS access min level A minimum threshold for Ec/No for UTRAN FDD cell re-selection Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 54/629 V17.0 BSS Parameter User Guide (BPUG) Nortel Parameter Name uMTSReselectionARFCN 3GPP Parameter Name FDD_ARFCN Description Neighbouring UMTS cell ARFCN These parameters are controlled by O&M and broadcasted on BCCH in the System Information 2quater message. CAUTION! In order to enable the broadcasting of the SI2Quater on the BCCH the parameter uMTSReselectionARFCN must be set to a non-null value. PROCESS IN THE BSS The cell reselection does not require any specific algorithm in the GSM-BSS. The intersystem reselection only requires new piece of information to be broadcast on the BCCH by the GSMBSS: • • new intersystem cell reselection control parameters (as described above) neighboring UMTS cell list The broadcast of this new information is ensured using the "System Information 2quater" message. When the information is updated (following a change at the OMC-R), the CHANGE MARK bit is set to a new value. The System Information 2quater is scheduled either on Normal or Extended BCCH (see chapter SI2Quater & SI13 on Extended or Normal BCCH): • If sent on Normal BCCH: it shall be sent when TC = 5 if neither of 2bis and 2ter are used otherwise it shall be sent at least once within any of 4 consecutive occurrences of TC = 4 • If sent on BCCH Ext, it is sent at least once within any of 4 consecutive occurrences of TC = 5 As a consequence, System Information 3 message has been updated in order to indicate to the mobile: • • whether or not SI2quater is broadcast if broadcast is done on Normal or Extended BCCH 4.4.2 3G NEIGHBOURING CELL INFORMATION IN SI2QUATER The GSM standard offers different possibilities to broadcast 3G neighbouring cell information using SI2quater: • • 1) The BSS broadcast FDD_ARFCN and primary scrambling code for each of the UMTS FDD neighbouring cells. 2) The BSS only broadcast FDD_ARFCN. This is the most simple solution from a Network point of view. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 55/629 V17.0 BSS Parameter User Guide (BPUG) In Nortel’s choice, neighboring cell scrambling codes will not be broadcast, and it will be assumed that only one UTRAN/FDD carrier is deployed by cell, e.g. it possible to have different carriers on different cell but only one per cell. As it will take "some" additional time with that solution (the mobile have to decode the UTRAN FDD neighbouring cells scrambling codes) 2 additional informations are provided and used by the network and the mobile when the mobile reports measurement in connected mode: • • a one bit 3G-BA_IND field used to correlate the measurements with a neighbouring cell list a Absolute_Index_Start_EMR used for building the neighbouring cell list in the mobile. The value of this parameter is dynamic, and depends on the number of 2G neighbouring cells (this allows shorter Meas. Report messages from the UE). 4.4.3 CONTROL INFORMATION IN SI2QUATER The following Control information is broadcast by SI2quater message : • • • FDD_Qoffset (uMTSReselectionOffset) FDD_Qmin (uMTSAccessMinLevel) Qsearch_I (uMTSSearchLevel) Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 56/629 V17.0 BSS Parameter User Guide (BPUG) 4.5. LEGACY MEASUREMENT REPORTING 4.5.1 PRINCIPLE Legacy measurement reporting consists in a mobile in dedicated mode - on a TCH or an SDCCH - sending downlink signal measurements to the network, at regular intervals. The BSS then uses these measurements in the uplink power control and handover procedures. 4.5.2 NEIGHBOUR CELL MONITORING DOWNLINK SIGNAL STRENGTH MEASUREMENTS In this entire section, the mobile is assumed to be in dedicated mode. While in dedicated mode, the mobile performs signal strength monitoring on all declared neighbouring BCCH carriers. Signal strength measurements are done in every TDMA frame on at least one of the BCCH carriers indicated in the BCCH allocation (BA), one after another. As an exception, a dual-mode MS may omit GSM measurements during up to 9 TDMA frames per SACCH multiframe and use these periods for measurements on UMTS. Furthermore, an MS on SDCCH is allowed to schedule the measurements freely within the multiframe as long as the total number of measurement samples is maintained and the samples on each carrier are evenly spaced. BSIC DECODING It is essential for the MS to identify precisely which surrounding BTS is being measured in order to ensure reliable handover. Because of frequency re-use with small cluster sizes, the BCCH carrier frequency may not be sufficient to uniquely identify a neighbouring cell, i.e. the cell in which the MS is situated may have more than one surrounding cell using the same BCCH frequency. Thus it is necessary for the MS to synchronize to and identify the base station identification code (BSIC). The 6-bit BSIC shall be transmitted by the network on the SCH channel of each cell. The MS shall use at least 4 spare frames per SACCH block period for the purpose of decoding the BSICs (e.g. in the case of TCH, the four idle frames per SACCH block period). These frames are termed "search" frames. The MS shall attempt to demodulate the SCH on the BCCH carrier of as many neighbouring cells as possible, and decode the BSIC as often as possible, and as a minimum at least once every 10 seconds. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 57/629 V17.0 BSS Parameter User Guide (BPUG) 4.5.3 SERVING CELL MONITORING DOWNLINK SIGNAL STRENGTH MEASUREMENTS For each channel, the measured downlink RXLEV shall be the average of the received downlink signal level measurement samples in dBm taken on the TCH or SDCCH channel within the reporting period of length one SACCH multiframe. Signal strength measurement samples shall be taken on all bursts of the physical channel that carries the TCH or the SDCCH, including those of the SACCH. DOWNLINK SIGNAL QUALITY MEASUREMENTS The received downlink signal quality shall be measured by the mobile in a manner that can be related to the average BER before channel decoding, assessed over all received bursts in the multiframe, except bursts carrying a portion of a SACCH frame. 4.5.4 REPORTING PERIOD A measurement report contains values averaged over samples collected over 104 TDMA frames for a TCH (480 ms = duration of 4 TCH multiframes) and 102 TDMA frames for an SDCCH (471 ms = duration of 2 SDCCH multiframes). The mobile sends 1 measurement report every 480 ms for a TCH, and every 471 ms for an SDCCH. Measurements performed during that measurement period are reported on the next SACCH block occurrence. The transmission of a single measurement report message is done on four consecutive bursts of the SACCH channel : • • For a TCH, there is one SACCH burst available every 120 ms. For an SDCCH, the 4 SACCH bursts occur in 4 TDMA frames in immediate succession, but these 4 TDMAs in succession occur once every 471 ms. Note : The BTS also performs uplink signal strength and uplink signal quality measurements . However, the BTS delays the processing of these uplink measurements by 480 ms or 471 ms to ensure that they are synchronised with the downlink measurements from the mobile (i.e. they relate to the same reporting period as the downlink measurements, which the BTS receives with a 480 ms or 471 ms delay). 4.5.5 NEIGHBOUR CELL LISTS Reporting with the MEASUREMENT REPORT message is usually performed on the BCCH allocation list (i.e. GSM cells only), but could also use cells from the 3G neighbour list in the case of 2G/3G mobiles. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 58/629 V17.0 BSS Parameter User Guide (BPUG) The BCCH Allocation list is provided by the network to the mobile through SI5 messages on SACCH. The number of neighbour cell BCCH carriers in the BCCH allocation cannot exceed 32. The UTRAN neighbour list is provided to the 2G/3G mobile through Measurement Information messages sent on SACCH. 4.5.6 MEASUREMENT REPORT CONTENT 2G MEASUREMENT REPORT Each measurement report contains the following data : • (neighbour cells) RXLEV_NCELL : RXLEV computed from samples taken on the BCCH frequency of the 6 cells with the highest signal level. For each of the 6 cells, the number of samples that is used to compute the RXLEV of that cell depends on the total number of neighbours to be monitored (this number is the size of the BCCH Allocation list). (serving cell) RXLEV_FULL : RXLEV computed from 100 (resp. 12) measurement samples of the mobile’s TCH (resp. SDCCH). The samples are measured in each of the 100 (resp. 12) TDMA frames that transmit either the TCH burst (resp. SDCCH) or the SACCH burst, over the measurement period. (serving cell) RXQUAL_FULL : RXQUAL computed from 100 (resp. 12) measurement samples of the mobile’s TCH (resp. SDCCH) (serving cell) RXLEV_SUB : For a TCH, RXLEV computed from 12 samples taken from the 4 SACCH bursts and – in case of speech only - the 8 Silence Descriptor (SID) frames. Not applicable for SDCCH because DTX is not allowed on SDCCH : in that case, RXLEV_SUB = RXLEV_FULL. (serving cell) RXQUAL_SUB : For a TCH, RXQUAL computed from the same 12 samples as RXLEV_SUB. Not applicable for SDCCH and in that case, RXQUAL_SUB = RXQUAL_FULL. • • • • The mobile reports every 480 ms for a TCH and every 471 ms for an SDCCH. 3G MEASUREMENT REPORT The measurement report is the same as for 2G, except for the RXLEV_NCELL of neighbour UTRAN cells. The RXLEV_NCELL neighbour cell measurement is replaced by the appropriate measurement for UTRAN. The measurement quantity reported by mobiles could be either “CPICH RSCP” or “CPICH Ec/N0”. In Nortel implementation, mobiles are told by the network to report only RSCP measurements on CPICH channels. However, the mobile selects the UTRAN cells to report, based on internal measurements of the CPICH Ec/N0. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 59/629 V17.0 BSS Parameter User Guide (BPUG) 4.5.7 MULTIBAND REPORTING (V10) For a multi band MS the number of cells, for each frequency band supported, which must be included in the measurement report is indicated by the value of the parameter MULTIBAND_REPORTING, broadcast by the network in SI2ter on BCCH and SI5ter on SACCH. The value of this parameter is set by the BSS parameter multiBandReporting (class 3, bts object) : • • Value 0 : reporting of the six strongest cells, irrespective of the band used. No band is favoured. Value 1, 2 or 3 : reporting of the 1, 2 or 3 strongest neighbour cell(s) in the nonserving band. The remaining positions in the measurement report shall be used for reporting of cells in the band of the serving cell. If there are still remaining positions, these shall be used to report the next strongest identified cells in the other bands irrespective of the band used. 4.5.8 UTRAN CELL REPORTING USING LEGACY MEASUREMENT REPORTS (V17) If GSM to UMTS Handover feature is enabled (see §4.8.24), the network may request the 2G/3G mobiles to report on UTRAN cells as well as on GSM cells, using either : • • Legacy measurement reports : this option is covered in this subsection. Enhanced measurement reports : this option is covered in §4.6 Note that 2G only mobiles never report UTRAN cells. UTRAN cells’ reporting only concerns 2G-3G mobiles and is performed by these mobiles using normal measurement reports only when HO 2G-3G is enabled (parameter gsmToUMTSServiceHo not equal to gsmtoUMTSDisabled) and EMR is disabled. In that case, the network informs the 2G/3G mobiles of the type of measurement report to be used by sending a parameter called REPORT_TYPE (3GPP name) / reportTypeMeasurement (Nortel BSS parameter name) which can take only 2 values : “enhanced measurement report” or “normal measurement report”. It is sent on SACCH inside a message called MEASUREMENT INFORMATION. BSS PARAMETERS The choice criteria of 2G and 3G cells that the 2G/3G mobile must include in the Measurement Report in the list of the 6 cells are driven by 4 network parameters, the use of which is detailed further on in this subsection : • • • • fDDMultiratReporting (v17, bts object) fDDreportingThreshold2 (v17, handoverControl object) qsearchC (v17, handoverControl object) multiBandReporting (v10, bts object) Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 60/629 V17.0 BSS Parameter User Guide (BPUG) PARAMETER FDDMULTIRATREPORTING (V17) A 2G/3G mobile must report the number of best valid UTRAN cells belonging to the neighbour cell list, according to the value of the parameter fDDMultiratReporting. fDDMultiratReporting indicates the number of UTRAN cells that the 2G/3G mobile must include in the measurement report. The fDDMultiratReporting parameter is sent by the network to the 2G/3G mobile inside a Measurement Information message on SACCH. PARAMETER FDDREPORTINGTHRESHOLD2 (V17) Only UTRAN cells with a CPICH Ec/No value equal or higher than fDDreportingThreshold2 shall be reported. If that criterion is met, the reported quantity is the CPICH RSCP. “Valid” UTRAN cells are identified cells where the primary CPICH has been received when using the scrambling code provided for that frequency in the neighbour cell list. The fDDreportingThreshold2 parameter is sent by the network to the 2G/3G mobile inside a Measurement Information message on SACCH. PARAMETER MULTIBANDREPORTING (V10) The remaining positions in the measurement report shall be used for reporting of GSM cells as defined by multiBandReporting parameter. If there are still remaining positions, these shall be used to report the next best valid UTRAN cells. PARAMETER QSEARCHC (V17) The qsearchC parameter is sent by the network to the 2G/3G mobile inside a Measurement Information message on SACCH. For a 2G/3G mobile, qsearchC defines a power level threshold (in dBm) and also indicates whether these tasks shall be performed when RXLEV of the BCCH of the serving cell is below or above the threshold : • • search for UTRAN cells if RXLEV of the BCCH of the serving cell is below threshold (values 0 to 7): - 98, - 94, … , - 74 dBm, ∞ (always) or search for UTRAN cells if RXLEV of the BCCH of the serving cell iis above threshold (values 8 to 15): - 78, - 74, … , - 54 dBm, ∞ (never) If the serving cell is not included in the GSM neighbour list defined for handover purposes (this is always the case according to Nortel Engineeering best practice), and if the dedicated channel is not on the BCCH frequency, and if qsearchC is not equal to 15, then the mobile must ignore the qsearchC parameter value and must always search for UTRAN cells. If qsearchC is equal to 15, the MS must never search for UTRAN cells. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 61/629 V17.0 BSS Parameter User Guide (BPUG) If the dedicated channel (TCH or SDCCH) uses the BCCH frequency, then qsearchC is meaningful. However, in that case, the recommended Nortel value is 7 (always search for UTRAN cells regardless of the downlink power level of the serving cell BCCH carrier). Conclusion : with Nortel’s recommended value qsearchC = 7, the 2G/3G mobile is required to always search for and measure UTRAN cells, regardless of the downlink power level of the serving cell BCCH carrier CELL CHOICE ALGORITHM The MS fills the normal measurement report with measurements from 6 neighbour cells chosen in the following order : • Strongest valid UTRAN FDD cells : o a valid UTRAN cell is an identified cell where the primary CPICH has been received by the mobile when using the scrambling code provided for that frequency in the neighbour cell list. to be eligible, a valid fDDReportingThreshold2. cell’s Ec/N0 must also be greater than o o these valid and eligible cells are ranked according to the CPICH RSCP value and the strongest are included first. The number of such reported cells is defined by the fDDMultiratReporting parameter. • Strongest GSM cells (including GSM cells of unknown BSIC) in each of the nonserving frequency bands in the neighbour list. The number of such reported cells is defined by the multiBandreporting parameter. Strongest GSM cells (including unknown BSIC) in the frequency band of the serving cell. There is no limitation on the number of such reported cells. Remaining strongest GSM cells in each of the non-serving frequency bands in the BA list. Remaining strongest UTRAN FDD cells. • • • Comments: • • • • Unlike EMR (§4.6), this algorithm does not discriminate between GSM cells with known BSIC and GSM cells with unknown BSIC. Unlike EMR (§4.6), the RxLev of serving band GSM cells are not required to exceed a reporting threshold. Unlike EMR (§4.6), the RSCP of UTRAN cells is not required to exceed a reporting threshold. Unlike EMR (§4.6), UTRAN cells are included before GSM cells. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 62/629 V17.0 BSS Parameter User Guide (BPUG) ENGINEERING RECOMMENDATION Unlike EMR, a normal measurement report contains 6 cells. Therefore, it is necessary to exercise caution when setting the parameters fDDMultiRatReporting and multiBandReporting. These parameters define the number of UTRAN cells and non-serving band GSM cells, repsectively, that must be included by the mobile in the list of strongest cells in the measurement report. Therefore it leaves (6 - fDDMultiRatReporting - multiBandReporting) spaces for the serving band cells. Therefore, if EMR is disabled, it is recommended not to exceed fDDMultiRatReporting = 2 and multiBandReporting = 2. 4.5.9 NOTE ON POWERCONTROLINDICATOR PARAMETER powerControlIndicator is a BSS parameter that sets the value of the flag "PWRC". "PWRC" is a field that is broadcast on BCCH channel inside SYSTEM INFORMATION n°3 messages. PWRC = 1 is equivalent to powerControlIndicator = "do not include BCCH measurements" PWRC = 0 is equivalent to powerControlIndicator = "include BCCH measurements" The mobiles are required to interpret this flag as follows : • • • if frequency hopping is not used : MS ignores the PWRC flag if frequency hopping is used and the BCCH frequency is not part of the Mobile Allocation frequency list : MS ignores the PWRC flag if frequency hopping is used and the BCCH frequency is part of the Mobile Allocation frequency list : o if PWRC = 1 : in the RXLEV averaging process, the MS shall discard the samples measured on the TCH channel's Downlink bursts that have been transmitted by the BTS on the BCCH frequency if PWRC = 0 : in the RXLEV averaging process, the MS shall use the samples measured on the TCH channel's Downlink bursts that have been transmitted by the BTS on the BCCH frequency o In practice, in our networks : • In case of Synthesized Frequency Hopping, there is one TRX which is dedicated to transmitting the BCCH frequency all 8 Timeslots of the TDMA. If the BCCH frequency was part of the hopping list of a TCH (on another TRX, of course), then there would be systematic collisions. Therefore, in case of SFH, BCCH frequency cannot be part of the hopping frequency list. Therefore, in case of SFH, the setting of powerControlIndicator is irrelevant. In case of Baseband Frequency Hopping (BB FH is the only hopping scheme possible with Cavity coupling), it is theoretically possible - but not recommended by Nortel - to include the BCCH frequency in the hopping frequency list. If, in spite of our recommendation, the BCCH frequency is part of the hopping frequency, then : Nortel confidential • PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 63/629 V17.0 BSS Parameter User Guide (BPUG) o if downlink power control is activated, then the TCH channel's Downlink bursts transmitted on the BCCH frequency should not be used in the Rxlev averaging process because, unlike the samples from other frequencies, they are transmitted at full power : so, PWRC must be = 1 and powerControlIndicator = "do not include BCCH measurements". if downlink power control is not activated, then the TCH channel's Downlink bursts transmitted on the BCCH frequency may be used in the Rxlev averaging process : PWRC = 0 and powerControlIndicator = "include BCCH measurements" o 4.5.10 NOTE ON RXLEV UPLINK/DOWNLINK DIFFERENCE On the mobile side, every downlink sample is made up of measurements performed on several bursts in dBm. On the BTS side, uplink measurements are performed in Watts. So, the uplink RxLEv average is first computed in Watts before it is converted into dBm. These two different ways of calculating the RxLev average yield results that are artificially approximately 2,5 dB higher for the uplink than for the downlink (see chapter Difference Between Uplink and Downlink Levels. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 64/629 V17.0 BSS Parameter User Guide (BPUG) 4.6. ENHANCED MEASUREMENT REPORTING (EMR) 4.6.1 PRINCIPLE Compared to Legacy Measurement Reporting, Enhanced Measurement Reporting allows the mobile to: • • Report more GSM neighbouring cells and, if required, 3G cells Enhance the information reported about the quality of the signal received by the mobile (MEAN_BEP and CV_BEP, downlink FER). Enhanced Measurement Reporting by the mobile may be used in the context of 2G-3G handover but is not a mandatory prerequisite. 4.6.2 REPORTING PERIOD Same as Measurement Reporting. 4.6.3 ENHANCED MEASUREMENT REPORT CONTENT The Enhanced Measurement Report contains the following information : • (GSM neighbour cells) RXLEV computed from samples taken on the BCCH frequency of GSM neighbour cells with the highest signal level. The number of neighbour cells to be reported belonging to the serving GSM band on the one hand, and to the nonserving GSM band on the other hand, depends on the values of parameters sent by the network multibandReporting (v10 parameter), servingBandReporting (v17.0 parameter), and servingBandReportingOffset (v17.0 parameter) (3G neighbour cells) The reported value for 3G neighbour cells is the CPICH RSCP. The CPICH Ec/N0 is not reported in Nortel’s current implementation. The number of neighbour cells to be reported belonging to the 3G technology depends on the values of parameters sent by the network fDDMultiratReporting (v17.0 parameter), fDDreportingThreshold (v17.0 parameter) and fDDreportingThreshold2 (v17.0 parameter) (GSM serving cell) : The reported values for the GSM serving cell are : o RXLEV_VAL : The average over the reporting period of RXLEV measured on bursts whose associated FACCH, SID, or traffic frame has been the last time slots of each fully received and correctly decoded data block and on all SACCH frames. For speech traffic channels, blocks that have not been erased, shall be considered as correctly decoded. For non-transparent data, blocks are considered as correctly decoded according the CRC received. For transparent data, all blocks are considered as correctly decoded. • • Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 65/629 V17.0 BSS Parameter User Guide (BPUG) o MEAN_BEP : The average over the reporting period of the Mean Bit Error Probability, computed from each fully received and correctly decoded data block and from all SACCH frames. CV_BEP : The average over the reporting period of the Coefficient of Variation of the Mean Bit Error Probability, computed from each fully received and correctly decoded data block. RXQUAL_FULL : RXQUAL computed over the reporting period from 100 measurement samples of the mobile’s dedicated traffic channel TCH NBR_RCVD_BLOCKS : the number of correctly decoded TCH blocks that were completed during the measurement report period. o o o 4.6.4 NEIGHBOUR CELL LISTS EMR reporting is performed on the Neighbour Cell List. The Neighbour Cell List is the concatenation of 2 lists • • The GSM neighbour cell list The 3G neighbour cell list (if any) GSM NEIGHBOUR CELL LIST The GSM neighbour cell list is the combination of the BCCH Allocation list received in SI5/SI5bis/SI5ter with the BSIC list received in one or more instance of the MEASUREMENT INFORMATION message. 3G NEIGHBOUR CELL LIST This applies only to a 2G-3G mobile. One or more instances of the Measurement Information message may provide UTRAN Neighbour Cell Description information. This is used to build the 3G Neighbour Cell list. MAXIMUM LIST SIZE In Nortel’s v17 implementation, the maximum number of cells of the lists in the Measurement Information message is : • • • maximum 32 UMTS cells If the 3G list is void, maximum 32 GSM cells If the 3G list is non-void, maximum 31 GSM cells Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 66/629 V17.0 BSS Parameter User Guide (BPUG) 4.6.5 ORDER OF REPORTING PRIORITY OF NEIGHBOUR CELLS The Mobile includes measurement results of neighbour cells using the following priority order: • • Highest priority : the number of strongest GSM cells with known and valid BSIC in the frequency band of the serving cell, according to the value of servingBandReporting; 2nd highest priority : the number of strongest GSM cells with known and valid BSIC in each of the frequency bands in the BCCH Allocation list, excluding the frequency band of the serving cell, according to the value of multiBandReporting; 3rd highest priority : the number of best valid UTRAN cells with a reported value equal or greater than fDDReportingThreshold in the 3G neighbour cell list, according to the value of fDDmultiRatReporting. Additionally the CPICH Ec/No shall be equal or greater than fDDReportingThreshold2. A valid cell is an identified cell where the primary CPICH has been received when using the scrambling code provided for that frequency in the neighbour cell list. 4th highest priority : the remaining GSM cells with known and valid BSIC or, if allowed by the flag INVALID_BSIC_REPORTING, with known and allowed NCC part of the BSIC in any frequency band. Last priority : remaining valid UTRAN cells • • • For each of the priority levels above, the mobile shall apply the following rules : • • if the number of valid cells is less than indicated, the unused positions in the report shall be left for cells of lower priority; if there is not enough space in the report for all valid cells of a given priority, cells shall be ranked according to : o for GSM cells belonging to the serving band : RxLev + servingBandReportingOffset. Note that this ranking criterion shall not affect the value that is effectively included in the report, which remains RxLev. for GSM cells belonging to the non-serving band : RxLev. (reporting offset = 0) for UTRAN cells : RSCP. (reporting offset = 0) o o 4.6.6 MEASUREMENT INFORMATION MESSAGE PURPOSE OF MI MESSAGE The activation of EMR in the network requires the network to inform the relevant mobiles that EMR reports are expected from them. To do this, the network sends a new information message to the mobiles, called Measurement Information. The Measurement Information message is regularly sent by the network to the mobiles in dedicated mode on the SACCH, in addition to System information messages 5, 5bis, 5ter, and 6. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 67/629 V17.0 BSS Parameter User Guide (BPUG) The following mobiles receive MI messages : • • 2G-3G mobiles that are at least Release 99 2G-only mobiles that are at least Release 4 CONTENT In the version of EMR reporting currently implemented, the MI message contains essentially the following information : • • • EMR activation flag. The value of this flag is set by the reportTypeMeasurement parameter. Information enabling the mobile to derive the full list of GSM neighbour cells, i.e. (BCCH frequency, BSIC) pairs, that may be reported in EMR reports. INVALID_BSIC_REPORTING : 0 for disabled, 1 for enabled. When set to 1, report on cells with invalid BSIC and allowed NCC part of BSIC is allowed. The value 1 is mandatory if feature “switch interference matrix” is activated. Number of GSM neighbour cells of the serving band that the Mobile shall include in the list of strongest cells in the EMR report (up to 3). The value of this number is set by the servingBandReporting parameter. Threshold power level above which serving band cells may be reported among the servingBandReporting number of reported cells. In v17 implementation, this threshold is -110 dBm, meaning that all serving band cells may be reported regardless of their power level. (applicable to multi-band mobiles only) Number of GSM neighbour cells of the other band that the Mobile shall include in the list of strongest cells in the EMR report (up to 3). The value of this number is set by the multiBandReporting parameter (v10 parameter). (applicable to multi-band mobiles only) Offset to apply to the reported value when prioritizing the cells for reporting for GSM serving frequency band. The value of this offset is set by the servingBandReportingOffset parameter (applicable to 2G-3G mobiles only) UTRAN neighbour cell list : list of FDD (ARFCN, scrambling code, diversity) triplets, identifying each 3G neighbour cell. The values of these triplets are set by the following AdjacentCellUTRAN object parameters : o o o • fDDARFCN, scramblingCode, diversityUTRAN • • • • • (applicable to 2G-3G mobiles only) UTRAN cells’ measurement parameters : o Number of FDD cells to be reported in the list of strongest cells in the EMR message. This number is set by the O&M network parameter fDDMultiRatReporting. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 68/629 V17.0 BSS Parameter User Guide (BPUG) o CPICH RSCP level above which the mobile will apply a higher priority to UTRAN cells in the EMR message. The value of this level is set by the O&M network parameter fDDReportingThreshold. CPICH Ec/N0 level above which the mobile will report UTRAN cells in the EMR message. The value of this level is set by the O&M network parameter fDDReportingThreshold2. Serving cell BCCH frequency power threshold above which, or below which, the mobile may search for UTRAN cells. The value of this level is set by the O&M network parameter qsearchC. Type of reporting quantity (value always equal to RSCP in v17 implementation) o o o RELATION WITH 2G-3G HANDOVER Note that 2 different versions of the Measurement Information message may be sent by the network depending on the mobile’s radio access capability (2G or 2G-3G) : • If EMR reporting is activated but not 2G-3G handover (i.e. the gsmToUMTSServiceHo parameter is set to "gsmToUMTSDisabled") : o the BSC only sends 2G Measurement Information to the BTS. However, the BSC does send the whole L1M configuration to the BTS. The BTS is therefroe aware of the UTRAN neighbouring cells. The BTS only sends 2G Measurement Information messages to 2G-3G Release 99 mobiles and Release 4 2G mobiles. Thus UMTS cells are hidden from the mobiles so that mobiles do not report 3G measurement results in vain, which could adversely affect their performance. (i.e. the o • If both EMR reporting and 2G-3G handover are activated gsmToUMTSServiceHo parameter is not set to "gsmToUMTSDisabled") : o the BSC sends to the BTS both the 2G Measurement Information and the 2G/3G Measurement Information messages. The BTS sends the 2G/3G Measurement Information to 2G-3G Release 99 mobiles and the 2G Measurement Information to the Release 4 2G mobiles. o 4.6.7 MI/SACCH SCHEDULING The scheduling of Mesaurement Information and System Information messages in the SACCH channel is : SI 5 SI5bis SI 5ter SI 6 Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 69/629 V17.0 BSS Parameter User Guide (BPUG) MI SI 5 ... etc. 4.6.8 MAIN DIFFERENCES BETWEEN NORMAL AND ENHANCED MEASUREMENT REPORTING This section attempts at summarising the main differences between normal measurement reporting (§4.5) and enhanced measurement reporting (§4.6). MR A normal measurement report contains up to 6 neighbour cells No reporting offset is applied to rank cells. Competing cells are ranked based only on the strongest RxLev (GSM) and RSCP (UTRAN) values One (1) reporting threshold is used to define eligible UTRAN cells : fDDReportingThreshold2 for Ec/No (non-reported quantity). No threshold for RSCP. A parameter (fDDMultiRatReporting) defines the number of UTRAN cells to be included in the report as a matter of priority A parameter (MultiBandReporting) defines the number of nonserving band GSM cells to be included in the report as a matter of priority There is no required minimum number of serving band GSM cells in the report GSM cells with known BSIC and GSM cells with unknown BSIC are treated the same UTRAN cells have top priority in the report EMR An enhanced measurement report contains up to 32 neighbour cells servingBandReportingOffset is applied to the RxLev of serving band GSM cells for ranking purposes. No offset is applied for non-serving band GSM cells and UTRAN cells 2 reporting thresholds are used to define eligible UTRAN cells : fDDReportingThreshold for RSCP (reported quantity) and fDDReportingThreshold2 for Ec/No (non-reported quantity) A parameter (fDDMultiRatReporting) defines the number of UTRAN cells to be included in the report as a matter of priority A parameter (MultiBandReporting) defines the num ber of nonserving band GSM cells to be included in the report as a matter of priority A parameter (servingBandReporting) defines the number of serving band GSM cells to be included in the report as a matter of priority GSM cells with known and valid BSIC have higher priority Sering and GSM cells have top priority in the report 4.6.9 NEW BSS PARAMETERS The following parameters are created in v17.0 and are needed to support Enhanced Measurement Reporting : Parameter name fDDMultiratReporting fDDReportingThreshold Definition Number of FDD UTRAN cells to be reported in the list of strongest cells in the EMR message defines the CPICH RSCP level above which the MS will apply a higher priority to UTRAN cells in the enhanced measurement report message defines the CPICH Ec/N0 level above which the MS will report UTRAN cells in the enhanced measurement report message search for UTRAN cells if signal level on BCCH of serving cell : Nortel confidential Equivalent in GSM specification FDD_MULTIRAT_REPORTING FDD_REPORTINGTHRESHOLD fDDReportingThreshold2 qsearchC FDD_REPORTINGTHRESHOLD2 Qsearch_C PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 70/629 V17.0 BSS Parameter User Guide (BPUG) is below threshold (0-7): -98, -94, … , -74 dBm, ∞ (always) or is above threshold (8-15): -78, -74, … , -54 dBm, ∞ (never) If the serving BCCH frequency is not part of the BA(SACCH) list, the dedicated channel is not on the BCCH carrier, and qsearchC is not equal to 15, the MS shall ignore the qsearchC parameter value and always search for UTRAN cells. If qsearchC is equal to 15, the MS shall never search for cells on 3G. reportTypeMeasurement type of measurement report to be reported on this cell : enhanced measurement report or legacy measurement report defines the number of cells from the GSM serving frequency band that shall be included in the list of strongest cells in the measurement report. If there is not enough space in the report for all valid cells, the cells shall be reported that have the highest sum of the reported value (RXLEV) and the parameter servingBandReportingOffset (XXX_REPORTING_OFFSET) for the serving GSM band. Note that this parameter shall not affect the value itself of the reported measurement. REPORT_TYPE servingBandReporting SERVING_BAND_REPORTING servingBandReportingOffset XXX_REPORTING_OFFSET (XXX=900,1800,400,850,1900) 4.6.10 IMPACT OF EMR ON INTERFERENCE MATRIX IMPROVED ACCURACY There are more GSM neighbours reported with EMR than with legacy measurement reporting : • • With EMR, up to 32 GSM neighbours if no UTRAN cells are defined in the Neighbour Cell List With standard MR, 6 neighbour cells. This means that the statistical processing induces less systematic bias error in the case of EMR. GREATER NUMBER OF CYCLES If no 3G cells are declared as neigbours, the number of cycles depends only on the number of declared real neighbours and the number of fake neighbours, so it is not impacted by EMR. However, if 3G cells are declared as neighbours, the maximum number of GSM neighbours (real + fake) is 31 instead of 32. Therefore, more cycles may be required if 3G cells are present in the Neighbouring Cell List. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 71/629 V17.0 BSS Parameter User Guide (BPUG) CHANGE OF TRAFFIC DISTRIBUTION If, during the Interference Matrix campaign in a dual band network, the reporting of serving band neighbours is deliberately favoured by using the servingBandReportingOffset, then, as a side-effect, the traffic distribution may be modified. This undesirable side-effect may in turn modify the results of the IM measurements, whjich therefore may no longer reflect the real situation in the field once the IM has ceased. Therefore it is recommended to ensure that the chosen value of servingBandReportingOffset does not cause unacceptable changes in the traffic distribution. 4.6.11 IMPACT OF EMR ON RADIO MEASUREMENT DISTRIBUTION (RMD) Thanks to enhanced measurement reports, the downlink FER indicator is available to the network. Specific distributions are added for the different codec types. Also, a distribution of estimated downlink voice quality is added. This indicator is based on the same principle as MOS for uplink, but is a marginally less accurate because the mobile does not provide the distribution of codecs used during the measurement period. The post processing tool WQA is modified accordingly. DOWNLINK FRAME ERASURE RATE In the EMR message, the mobile provides the number of received traffic frames : NBR_RCVD_BLOCKS. The BTS knows the number of times each codec have been used during the measurement period so it is now possible to get a rough estimate of the probable number of frames, per codec, that have not been decoded by the mobile and a rough estimate, per codec, of the probable downlink FEP (Frame Erasure Probability). Note that each sum of estimated number of bad frames is rounded to the nearest integer value at the end of the connection. Thanks to RMD feature, downlink FER distributions at the OMC-R level are made available for the following types of circuit calls: • • • EFR and FR speech calls, AMR FR speech calls, AMR HR speech calls. DOWNLINK VOICE QUALITY INDICATOR With EMR, it is possible to estimate the downlink voice quality (DVQI) in the same way as TEPMOS estimates the uplink voice quality. Distinction is done for the different codec types (EFR (and FR), AMR FR and AMR HR). As the downlink FER per codec is an estimated one, the downlink voice quality indicator will be less precise than TEPMOS, but the formula used to calculate DVQI is similar to the TEPMOS one. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 72/629 V17.0 BSS Parameter User Guide (BPUG) 4.7. UPLINK MEASUREMENT PROCESSING 4.7.1 PRINCIPLE Each sample on the uplink side used by the Layer 1 Management in the average computation is composed of measurements performed in Watts on several bursts. So the uplink samples are first computed in Watts before being translated into dBm. The general idea is to perform arithmetic averages. These averages are stored, and each time a decision has to be taken, an other average (weighted-average) is computed. This weightedaverage is based on a defined number (Hreqt) of arithmetic averages, which are weighted in order to favor the latest results. In the new version of the Layer 1 Management (L1mV2), the process of averaging is based on fully sliding windows. Examples for Hreqave = 8, Hreqt = 1, run xx = 4 Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 73/629 V17.0 BSS Parameter User Guide (BPUG) 4.7.2 AVERAGING PROCESS • for quality and level: rxLevHreqave, rxQualHreqave: number of measurement results to compute an arithmetic average. rxLevHreqt, rxQualHreqave: number of arithmetic averages necessary to compute a weighted average, each one being associated to rxLevWtsList and rxQualWtsList (highest weight for the most recent data). missRxLevWt, missRxQualWt: weight applied to latest arithmetic average if existing or latest received value to replace a missing downlink measurement. In case there have been no previous measurements, a default value is used. • • for distance, weighted average applies directly to distHreqt raw figures. for neighbor cells, only the arithmetic average is computed. Furthermore, for L1mV2, when 10 SACCH blocks are missing, that cell is no longer considered and corresponding data is deleted. Note: cellDeletionCount is used as an eligibility criterion. Arithmetic averaging is performed with xx_Hreqave period whereas weighted averaging is done before algorithm processing, thus, weighted average is executed if run_xx is not a multiple of xx_Hreqave. Example for Hreqave = 3, Hreqt = 2, run xx = 4 Notes: In L1mV2, the weighted average is done with the latest not overlapped arithmetic averages. Reactivity of the L1mV2 has been improved. The measurements done by the MS and the BTS during the first SACCH block period is proceeded by the BTS during the second SACCH block period instead of the third SACCH block period. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 74/629 V17.0 BSS Parameter User Guide (BPUG) 4.7.3 RESCALING Measurements are stored along with the MS and BS power level (meas_txpwr) reported in MEAS RESULT, latest power control (MS or BS) is also stored (ref_txpwr). From the L1mV2, rescaling is done at maximum transmission power (txPwrMax). It means that the values or averages are adjusted as follows newLev = oldLev + ((txPwrMax – meas_txPwr) * Pwr_to_dbm) In this way BTS attenuation is already included in RxLevDL and handovers are better anticipated. 4.7.4 MISSING DOWNLINK MEASUREMENTS In case of Air interface problems, it’s possible to loose some SACCH blocks. Four rules of substitution are applied to compensate for the missing measurements. RULE 1 If averaged values are available, missing measurements are replaced by the latest averaged value multiplied by a weighting factor (missDistWt, missRxLevWt, missRxQualWt). r1 r2 r3 m1 r4 r5 r6 r7 m5 r8 m2 m3 m4 time Example: If r8 is missing, then r8 = m4 X weighting factor. RULE 2 If no average value is available, missing measurements are replaced by the latest measurement value multiplied by a weighting factor (missDistWt, missRxLevWt, missRxQualWt). Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 75/629 V17.0 BSS Parameter User Guide (BPUG) r1 r2 r3 m1 r4 r5 r6 r7 m5 r8 m2 m3 m4 time Example: If r3 is missing, then r3 = r2 X weighting factor. RULE 3 If no measurement value is available, the missing measurement is replaced by a default value. r1 r2 r3 m1 r4 r5 r6 r7 m5 r8 m2 m3 m4 time Example: If r1 is missing, then r1 = default value. RULE 4: In the following, the substitution of a missing value is only done when 6 neighbouring cells are reported during the considered period. From L1mV2 missing measurements for neighboring cells are replaced as follows; for both cases, inputs are: • • First case: IF RxLevNCell1(T) ≤ min(RxLevNCell(T+1) of the 6 reported cells) THEN RxLevNCell1(T+1) = RxLevNCell1(T) Ncell1 no longer belongs to the list of 6 preferred cells at T+1 period, T, T+1 correspond to measurement periods. Second case: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 76/629 V17.0 BSS Parameter User Guide (BPUG) IF RxLevNCell1(T) > min(RxLevNCell(T+1) of the 6 reported cells) THEN RxLevNCell1(T+1) = min(RxLevNCell(T+1)) - missOffsetdB missOffset has a fixed value of 3 dB. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 77/629 V17.0 BSS Parameter User Guide (BPUG) 4.8. DIRECT TCH ALLOCATION AND HANDOVER ALGORITHMS Since V14, a new version of the Layer 1 Management (L1mV2) is applicable (see chapter Measurement Processing) CAUTION! It is understood in all the following formulas that RxLev_XX is computed with L1mV2. 4.8.1 GENERAL FORMULAS PBGT The general PBGT formula is computed in the band0 because HO_MARGIN is always specific to the band0: PBGT(n) = Min [msTxPwrCapability(Band0), msTxPwrMax] - Min [msTxPwrCapabilityCell(n), msTxPwrMaxCell(n)] + (RxLevNCell(n)ave - RxLevDLave)) • • • • • • msTxPwrCapability: maximum transmission power capability of the MS according to the BCCH frequency (Band0) and its power class (§ 4.2.2). msTxPwrMax: maximum transmission power level the MS is allowed to use on a traffic channel in the current cell. msTxPwrMaxCapabilityCell(n): maximum transmission power capability of the MS (in the BCCH frequency band) of an adjacent cell (n), according to: o the BCCH frequency band of the adjacent cell (n) o the power class of the mobile in this band (§ 4.2.2) msTxPwrMaxCell(n): maximum transmission power level the MS is allowed to use on a traffic channel of neighbour cell n (or the band0 of the neighbour dual band cell n) RxLevNCell(n) ave: averaged downlink signal strength of the neighbour cell n RxLevDLave: averaged downlink signal strength of the serving cell However, if the MS is in band1 the PBGT formula is changed. Indeed, RxLevNCell(n)ave should be replaced by RxLevNCell(n)ave + biZonePowerOffset in order to simulate what the field strength would be like in band0. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 78/629 V17.0 BSS Parameter User Guide (BPUG) EXP1 The expression named EXP1 used for defining eligible cells: EXP1(n) = RxLevNCell(n) ave - [ rxLevMinCell(n) + Max(0, msTxPwrMaxCell(n) msTxPwrCapability(n) ) ] It is also used in the following process: EXP1Capture(n) = RxLevNCell(n) ave - rxLevMinCell(n) EXP1DirectedRetry(n) = RxLevNCell(n) ave - [directedRetry(n) + Max(0, msTxPwrMaxCell(n) - msTxPwrCapability(n)] EXP1Forced HO (n) = RxLevNCell(n) ave - [forced handover algo(n) + Max(0, msTxPwrMaxCell(n) - msTxPwrCapability(n)] • • • • • • RxLevNCell(n) ave: averaged downlink signal strength of the neighbour cell n rxLevMinCell(n): minimum RXLEV value required for a MS to handover towards cell n msTxPwrMaxCell(n): maximum transmission power level the MS is allowed to use on a traffic channel of neighbour cell n / in the band0 of the neighbour dual band cell msTxPwrCapability(n): maximum transmission power capability of the MS according to the power class of the mobile and the BCCH frequency (the band0) of the neighbour cell n directedRetry(n): minimum signal strength level received by the MS to process directed retry handovers in BTS mode forced handover algo(n): minimum signal strength level received by the mobiles to be granted access to a neighbor cell in case of forced handover. Note: If HO decision is made toward the inner zone of a multizone cell, then related EXP1XX(n) is computed with biZonePowerOffset(n). Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 79/629 V17.0 BSS Parameter User Guide (BPUG) EXP2 The expression named EXP2 used for defining suitable cells: EXP2PBGT(n) = Pbgt(n) - AdaptedHoMargin(n) EXP2Traffic(n) = Pbgt(n) - [hoMargin(n) - hoMarginTrafficOffset(n)] EXP2Quality(n) = Pbgt(n) - hoMarginRxQual(n) EXP2Strength(n) = Pbgt(n) - hoMarginRxLev(n) EXP2Distance(n) = Pbgt(n) - hoMarginDist(n) EXP2AMR(n) = Pbgt(n) - hoMarginAMR(n) EXP2bis(n) = rxLevDLPBGT(n) - RxLevDL ave • • • • • • • • AdaptedHoMargin(n): margin computed when AHA feature is enabled. It takes into account neighDisfavorOffset and servingfactorOffset parameters (see chapter Automatic handover adaptation) hoMargin(n): margin to be used for power budget HO hoMarginTrafficOffset(n): offset to be applied to hoMargin(n) for traffic HO decision (when current cell is overloaded) hoMarginRxQual(n): margin to be used for quality HO hoMarginRxLev(n): margin to be used for signal strength HO hoMarginDist(n): margin to be used for distance HO hoMarginAMR(n): margin to be used for quality intercell HO defined for AMR TCH channels rxLevDLPBGT(n): maximum downlink RxLev received from serving cell to allow a power budget or traffic HO towards this NCell Note: If HO decision is made in the inner zone of a multizone cell, then related EXP2XX(n) is computed with (hoMarginXX(n) + biZonePowerOffset). Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 80/629 V17.0 BSS Parameter User Guide (BPUG) 4.8.2 DIRECT TCH ALLOCATION This chapter describes the Direct TCH Allocation feature which applies to the dualband cell, the concentric cell and the dualcoupling cell features. Direct TCH Allocation has been enhanced in v17.0. PRINCIPLE The principle of “Direct TCH Allocation” is manifold. It consists in the following aspects : • • • • At call setup, to allocate a FR TCH directly into the inner-zone of a multizone cell At call setup, to allocate an HR TCH directly into the outer-zone of a multizone cell At call setup, to allocate an HR TCH directly into the inner-zone of a multizone cell On intercell handover, to allocate a TCH directly into the inner-zone of the target multizone cell. At call setup, while the mobile is still on SDCCH (SDCCH is always allocated in the large zone of a multi-zone cell), the BSC asks the BTS if the call (FR or HR) may be directed to the appropriate zone by sending the BTS an “Abis Connection state request” message. The acknowledgement of this request by the BTS provides the BSC with the information allowing the BSC to decide to perform the requested TCH allocation. The BTS uses several criteria to decide which zone is eligible. These criteria have been altered in v17.0 as explained in the next section. V17.0 ENHANCEMENT PRINCIPLE Call setup In initial phase of call establishment, the time spent on SDCCH is usually too short for the BTS to compute a weighted average on downlink Rxlev measurement before the BST receives the Abis connection state request from the BSC. Therefore, the allocation criteria for direct TCH allocation use, by decreasing order of priority: • • • a weighted average computed with RxLevHreqAve*RxLevHreqT latest measurements (unlikely to happen on SDCCH). an arithmetic average computed with RxLevHreqAve latest measurements (unlikely to happen on SDCCH) a short and fully reliable average (RxLevHreqAveBeg measurements) in the sense of the Automatic handover Adaptation feature if this feature is enabled and if the MS is fast enough or hopping on enough frequencies to filter the Raleigh fading. a short, not fully reliable average (from RxLevHreqAveBeg up to RxLevHreqAve-1 measurements) in all other cases. • In the last case, the v17 enhancement consists in the L1M compensating for the lower reliability of the short average by adding the hoMarginBeg margin to the various allocation thresholds. For all other cases, there is no change in v17.0. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 81/629 V17.0 BSS Parameter User Guide (BPUG) Note : If hoMarginBeg parameter is set to 63, the Direct TCH allocation procedure only uses normal averages. Intercell handover Some handover decisions (Early Power budget or Directed Retry) may be taken using less than RxLevNcellHreqAve measurements on the neighbouring cell. So, the allocation information for direct TCH allocation uses by decreasing order of priority: • • an arithmetic average computed with RxLevNcellHreqAve latest measurements. a short and fully reliable average (RxLevNcellHreqAveBeg measurements) in the sense of the Automatic Handover Adaptation feature if this feature is enabled and if the MS is going fast enough to filter the Raleigh fading a short not fully reliable average (from RxLevNcellHreqAveBeg RxLevNcellHreqAve -1 measurements) in all other cases. up to • In the last case, the L1M now compensates for the lower RxlevNcell average reliability by adding the hoMarginBeg margin to the BizonePowerOffset(n) parameter in order to ensure the same grade of service. Note : If hoMarginBeg parameter is set to 63, inter-cell handover Direct TCH allocation procedure only uses normal averages. DIRECT FR TCH ALLOCATION IN INNER-ZONE, AT CALL SETUP In v17, if using a not fully reliable short average, hoMarginBeg is added to the following thresholds : • concentAlgoExtRxLev CONCENTRIC CELLS The criteria for a successful direct TCH allocation in the inner-zone are : RxLevDL > concentAlgoExtRxLev and MS_BS_Dist < concentAlgoExtMsRange (timing advance criterion) DUALBAND OR DUALCOUPLING CELLS The timing advance criterion is disabled for a dualcoupling or dualband cell since the algorithm only needs to check that the BS Tx power in the innerzone is sufficient to maintain the communication. For dualband cells, obviously, a test is also performed on the capability of the mobile to support the band1. The criterion for a successful direct TCH allocation in the inner-zone is : Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 82/629 V17.0 BSS Parameter User Guide (BPUG) RxLevDL > concentAlgoExtRxLev DIRECT HR TCH ALLOCATION IN OUTER-ZONE, AT CALL SETUP In v17, if using a not fully reliable short average, hoMarginBeg is added to the following thresholds : • • amrDirectAllocRxLevDL amrDirectAllocRxLevUL CONCENTRIC CELLS The criteria for a successful direct HR TCH allocation in the outer-zone are : RxLevDL > amrDirectAllocRxLevDL and RxLevUL > amrDirectAllocRxLevUL DUALBAND OR DUALCOUPLING CELLS The criteria for a successful direct HR TCH allocation in the outer-zone are : RxLevDL > amrDirectAllocRxLevDL and RxLevUL > amrDirectAllocRxLevUL DIRECT HR TCH ALLOCATION IN INNER-ZONE, AT CALL SETUP In v17, if using a not fully reliable short average, hoMarginBeg is added to the following thresholds : • • amrDirectAllocIntRxLevDL amrDirectAllocIntRxLevUL CONCENTRIC CELLS The criteria for a successful direct HR TCH allocation in the inner-zone are : Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 83/629 V17.0 BSS Parameter User Guide (BPUG) RxLevDL > amrDirectAllocIntRxLevDL and RxLevUL > amrDirectAllocIntRxLevUL and MS_BS_Dist < concentAlgoExtMsRange (timing advance criterion) DUALBAND OR DUALCOUPLING CELLS The criteria for a successful direct HR TCH allocation in the inner-zone are : RxLevDL > amrDirectAllocIntRxLevDL and RxLevUL > amrDirectAllocIntRxLevUL DIRECT TCH ALLOCATION ON INTER-CELL HANDOVER In v17, if using a not fully reliable short average, hoMarginBeg is added to bizonePowerOffset. If the target cell for handover is a multi-zone cell, the BTS is in charge of indicating to the BSC if a TCH can be allocated in the inner zone of the target cell. This information is provided in the "additional cells information” IEI within Abis Handover indication or Connection state ack messages : This capability (to handover directly in the innerzone/band1 of the adjacent cell) is inhibited when biZonePowerOffset(n) is set to 63. CONCENTRIC OR DUALCOUPLING CELLS The criterion for the inner-zone of the neighbour cell to be eligible is : RxLevNCell(n)ave > rxLevMinCell (n) + bizonePowerOffset (n) + Max(0, msTxPwrMaxCell(n) msTxPwrCapabilityCell(n) ) DUALBAND CELLS The criteria for the inner-zone (band 1) of the neighbour dualband cell to be eligible are : MS supports band 1 of NCell Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 84/629 V17.0 BSS Parameter User Guide (BPUG) and RxLevNCell(n)ave > rxLevMinCell (n) + bizonePowerOffset (n) + Max(0, msTxPwrMaxCell(n) msTxPwrCapabilityCell(n) ) REMARK ON OUTER TO INNER ZONE INTRA CELL HANDOVER It should be noted that the BTS provides the same allocation information to the BSC on an intra-cell handover initiated from a TCH belonging to the Large zone. However, no hoMarginBeg margin applies to allocation thresholds because a Weighted average is always available. 4.8.3 HANDOVERS Each runHandOver, after L1M initialisation process for handover, the BTS performs handover decision process based on regular uplink and downlink measurements on the current cell (level and quality) and neighbouring cells (level only); the main steps of this process are: • Triggering: the BTS detects that a handover is needed by comparison with thresholds: lRxLevXLH for alarm on level; lRxQualXLH for alarm on Quality; msRangeMax for alarm on distance, there is no “triggering” for handover on PBGT Screening: the BTS determines what are the n best suitable cells (n=6 from V12) for the handover (preferred cells list) and sends them to the BSC in the Handover Indication message; to be in the preferred cells list, a cell must first be eligible (eligibility checking) then sorted (Ncells list sorting); the preferred cells list is an ordered list of sorted cells. Selecting: the BSC determines THE target cell according to the resource found after reducing the preferred cells list to a maximum of three elements Executing: allocation, activation, assignment of the new channel, switching onto this channel • • • HANDOVERS TRIGGERING Intercell handover normally occurs for two main reasons: • Rescue handovers: when the MS gets too far from the BS (Distance) and/or radio link measurements show low received signal strength (DL/UL signal Strength) and/or signal quality on the current serving cell (DL/UL signal Quality) Network Optimization Handovers: a better signal strength is available on an adjacent cell (Power Budget), the serving cell gets overloaded (Traffic) or in the particular case of a multilayer network (Capture) • Note: new intercell handover decisions have been introduced for AMR channels Intracell handovers normally occur for the following reasons: • • Interference handover: radio measurements show a low received signal quality but a high received signal strength on the serving cell. inter-zone handover from a "zone" of a multizone cell to another "zone". Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 85/629 V17.0 BSS Parameter User Guide (BPUG) • • frequency tiering handover specific intracell handover for AMR TCH channels, HANDOVERS SCREENING To a given handover is associated (hard coded) a set of expressions used both to check eligibility of a neighbour cell (a cell from the list of Ncells reported by the MS is eligible if all expressions attached to this HO cause and neighbour cell are strictly positive) and to sort target cells list. See the chapter General formulas to get the detail of each expression. According to the handover cause, the candidate cell’s expressions must then fulfil the following formulas to be declared eligible HO cause / connection state request type Eligibility criteria powerBudgetInterCell(n) = true EXP1(n) > 0 Power Budget EXP2PBGT(n) > 0 EXP2bis(n) > 0 deleteCounter(n) < cellDeletionCount(n) trafficInterCell(n) = true EXP1(n) > 0 EXP2Traffic(n) > 0 EXP2bis(n) > 0 ul/dlQualityInterCell(n) = true Traffic UL / DL signal quality EXP1(n) > 0 EXP2Quality(n) > 0 ul/dlSignalStrengthInterCell(n) = true UL / DL signal strength EXP1(n) > 0 EXP2Strength(n) > 0 msBtsDistanceInterCell(n) = true Distance EXP1(n) > 0 EXP2Distance(n) > 0 captureInterCell(n) = true EXP1Capture(n) > 0 interBtsForcedHO(n) = true EXP1ForcedHO(n) > 0 interBsDirectedRetry(n) = true EXP1Directedretry(n) > 0 ul/dlAMRQualityInterCell(n) = true EXP1(n) > 0 EXP2AMR(n) > 0 EXP2bis(n) > 0 Capture Forced HO Directed Retry Quality intercell HO on UL / DL mode for AMR TCH channels Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 86/629 V17.0 BSS Parameter User Guide (BPUG) 4.8.4 HANDOVERS DECISION PRIORITY HANDOVER DECISION FUNCTIONS FOR SDCCH & TCH/F CHANNELS The whole set of HO decision functions currently implemented for non AMR channels, with their priority, is defined in the table below (handover functions are executed in increasing order of priority as shown below): HO decision function Capture UL signal quality DL signal quality UL signal strength DL signal strength Distance Power Budget Traffic Intracell on UL signal strength & quality Intracell on DL signal strength & quality Interband HO (dualband cells) Interband HO (concentric cells) Interband HO (dualcoupling cells) Frequency tiering Directed Retry early HO intercell HO priority comment false false false false false false true false false false false false false false false intercell intercell intercell intercell intercell intercell intercell intercell intracell intracell intracell intracell intracell intracell intercell 1 2 3 4 5 6 7 8 9 10 11 11 11 12 0 (d) (a) (c) (a) (c) (b) (c) (b) (c) (b) (c) (a) (c) (a) intracell and tiering handover functions are exclusive from each other (b) these handover functions are exclusive from each other (a given cell may be of only one type among concentric, dual-coupling & dual-band) and do not apply to SDCCH channels. (c) these intracell handover functions are ihnibited when in directed retry mode. (d) only for a monozone cell or in the large zone of a multizone cell. Note: The so-called "Directed Retry" handover is a "pseudo" handover indication message sent upon request from the BSC. This specific case is mainly intended to provide BSC with a target cells list for intercell HO and is discussed in chapter Directed Retry Handover. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 87/629 V17.0 BSS Parameter User Guide (BPUG) HANDOVER DECISION FUNCTIONS FOR AMR TCH CHANNELS HO decision function Capture quality intercell HO on UL codec mode quality intercell HO on DL codec mode UL signal strength DL signal strength Distance Power Budget Traffic capacity intracell HO on UL / DL codec modes quality intracell HO on UL codec mode quality intracell HO on DL codec mode Interband HO (dualband cells) Interband HO (concentric cells) Interband HO (dualcoupling cells) Frequency tiering Directed Retry early HO intercell HO priority comment false false false false false false false false false false false false false false false false intercell intercell intercell intercell intercell intercell intercell intercell intracell intracell intracell intracell intracell intracell intracell intercell 1 2 3 4 5 6 7 8 9 10 11 12 12 12 13 0 (d) (b) (c) (b) (b) (a) (b) (a) (b) (a) (b) (b) (a) these handover functions are exclusive from each other (a given cell may be of only one type among concentric, dual-coupling & dual-band). (b) these intracell handover functions are ihnibited when in directed retry mode or in dual tranfer mode. (c) this intracell handover function applies to TCH/AFS (Full Rate) channels only. (d) only for a monozone cell or in the large zone of a multizone cell. Note: The so-called "Directed Retry" handover is a "pseudo" handover indication message sent upon request from the BSC. This specific case is mainly intended to provide BSC with a target cells list for intercell HO and is discussed in chapter Directed Retry Handover. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 88/629 V17.0 BSS Parameter User Guide (BPUG) 4.8.5 DIRECTED RETRY HANDOVER After the initial establishment procedure, if the MS is attached to a SDCCH and if there is no TCH resource available, a directed retry handover is required. The following parameters enable this feature: • • • • intraBscDirectedRetry (bsc) interBscDirectedRetry (bsc) intraBscDirectedRetryFromCell (bts) interBscDirectedRetryFromCell (bts) Previously to V15.0, it is mandatory to activate the Queuing when the Directed Retry is enabled. From V15.0, the feature “Directed retry without queuing activation” removes this constraint and allows the activation indepently from queuing. DIRECTED RETRY HANDOVER: BSC (OR LOCAL) MODE This mode is enabled by the bts object parameter directedRetryModeUsed set to “bsc”. Until V9, bsc mode could only be applied from a micro cell towards a macro cell (system rule). One of the adjacent cells is predefined as the one used for directed retry. The adjacentCellUmbrellaRef parameter gives the position of this cell in the neighbor list. CAUTION! In this mode, there is no check of the RF conditions on the predefined target cell before the directed retry HO occurs: the predefined cell must cover the whole area of the current cell. To ensure that the MS is pre-synchronised with the predefined target cell (MS has decoded GSM time and the BSIC), the neighbor cell BCCH must be put in the adjacentCellReselection parameter bCCHFrequency. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 89/629 V17.0 BSS Parameter User Guide (BPUG) DIRECTED RETRY HANDOVER: BTS (OR DISTANT) MODE This mode is enabled by the bts object parameter directedRetryModeUsed set to “bts”. It is used, for example in the case of a high traffic cell covered by several neighbors. When the BSC receives the Assign Request message from the MSC, the BSC requests the BTS through a Connection State Request message to return a list of eligible neighbor cells generated by the following criteria. This list is immediately sent through a Connection State Acknowledgement message to the BSC. If the list is empty, the BTS tries to regenerate it later. As soon as handover conditions are fulfilled for at least one neighbouring cell, the BTS sends the BSC a spontaneous Handover Indication message with the specific cause “Directed Retry”. If RxLevNcell(n) > directedRetry(n) + Max[0, (msTxPwrMaxCell(n) - P)] where P = maximum RF output power of the MS then cell n is candidate for Directed Retry Handover If RxLevNcell(m) = Max(RxLevNcell(n)) then Cell m is chosen by the BSC as the target cell for the Directed Retry HO CAUTION! The Directed Retry criterion is based on only one measurement of RxLevNcell(n) and not on NCellHreqave measurements. In a microcell network, a directed retry HO may handover a call from a macro cell to a micro cell even if the stability criteria is not fulfilled (microcellular handover type A). In this environment, to avoid a ping-pong HO, one may put a high value to the adjacentCellHandOver parameter directedRetryAlgo. DIRECTED RETRY AND QUEUING Before V15.0, queuing must be activated to enable directed retry. In that case, when the BSC receives from the MSC an Assignment Request and there is no TCH available in the cell, then the request is queued and the directed retry procedure is started. The BSC sends to the MSC a Queuing Indication message. • If there is a resource in the target cell, the directed retry procedure is successful and the communication is established, and the resources of the serving cell are released If there is no resource available in the target cell, the directed retry procedure fails and the request remains queued in the source cell until a TCH is available, the timer associated to the queue expires (allocPriorityTimers), a handover indication is received from the BTS and is successfully executed, or other events which lead to the release of the communication (MS is lost, MS disconnect the call …). Nortel confidential • PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 90/629 V17.0 BSS Parameter User Guide (BPUG) • If there is no neighbouring cells indicated by the BTS in the connection state ack message, then the request remains queued in the source cell until a TCH is available, the timer associated to the queue expires, a handover indication (cause “directed retry”) is received from the BTS and successfully executed, or other events which lead to the release of the communication (MS is lost, MS disconnect the call …). In case the request could not be queued (queue full for instance), BSS sends an Assignment failure (cause “no radio resource available”) message to the MSC. From V15.0, as soon as the directed retry is enabled in the BSS, whatever is the queuing activation, the directed retry is processed. In that case, • if queuing is activated, it is the same behavior as before V15.0. The only change is that if the request could not be queued, the directed retry (if allowed) is processed independently from the queuing. If queuing is desactivated, (or if the request could not be queued), then the procedure is as follow: when the BSC receives from the MSC an Assignment Request and there is no TCH available in the cell, then the directed retry procedure is started and the BSC sends to the MSC a Queuing Indication message to inform the MSC of a delay in the TCH allocation, and the MS remains on SDCCH channel. If there is a resource in the target cell, the directed retry procedure is successful and the communication is established. If there is no resource available in the target cell, the directed retry procedure fails and the BSS sends an Assignment failure (cause “no radio resource available”) message to the MSC. If there is no neighbouring cells indicated by the BTS in the connection state ack message, it means that neighbouring cells information are not available in the BTS (it depends also on the MS performances) or handover conditions are not met. Then the BSC starts an internal timer directedRetryWithNoQueuingTimer (5 seconds, non configurable) in order to wait for a handover indication message (cause “directed retry”) the BTS sends if the handover conditions are fulfilled. The BSC processes this handover indication message as described here above. In case the timer directedRetryWithNoQueuingTimer expires, the BSC sends an Assignment failure message (cause “no radio resource available”) to the MSC. • Note: during a directed retry procedure, if there is no TCH available in the target cell, the procedure can neither be queued, nor execute another directed retry from the target cell. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 91/629 V17.0 BSS Parameter User Guide (BPUG) 4.8.6 CONCENTRIC/DUALCOUPLING/DUALBAND CELL HANDOVER CONCENTRIC CELL PRINCIPLES From V9 a cell is defined as concentric if two pools of ressources (TDMAs) are defined using Rxlev and optionally Timing Advance as allocation criteria. One or two types of TRXs can be used. From V12, the concept is enlarged and concentric cell parameter may have 4 possible values: monozone, concentric, dualband or dualcoupling. CONCENTRIC CELL Definition: a cell is defined as concentric if it exists two transceiverzones configured to transmit at different power resulting in two different coverage areas. For the two different transceiverzones, the same antenna is used. Innerzone traffic channels Outerzone BCCH and signalling channels The principle of the concentric cells is to share the ressources in both zones assuming that the TRXs are transmitting at different power. The BCCH and the signalling channels use the high power TRXs (outer zone) thus the BTS needs to check if the link budget MS-BTS is sufficient to allocate a ressource of the inner zone. Furthermore, to avoid a subsequent intracell handover, the BSC is checking this condition with the BTS each time a first TCH has to be allocated at the end of the call setup, i.e an Assign Request has been sent by the MSC. The same checking is done by the curent BTS when an intercell handover is required. The smaller range of the frequencies in the internal zone, due to low maximum available power for transmission, means that these internal zone frequencies can be reused a short distance away. With this greater re-utilization of frequencies an operator can achieve the same coverage using less bandwidth. From V12 functionalities have been deployed allowing an easier frequency planning in case of frequency hopping (fractional reuse techniques), and a major enhancement with the TCH allocation directly in the relevant zone in case of calll setup and handover. Note: a configuration with HePA on the outer zone and ePA on the inner zone is a kind of concentric cell and not a kind of dualcoupling cell, eventhough the biZonePowerOffset parameter has to be set accordingly to that particular case. Please refer to the associated Functional Note [R10] Concentric cell improvements (CM888/TF889). See also chapter Concentric Cells. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 92/629 V17.0 BSS Parameter User Guide (BPUG) DUALBAND CELL Definition: a cell is defined as dualband if GSM900 TRXs and DCS1800 TRXs coexist and share the same BCCH. The propagation loss being different, it results in two different coverage areas. Outerzone Innerzone / band1 band0 DCS (or GSM) traffic channels BCCH and signalling channels GSM (or DCS) Main benefits of dualband cell functionality are: • • • • • The number of cells to configure and monitor is roughly divided by two No BCCH pattern has to be defined in the second band Frequency Hopping, Power Control, Downlink DTX are available on all second band DRX’s (instead of all but one with conventional management) Slight increase in capacity: one TS saving + DCS and GSM DRX’s in one pool, which provides more network control of the traffic distribution Intra cells Handover between DCS and GSM DRX’s of a same cell instead of synchronous inter cell handovers reduce the muting time Please refer to the associated Functional Note [R9] Dual band cells management:TF875. See also chapter Concentric Cells. DUALCOUPLING CELL Definition: a cell is defined as dualcoupling if the TRXs are not combined with the same type of combiner and thus have not the same coupling loss resulting in two different coverage areas. Innerzone H4D traffic channels Outerzone H2D BCCH and signalling channels In a dualcoupling cell, as the TRXs are not combined with the same type of combiner the most powerful TRXs define the large zone. Such cells are managed with the concentric cell principle and dualcoupling cell feature take advantage of it using different coupling modules rather than a mono type coupling module in a sector. Please refer to the associated Functional Note [R11] FN for stepped coupling. See also chapter Concentric Cells. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 93/629 V17.0 BSS Parameter User Guide (BPUG) INTERZONE HANDOVERS FOR CONCENTRIC CELL / DUALCOUPLING CELL LARGE ZONE TO SMALL ZONE The MS is permitted to migrate from the large zone to the small zone if: • • the MS is close to the BTS (Timing Advance used to estimate the MS to BTS distance, only for concentric cells)) and if RF conditions are good enough (RxLev downlink). Note: The transceiverZone object parameter zone Tx power max reduction value is always set to 0 for the large zone, and in the range of [1 to 55]dB for the small zone. The Concentric/Dualcoupling Cell Handover from Large to Small zone is triggered if: RxLev_DL > concentAlgoExtRxLev AND (only for concentric cells) MS_BS_Dist < concentAlgoExtMsRange SMALL ZONE TO LARGE ZONE The MS is handed over from the small zone to the large one if: • • the MS is far from the BTS (Timing Advance, used to estimate the MS to BTS distance, only for concentric cells) or if RF conditions are too bad (RxLev downlink, RxQual uplink and downlink). Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 94/629 V17.0 BSS Parameter User Guide (BPUG) For a non-AMR channel, or an AMR channel with legacy L1M, the Concentric/Dualcoupling cell handover from small to large zone is triggered if: RxLev_DL < concentAlgoIntRxLev OR RxQual_DL > lRxQualDLH OR RxQual_UL > lRxQualULH OR (only for concentric cells) MS_BS_Dist > concentAlgoIntMsRange For an AMR channel with AMR L1M, the Concentric/Dualcoupling cell handover from small to large zone is triggered if: RxLev_DL < concentAlgoIntRxLev OR (only for concentric cells) MS_BS_Dist > concentAlgoIntMsRange OR Quality intercell HO on UL codec mode criterion is satisfied OR Quality intercell HO on DL codec mode criterion is satisfied Please note that an external priority [0...17] can be given to the Concentric Cell Handover from a Small to Large zone, because of the small to large Zone HO priority parameter. INTERZONE HANDOVERS FOR DUALBAND CELLS (FROM V12) Convention: • • if BCCH gsm, then band 0 = gsm, band 1 = dcs and standardIndicator = gsmdcs If BCCH dcs, then band 0 = dcs, band 1 = gsm and standardIndicator = dcsgsm The algorithms created for concentric cell are the same for dualband cells, except the timing advance criterion is not used and the dualband capability of the mobile is checked. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 95/629 V17.0 BSS Parameter User Guide (BPUG) SUMMARY OF CONCENTRIC/DUALCOUPLING/DUALBAND CELL HO Interzone HO: band1 to band 0 Non AMR : rxLevDL < concentAlgoIntRxLev OR RxQual_DL > lRxQualDLH OR RxQual_UL > lRxQualULH OR (only for concentric cells) MS_BS_Dist>concentAlgoIntMsRange AND (only for dual-band cells) MS_Band_supported(standardIndicatorBand0) is true AMR : rxLevDL < concentAlgoIntRxLev OR Quality intercell HO on UL codec mode criterion is satisfied OR Quality intercell HO on DL codec mode criterion is satisfied OR (only for concentric cells) MS_BS_Dist>concentAlgoIntMsRange AND (only for dual-band cells) MS_Band_supported(standardIndicatorBand0) is true Interzone HO: band0 to band 1 1) rxLevDL > concentAlgoExtRxLev 2) (only for dual-band cells) MS_Band_supported(standardIndicatorBand1) is true 3) (only for concentric cells) MS_BS_Dist<concentAlgoExtMsRange Intracell intraband HO: band0 --> band0 or band1--> band1 normal intracell HO Intercell intraband HO: band0 --> band0: normal intercell inter or intra BSS Intercell interband HO: band0 --> band1 1) EXP1(n) + biZonePowerOffset(n) > 0 2) EXP2PBGT(n) > 0 3) MS_Band_supported(standardIndicatorBand1) is true Note : in v17, if only short not fully unreliable averages are available, hoMarginbeg is added to bizonePowerOffset Intercell intraband HO: band1 --> band1 1) EXP1(n) + biZonePowerOffset(n) > 0 2) EXP2PBGT(n) + biZonePowerOffset > 0 where PBGT uses msTxPwrMax2ndBand 3) MS_Band_supported(standardIndicatorBand1) is true Note : in v17, if only short not fully unreliable averages are available, hoMarginbeg is added to bizonePowerOffset Intercell interband HO: band1 --> band0 Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 96/629 V17.0 BSS Parameter User Guide (BPUG) 1) EXP1(n) > 0 2) EXP2PBGT(n) + biZonePowerOffset > 0 where PBGT uses msTxPwrMax2ndBand POWER ADAPTATION AFTER INTERZONE HO In V17.0, the system implements a mechansim to compensate for the power gap between the old and new channel channels in the inner (or outer) and outer (or inner) zones immediately after a handover. Please refer to the section Power adaptation after an interzone ho (V17). Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 97/629 V17.0 BSS Parameter User Guide (BPUG) 4.8.7 RESCUE HANDOVER INTRACELL HANDOVER DECISION FOR SIGNAL QUALITY The interferences are generally related to a specific TDMA. When signal quality is bad but signal strength is sufficient, the BSC allocates another channel in the current cell. Condition to be fulfilled is: (((RXLEV_UL > rxLevULIH) AND (RXQUAL_UL > rxQualULIH)) OR ((RXLEV_DL > rxlevDLIH) AND (RXQUAL_DL > rxQualDLIH)) Thresholds should be set in order to ensure good subjective voice quality (rxqualXLIH 5 with frequency hopping or rxqualXLIH 4 without hopping). This feature is enabled by intraCell or intraCellSDCCH flags. CAUTION! In order to avoid the choice of a more interfered channel, channels are allocated in the 2 low interference pools (hopping and not hopping); if no free channel is detected among these 2 pools and although queuing is allowed, the intracell HO must not be done; if queuing is allowed, the request is queued then satisfied only after reception of suitable interference level on idle channels (RF_RESOURCE_INDICATION message); when TDMA removals leads to intracell HO, the first free resource is taken whatever its interference level. Note: RF_RESOURCE_INDICATION message is received from BTS and induces the interference level of channels of a particular TDMA. Therefore a channel has 3 states for the BTS: • • • Busy Free with interference measure level available Free without interference measure level available (for example the channel has just been release and the measure are not yet done) No interference level management is performed on PDTCH channels. The level status of PDTCH resource is always high (bad level). So intracell HO is not performed on PDTCH Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 98/629 V17.0 BSS Parameter User Guide (BPUG) HANDOVER CONDITION FOR LEAVING A CELL ON RXQUAL There is no parameter to disable this feature but this can be done by assigning thresholds rxqual maximum value (7). Thresholds should be set in order to ensure good subjective quality (rxqual 5 with frequency hopping or rxqual 4 without hopping). This handover is triggered when quality exceeds signal quality thresholds: (RXQUAL_DL > lRxQualDLH) OR (RXQUAL_UL > lRxQualULH) HANDOVER CONDITION FOR LEAVING A CELL ON RXLEV There is no parameter to disable this feature but this can be done by assigning threshold RxLev minimum value (-110 dBm). This handover is triggered when the signal strength falls below the following thresholds: (RXLEV_DL< lRxLevDLH) OR (RXLEV_UL < lRxLevULH) HANDOVER CONDITION FOR LEAVING A CELL ON DISTANCE This feature is enabled by the msBtsdistanceIntercell parameter. MS_BS_Dist > MsRangeMax Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 99/629 V17.0 BSS Parameter User Guide (BPUG) 4.8.8 POWER BUDGET HANDOVER POWER BUDGET FORMULA If powerBudgetInterCell parameter is set to “enabled” (handover on Power Budget is allowed), the following formula is used to determine handover condition for power budget reason. This handover is preventive and ensures best allocation of a serving cell for a given communication. The formula used to determine handover condition for power budget reason is: EXP2PBGT(n) = Pbgt(n) - AdaptedHoMargin(n) AdaptedHoMargin(n) is the margin computed when AHA feature is enabled. It takes into account neighDisfavorOffset and servingfactorOffset parameters (see chapter Automatic handover adaptation) MINIMUM TIME BETWEEN HANDOVER From V12 this feature is replaced by the General protection against HO ping-pong feature. However, in order for the new feature to be enabled the timeBetweenHOConfiguration parameter must be set to “used”, and the bts Time Between HO configuration parameter must be set to “1”. 4.8.9 HANDOVER FOR TRAFFIC REASONS (FROM V12) This feature introduced in V12 aims at improving the network behaviour when one or several cells are overloaded by attempting to redirect the most appropriate calls in progress to neighbour cells with a PBGT handover procedure. Please refer to the associated Functional Note [R12] Handover for traffic reasons: TF132. See also chapter Handover for Traffic Reasons Activation Guideline. This feature is enabled by the new BSC object parameter hoTraffic and by the new BTS object parameter hoTraffic. For each neighboring cell of the cell (adjacentCellHandover object), a parameter is defined: hoMarginTrafficOffset is the offset to (negatively) apply to the hoMargin parameter linked to the power budget when the cell status becomes overloaded (if 0, the handover for traffic reason is not allowed for this adjacent cell). This features relies on the definition of the overload condition ; a cell overload condition can only be determined by the radio resource allocator when the detection mechanism is activated; it is activated as soon as the handover for traffic reasons feature or the Barring of access class feature is authorized. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 100/629 V17.0 BSS Parameter User Guide (BPUG) This overload detection mechanism is based on the number of free TCH or the number of queued TCH requests in the cell ; TCH resources reserved for maximum priority requests are not taken into account ; in a concentric cell, TCH resources of the small zone are not taken into account (no queuing procedure in the small zone) ; in a dualband cell, TCH resources of the band1 are not taken into account (no queuing procedure in the band1) ; no more operator warning is sent at the beginning and the end of the overload phase. The overload begins when: the number of free TCH <= numberOfTCHFreeBeforeCongestion OR the number of queued TCH requests >= numberOfTCHQueuedBeforeCongestion The overload ends when: the number of free TCH >= numberOfTCHFreeToEndCongestion OR the number of queued TCH requests <= numberOfTCHQueuedToEndCongestion When the cell status becomes overloaded, a request is done to the L1M to consider a new ho_margin (hoMargin-hoMarginTrafficOffset) ; this request is sent only to the TRXs which belong to the large zone/band0 (for concentric/dualband cells). In case of intra BSS handover (for traffic reasons), the BSC checks the target cell status during the handover selection phase and if overload condition is set, the BSC will try on the following cell of the list (a handover between the band0 of a serving cell and the band1 of a target cell is possible if the eligibility of band1 is indicated in the handover indication message). In case of inter BSS handover (for traffic reasons), the target cell overload status is not known until the HO procedure is launched (HO request). Also, a handover between the band0 of a serving cell and the band1 of a target cell is not possible (due to the present A interface). It is advised to set the General protection against HO ping-pong feature with this feature in order to overcome the associated risk of ping-pong. CAUTION! This feature is not applicable for S4000/S2000E-DCU2 or S4000/S2000E-DCU2/DCU4. This feature is applicable for all cases where PBGT handover is possible; so, handover for traffic reasons is not possible between microcell and macrocell. This feature is applicable to concentric/dualband cells but is restricted to the large zone/band0 since the thresholds used to define the overload conditions concern the large zone/band0 ; if a handover indication is received by the BSC with a cause set to traffic reasons and concerns a communication established in the small zone/band1 of the cell, the message is discarded. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 101/629 V17.0 BSS Parameter User Guide (BPUG) This feature is not applicable to a network which sets all the TCH request priorities to the maximum priority since the cell is always overloaded whatever are the cell overload thresholds. Since the handover for traffic reasons feature uses the PBGT handover procedure, the powerBudgetInterCell parameter shall be set to “true” (the BSC does not control this flag to modify the hoMarginTrafficOffset). The BTS never transmits the Handover for traffic reasons if this flag is not set. There is no standby chain updating for the cell overload status ; thus, in case of switch-over, the L1M value for hoMarginTrafficOffset is set to 0 and the cell is no longer overloaded. About hoMarginTrafficOffset setting: Typically, when hoMargin is reduced by 1dB (which implies that hoMarginTrafficOffset=1 dB), this affects around 13% of the mobiles, assuming that cell overlapping is larger than the hoMargin; roughly: • • • 1dB of power reduction decreases the cell radius by 6.8% thus the cell coverage by 13% 2dB of power reduction decreases the cell radius by 14% 3dB of power reduction decreases the cell radius by 21.9% If hoMarginTrafficOffset is set to 0 dB, the HO traffic is somehow disabled since PBGT will be done before the traffic has a chance to be done (higher priority). Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 102/629 V17.0 BSS Parameter User Guide (BPUG) 4.8.10 HANDOVER DECISION ACCORDING TO ADJACENT CELL PRIORITIES AND LOAD (FROM V12) The objective of this feature is to optimize the traffic distribution both between layers according to cell priorities and cells of the same layer according to their overload conditions. In the selection phase, the BSC places the cells in descending order according to their priority and if cells have the same priority, the order given in the “handover indication” message is maintained. Then, for those cells, the BSC calculates the following expression: EXP4(n) = EXPi(n) – [offsetLoad(n) * stateLoad(n)] where EXPi(n) = EXP1(n) for the handover causes capture or directed retry in distant mode or EXPi(n) = EXP2(n) for other causes EXP1 or EXP2 are added in the “handover indication” message from V12 ; offsetLoad(n) is a neighbour cell parameter in dB and stateLoad is an overload status parameter. stateLoad=1 for an intra BSS neighbor cell which is overloaded and 0 otherwise, including an inter BSS neighbor cell overloaded ; the BSC sorts the cells that have the same priority by decreasing values of EXP4 before reducing the preferred cells list from six to three. offsetLoad(n) corresponds to the new offsetLoad parameter, offsetPriority defines the range of the priority from 1 to 5 (1 is the highest level). The overload detection relies on the same principle as that described in the Handover for traffic reasons feature. If the overload detection is not activated, obviously, the priority is the only criterion which is taken into account. With such an algorithm, it can be noticed that the priority parameter is an important criterion in a multi-layer network and that the overload situation is an important criterion in a network where the cells have the same priority. For multi-layer networks, a problem may occur when the higher priority cell (which captures traffic) becomes consequently overloaded and then induces HOs for traffic in the other adjacent cells ; this can be awkward when the overlapping area between the higher priority cell and its adjacent cells is wide ; in such a case, too much traffic is captured and this prevents from doing new calls in this cell. In a network where the cells have the same priority, another problem could be noticed: the overload condition of adjacent cells is not managed in a uniform way if the adjacent cells do not belong to the same BSC ; the overload condition for cells belonging to another BSC is not considered and may induce longer handover procedure if this one is overloaded. Indeed , the overload state will only be known when the HO is triggered. Then, if the cell is overloaded, the request will be refused and the BSC will try the next cell on the list of preferred cells. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 103/629 V17.0 BSS Parameter User Guide (BPUG) 4.8.11 AUTOMATIC CELL TIERING (FROM V12) PREREQUISITE It requires the implementation of L1mV2 and is exclusively applicable to fractional reuse pattern networks (see chapter Frequency Hopping). GOAL The frequency tiering technique aims at decreasing the global interference level in a fractional reuse pattern network and offers efficient traffic management at a TRX level through the selftuning system at the BTS EXPECTED GAINS The main benefits expected are: • A large capacity increase: The cell tiering increases the fractional load capabilities, therefore, permits bigger BTS configurations with the same amount of available frequencies.). In a 1x1 network, the fractional load can go up to 33.3% and up to 100% in 1x3. A better network quality (worst communications, typically at the cell boundary, do no longer corrupt other communications). The reduction of the global level of interference may also significantly decrease the global number of dropped calls and other faults in particularly loaded networks. A better uplink/downlink balancing (the uplink interference cancellation gain is balanced by a significant downlink cell tiering improvement) • • PRINCIPLES The mechanism relies on simple dynamic resources allocation strategies that are intended to allocate the worst communications, in terms of downlink Carrier on Interference ratio (CIR), to the non-hopping frequencies (like BCCH), taking advantage of their larger reuse pattern and consequently of their better resistance to interference, while the best communications are driven to the hopping frequencies. Evaluation of the calls is based on a ratio (in Watts) of the RxLevDL measured for the serving cell over the sum of RxLevNCell measured for the BCCH of each neighbour, weighted according to the type of interference brought (adjacent or co-channel). This evaluation, called Potential Worst C/I (PWCI), potential because it does not include the frequency hopping gain, is meant to simulate what the interference on the small pattern would be like. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 104/629 V17.0 BSS Parameter User Guide (BPUG) The PWCI is computed by the BTS for all the calls in progress in the cell and arranged into an averaged PWCI distribution that provides 2 handover decision parameters: lCirDLH (low) and uCirDLH (high): • • lCirDLH is the abscissa corresponding to an ordinate of P% (percentage of TCH resources in the large pattern) on the averaged PWCI distribution curve. uCirDLH is determined from: uCirDLH = lCirDLH + hoMarginTiering In V12 P% is calculated as follow: P%= Number of non hopping TCH - nbLargeReuseDataChannel Total number of TCH in the cell - nbLargeReuseDataChannel In V14, with AMR introduction P% is now calculated as follow: P%= (Number of non hopping TCH – nbLargeReuseDataChannel) * (1 + Non_FH_HR%) (Total number of TCH in the cell – nbLargeReuseDataChannel) * (1 + HR%) • • FH_HR% is the percent of HR calls managed by the hopping pattern in the cell, HR% is the percent of HR calls managed in the cell. The tiering handover decision can be summarised as: • • If PWCI > uCirDLH => HO is performed from large to small pattern If PWCI < lCirDLH => HO is performed from small to large pattern The number of values required to trace the PWCI distribution curve may be modified via MMI with the numberOfPwciSamples parameter (whereas cell tiering HO thresholds cannot be tuned via MMI). The lCirDLH is defined from the available traffic channels (i.e. TCH & PDTCH) in the non hopping layer (because these one will be allocated to communications with worst PWCI). In order to manage speech and data interworking, the averaged number of TCHs reserved for data is defined with the nbLargeReuseDataChannels parameter. To avoid the introduction of new configuration parameters or thresholds required by such a function, the associated selfTuningObs functionality enables to set tiering working parameters at their most relevant values, fitting with cell real radio profile and dynamically adapted to O&M events or radio environment modifications ensuring that the gains of the tiering strategy are always optimum. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 105/629 V17.0 BSS Parameter User Guide (BPUG) Formula of PWCI in Watts: PWCI= With • • RxLevDL Watts SUM [RXLevNCell (i)] Watts SUM [RXLevNCell (j) - ADC] Watts • • RXLEV(0) the DL signal strength in Watts received from the serving cell, re-scaled at maximum power (RxLev_DL + BS_Att) RXLEV (i) is the level in Watts measured on the BCCH of a neighbor cell using the same TCH frequencies set as the current cell. These neighbors generate cochannel interferences. RXLEV (j) is the level in Watts measured on the BCCH of a neighbor cell using a TCH frequencies set different from that of the current cell. These neighbors generate adjacent channel interferences. ADC corresponds to the first adjacent channel protection factor which is fixed in the BTS software typically to 18dB The PWCI value is the same whatever the effective load. COMPATIBILITY WITH MULTIZONE CELLS With concentric/dualband/dualcoupling cells, ACT is only applicable within the large zone. Indeed, the tiering handover decision relies on the following algorithm: • IF the TDMA bearing the considered channel belongs to the small pattern AND does not belong to the small zone of a multizone cell: IF pwCi < lCirDLH THEN the channel will be put on the large pattern • IF the TDMA bearing the considered channel belongs to the large pattern (which implies that it belongs to the large zone): IF pwCi > uCirDLH THEN the channel will be put on the small pattern Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 106/629 V17.0 BSS Parameter User Guide (BPUG) In this case, P is computed by considering exclusively the resources in the large zone (hopping as well as non hopping). In order to perform a tiering handover, the communication must be in the large zone and there must be fractional reuse in it. The large pattern will only be the BCCH frequency (the other TRXs in the large zone must hop) and the communication will stay in the Large zone. CELL TIERING MONITORING The PWCI statistics and uCirDLH/lCirDLH may be transmitted on the Abis interface according to the selfTuningObs parameter; these statistics are available independently of the activation of the feature. The hoRequiredTch counter C1138 has 2 new screenings (tiering handover from large to small pattern and tiering handover from small to large pattern) ; two new counters are added: C1802 (hoSuccessTieringTch) and C1801 (hoFailureTieringTchNorr) with 2 screenings each (0: large pattern to small pattern & 1: small pattern to large pattern). The table below gives indicative values for the time required to gather nbPwCISamples measurements for different cell configurations, assuming the average TCH occupancy rate is 75% and that one TCH provides 1 PwCI measurement every 480 ms which is roughly 2 PwCI measurements per second: Cell configuration O2 (14 TCH) O4 (29 TCH) O8 (59 TCH) O16 (121 TCH) 20000 nbPwCISamples 60000 nbPwCISamples # 16 min # 8 min # 4 min # 2 min # 48 min # 24 min # 12 min # 6 min The time required to reach a sufficient statistics as well as the time between two consecutive tiering threshold updates depends on the number of samples required, and the capacity (number of TCH) and load of the cell. So a way to decrease the period between 2 consecutive threshold updates is about the half of the time required to reach a first reliable statistics. CAUTIONS Because it takes advantage of BTS O&M centralization, this feature applies also to 2G products (equipped exclusively with DRXs). The activation of this feature implies a previous activation of the L1mV2. The statistics (for PWCI) are not kept during upgrade and must be gathered again after the site reconfiguration. Intracell handover for quality and intracell tiering handover are exclusive (choice managed with the intracell parameter of the handOverControl object). For mobiles at cells boundaries, if for PBGT reasons, a handover is decided towards a new cell on a hopping TCH, a subsequent handover for tiering reasons will be possible towards a non hopping TCH and so on, so Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 107/629 V17.0 BSS Parameter User Guide (BPUG) inducing a risk of ping-pong handovers ; this drawback will be avoided with the well tuning of hoMarginTiering parameter. No tiering handover decision is possible if the TDMA bearing the current TCH belongs to the small zone/band1 of a multizone/dualband cell. If tiering is activated, no tiering decision is undertaken by the BTS as long as a reliable statistics has not been gathered (minimum nbPwCISamples for PWCI measurements); field experiments have shown that at least 20000 PWCI samples are needed. In V12, statistics are not maintained on the BCF passive chain. The cell tiering configuration relies on a correct definition of interferes for each cell (through interfererType). This feature is based on values of PWCI that depend on the overlap, the available spectrum and the sites' density but neither on the traffic nor the fractional load. However, when the traffic is low, there are fewer samples than at the busy hour and the PWCI distribution is therefore a touch less relevant. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 108/629 V17.0 BSS Parameter User Guide (BPUG) 4.8.12 MICROCELLULAR HANDOVER HANDOVER PECULIARITIES IN MICROCELL ENVIRONMENT Microcellular algorithms were initially defined to avoid issues due to fast moving mobiles connected to microcells. People thought that fast moving mobiles would not have enough time to receive handover information coming from the network or would jump some microcells. To avoid communication failures, specific handover algorithms were defined to send fast moving mobiles to the macro layer. However, experiments performed on several microcellular networks demonstrated that fast moving mobiles linked to outdoor microcells do not present any issues. Microcellular algorithms are used mainly to split traffic loads on the two layers, regardless of mobile speed. Most microcellular algorithms are based on a “capture” threshold. Mobiles linked to a macrocell perform a handover towards the micro layer as soon as the field strength received from a microcell is sufficiently high (whatever the field strength received from the macrocell) for a sufficient duration. The microcellular handover algorithm type A is also based on the stability of the signal. Before V12, with L1mV1, the stability was checked on the best neighbouring microcell, now L1mV2 launches in parallel the confirmation process for the 6 best microcells. L1mV2: Selection of the 6 best microcells MS stability check on these 6 microcells Selection of the 6 new best microcells (transmitted to BSC) Handover execution MICROCELLULAR ALGO TYPE A The following table describes permitted handover causes according to the type of the serving cell and the neighbor cell. Note: the traffic handover is only possible from a large zone (or monozone). The capture handover algorithm can only be defined from a macrocell to a microcell. However the type of a cell is defined relative to the type of the neighboring one. It means that the type of a cell A can be a macrocell from the cell B point of view but can be a microcell from the cell C point of view. This way, it is possible to use the capture handover algorithm on both sides, macrocell to microcell and microcell to macrocell. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 109/629 V17.0 BSS Parameter User Guide (BPUG) Neighbour cell cellType [adjacentCellHandover] normalType umbrellaType microType signal quality signal strength distance normalType signal quality signal strength distance power budget traffic directedRetry (BTS mode) forced handover signal quality signal strength distance power budget traffic directedRetry (BTS mode) forced handover signal quality signal strength distance power budget traffic directedRetry (BTS mode) forced handover power budget traffic directedRetry (BTS mode) forced handover Serving cell cellType [bts] signal quality signal strength distance umbrellaType power budget traffic directedRetry (BTS mode) forced handover signal quality signal strength distance power budget traffic directedRetry (BTS mode) forced handover capture directedRetry (BTS mode) forced handover signal quality signal strength distance directedRetry (BTS mode) forced handover signal quality signal strength distance power budget traffic directedRetry (BTS mode) forced handover microType However the Type A handover algorithm has not been specifically defined to perform handovers from microcells to the macrocell layer. A timer linked to that algorithm is tunable via the microCellCaptureTimer parameter. That timer prevents the BSC from doing a handover on capture reason during a fixed period. See also General formulas for the capture expression: EXP1Capture(n) = RxLevNCell(n) ave - rxLevMinCell(n) Furthermore a strength level stability Criterion (microCellStability) has to be respected before triggering a handover toward the microcell. While microCellCaptureTimer(n) goes on, if a normal handover decision is verified, a handover towards a cell of the same type or a normal cell is allowed. While a handover is decided, the list of eligible cells is provided at each runHandover (microCellCaptureTimer (n) is not reinitialised). The threshold microCellStability(n) must be put previously to 63 dB. This value ensures that a handover is performed as long as the field strength received from the neighbor cell is higher than the “capture” threshold. The value can then be reduced case by case. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 110/629 V17.0 BSS Parameter User Guide (BPUG) CAUTION! The microcellular feature is an OMC-R option (must be activated at OMC-R installation). From V15.1 and thanks to the Advanced Speech Call Items Evolution functionality (refer to [R30]) the range of the microCellCaptureTimer has been modified. Initially that modification was designed for GSM-R applications: microcellCaptureTimer at 500s is to avoid to be captured by a railway station cell for a communication established in the train and thus to avoid that an on going communication from a train arriving in a railway station with no stop, is captured by the railway station cells and when leaving the railway station, leads to a new handover to the railways track cells. Before V15.1 microCellCaptureTimer, on adjacentCellHandover object, has a range [0 … 255] which means a maximum of about 255 * runHandOver (runHandOver is expressed in multiples of 480 ms for SACCH frames and multiples of 470 ms for SDCCH frames) for a communication, before being captured by a neighbouring cell which has a minimum and a stable rxlev during this period. The request consists in increasing the range of this parameter, so as it is kept as it is, but the meaning of specific values are changed to give them greater values (conversion to a value greater than 255). microCellCaptureTimer value received by the BTS microCellCapture value used by the BTS for the computation (number of reporting period x*480ms) 0 to 249 250 251 252 253 254 255 0 to 249 512 1024 2048 4096 8192 16384 245 s 491 s 983 s 1966 s 3932 s 7864 s This table is applicable for a runHandOver = 1. If runHandOver = 2, then 491 seconds are obtained with MicrocellCapture value set to 250. Note: if the Handover on SDCCH feature is activated, the timer must be computed by multiplying the BTS used value by 470 ms. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 111/629 V17.0 BSS Parameter User Guide (BPUG) 4.8.13 FORCED HANDOVER This feature is used to force a handover towards neighboring cells. If a cell is to be shut down, forcing handovers avoids dropped calls. It has to be used in addition to the soft blocking feature (barring of incoming Handover, barring of new calls). Through a Connection State Request message, the BSC requests that the BTS sends it a list of eligible neighbor cells. This list, immediately sent through a Connection State Acknowledgement message to the BSC, is generated by the following criteria: EXP1Forced HO =(n) RxLevNCell(n) ave - [forced handover algo(n) + Max(0, msTxPwrMaxCell(n) - msTxPwrCapability(n)] By putting a low value to forced handover algo(n) , the HO becomes easier: the cell is released more rapidly. CAUTION! A forced HO is possible after a certain communication duration: duration = Max( rxQualHreqave * rxQualHreqt, rxLevHreqave * rxLevHreqt, rxNCellHreqave). Therefore, when integrating this feature in the soft blocking procedure, the operating mode is the following: • • • soft blocking, wait a certain time (20 seconds), trigger the forced HO. There is only one attempt per cell. Another reason to use a Forced HO with soft blocking is that a Forced HO may interrupt a Directed Retry HO (if the Connection State Request message of the Forced HO arrives before the Handover Indication cause Directed Retry message). One must wait a period of time after the soft blocking so that all calls have time to move from SDCCH channels to TCH channels. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 112/629 V17.0 BSS Parameter User Guide (BPUG) 4.8.14 EARLY HANDOVER DECISION PROBLEM DESCRIPTION The time for a mobile to reselect a cell in idle mode is quite long. So, a mobile can start a communication while camping in another cell, leading to a call drop in the worst case. cell A actually selected cell B cell A End of last call Beginning of new call If the reselection algorithm execution occurs close to the border of cell A the mobile can setup a call a short moment after in the cell B while the cell A is still selected. Unfortunately, the MS has to wait a certain period of time before being able to make an handover. The system has to perform some measurements before taking some handovers decisions. This period of time is quite critical, there are some risks of call drop because of the low level of the signal. Another issue is concerned by this feature ; that is the problem of a mobile turning at a street corner, when the RxLev suddenly decreases in the serving cell and increases for a neighbour cell. FEATURE DESCRIPTION The principle is not to speed the selection process but to allow a handover on PBGT quicker. Cell A 1 Risk of call drop 2 3 1 sel/reselection algo execution 2 call setup in cell A 3 HO toward cell B Cell B Time Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 113/629 V17.0 BSS Parameter User Guide (BPUG) From V11, two shorter averages are defined for the level of the serving cell (rxLevHReqaveBeg) and for the level of the neighbouring cells (rxLevNCellHReqaveBeg). The L1M will use this new shorter averages at the beginning of the call until Max (rxLevHreqave*rxLevHreqt, rxQualHreqave*rxQualHreqt) is reached and after loss and recovery of BSIC. So from V11, the L1M must only wait: • • shorter level arithmetic average of serving cell (rxLevHReqaveBeg) shorter level average of the neighbouring cell (rxLevNCellHReqaveBeg) Therefore, the handover can be performed more quickly and with less measurements. The principle is not to speed the selection process but to allow a handover on PBGT quicker. It allows to reduce the zone which represents the critical period of time. The first impact of this feature is to reduce the probability of establishment failure and the call drop ratio. A third parameter has been created (HOMarginBeg) in order to compensate the lack of measurements by increasing the HOMargin. The parameter rxLevNCellHReqaveBeg is used each time a new cell is detected by the mobile. Therefore, it increases the system reactivity. EXP2PBGT(n) early = Pbgt(n) - [hoMargin(n) + hoMarginBeg(n)] UNTIL Max(rxLevHreqave * rxLevHreqt, rxQualHreqave * rxQualHreqt) is reached 4.8.15 MAXIMUM RXLEV FOR POWER BUDGET One of the issues to solve, in a microcellular network, is street corner (cross road) environment: In case of mobile moving straight the cross road (two orthogonal cells A and B), a handover for Power Budget may be processed from cell B to cell A. Once the cross is passed, the mobile is handed again over the cell B. This ping-pong handover shall be avoided as useless handover leads to voice quality degradation and signalling increase. Another advantage of this feature is the possibility to reduce unnecessary handovers at border of Location Area, interBSC or interMSC HO. In this case the need to perform Power Budget handovers is diminished against the extra load on NSS and the voice quality. The feature provides a solution by preventing handover for power budget from the serving cell if the RXLEV downlink serving cell level exceed a specific threshold To prevent handovers for power budget from the serving cell if the RXLEV downlink serving cell level exceed a specific threshold (rxLevDLPBGT), the following expression used in combination with existing cell selection criteria is actually: RXLEV_DL < rxLevDLPBGT Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 114/629 V17.0 BSS Parameter User Guide (BPUG) 4.8.16 PRE-SYNCHRONIZED HO During an asynchronous handover, the MS repeats the HO access bursts until it receives the physical information message containing the timing advance of the new cell. So the speech cut duration may last as long as the MS receives the new TA (Timing Advance) applied in the new cell. The pre-synchronized handover feature allows a Phase 2 MS to make a synchronized handover between two (2) cells not belonging to the same site but managed by the same BSC. The procedure is the same as for an intra-site synchronized handover, excepted that the TA is set in advance and is transmitted to the MS at the beginning of the HO procedure. CAUTION! Only intra BSC synchronized handover are possible. There are two possibilities to set the timing advance in case of pre-synchronized HO: Presynchro with default value or with a determined Timing Advance. Two parameters are impacted in the adjacentCellHandOver object to enable this feature: • • synchronized is set to the value “pre sync HO, with timing advance” or “pre sync HO,default timing advance”. preSynchroTimingAdvance indicates the value of the TA. By comparing not synchronized handovers with synchronized handover, a phonetic gain from 20ms to 40 ms is expected. This is due to the Physical_Info message suppression, which is not necessary because on pre-synchronized handover, the timing advance value is carried by the Handover_Command message. Moreover, only four Handover_Access messages are used on pre-synchronized handover instead of more than four in case of not synchronized handover. 4.8.17 RADIO CHANNEL ALLOCATION The radio channel allocation is based on the interference levels computed on the BTS free channels (SDCCH and TCH). Every averagingPeriod the BTS sends RF RESOURCE INDICATION messages to the BSC. These messages are related to one TRX and contain the level of interference of the free channels. These interference levels are classified into one from the five possible interference bands (thresholdInterference parameter). In each of the five bands, the resources are sorted from the least to the most recently used. At the BSC level the free channels are divided into two new groups depending on whether their interference level is above or below the RadChanSellIntThreshold value. Each group is itself divided into two sub-groups, depending on whether the resource supports the Frequency Hopping. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 115/629 V17.0 BSS Parameter User Guide (BPUG) CAUTION! • If, during three (3) successive RF RESOURCE INDICATION messages, an incoherency is noticed at the BSC level concerning the avaibility of a radio channel, the channel is released and is returned free to the allocator. • When a resource is released upon a call termination, it always returns to the pool of worst interference level, whatever its level before the allocation. The next measurement received from the BTS for this resource will be used to update the level and, consequently, to find the appropriate pool. • The inner zone of a concentric cell does not support SDCCH channels. Till V11, although they belong to the same cell, TCH pools for the inner zone are separated from the same pools of the outer zone, and there are no possible channel exchanges between the two zones. • When a SDCCH is requested and no SDCCH is available, the external priorities are considered as a TCH can be allocated instead of a SDCCH, following the TCH allocation principles. • If a TCH is requested and the priority threshold is reached, only priority 0 requests will be served. Other priorities will generate negative responses from the allocator. 4.8.18 DEFINE ELIGIBLE NEIGHBOR CELLS FOR INTERCELL HANDOVER (EXCEPT DIRECTED RETRY) When an intercell handover is required, the BTS sends a list of at most n best suitable cells (n=6 from V12) according to EXP1 and EXP2 formulas. The following diagram shows an example of cell interlapping produced by different values of lRxLevDLH (threshold out of Cell A) and rxLevMinCell (threshold in Cell B, assuming it is a 2W mobile and msTXPwrMaxcell is set to 33dB). If values are too restrictive, then Cell B will not be considered as an eligible cell for handover and the call might be dropped. This might be the case especially in rural areas where cells have little overlap. Putting a high value for rxLevMinCell(n) or a high value for msTXPwrMaxCell(n) results in restricting access to that cell (see following diagram). Cell A lRxLevDLH -100 dBm HO 1 -98 dBm Cell B rxLevMinCell (B) -95 dBm HO 2 -92 dBm There is a different margin for each handover cause: hoMarginDist, hoMarginRxLev, hoMarginRxQual (can be negative), hoMargin (for power budget), thus compliance to that formula becomes mandatory i.e a handover can only be performed towards a neigbourCell for which the (PBGT(n) - hoMargin(dist, rxqual, rxlev)) is positive. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 116/629 V17.0 BSS Parameter User Guide (BPUG) 4.8.19 HANDOVER TO 2ND BEST CANDIDATE WHEN RETURN TO OLD CHANNEL This feature is triggered by a handover failure during the execution phase. If hoSecondBestCellConfiguration = 1 then no HO attempt to 2nd best candidate cell If hoSecondBestCellConfiguration = 2 then HO attempt to 2nd best candidate cell If hoSecondBestCellConfiguration = 3 then HO attempt to 2nd best candidate cell and to 3rd best candidate cell (if the HO attempt to 2nd best candidate cell fails) When the HO attempt towards the last candidate fails, the bssMapTchoke starts at the BSC. At the expiry of the timer, the BSC asks the BTS to provide a new list of eligible cells. 4.8.20 PROTECTION AGAINST RUNHANDOVER=1 The objective is to get a more responsive handover detection mechanism. To reach this goal, the HO algorithm shall be run every 480 milliseconds (i.e runHandover =1 SACCH period). This feature is useful for call drop rate improvement. With this configuration (runHandover=1), a protection shall be implemented to avoid BSC overload. In case of saturated network (no free TCH) the request for handover (HO-Indication message) will be repeated every 480 ms by the BTS, even if the target cell list has not changed. This could cause SICD overload problems at the BSC. Although the BSC is protected against this, such a situation should be avoided as much as possible in order not to disturb cells not concerned by the congestion situation that could also be supported by the overloaded SICD. As a consequence, the HO_Indication shall be repeated every 2 SACCH periods (1 second) in case of run HO = 1. If the content of the “preferred cell list” IE is modified (i.e. the content or the order of the cell list), the HO_IND message shall be repeated every runHandover (even if runHandover=1). In addition to that, the HO_IND message has also to be sent if the reason for handover has changed, for the reason that there is no “preferred cell list” IE in case of intracell handover for example. The value of 1 second is justified by the fact that existing operational networks are currently working with the value of runHandover=2, and therefore no strongest protection is needed. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 117/629 V17.0 BSS Parameter User Guide (BPUG) 4.8.21 GENERAL PROTECTION AGAINST HO PING-PONG (FROM V12) This feature allows to easily solve some ping-pong handover problems (like ping-pong after directed retry or ping-pong microcell -> macrocell -> microcell or ping-pongs already managed by the previous feature Minimum time between Handover). It is enabled by the BSC object parameter timeBetweenHOConfiguration and by the BTS object parameter bts Time Between HO configuration (0 means “not used” and value greater than 0 means “used”). For each neighboring cell of a cell (adjacentCellHandover object), two new (from V12) parameters are defined: hoPingpongCombination defines up to four combinations (incoming cause, outgoing cause) used in order to define forbidden handovers during hoPingpongTimeRejection seconds for all combinations. When the BSC receives from the BTS a Handover Indication, it calculates the time spent in the cell since the last handover (named connection_time) and removes from the preferred cells list the eligible cells for which the connection_time is lower than the corresponding timeRejection and for which the combination (incoming cause, outgoing cause) corresponds to a combination defined in HOPingpongCombination. The incoming causes may be: RXLEV (indifferently for uplink and downlink), RXQUAL (indifferently for uplink and downlink), DISTANCE, PBGT, CAPTURE, DIRECTED_RETRY, O&M (for forced handovers), TRAFFIC, AMRQUALITY, ALL (if the incoming cause matches all the preceding causes), ALLCAPTURE, ALLPBGT. The outgoing causes may be: • • • • • • • • • • • RXLEV (indifferently for uplink and downlink) RXQUAL (indifferently for uplink and downlink) DISTANCE PBGT CAPTURE O&M (for forced handovers) TRAFFIC AMR QUALITY ALL (if the incoming cause matches all the preceding causes) ALLCAPTURE (if the outgoing cause matches the CAPTURE cause for all the microcells belonging to the current macrocell) ALLPBGT (if the outgoing cause matches the PBGT cause for all the neighboring cells of the current cell ; this cause can be used to restore the “Minimum time between handovers” feature used from V9 to V11). This feature works even if the BSC V12 is in front of BTS V11 or V10. AMR QUALITY cause has been introduced in V14.3 fro AMR purpose. See also chapter General protection against HO Ping Pong in the feature interworking part of AMR chapter. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 118/629 V17.0 BSS Parameter User Guide (BPUG) CAUTION! The parameters hoPingpongCombination and hoPingpongTimeRejection must be defined at the “entering cell” (relatively to the first HO of the combination) level, for the neighbouring cell (adjacentCellHandover object) corresponding to the “left cell” (still relatively to the first HO of the combination). Thus, these parameters are known by the “new BSC” whatever the type of HO is (intra or interBSC). For interBSS handovers, if the Cause element is not included in the HANDOVER_REQUEST message sent from the MSC to the target BSC, then this feature is not applied except when the incoming_cause in hoPingpongCombination parameter is set to ALL. During upgrades to V12, if bts Time Between HO configuration is greater than 0, then bts Time Between HO configuration is set to 1, hoPingpongTimeRejection is set to the previous value of bts Time Between HO configuration and hoPingpongCombination is set to (all, allPBGT) and if bts Time Between HO configuration is equal to 0, then it keeps the same value, hoPingpongTimeRejection is set to 0 and hoPingpongCombination is set to empty. The C1166 counter related to the “Minimum time between handover” feature is removed and replaced by the C1782 counter incremented when a cell is removed of the preferred cells list (so, for one handover indication message, it can be incremented several times). This feature gives no protection against intracell or interzone ping-pong handovers and gives no protection against ping-pong handovers between more than 2 cells except for allCapture or allPBGT outgoing causes. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 119/629 V17.0 BSS Parameter User Guide (BPUG) 4.8.22 AUTOMATIC HANDOVER ADAPTATION This feature adapts handover parameters to radio environment of each call, taking into account mobile speed and frequency hopping (this BSS feature is available from V14.3). The objective is to minimize call drops and bad quality transients. That feature is available from V15.1 for BSC3000 and BSC12000. PRINCIPLE In order to eliminate the fading in the measurement processing, some averaging mechanisms are implemented. But the frequency hopping and the mobile speed introduce frequency and space diversity and average the attenuation of the received signal: As shown on the diagram above, the faster the mobile moves the less the fading is impacting (space diversity). Mobiles can also be sensitive to the frequency diversity as shown on the diagram below. The more hopping frequencies are used the less fading is impacting. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 120/629 V17.0 BSS Parameter User Guide (BPUG) The principle of this feature is to use these averages introduced by the frequency hopping and the MS speed, in order to decrease the number of measurements take into account or the handover margin. DECISIONS FACTORS FREQUENCY HOPPING In order to have a sufficient averaging of the Rayleigh fading, the number of frequencies in the hopping law has to be greater or equal than 4. If the number of frequencies in the hopping law is less than 4, mobiles are considered as non-hopping, and all processing defined for non hopping mobiles are applied. This criterion and all associated mechanisms are applied to the following channels: • • • TCH full rate whatever the channel coding (data circuit, EFR, FR, AMR…), TCH half rate, SDCCH. MS SPEED EVALUATOR From internal studies and simulation, a mobile can be considered as a fast mobile, if the standard deviation in dB of the Rxlev during one period of measurement (i.e. 104 bursts, thus 480ms) is less than 1.4dB. This standard deviation represents approximately: • • 20 km/h in GSM900, 10km/h in GSM1800 and GSM1900, and is sufficient to have a good averaging of the Rayleigh fading. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 121/629 V17.0 BSS Parameter User Guide (BPUG) HALF RATE AND SDCCH CHANNELS For half rate channels, the number of bursts during one period is sufficient to evaluate with a correct accuracy the standard deviation criteria, then all treatments associated to this criteria are relevant for this kind of channels. UPLINK DTX In case of uplink DTX activation during the period, the number of bursts received is decreased, thus the accuracy of the calculated standard deviation is decreased. In this case, the standard deviation is not evaluated and the last calculated standard deviation is taken. UPLINK POWER CONTROL In case of uplink power control, the BTS is not able to distinguish between a variation due to Rayleigh fading and one due to a power control attenuation. Thus if the power control required a variation of more than 8 dB during the period, then the standard deviation is not evaluated and the last calculated standard deviation is taken. AUTO ADAPTATION MECHANISMS This feature is activated if the selfAdaptActivation parameter is set to “enabled”. PBGT HANDOVER ADAPTATION For this mechanism, two new parameters are added: servingfactorOffset, neighDisfavorOffset and the previous factor hoMarginBeg from V11 is reused. Following tables show for each case, the AdaptedHoMargin value and the averaging windows taken into account in the PBGT handover mechanism according to • • • the MS type: fast or slow mobile or managed by a hopping TCH, the number of measurement of the serving cell compared with the normal averaging window, the number of measurement of the neighbouring cell compared with the normal averaging window. See chapter EXP2 to understand how AdaptedHoMargin is used. For each cases of measurement, the tables below give the HO Margin result. Example: IF number of available measurements for the cell < normal window AND IF number of available measurements for the neighbour cell < normal window THEN AdaptedHoMargin = hoMargin+ neighDisfavorOffset Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 122/629 V17.0 BSS Parameter User Guide (BPUG) Mobile Type: SFH MS cell measurement neighbour cell measurement AdaptedHoMargin < rxLevHreqaveBeg < rxLevHreqaveBeg ≥ rxLevHreqave ≥ rxLevHreqave < rxLevNCellHreqaveBeg ≥ rxNCellHreqave < rxLevNCellHreqaveBeg ≥ rxNCellHreqave hoMargin + neighDisfavorOffset hoMargin hoMargin + neighDisfavorOffset - servingfactorOffset hoMargin - servingfactorOffset Mobile Type: Slow non SFH MS cell measurement neighbour cell measurement AdaptedHoMargin < rxLevHreqaveBeg < rxLevHreqaveBeg ≥rxLevHreqave ≥ rxLevHreqave < rxLevNCellHreqaveBeg ≥ rxNCellHreqave < rxLevNCellHreqaveBeg ≥ rxNCellHreqave hoMargin + hoMarginBeg hoMargin + hoMarginBeg hoMargin + neighDisfavorOffset hoMargin Mobile Type: Fast non SFH MS cell measurement average neighbour cell average AdaptedHoMargin rxLevHreqaveBeg rxLevNCellHreqaveBeg hoMargin POWER CONTROL ADAPTATION For this mechanism, a new parameter is added: rxQualAveBeg. The following table shows for each case, the averaging taken into account in the power control mechanism. Mobile type SFH MS “Fast” non SFH MS “Slow” non SFH MS RxLev average RxQual average rxLevHreqaveBeg rxLevHreqaveBeg no modification rxQualAveBeg rxQualAveBeg In case of short averaging, due to the measurement quality, no specific value of K (refer to chapter One shot power control (Pc_2) for more details on this value) is taken into account. For slow mobile, Fast power control at TCH assignment (Pc_3) is still available in order to reduce the power control activation time, but the first decision of power control is now taken with Max[rxLevHreqAveBeg, rxQualAveBeg] measurements, instead of rxLevHreqAveBeg. 4.8.23 PROTECTION AGAINST INTRACELL HO PING-PONG This feature controls the overall handover process, to avoid oscillations or so called "pingpong" handovers, to deal with the complexity introduced by all various situations with BSC3000 (this BSS feature is available from V14.3). Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 123/629 V17.0 BSS Parameter User Guide (BPUG) There are various reasons where intracell handovers needs to be triggered, for instance: • • but also • • transition from AMR-FR to AMR-HR, transition from outer zone to inner zone in a multi-zone cell. RxQual degradation with high RxLev, transition from inner zone to outer zone in a multi-zone cell The first two cases are required to maintain call quality, whereas the last two cases are decided to optimise system capacity. PRINCIPLE For this feature, two kinds of intracell handover are distinguished: • capacity intracell handover: this expression groups all intracell handovers, which are triggered in order to increase the network capacity: interzone handover from the outer to the inner zone, AMR handover from FR to HR TCH, tiering from BCCH to TCH frequency pattern. • quality intracell handover: this expression groups all intracell handovers, which are triggered if the quality of the call is not sufficient: normal intracell handover, inter-zone handover from the inner to the outer zone, AMR handover from HR to FR TCH, tiering from TCH to BCCH frequency pattern. The principle of this feature is to introduce two timers, associated to the intracell handover type, which delay an intracell handover after an intracell handover: • • capacityTimeRejection: defines the rejection time of a capacity intracell handover after an intracell handover, minTimeQualityIntraCellHO: defines the rejection time of a quality intracell handover after an intracell handover. First intracell HO Quality intracell Capacity intracell HO request HO request minTimeQualityIntraCell HO capacityTimeRejection Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 124/629 V17.0 BSS Parameter User Guide (BPUG) In order to avoid some load, this filtering is done at the BTS level, thus at the L1M activation for the dedicated channel the BSC has to precise the cause: • • • • initial assignment, capacity intracell handover quality intracell handover intercell handover. Due to the following handover non AMR priority: • • • • • • • • RXQUAL RXLEV DISTANCE PBGT TRAFFIC INTRACELL AMR INTRACELL INTERZONE the BTS has to check if one cause of a lower priority is fullfilled. At the TS release, the BTS sends in the Stop Measurement Ack, to the BSC the number of each kinds of filtered intracell handovers. The BSC uses this information in order to generate 2 counters. The feature is deactivated at the OMC-R, minTimeQualityIntraCellHO parameters are set to 0. if the capacityTimeRejection and CAUTION! Due to AMR L1m introduction, a new cause value is added in hoPingpongCombination: • AMRquality. This value is used in case of AMR handover triggered for alarm purpose. This type of handover can be chosen via the parameter amrReserved2 In case of interBSC handover, in order to distinguish between RxQual handover and AMR quality handover (according to amrReserved2 chosen), the BSC uses following rules: IF the handover cause = RxQual AND IF the speech version <> AMR THENHandover cause = RxQual. IF the handover cause = RxQual AND IF the speech version = AMR THEN Handover cause = AMR quality. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 125/629 V17.0 BSS Parameter User Guide (BPUG) 4.8.24 GSM TO UMTS HANDOVER PRINCIPLE Thanks to this feature, GSM to UMTS handover is possible for dual-mode mobiles in areas of 2G-3G coverage. This feature requires the setting of O&M parameters in the following domains : • • • • Normal or Enhanced Measurement Reporting activation and configuration UTRAN classmark activation and configuration Declaration of neighbouring cells belonging to the UTRAN Handover timers, thresholds and margins PREREQUISITES Note that EMR is not a preequisite for 2G-3G handover. The system can perform handover on mobiles that perform normal reporting. EARLY CLASSMARK SENDING ACTIVATION Early classmark sending consists in the mobile sending as early as possible after access a CLASSMARK CHANGE message to provide the network with additional classmark information. Early classmark sending activation is mandatory as EMR capability and FDD radio capability is provided by the mobile to the BSS in the Classmark 3 IE sent in the CLASSMARK CHANGE message. Rule : earlyClassmarkSending (v10 parameter) = allowed. 3G CLASSMARK SENDING ACTIVATION Although it is not used by the BSS, the UTRAN classmark information is mandatory to perform a GSM to UMTS handover as the "INTER RAT HANDOVER INFO" IE shall be included by the BSC in HANDOVER REQUIRED message. The activation flag earlyClassmarkSendingUTRAN is used by the BSC and the MS: • when the “3G Early Classmark Sending Restriction” field in SYSTEM INFORMATION TYPE 3 message is set 1 (enabled), the MS is asked to the send its UTRAN capabilites at the call set-up in the UTRAN CLASSMARK CHANGE message subsequent to the CLASSMARK CHANGE one. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 126/629 V17.0 BSS Parameter User Guide (BPUG) • on an incoming handover, if the UTRAN capabilities have not been received by the the target BSC in the HANDOVER REQUEST message, this BSC sends a CLASSMARK ENQUIRY message in order to ask the MS to send the UTRAN CLASSMARK CHANGE message. Rule : earlyClassmarkSendingUTRAN = ”enabled”. USE OF MEASUREMENT INFORMATION MESSAGE The MEASUREMENT INFORMATION message is used for 3 different purposes: • • declaration of UTRAN neighbouring cells and configuration of UTRAN reporting requirements activation/deactivation of EMR feature The feature GSM to UMTS handover can be used with either normal measurement reporting or enhanced measurement reporting. The part of the MEASUREMENT INFORMATION message related to EMR feature activation is fully described in §4.6.6. When the mobile does not have the UMTS FDD RAT capability, it shall not receive information about UTRAN cells. As a consequence, the BSC sends two different version of Measurement information to the BTS: a 2G version with GSM cell information only and a 2G/3G version with both GSM and UTRAN cell information. The BTS then broadcasts the appropriate message according to each mobile’s capability and according to the status of the “GSM to UMTS handover” activation, as specified in the table below. GSM to UMTS HO disabled GSM to UMTS HO enabled EMR disabled Release 4 2G only mobiles 2G-3G mobiles No MI message No MI message EMR enabled MI 2G message MI 2G message EMR disabled None MI 2G-3G message EMR enabled MI 2G message MI 2G-3G message The 2G measurement information message (2G MI) contains mainly the following information: • • • reportTypeMeasurement : parameter that defines the type of measurement report that the mobiles are required to use common (EMR and non-EMR) reporting configuration parameters : multiBandReporting EMR-specific configuration parameters : servingBandReporting, servingBandReportingOffset The 2G-3G measurement information message (2G-3G MI) contains mainly the following information: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 127/629 V17.0 BSS Parameter User Guide (BPUG) • • • • reportTypeMeasurement : parameter that defines the type of measurement report that the mobiles are required to use common (EMR and non-EMR) reporting configuration parameters : multiBandReporting, qsearchC, fDDMultiRatReporting, fDDReportingThreshold2 EMR-specific reporting configuration parameters : fDDReportingThreshold, servingBandReporting, servingBandReportingOffset UTRAN cells definition : mobileCountryCodeUTRAN, mobileNetworkCodeUTRAN, locationAreaCodeUTRAN, rNCId, cId, fDDARFCN, scramblingCode, diversityUTRAN NEIGHBOUR CELL LISTS DEFINITION The Neighbouring Cell List is built by a concatenation of two lists: • The GSM Neighbour Cell List : it is the list of GSM cells, ordered by ARFCN and BSIC, as defined in the BSIC_Description parameter of the MEASUREMENT_INFORMATION message, which takes the first position in the list The 3G Neighbour Cell list: it is the list of UMTS cells, ordered by ARFCN & scrambling code (the ARFCN are ordered the same way as received from the network. For each ARFCN, scrambling codes are ordered in increasing number). • MAXIMUM SIZE In this version the list is limited to 32 GSM cells and 32 UMTS cells. When at least one UTRAN neighbouring cells is declared, only 31 different BCCH frequencies for GSM neighbouring cells can be declared. NEW BSS PARAMETERS CREATION OF A NEW OBJECT A new object is created alongside adjacentCellHandover: adjacentcellUTRAN. 2G-3G HANDOVER ACTIVATION : GSMTOUMTSSERVICE HO PARAMETER The following parameter (gsmToUMTSServiceHO) belonging to bsc object serves to deactivate the 2G-3G Handover feature in all cells of the BSC or to provide a default GSM to UMTS handover strategy when the MSC has failed to set one for the call : Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 128/629 V17.0 BSS Parameter User Guide (BPUG) gsmToUMTSServiceHO value range : • • • • Shall not Should not Should GsmToUMTSDisabled The MSC may include a similar “service handover” field in BSSMAP “ASSIGNMENT REQUEST” and BSSMAP “HANDOVER REQUEST” messages sent to the BSS: • • Shall not: the BTS shall never hand off the communication to UTRAN (No UMTS neighbouring cell can be present in the candidate cells list) Should not: the BTS shall not hand off the communication to UTRAN for a PBGT reason but other criteria are nevertheless authorized to avoid call drop (handover for alarm reason) or to reduce the load of the current cell when in congestion state (handover for traffic reason) Should: It can be understood either as “immediate” or as “when possible or if necessary”. The hoMarginUtran(n) parameter setting allows dual-mode MS to go more or less easily on UTRAN layer. With a very negative values, the PBGT emulates a capture in order to recover the UTRAN service as soon as possible. • For each call, we must differentiate the following cases : • Case n°1 : gsmToUMTSServiceHO is set to GsmToUMTSDisabled. Handover to UMTS is disabled. • Case n°2 : "service handover" is provided by the MSC, and gsmToUMTSServiceHO value is different from GsmToUMTSDisabled. The MSC "service handover" value is sent to the BTS and the handover strategy is decided by the MSC (according to OMC hoMarginXX setting). • Case n°3 : "service handover" field is not provided by the MSC and gsmToUMTSServiceHO is different from GsmToUMTSDisabled Then, the default OMC "service handover" (i.e. the gsmToUMTSServiceHO parameter) value is sent to the BTS and the handover strategy is decided by the Access network instead of the Core network. Note: In case the gsmToUMTSServiceHO is modified, the change only applies to new calls (or after a handover) except for a feature deactivation. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 129/629 V17.0 BSS Parameter User Guide (BPUG) CONFIGURATION PARAMETERS OF CLASSMARK SENDING The following parameter should be set to “enabled” to allow the mobile to send its UTRAN Classmark at call setup : • earlyClassmarkSendingUTRAN The UTRAN_CLASSMARK_CHANGE message takes about 2 or 3 radio frames to transmit. However, when supported by the UTRAN network, it is possible to reduce the size of the message thanks to the compression of UE radio access capabilities and predefined configuration Information Elements : compressedModeUTRAN = enabled Note: During IOT activities, it is recommended to disable this compression. UMTS NEIGHBOUR CELLS DECLARATION PARAMETERS The following 8 new parameters belonging to adjacentcellUTRAN object define the UMTS neighbours : • • • • • • • • mobileCountryCodeUTRAN mobileNetworkCodeUTRAN locationAreaCodeUTRAN rNCId cId fDDARFCN scramblingCode diversityUTRAN Up to 32 UMTS neighbours and 31 GSM neighbours may be declared. MEASUREMENT REPORTING PARAMETERS EMR must be activated for 2G-3G handover. The following 7 new parameters serve to configure the Enhanced Measurement Reporting for 2G-3G handover purposes: • • • • • reportTypeMeasurement qsearchC fDDMultiRatReporting fDDReportingThreshold fDDReportingThreshold2 Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 130/629 V17.0 BSS Parameter User Guide (BPUG) • • servingBandReporting servingBandReportingOffset 2G-3G HANDOVER TIMER t3121 has the same use as t3103 in the GSM inter-BSC handover procedure. It sets the value before countdown of T3121 timer deined in the GSM specification: • • T3121 starts when the BSC sends an INTER SYSTEM TO UTRAN HANDOVER message to the mobile. T3121 stops when the mobile has correctly seized the UTRAN channel. The purpose of this timer is for the BSC to keep the old channels long enough for the mobile to be able to return to the old channels. On expiry of T3121 (indicating the mobile is lost), the BSC may release the channels. • 2G-3G HANDOVER THRESHOLDS The following new parameters serve to configure thresholds : • • rxLevMinCellUTRAN rxLevDLPbgtUTRAN These parameters have the same meaning as their counterparts on adjacentCellHandOver object, but apply to a UTRAN neighbouring cell instead of a GSM neighbour cell. 2G-3G HANDOVER MARGINS The following new parameters serve to configure margins for various types of handovers to 3G cells : • • • • • • • hoMarginUTRAN hoMarginAMRUTRAN hoMarginRxLevUTRAN hoMarginRxQualUTRAN hoMarginDistUTRAN hoMarginTrafficOffsetUTRAN offsetpriorityUTRAN All these parameters have the same meaning as their counterpart on adjacentCellHandOver object, but apply to a UTRAN neighbouring cell instead of a GSM neighbour cell. In practice, all handovers algorithms except Capture and Directed retry are allowed towards an UMTS neighbouring cell. Note : the Power Budget handover as defined in GSM may be used to emulate a capture by UTRAN layer. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 131/629 V17.0 BSS Parameter User Guide (BPUG) CONFIGURATION PARAMETERS OF PING-PONG MECHANISM FOR 2G3G HANDOVERS The existing mechanism to protect against ping-pong handover is used also for 2G-3G handovers. The list of outgoing causes for handovers towards UMTS neighbour cells is : traffic, pbgt, rxLev, rxQual, dist, O&M (forced ho), all. This list is defined by setting the new parameter hoPingpongCombinationUTRAN. A specific timer is defined for time Rejection : hoPingpongTimeRejectionUTRAN. If a pair of causes in the hoPingpongCombinationUTRAN parameter list refers to an incoming or an outgoing cause that is not implemented in the source or in the target system, the existing causes will be ignored. On an incoming UMTS to GSM handover, if the BSC has not received the source "UTRAN Cell identifier" (HANDOVER REQUIRED message / Old BSS to new BSS information" container / “Cell load information group” IE), no rejection timer will be started for that UTRAN cell. UMTS CELL LOAD MANAGEMENT UMTS cell load management is managed three different ways: • • Through existing anti ping-pong mechanism for incoming 3G to 2G handovers Through a new mechanism for outgoing handover failures : When a UMTS cell rejects the handover, the 2G-MSC sends a BSSMAP HANDOVER REQUIRED REJECT message including cause “Traffic Load in the target cell higher than in the source cell” or “no radio resource available”. The BSC stores this information and does not attempt a new handover towards this cell for a given time equal to hoRejectionTimeOverloadUTRAN parameter. Through a new mechanism for incoming handover from UTRAN : o if the handover cause in the BSSMAP HANDOVER REQUEST message is either “traffic”, “directed retry” or “reduce load in serving cell” , and if the source RNC and the MSC have implemented the “old BSS to new BSS information” container and if the source RNC has included the “Cell load information group” within this container then the BSC stores the information and will not try a handover towards this UTRAN cell for a given time equal to hoRejectionTimeOverloadUTRAN parameter, otherwise, the BSC does not start any rejection timer for that UTRAN cell. • o o o o SUMMARY OF HO 2G-3G PARAMETERS (V17) Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 132/629 V17.0 BSS Parameter User Guide (BPUG) Parameter name Definition object cId Cell identity of the UMTS neighbouring cell for handover flag to indicate whether compressed mode UTRAN is supported or not. This flag is used by the network to indicate to mobiles whether to use a compressed version of the INTER RAT HANDOVER INFO message (UE to UTRAN message). flag indicating whether there is deiversity in the neighbouring UTRAN cell flag indicating whether UTRAN classmark change message shall be sent with Early Classmark Sending fDD channel number of the UTRAN neighbouring cell Number of FDD UTRAN cells to be reported in the list of strongest cells in the MR or EMR message (used in EMR only) defines the CPICH RSCP level above which the MS will apply a higher priority to UTRAN cells in the enhanced measurement report message (used in MR and EMR) defines the CPICH Ec/N0 level above which the MS will report UTRAN cells in the normal or enhanced measurement report message This parameter serves to disable 2G-3G handover at BSC level or to indicate the preference (2G versus 3G cells) to be applied for handovers Handover margin for PBGT handover to a UMTS cell Handover margin for intercell quality handovers to UMTS, for AMR calls handover margin for handover to UMTS on distance criterion handover margin for signal strength handover to UMTS handover margin for signal quality handover to UMTS offset to be subtracted to the homarginUTRAN to allow handover for traffic reason when the current cell is congested list of pair of causes indicating the causes of ping-pong handovers in the overlapping areas. time that must elapse before attempting another handover towards an UTRAN cell. time that must elapse before attempting another handover towards a congested UTRAN cell Location area code of the UMTS neighbouring cell Mobile country code of the UMTS neighbouring cell Mobile network code of the UMTS neighbouring cell priority offset applied by the BSC when selecting the candidate cell for the handover process search for UTRAN cells if signal level on the BCCH of serving cell : is below threshold (0-7): -98, -94, … , -74 dBm, ∞ (always) or is above threshold (8-15): adjacentCell UTRAN bts adjacentCell UTRAN bts adjacentCell UTRAN bts Handover control Handover control bsc adjacentCell UTRAN adjacentCell UTRAN adjacentCell UTRAN adjacentCell UTRAN adjacentCell UTRAN adjacentCell UTRAN adjacentCell UTRAN adjacentCell UTRAN adjacentCell UTRAN adjacentCell UTRAN adjacentCell UTRAN adjacentCell UTRAN adjacentCell UTRAN compressedModeUTRAN diversityUTRAN earlyClassmarkSendingUTRAN fDDARFCN fDDMultiratReporting fDDReportingThreshold fDDReportingThreshold2 gSMToUMTSServiceHO hoMarginUTRAN hoMarginAMRUTRAN hoMarginDistUTRAN hoMarginRxLevUTRAN hoMarginRxQualUTRAN hoMarginTrafficOffsetUTRAN hoPingpongCombinationUTRAN hoPingpongTimeRejectionUTRAN hoRejectionTimeOverloadUTRAN locationAreaCodeUTRAN mobileCountryCodeUTRAN mobileNetworkCodeUTRAN offsetPriorityUTRAN qsearchC -78, -74, … , -54 dBm, ∞ (never) If the serving BCCH frequency is not part of the BA(SACCH) list, and if the dedicated channel is not on the BCCH carrier, and if qsearchC is not equal to 15, the MS shall ignore the qsearchC parameter value and always search for UTRAN cells. If qsearchC is equal to 15, the MS shall never search for UTRAN cells. Nortel confidential Handover control PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 133/629 V17.0 BSS Parameter User Guide (BPUG) Parameter name Definition object reportTypeMeasurement rNCId rxLevDLPbgtUTRAN rxLevMinCellUTRAN scramblingCode servingBandReporting type of measurement report to be reported on this cell : enhanced measurement report or legacy measurement report identity of the UTRAN neighbouring cell’s RNC downlink signal strength threshold above which handovers to UTRAN for cause power budget are inhibited minimum signal strength level that the MS must measure on an UMTS neighbour cell to be able to be granted a handover to this UMTS neighbour cell Scrambling code of the UMTS neighbouring cell defines the number of cells from the GSM serving frequency band that shall be included in the list of strongest cells in the measurement report. If there is not enough space in the report for all valid cells, the cells shall be reported that have the highest sum of the reported value (RXLEV) and the parameter servingBandReportingOffset (XXX_REPORTING_OFFSET) for the serving GSM band. Note that this parameter shall not affect the value itself of the reported measurement. t3121 has the same use as t3103 in the GSM inter-BSC handover procedure. It sets the value before countdown of T3121 timer defined in the GSM specification . bts adjacentCell UTRAN adjacentCell UTRAN adjacentCell UTRAN adjacentCell UTRAN bts servingBandReportingOffset Handover control t3121 T3121 starts when the BSC sends an INTER SYSTEM TO UTRAN HANDOVER message to the mobile. T3121 stops when the mobile has correctly seized the UTRAN channel. The purpose of this timer is for the BSC to keep the old channels long enough for the mobile to be able to return to the old channels if necessary. On expiry of T3121 (indicating the mobile is lost), the BSC may release the channels. bts 2G-3G HANDOVER ALGORITHMS REPORTING QUANTITY In the Enhanced Measurement Report message, the downlink received power level of UMTS neighbouring cells may be reported by the mobiles using one of two possible reporting quantities : • • either CPICH RSCP or CPICH Ec/N0 In our v17.0 implementation, the reporting quantity that mobiles are expected to report to the network is always CPICH RSCP. The mobiles are informed of this obligation by the FDD_REP_QUANT flag that is sent by the network on SACCH in Measurement Information messages. MAPPING BETWEEN RSCP (3G) AND RXLEV (2G) This CPICH RSCP value is directly comparable to a “classical” RxLev value. According to the mapping specified in the GSM specification, we can define the following conversion table between RSCP values and the reported values in range [0..63]. Values below 0 are reported as 0 and values above 63 are reported as 63 by the mobiles. The L1M then subtracts 5 to the reported value to obtain the equivalent Rxlev signal strength. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 134/629 V17.0 BSS Parameter User Guide (BPUG) RSCP (unit : dBm) Reported value inside EMR (no unit) L1M converted value (no unit) RxLev “equivalent” in dBm RSCP<-120 -120<RSCP<-119 -119<RSCP<-118 -118<RSCP<-117 -117<RSCP<-116 -116<RSCP<-115 -115<RSCP<-114 -114<RSCP<-113 -113<RSCP<-112 -112<RSCP<-111 -111<RSCP<-110 -110<RSCP<-109 … -54<RSCP<-53 -53<RSCP<-52 -52<RSCP<-51 … -26<RSCP<-25 -25<RSCP 0 0 0 0 0 0 1 2 3 4 5 6 … 62 63 63 … 63 63 0 0 0 0 0 0 0 0 0 0 0 1 … 57 58 58 … 58 58 <-110 <-110 <-110 <-110 <-110 <-110 <-110 <-110 <-110 <-110 <-110 -110<RxLev<-109 … -54<RxLev<-53 -53<RxLev<-52 -53<RxLev<-52 … -53<RxLev<-52 -53<RxLev<-52 ALGORITHMS Once the power level of all 2G and 3G neighbouring cells can be compared with one another, all L1M handover algorithms are directly reusable. For example, the algorithm for a Power Budget handover to UTRAN can be described as follows : • • • • The MS listens to UTRAN cells if RxLev < qsearchC The MS reports the measured RSCP of the UTRAN cells for which CPICH Ec/N0 ≥ fDDReportingThreshold2 The “service handover” shall be set to “should” The BTS discards UTRAN cells for which : o o • either CPICH RSCP < rxLevMinCellUTRAN(n) or RxLev of the serving cell > rxlevDLPbgtUTRAN(n) PBGT handover decision is taken if : o CPICH RSCP(neighbour 3G cell) hoMarginUtran(neighbour 3G cell). > RxLev (serving 2G cell) + • UTRAN cells are sorted according to EXP2() values Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 135/629 V17.0 BSS Parameter User Guide (BPUG) IMPACT OF HO 2G-3G ON INTERFERENCE MATRIX UMTS cells are not measured by the Interference Matrix feature. EMR CASE The introduction of UTRAN neighbouring cells has an impact on Interference Matrix feature because of the number of GSM neighbour cells it induces. If at least one UTRAN neighbour cell is declared, no more than 31 GSM neighbour cells can be declared, instead of 32. The impacts on IM are the following: • • • • The algorithm that calculates the number of cycles (used by launching tool on OMC-R and by BSC for cycle definition) shall be done with only 31 BCCH frequencies UTRAN neighbour cell creation must be forbidden if 32 different BCCH frequencies are already declared for GSM neighbour cells GSM neighbour cell creation with a 32nd different BCCH frequency must be forbidden if at least one UTRAN neighbour cell is declared. UTRAN neighbour cell creation, UTRAN neighbour cell deletion, fDDARFCN change, scramblingCode change, must be forbidden while Interference Matrix feature is running on the BSC. the control that warns the operator if he tries to activate Interference matrix when one cell has 32 GSM neighbouring cells (this control exists already in this case) must be extended to the case where one cell has 31 GSM neighbouring cells and at least one UTRAN neighbouring cell. • NORMAL MR CASE Although fewer possibilities are available with MR than with EMR, the way GSM and UTRAN neighbouring cells are reported in Measurement report messages is manageable, thanks to multiBandReporting and fDDMultiratReporting parameters. Unlike EMR, the number of reported non-serving band GSM and UTRAN valid neighbouring cells has an impact on the number of remaining spare places in the Measurement report message that could be used for fake neighbours in Interference Matrix. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 136/629 V17.0 BSS Parameter User Guide (BPUG) 4.9. HANDOVER ALGORITHMS ON THE MOBILE SIDE For an intracell handover, the mobile receives an ASSIGNMENT COMMAND and simply switches to another timeslot belonging to any TDMA of the cell. For an intercell handover, upon reception of the HANDOVER COMMAND, the mobile checks if it has the synchronization information. If not a handover failure is reported and communication remains on old channel. Then, if it is a synchronized handover, four access bursts are sent on the new channel before actually switching to it. If it is a non synchronized handover, the mobile will send contiguous access bursts on new cell, expecting a PHYSICAL INFORMATION message to be sent back by the BTS, in order to know the Timing Advance to be used on the new channel and actually switch to it. If that message is not received within one second, then there is a handover failure and the mobile returns to the old channel. Once on the new cell, the mobile tries to establish level 2 connexion (SABM and UA exchange procedure). If that procedure fails, then the mobile returns to the old channel, but if it succeeds the synchronization information with previous best cells is kept for updating with new cell parameters. To conclude this paragraph, one realizes that a handover can be a rather lengthy process, which should not be performed too late in order to ensure its success and not too often to maintain a smooth voice or data flow. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 137/629 V17.0 BSS Parameter User Guide (BPUG) 4.10. POWER CONTROL ALGORITHMS The aim of the Power Control feature is to reduce the average interference level on the Network and to save mobile batteries. 4.10.1 STEP BY STEP POWER CONTROL CAUTION! From V14 in L1mV2, RxLevXX is always rescaled at the maximum power output (see chapter Measurement Processing) This algorithm is a step by step full path loss compensation. The algorithm determines the gap between the received level at Pmax (theoretical maximum power without taking into account Power Control) and the power control threshold (lRxLevDLP, lRxLevULP) and compensates the path loss step by step until the received level reaches the threshold. That algorithm has been improved in L1mV2 with the introduction of a limitation based on the one shot computation when there is a need to re-compute the attenuation (high level and good quality) The basic idea of the step by step power control algorithm is: • • to reduce transmitted power when reception level is high and quality is good to compute a new transmitted power with total path loss compensation when reception level is high and quality is good At every runPwrControl event, the Weighted Average is computed at Pmax (SAveRxlev) and the following algorithm is perfomed by Ms/Bs: IF (SAveRxLev < lRxLevP) OR (SAveRxQual > lRxQualP) NewAttRequestdB = Max (CurrentAttRequestdB - IncStepSizeXX, 0) ELSE IF [(SAveRxLev > uRxLevP) AND (SAveRxQual < uRxQualP)] TempAttRequestdB = SAveRxLev – lRxLevP IF (TempAttRequestdB < CurrentAttRequest –IncrStepSizeXX) NewAttRequestdB = CurrentAttRequestdB – IncStepSizeXX ELSE IF (TempAttRequestdB > CurrentAttRequest + RedStepSizeXX) NewAttRequestdB = CurrentAttRequestdB + RedStepSizeXX ELSE NewAttRequestdB = TempAttRequestdB ELSE ((lRxLevP≤SAveRxLev ≤ uRxLevP) OR (uRxQualP≤ SAveRxQual ≤ lRxQualP)) NewAttRequestdB = LastCommandedAttRequestdB The resultfor the new attenuation request is stored into NewAttRequestdB Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 138/629 V17.0 BSS Parameter User Guide (BPUG) The figure below summarizes the command for (UL or DL) transmission power according to RxLev/RxQual values. RxQual Increase Tx Power lRxQual No new command for MS (or BS) transmission power uRxQual New Tx Power computation lRxLev uRxLev RxLev CAUTION! When the MS or the BTS is in the “NEW TX POWER COMPUTATION” zone, the recomputation of the attenuation does not lead necessarily to a reduction of the emitted power. Note: This feature is activated at the BTS level by setting the following parameters: • • powerControl object: uplinkPowerControl = enabled and bsPowerControl = enabled bts object: new power control algorithm = step by step 4.10.2 ONE SHOT POWER CONTROL CAUTION! From V14 in L1mV2, RxLevXX is always rescaled at the maximum power output (see chapter Measurement Processing). The enhanced power control is a one shot partial path loss compensation algorithm. The one shot power control algorithm determines the “optimal” transmit power by computing a partial path loss compensation and compensates it in one step. This feature is activated at the BTS level by setting the following parameters: • • powerControl object: uplinkPowerControl = enabled and bsPowerControl = enabled BTS object: new power control algorithm = one shot Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 139/629 V17.0 BSS Parameter User Guide (BPUG) At every runPwrControl event, the Weighted Average is computed at Pmax (SAveRxlev) and the following algorithm is perfomed by Ms/Bs: IF (SAveRxLev < lRxLevP) OR (SAveRxQual > lRxQualP) NewAttRequestdB = 0 ELSE NewAttRequestdB = K * (SaveRxLev - lRxLevP) The values of K depend on the activation of frequency hopping and of the RxQual. Here are the values of K, which come from simulation results: RXQUAL K with Frequency Hopping K without Frequency Hopping 0 1 2 3 4 5 6 7 0,9 0,7 0,8 0,6 0,7 0,5 The figure below summarizes the command for (UL or DL) transmission power according to RxLev/RxQual values. RxQual Tx Power max (MS or BS attenuation = 0) lRxQual New Tx Power computation lRxLev RxLev Please note that if NewAttRequestdB = 0 then the MS power becomes equal to the maximum power possible in the cell, i.e. Min(msTXPwrMaxCell(n), MSTxPwrMax). The limitation can come from the mobile (MSTxPwrMax) or from the cell (msTxPwrMax). Concerning the BTS, the attenuation (difference between current power and max power) is considered, so if NewAttRequestdB = 0 then the BTS power becomes equal to the maximum static power possible. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 140/629 V17.0 BSS Parameter User Guide (BPUG) CAUTION! From V12, an 8 dB limitation applies on decrease, e.g.the BTS will never decrease its power by more than 8 dB (some mobiles would lose the BTS) 4.10.3 FAST POWER CONTROL AT TCH ASSIGNMENT CAUTION! From V14 in L1mV2, RxLevXX is always rescaled at the maximum power output (see chapter Measurement Processing). This V12 feature is an improvement of the one shot power control (described above). One shot power control reactivity is improved by deciding power control on SDCCH allocation and on TCH allocation with only rxLevHreqaveBeg or rxQualAveBeg measurements. With this feature, attenuation (possibly decided on SDCCH) is kept at TCH assignment and for each channel switch-over (start on SDCCH, SDCCH to TCH or TCH to TCH), the few first measurements (from Max[rxLevHreqAveBeg, rxQualAveBeg] to Max[rxLevHreqave * rxLevHreqt, rxQualHreqave * rxQualHreqt]-1) may be used to decide power control. This feature is activated by setting the following parameters: • • powerControl object: uplinkPowerControl = enabled and bsPowerControl = enabled BTS object: new power control algorithm = enhanced one shot The triggering of the one shot power control is accelerated because rxLevHreqaveBeg or rxQualAveBeg measurements are taken into account. Until Max[rxLevHreqave * rxLevHreqt, rxQualHreqave * rxQualHreqt] is reached, the attenuaton is computed with the compensation factor K for uplink and downlink. This factor no more depends on the rxQualHreqave measurements but only on the frequency activation: NewAttRequestdB = K * (SaveRxLev - lRxLevP) • • K = 0.5 in case of non hopping channel, K = 0.7 in case of hopping channel, * rxLevHreqt, When Max[rxLevHreqAveBeg, rxQualAveBeg] > Max[rxLevHreqave rxQualHreqave * rxQualHreqt] this feature is no more activated. When Max[rxLevHreqave * rxLevHreqt, rxQualHreqave * rxQualHreqt] is reached the usual average of the one shot power control described before is computed with the K value depending of the rxQualHreqave measurements. CAUTION! This feature is not supported with DCU2 boards or with a mix of DCU2/DCU4 boards. Note: In some very specific cases with a poor quality and a good level strength (very interfered environment) the Fast Power Control algorithm may prevent from powering up after a TCH assignment until max(rxLevHreqave*rxLevHreqt, rxQualHreqave*rxQualHreqt) is reached. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 141/629 V17.0 BSS Parameter User Guide (BPUG) 4.10.4 POWER CONTROL ON MOBILE SIDE In RACH phase, the MS power is equal to Min [msTxPwrMax, msTxPwrMaxCCH]. When the MS switches from RACH to SDCCH or TCH, it keeps the same power. In dedicated mode, the mobile transmits at the power required in the POWER COMMAND message transmitted in the layer1 header of SACCH blocks. This command will be received at the end of a reporting period (102 frames in SDCCH, 104 in TCH). It will be applied at the beginning of the following period at a rate of 2dB per 13 frames. Before triggering an intercell handover due to uplink causes (RXQUAL or RXLEV) and only step by step power control and for L1mV1 (only), the BTS should request the MS to transmit to its maximum power capability. In such cases, if the MS can increase its transmit power, no Handover Indication is transmitted by the BTS. In the case of a handover, the maximum transmitted power allowed in the target cell is sent to the mobile in the handover command message (msTxPwrMaxCell). In case of intracell handover, the power reduction is kept. The current txpwr value is saved so that it can be sent in the next transmitted uplink SACCH. For the BTS, the duration of the entire process (from order to acknowledgment) is three multiframes. BTS sends PC andTA commands in a SACCH block One SACCH reporting period 26 * 4 = 104 frames (480 ms) BTS gets the Measurement Report SA0 SA1 SA2 SA3 SA0 SA1 SA2 SA3 SA0 SA1 SA2 SA3 MS starts applying New PC and TA MS gets the SACCH block MS starts transmitting SACCH concerning Previous multiframe 4.10.5 AMR POWER CONTROL With the introduction of the AMR feature a new Layer 1 Management has been desgined to take into account AMR channels specificity, including new algorithm for Power Control. Please refer to section Power Control in the chapter AMR - Adaptative Multi Rate FR/HR. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 142/629 V17.0 BSS Parameter User Guide (BPUG) 4.10.6 POWER ADAPTATION AFTER AN INTERZONE HO This section is only applicable to RF power Concentric/DualCoupling/DualBand Cell Handover). control in multizone cells (see PURPOSE Before V17.0, after an inter-zone handover, the BSC sets the BTS and MS initial powers on the new channel of the new zone to values that are identical to those used on the previous channel in the other zone. As a result, the strength of the uplink and the downlink received signal may decrease significantly on the establishment on the new channel. The risk is that the handover could fail or the voice quality could deteriorate until the BTS has adjusted the BTS and MS output TX power on the first run of the L1M power control process. In v17.0, if the BSC expects the reception level to decrease following the interzone handover, the BSC shall adapt the BTS and the MS output power, when activating the new channel, to ensure a constant reception level for the MS and for the BTS. If on trhen other hand, the BSC expects the reception level to increase, the BSC shall keep the BTS and MS power levels unchanged and will simply wait for the L1M to adjust them via the standard power control process. ESTIMATION OF THE THEORETICAL POWER GAP The BSC has to estimate the power gap in uplink and in downlink that would exist after an inner to outer zone handover and an outer to inner handover : • • • • Delta_RxLev_DL_oz_to_iz : DL signal strength gap following an outer to inner HO Delta_RxLev_UL_oz_to_iz : UL signal strength gap following an outer to inner HO Delta_RxLev_DL_iz_to_oz : DL signal strength gap following an inner to outer HO Delta_RxLev_UL_iz_to_oz : UL signal strength gap following an inner to outer HO This estimation depends only on the following O&M parameters : • • concentric_cell (bts object): parameter defining the type of multizone cell : concentric, dualband or dualcoupling. zoneTxPowerMaxreduction (transceiverZone object): attenuation to be applied to bsTxPwrMax (maximum theoretical level of BTS transmission power in a cell), defining the maximum TRX/DRX transmission power in the zone. bizonePowerOffset (handoverControl object): Estimated downlink power offset between inner zone and outer zone TRXs of a multizone cell. For a dual-band cell, this parameter has to be estimated in a worst case (edge of band1 zone). For a concentric or dualcoupling cell, bizonePowerOffset = zoneTxPowerMaxreduction • The 3 different cases of concentric cell give different resultrs for the power gap : Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 143/629 V17.0 BSS Parameter User Guide (BPUG) Concentric Dual-coupling Dual-band Delta_RxLev_DL_ oz_to_iz Delta_RxLev_UL_ oz_to_iz Delta_RxLev_DL_ 5 iz_to_oz( ) Delta_RxLev_UL_ 5 iz_to_oz( ) ZoneTxPowerMaxReduction [oz] - ZoneTxPowerMaxReduction [iz] 0( ) -(Delta_RxLev_DL_oz_to_iz) 0( ) 1 1 ZoneTxPowerMaxReduction [oz] - ZoneTxPowerMaxReduction [iz] 0( ) -(Delta_RxLev_DL_oz_to_iz) 0( ) 1 1 ZoneTxPowerMaxReduction [oz] - ZoneTxPowerMaxReduction 3 4 [iz] - bizonePowerOffset( )( ) - bizonePowerOffset ( ) -(Delta_RxLev_DL_oz_to_iz) bizonePowerOffset 3 Notes : (1) : for concentric and dualcoupling cells, there is no uplink signal strength gap. The uplink gap only applies to dualband cells. (2) : the type of coupler (D, H2D etc) does not impact the formula because the BTS takes the coupling into account to reach the required output power which is equal to bstxpwrmax zonetxpowermaxreduction. So it is the same formula as concetric cell. (3) : The higher the frequency, the steeper the signal strength decrease as a function of MSBTS distance. “bizonePowerOffset” is a worst case assessment of this path loss performed at the inner-zone boundary. (4) : As both heterogeneous coupling and dual-band could be applied simultaneously to a cell, zoneTxPwrMaxReduction must be taken into account in te downlink formula (5) : We hold this truth to be self-evident, that the inner-to-outer zone power gap is the opposite of the outer-to-inner zone power gap. CORRECTION OF THE POWER GAP Upon activating the channel in the destination zone, the BSC considers the relevant theoretical power gap as well as the last BTS transmission power and MS transmission power used on the channel of the initial zone. These are reported by the BTS to the BSC in the Abis connection state ack message. MS TRANSMISSION POWER ADAPTATION As explained above, no power adaptation is required on the uplink for a Concentric cell or a Dual-coupling cell. In a Dual-band cell : • • if the uplink power gap is less than zero, this power loss shall be corrected with a command sent to the MS to increase its transmission power if the uplink power gap is more than zero, the last MS transmission power level shall be kept unchanged. However, the new MS transmission power level shall not be allowed to exceed the maximum power allowed by the network and the maximum MS output power allowed in that band. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 144/629 V17.0 BSS Parameter User Guide (BPUG) BTS TRANSMISSION POWER ADAPTATION Unlike MS transmission power adaptation, BTS transmission power adaptation applies to all three types of multizone cells : • • If the downlink power gap is less than zero, this power loss shall be corrected with a BTS transmission power increase (i.e. BTS attenuation decrease) If the downlink power gap is more than zero, the last BTS transmission power level shall be kept unchanged. The new BS transmission power level is sent by the BSC to the BTS inside the Abis Channel activate message (used to initialise the BTS transmission power for the channel) as well as in the Abis Start measurement Req message (used to initialise the L1M power control algorithm). REMARKS If BTS power control is disabled, there is in effect no power adaptation, as the BTS shall emit at the maximum power allowed in the zone. A dedicated TCH channel shall be activated at full BTS transmission power if it belongs to the BCCH TDMA. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 145/629 V17.0 BSS Parameter User Guide (BPUG) 4.11. TCH ALLOCATION MANAGEMENT 4.11.1 TCH ALLOCATION AND PRIORITY ALLOCATION AND PRIORITY (RUN BY THE BSC) (ALL_1) Different priorities are defined in GSM to prioritise TCH resource usage for the different types of procedures. Basically, GSM procedures can be divided into the following types: • Assignment Request Messages: coming from MSC. It includes Public calls and WPS calls. The only difference between the types of Assignment Requests is basically the priority included in the message. InterBSC Handovers IntraBSC Intercell Handovers Directed Retry Handovers IntraCell Handovers: normal Intracell HO, small to Large zone, AMR, cell tiering … TCH overflow cases: this includes different procedures in the signaling phase when trying to get a resource SDCCH. If this one is not available, a resource TCH will be requested instead. • • • • • For certain procedures like the handovers, where reactivity is crucial, it is important to immediately have TCH resources available. This can be done by reserving some resources for them. For other procedures like the Assignment Requests where the communication is not established yet, it might be more interesting to allow the queuing of the requests for some seconds in order to gain access to the network even if it is a few seconds later. The reactivity time in this last context is not as important as for the handovers. To be able to control this, a priority system has been created. Priorities can be divided into two different groups: external and internal. The BSC is in charge of converting external priorities into internal ones. Conversion rules will be detailed. Two kinds of external priorities, NSS external priorities and BSS external, can be defined: • NSS external priorities are those included in the BSSMAP message coming from the MSC. As only the Assignment Requests and the Handover Requests (for interBSC HO) can generate this type of messages, these are the only procedures having an external NSS priority. BSS external priorities are defined via OMC parameter settings. They are set for all types of procedures, even for the Assignment Requests. • The type of external priority of the Assignment Request procedures taken for conversion to an internal priority is depending on the value of another OMC parameter (bscQueuingOption) that indicates if the mode is “MSC driven” or “OMC driven”. The mode “MSC driven” means that it is the NSS external priority which is taken into account for internal priority conversion of Assignment Request Procedures. For Handover Request and TCH overflow, it is BSS external priority that is used for conversion. The mode “OMC driven” means it is the BSS external priority which is taken into account for conversion, whatever the procedure. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 146/629 V17.0 BSS Parameter User Guide (BPUG) CAUTION! Note that if we are in “MSC driven” mode there might be different Assignment Requests coming from MSC with different priorities, meaning that we could treat them differently according to the type of call. However, in “OMC driven” mode there is only one priority, set with a parameter, for all the types of Assignment Requests. In particular, assignment requests with cause emergency call are not differentiated from the other assignment requests. At this point we can start introducing some of the main OMC parameters used for the TCH allocation management: ALLOCATION AND PRIORITY PARAMETERS bscQueuingOption bscQueuingOption = allowed MSC driven mode bscQueuingOption = forced OMC driven mode bscQueuingOption = not allowed OMC driven mode Queuing is allowed NSS external priorities are taken into account for Assignment Request. BSS external priorities are taken into account for handover request and TCH overflow Queuing is allowed BSS external priorities are taken into account for all procedures Queuing is not allowed BSS external priorities are taken into account all procedures. allocPriorityTable It is probably the most important parameter for the allocation priority management. It is used to make the conversion between external and internal priorities and it consists of a vector containing 18 values. The values can go from 0 to 12 and define the internal priorities associated to the different procedures. The association between external and internal priority is done using the index number (or slot number) in this table that goes from 0 to 17. The index in the table represents the BSS external priority. When NSS external priority is used, in order to convert into internal priority, we look in the slot NSS external priority - 1. NSS external priority contained in the BSSMAP message can take a value from 1 to 14. Slots 1 to 5 are reserved for WPS call treatment. Example: allocPriorityTable = 0 8 9 10 11 12 2 2 2 2 2 2 2 2 3 0 4 2 Slot number allocPriorityTable 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 0 8 9 10 11 12 2 2 2 2 2 2 2 2 3 0 4 2 With this example in MSC driven mode, for a BSS external priority = 16, the internal priority defined is 4 and for a NSS external priority = 5, we have to look at the slot number = 5 – 1 = 4, so the internal priority is 11. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 147/629 V17.0 BSS Parameter User Guide (BPUG) bscQueuingOption "forced" "allowed" OMC driven MSC driven BSS ext. Priority = NSS ext. Priority - 1 (only for Ass. Requests) Slot nb. (BSS Ext. Prio.) allocPriorityTable 0 0 1 8 2 9 3 4 5 6 7 2 8 2 9 2 10 11 12 13 14 15 16 17 2 2 2 2 3 0 4 2 10 11 12 2 WPS allocPriorityThreshold Parameter that defines the number of TCH resources reserved for procedures with internal priority = 0. This internal priority is typically used for Handovers procedures where the reactivity time is very important. For all the other procedures with an internal priority > 0 a TCH will be assigned if at least allocPriorityThreshold + 1 TCH resources are free. If that is not the case the procedure will be rejected or queued depending on the provisioning and type of procedure (see chapter Queuing). CAUTION! The ressource reservation for priotity 0 procedures is independent from the queuing process, i.e. even if the parameter bscQueuingOption = not allowed, the TCH reservation is effective. Note also that this induces two pools of prioritie : • • {0}, for which TCH resources are reserved according to the parameter allocPriorityThreshold [1..12], for which the TCH resources reserved for priority 0 procedures are not available. BSS EXTERNAL PRIORITY PARAMETERS Parameters that are used to associate a BSS external priority to the different types of procedures. As the NSS external priorities can go from 1 to 14, so slots 0 to 13 in the AllocPriorityTable, we recommend using values from 14 to 17 for these parameters. Assign request procedures: • assignRequestPriority: BSS external priority for Assignment Request messages used when OMC driven mode is used. Note: If the MSC driven mode is used and the priority is not included in the incoming Assignment Request message from the MSC, the assignRequestPriority parameter will be used instead. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 148/629 V17.0 BSS Parameter User Guide (BPUG) Handover procedures : • • • • • directedRetryPrio: BSS external priority for incoming Directed Retry Handovers. interCellHOExtPriority: BSS external priority for interBSC interCell Handovers. interCellHOIntPriority: BSS external priority for intraBSC interCell Handovers. intraCellHOIntPriority: BSS external priority for intraCell Handovers (normal intracell Handovers, cell tiering Handovers or AMR intracell Handovers). small to large zone HO priority: BSS external priority for Small to Large Zone intracell Handovers in concentric/dualband/dualcouplig cells. Note: these are external priority taken into account whatever the value of bscQueuingOption. TCH overflow procedures : • • • • • answerPagingPriority: BSS external priority used for TCH overflow procedures for an answer to paging. callReestablishmentPriority: BSS external priority used for TCH overflow procedures during the signaling phase of a Call Reestablishment. emergencyCallPriority: BSS external priority used for TCH overflow procedures during the signaling phase of an Emergency Call. allOtherCasesPriority: BSS external priority used for TCH overflow procedures during the signaling phase of a call establishment with cause “other services”. otherServicesPriority: BSS external priority used for TCH overflow procedures during the signaling phase of a call establishment with cause “other services”. Note: these are external priority taken into account whatever the value of bscQueuingOption. The table below presents the sum up of recommanded setting for each BSS External priority and the mapping of each internal priority via the allocPriorityTable parameter: Parameter BSS Ext priority Internal priority Meaning interCellHOExtPriority interCellHOIntPriority emergencyCallPriority callReestablishmentPriority 15 0 Assigning the internal priority 0 to these procedure will allow to reserveTCH resources for them (using allocPriorityThreshold parameter) 1 assignRequestPriority directedRetryPrio 17 2 reserved for future use Internal priority 2 is assigned to assignment requests in order to perform some queuing as we will see in next section. Directed Retry Handovers are considered to have the same priority than assignment requests, even if queuing is not allowed for this type procedure intraCellHOIntPriority small to large zone HO priority allOtherCasesPriority answerPagingPriority otherServicesPriority 14 3 Internal priority 3 is assigned to IntraCell Handovers in order to perform some queuing as we will see in next section Internal priority 4 is assigned to the TCH overflow procedures 16 4 Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 149/629 V17.0 BSS Parameter User Guide (BPUG) 4.11.2 QUEUING Queuing is used to put TCH allocation request into a waiting queue when no TCH resource is available. Some types of procedures are interesting to queue up: the TCH requests wait during a certain time if these ones are not satisfied the first time. In this way the requests is more likely to succeed if TCH resources become free during the queuing time. This is typically the case of Assignment Requests or Intracell Handovers. By performing some queuing on the Assignment Request the end-user impact is a little increase in the call establishment duration. In the case of Intracell Handovers, as the call is already established, the effect of the queuing from an end-user point of view is barely perceptible. Assignment Requests and Intracell Handovers (normal intracell Handovers, small to large zone, cell tiering, AMR) are the only procedures for which queuing is allowed. TCH overflow procedures and intercell handovers are never queued. The activation of the Queuing must be viewed as a solution to prevent an exceptionnal saturation of TCH. For the waiting queue, a maximum waiting time (allocPriorityTimers) and a maximum number of TCH allocation requests affected to this queue and the queues of greater priorities (allocWaitThreshold) are defined via OMC-R parameters. Note: as intercell handover procedures can not be queued, the allocPriorityThreshold parameter must be correctly set to reserve TCH resource for incoming handovers (ie priority 0 for these procedures). CAUTION! Please note that when an assignment request is queued, the MS is still attached to a SDCCH channel and the measurement process keeps on going to allow the MS to perform a handover on SDCCH. One must so pay attention to: • • enable or not the feature intraBTS handovers on SDCCH (see intraCellSDCCH). Correctly dimension the allocWaitThreshold parameter to spare SDCCH resources QUEUING DRIVEN BY THE MSC (ALL_2) The MSC driven mode is enabled by the bscQueuingOption parameter set to “allowed”. In this mode queuing is used according to the priority defined in the message coming from the MSC for the assignment requests (Slots from 0 to 13) and those defined with BSS external priorities(Slots from 14 to 17) for the other procedures. As the NSS external priorities can take values from 1 to 14 and, according to the conversion rule (Slot Nb =NSS Priority - 1), these priorities match slots from 0 to 13 in the allocPriorityTable. According to this rule, the Assignment Requests with NSS internal priority set to 1, usualy for emergency calls, will be mapped to internal priority 0. In order to make a clear difference between NSS external priorities and BSS external priorities, the recommend values for BSS external priority parameters are from 14 to 17 (see chapter Allocation and priority Parameters). Interest of MSC driven mode is to allow distinction between assignment request and then the possibility to set different priority for them (WPS calls, VIP users …). Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 150/629 V17.0 BSS Parameter User Guide (BPUG) CAUTION! From V15, if WPS is activated, Slots from 1 to 5 are reserved for WPS priorities, as the assignment request coming from the MSC for WPS requests can go from 2 to 6 (see chapter WPS - Wireless Priority Service). QUEUING DRIVEN BY THE BSC (ALL_3) The OMC drive mode is enabled by the bscQueuingOption parameter set to “forced”. In this mode queuing is used according uniquely to the priority defined with the BSS external priorities (Slots from 14 to 17). Queuing is managed by the BSC whatever queuing information coming from the MSC are. So an assignment request priority is set accordingly to assignRequestPriority and the mapping associated to in the allocPriorityTable. CAUTION! In this mode, WPS can not be efficient because resource allocation request queuing depends on the type of operation only: thus the priority in the WPS assignement request is not considered (see chapter WPS - Wireless Priority Service). In the same way, assignment request with cause emergency calls cannot be differentiated in this mode, and are treated with priority according to assignRequestPriority. QUEUING PROCESS Whatever the queuing mode is, a queue is defined by its size and the maximum waiting time beyond which it is not allowed to queue the request anymore,. set by these two parameters: allocWaitThreshold This parameter is a 13 slot vector. The slot number (0…12) represents the internal priority queues and the values define the maximum number of TCH allocation requests queued for each internal priority. The last five slots set to 5 are reserved for WPS call treatment. These values are accumulative, so the value for one queue represents the maximum number of requests for that queue and all the queues with lower priorities. Note that the serving preference for these queues has an increasing order, e.g. if there are two TCH allocation requests waiting in two different queues, when a TCH resource is released, the request with the lowest priority is served. Slot number allocWaitThreshold 0 1 2 3 4 5 6 7 8 9 10 11 12 n 0 n n 0 0 0 0 5 5 5 5 5 n is the integer part of (number of SDCCH sub-channels in the cell)/2. Note: that while the TCH request is queued it remains in a SDCCH sub-channel. A queue size longer than the number of sub-channels SDCCH in the cell is so useless. On the other hand a value closed to the number of SDCCH channels may cause an increase of SDCCH blocking rate due to the lack of SDCCH resources. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 151/629 V17.0 BSS Parameter User Guide (BPUG) allocPriorityTimers This parameter is a 13 slot vector. The slot number (0…12) represents the internal priority queues and the values mean the maximum waiting time (in seconds) in the queue of a TCH allocation request for each internal priority. The last five slots set to 28 are reserved for WPS call treatment. Slot number allocPriorityTimers 0 1 2 3 4 5 6 7 8 9 10 11 12 5 0 5 5 0 0 0 0 28 28 28 28 28 Note: a too long timer is unrealistic as an user will not wait indefinetely. Sum up of the recommanded value Slot number allocPriorityTable Internal priority / queue number allocWaitThreshold allocPriorityTimers 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 0 8 9 10 11 12 2 2 2 2 2 2 2 2 3 0 4 2 0 n 5 1 0 0 2 n 5 3 n 5 4 0 0 5 0 0 6 0 0 7 0 0 8 5 28 9 5 28 10 5 28 11 5 28 12 5 28 • • • • • • • procedures coming with an external priority 0 or 15 are associated to internal priority and queue 0, but queuing is not allowed for intercell handovers (system rule). In this configuration, only Emergency Call can be queued for the external priority 0. internal priority and queue 1 are reserved for future use procedures coming with an external priority from [6 to 13] or 17 are associated to internal priority and queue 2 and queuing is allowed procedures coming with an external priority 14 are associated to internal priority and queue 3 and queuing is allowed procedures coming with an external priority 16 are associated to internal priority and queue 4 but queuing is not allowed procedures coming with an external priority from [1 to 5] are associated to internal priorities and queues [8 to 12] and queuing is allowed (if WPS activated) internal priorities and queues [5 to 7] are not used CAUTION! • There is no queuing for TCH in “signaling mode” (TCH overflow). • It is important to note that even if Directed Retry Handovers are associated to an internal priority 2 queuing is not allowed for this type of procedure, as for the other intercell handover procedures. • Queuing set for procedures with internal priority 0 has been intentionally configured for Assignment Requests cause “Emergency Call” (which should have in this case a NSS external priority set to 1 if in MSC driven mode). Indeed, the only other procedures with priority 0 are intercell handover for which queuing is forbidden. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 152/629 V17.0 BSS Parameter User Guide (BPUG) • It is recommended to give different BSS external priorities for the Assignment Requests and intracell Handovers in order to prioritise the queued allocations for Assignment Requests. This type of procedure is more sensitive from an end-user point of view. A user not succeeding in the assignment request will experience an establishment failure and have to re-establish the call, whereas in the intracell Handovers, the call is already established and even in case of Intracell Handover failure that does not necessarily mean a call drop. The intracell Handover may be re-tried without a real end-user impact. Below is the flowchart summarizing the TCH allocation handling if queuing is configured as recommended in MSC driven mode: Note: if directed retry handover is activated, another way of leaving the queue is a directed retry handover. Refer to Directed Retry Handover for more details. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 153/629 V17.0 BSS Parameter User Guide (BPUG) 4.11.3 BARRING OF ACCESS CLASS On SYS INFO messages, the list of mobile access classes that can not start a call on the cell is broadcast. Up to V8, this list is represented by the OMC-R parameter notAllowedAccessClasses. From V9, a feature allows the modification of what is sent on SYS INFO in case of congestion. CAUTION! As the MS reads SYS INFO messages every 30 seconds in idle mode, there could be a time window where non-authorized mobiles will still be allowed, e.g. if the MS did not read the message before the cell selection, it could start a call. DYNAMIC BARRING OF ACCESS CLASS (ALL_4) The mechanism consists of temporarily forbidding cell access to some of the mobiles (according to their access class) when a congestion situation is observed. The congestion condition is based on: • The number of free TCH channels. Note that TCH resources reserved for maximum priority requests (internal priority = 0) are not considered as free TCH channels. The parameters are numberOfTCHFreeBeforeCongestion and numberOfTCHFreeToEndCongestion. or • The number of queued requests in the cell. The parameters are numberOfTCHQueuedBeforeCongestion numberOfTCHQueuedToEndCongestion. and The feature is enabled at bsc level by the attribute bscMSAccessClassBarringFunction, and at bts level by the attribute btsMSAccessClassBarringFunction. PRINCIPLE In case of non-congestion, only the list of mobile access classes in notAllowedAccessClasses is not allowed to select the cell. In case of congestion, the list of mobile access classes in accessClassCongestion is not allowed. NO Congestion ? YES notAllowedAccessClasses Forbidden in the cell accessClassCongestion Forbidden in the cell Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 154/629 V17.0 BSS Parameter User Guide (BPUG) CONGESTION DETERMINATION To enter a congestion state, either the number of free TCH must be less than numberOfTCHFreeBeforeCongestion or the number of queued TCH requests must be greater than numberOfTCHQueuedBeforeCongestion. To leave a congestion state, either the number of free TCH is greater than numberOfTCHFreeToEndCongestion or the number of queued TCH request is less than numberOfTCHQueuedToEndCongestion. Example with a one TRX cell where one time slot is reserved for requests with an internal priority equal to 0: numberOfTCHFreeBeforeCongeston = 1 BCCH SA0 BCCH SA0 BCCH SA0 SA1 SA1 SA1 SA2 SA2 SA2 SA3 SA3 SA3 SA0 SA0 SA0 SA1 SA1 SA1 SA2 SA2 SA2 SA3 SA3 SA3 T: TDMA enter in congestion T+1: TDMA is still in congestion T+2: TDMA gets out of congestion numberOfTCHFreeToEndCongeston = 3 time SA1 Used TCH SA0 Free TCH SA3 reserved TS for priority 0 A congestion situation may be detected each time one of the following events occurs: • • • • • allocation of a TCH resource queuing of a TCH resource request blocking of a TCH resource (O&M action) TDMA removal for defense or O&M reason detection thresholds modification End of congestion situation may be detected each time one of the following events occurs: • • • • • release of a TCH resource a queued TCH resource request is served or aborted unblocking of a TCH resource (O&M action) TDMA attribution detection thresholds modification Note: The overload state duration of a cell can be monitored thanks to the counter C1714, but that counter is effectively reported to the OMC-R only if the load of the cell is taken into account (i.e. only if hoTraffic = enabled at cell and BSC levels). Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 155/629 V17.0 BSS Parameter User Guide (BPUG) V15.0 CHANGES OF DYNAMIC BARRING OF ACCESS CLASS (ALL_4) The previous “access class barring” mechanism can be improved on 3 main points: • • • The list of forbidden access classes is fixed, so the same customers are always impacted. The number of barred access classes is fixed, so the number of barred access classes may be insufficient. The mechanism is triggered on TCH allocation or release basis, but due to the Erlang law (which induces sudden traffic modification) and because the MS rereads the SYS INFO (only every 30 seconds), that mechanism could be improved. To ensure the functionning of the new mechanism, two levels of barring are created and run at the same time: • • One level (low level) to provide point 1 and point 3 One level (high level) to provide point 2 This feature is controlled by bscMSAccessClassBarringFunction on the bsc object and btsMSAccessClassBarringFunction on the bts object. HIGH LEVEL MECHANISM DESCRIPTION To provide point 2, the number of access classes can be modified (additional or less) in order to adapt to the length of congestion level. Once the cell enters in the congestion state, a supervision timer is set, and every 3 minutes (system rule), an adaptation is made based on the new cell congestion state: • • If the cell is still in the congestion state, 2 additional access classes are barred (assuming they are not all barred) If the cell is not in the congestion state, 2 less access classes are barred (until none are barred) Once the cell is no longer in the congestion state, and if no access classes are barred, the supervision timer (3 minutes) is stopped. Congestion level Beginning of congestion Beginning of congestion: 3 minutes timer is set End of congestion 3 minutes End of congestion : 3 minutes timer is running No more classes barred: 3 minutes timer is stopped time Number of access classes barred [0 to 2] [2 to 4] [4 to 6] [6 to 4] [4 to 2] [2 to 0] This mechanism is independent of the low level of barring mechanism. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 156/629 V17.0 BSS Parameter User Guide (BPUG) The barred access classes rotate inside the 3 minute time period according to the low level mechanism of barring described below: LOW LEVEL MECHANISM DESCRIPTION Two parameters are important accessClassCongestion parameter. in this mechanism: the periodicity and the Periodicity: the congestion condition is still triggered on a TCH allocation or TCH release basis, but once the congestion condition is triggered, a 60 seconds interval (system rule) is used to periodically change which access classes are barred. accessClassCongestion parameter: this parameter is a list of access classes which are eligible to be barred during the congestion condition. The principle is that, during each 60 seconds interval of congestion, a different subset of access classes (and thus a different set of mobile sets) may be barred. Access classes 11 to 15 are managed and can be automatically barred if they are included in the accessClassCongestion parameter. They can not be automatically barred if they are not in the accessClassCongestion parameter. LOW AND HIGH LEVEL MECHANISM EXAMPLE Congestion level Beginning of congestion Beginning of congestion: 3 minutes timer is set End of congestion 3 minutes 60 seconds time Number of access classes barred Barred access classes [0 to 2] [0,1] [2] [2,3] [2] [4,5] [2 to 4] [6,7,8,9] [4] [0,1,2,3] [4] [4,5,6,7] [4 to 2] [8,9] Let us take an example for the accessClassCongestion = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]. Next time the cell is in congestion, since the last barred access classes are memorised in the BSC, the new barred access class are the 2 followings in the list of access classes indicated in the accessClassCongestion parameter. In case the BSC12000 switchover, TMU reset for BSC3000 or lock/unlock of the cell, the first barred access class is the first one in the list of access classes indicated in the accessClassCongestion parameter. In case the feature is turned off (cell or BSC level), the BSC sends immediately the system information with notAllowedAccessClasses parameter included whatever is the cell congestion status. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 157/629 V17.0 BSS Parameter User Guide (BPUG) In case the accessClassCongestion parameter is modified while the cell is in congestion, the list of access classes to be barred will be re-evaluated on the 60s timer expiry, and on the 3 minutes timer expiry, the evaluation will be done on this new list (and not on the list of the previous 3 minutes timer expiry). NOTALLOWEDACCESSCLASSES PARAMETER MANAGEMENT Until BSS V15, the following principle applies: • • In case of non congestion, only the list of mobile access classes in “notAllowedAccessClasses” is not allowed to select the cell In case of congestion, the list of mobile access classes in “accessClassCongestion” is not allowed. Usually all users are authorized, and the notAllowedAccessClasses list is empty. With the redefinition of the access class barring functionality, the management of the notAllowedAccessClasses parameter is modified in the following way: • In case of non congestion, only the list of mobile access classes in the “notAllowedAccessClasses” parameter is not allowed to select the cell: there is no modification compared to the previous management. In case of congestion, the accessClassCongestion parameter is used to process access classes rotation on all the access classes listed in the accessClassCongestion except on the access classes listed in the notAllowedAccessClasses parameter, which remain barred during the congestion. • Let us take the example for the accessClassCongestion = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] and notAllowedAccessClasses = [3, 4]. This means, as described here above, that access class rotation will be done on the following access class list = [0, 1, 2, 5, 6, 7, 8, 9] and that access classes 3 and 4 remain barred during the congestion. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 158/629 V17.0 BSS Parameter User Guide (BPUG) 4.11.4 RADIO LINK FAILURE PROCESS (RUN BY THE MS) It is performed by the MS in dedicated mode on SACCH blocks. RLC counter is initialized to radioLinkTimeout at the beginning of a dedicated mode. IF good SACCH block THEN RLC = Min[RLC+2, radioLinkTimeout] IF bad SACCH block THEN RLC = RLC - 1 If RLC reaches 0, then call is dropped and re-establishment is tried if reselection is made on a cell with CallReestablishment set. 4.11.5 RADIO LINK FAILURE PROCESS (RUN BY THE BTS) The FrameProcessor sets the CT counter to 0 at channel activation On each correct SACCH: IF good SACCH block AND IF (CT = 0) THEN CT = 4*rlf1 + 4 ELSE CT = Min[4*rlf1 + 4,CT+rlf2] IF bad SACCH block CT = max(0,CT-rlf3) If CT reaches 0, a connection Failure Indication is sent to the BSC every T3115, until a Deactivate Sacch or RF Channel Release message is received. This process is started when the first SACCH frame is received correctly, and the CT counter is set according to rlf1 value. If SACCH frame is not received, then the radio link failure process is not started, CT value is kept to zero and is not modificated. Interest of the algorithm: the quality of an uplink communication is now considered for the decision to cut a communication. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 159/629 V17.0 BSS Parameter User Guide (BPUG) 4.11.6 CALL REESTABLISHMENT PROCEDURE The call re-establishment procedure allows a mobile station to resume a connection in progress after a radio link failure, possibly in a new cell and possibly in a new location area. So this feature avoids losing calls, improving in that way the quality of service. Moreover, in case of call drop, it reduces the SICD load by avoiding the subscriber to hang off and on. The Call Re-establishment can be launched following 2 different procedures depending on the entity which detects the radio link failure: • a) The radio failure is first seen at the MS side (RadioLinkTimeOut value): The mobile sends a call-reestablishment on a selected cell (previous one or new one) and the MSC re-allocate new resources. The old resources are free by the BSS after the rlf1 timer has expired. • b) The radio failure is first seen at the BSS side: The BTS send a radio_link_failure message to the BSC after rlf1 has expired, the BSC releases the radio resources and in the same time the MSC activates the t3109 timer and waits a call-reestablishment. Then, when the MS has detected the radio link failure as well, it performs the selection and sends a channel request on the selected cell. To attempt a call re-establishment on a cell, the parameter callReestablisment of the cell will be set to “allowed” and the cell will not be barred (see chapter Barring of access class). The mobile station is not allowed under any circumstance, to access a cell to attempt call reestablishment later than 20 seconds after it detects the radio link failure causing the call reestablishment attempt. The mobile station shall perform the following algorithm to determine which cell to use for the call re-establishment attempt within 5 seconds max: • 1) The level measurement samples taken on the serving cell BCCH carrier and on neigbhor cells carriers (carriers indicated in the BA (SACCH) received on the serving cell) received in the last 5 seconds shall be averaged. The carried with the highest average received level is selected. 2) On this carrier the MS shall attempt to decode the BCCH data block containing the parameters affecting cell selection. 3) If the parameter C1 is greater than zero call re-establishment shall be attempted on this cell. 4) If the MS is unable to decode the BCCH data block or if the call re-establishment is not allowed, the carrier with the next highest average received level shall be taken, and the MS shall repeat steps 2) and 3) above. 5) If the cells with the 6 strongest average received level values have been tried but cannot be used, the call re-establishment attempt shall be abandoned. • • • • • Beware, during a re-establishment attempt the mobile station does not return to idle mode, thus no location updating is performed even if the mobile is not updated in the location area of the selected cell, however the mobile station will update its location area at the end of the call. Generally a call re-establishment procedure lasts from 4 seconds to 20 seconds max. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 160/629 V17.0 BSS Parameter User Guide (BPUG) 4.11.7 CALL CLEARING PROCESS (RUN BY BTS) This process is used to drop calls with mobiles which are located too far away from a serving cell and that may disturb other communications on adjacent time slots. Every runCallClear: IF (MS_BS_Dist > CallClearing) THEN call needs clearing. 4.11.8 INTERFERENCE MANAGEMENT (BTS AND BSC) All interference measurements performed by the BTS on the idle channels are performed in Watts. Each sample is computed in Watt before being translated in dBm and sent to the L1M. This method of calculation provides a result which is 2.5 dB higher than the one directly performed in dB. Every averagingPeriod, BTS computes Interference levels of idle channels (SDCCH and TCH) according to the 4 defined thresholdInterference (resulting in 5 Interference ranges) and sends this information to the BSC. It is therefore possible to monitor interference levels at the OMC. From V8, the BSC will use RadChanSelIntThreshold parameter in order to sort available channels according to their interference level. Thus the BSC will allocate channels using the following priority: • • • • Hop and low_IF NoHop and low_IF Hop and (high_IF or just released) NoHop and (high_IF or just released). Note: No interference level management is performed for PDTCH channel, Therefore the level status of PDTCH resource is always high level (bad level). 4.11.9 UPLINK DTX DTX is possible both downlink and uplink, but configuration and activation are uncorrelated in the 2 mechanisms. The uplink DTX feature is enabled when dtxMode parameter is set to “msShallUseDtx” (the shall is dependent on the MS decision or capability. When uplink DTX is activated on the network, MS gets the information from the BTS (activation parameter). Then it is allowed to perform uplink DTX, i.e. to transmit discontinuously only a subset of TCH bursts. If the MS perform DTX on a call, the minimum number of transmitted bursts is 12 (out of 104 for a complete reporting period of 480ms). The 12 bursts correspond to the 4 SACCH + 8 fixed positioned TCH bursts. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 161/629 V17.0 BSS Parameter User Guide (BPUG) Compared to a full TCH frame (120ms to be multiplied by 4 for a complete message): DTX deactivated DTX activated 1 SACCH 12 bursts TCH 12 bursts TCH 1 idle (given fixed positions are only examples; for speech, a SID frame (Silence Descriptor frame: used to describe comfort noise) made of 8 consecutive TSs shall be sent at the start of every inactivity period and more are sent regularly, at least twice per second, as long as inactivity lasts) • Full frame x 4: (24 TCH + 1 SACCH + 1 idle) x 4 = 96 TCH + 4 SACCH + 4 Idle = 104 bursts • With DTX: (1 SACCH) x4 + 8 TCH = 12 bursts minimum Then, depending on the communications (presence of silences), the MS can use DTX or not. Note: To the minimum number of bursts (12) can be added other transmitted bursts depending on some criteria (user traffic activity and interleaving depth). The MS sends to the BTS 2 kinds of measurements, RxQual/RxLev Full, and RxQual/RxLev Sub. RxQual/RxLev Full corresponds to an average of measurements performed over 100 out of 104 frames in a SACCH reporting period. These measurements are valid if DTX has not been used by the MS. RxQual / RxLev Sub correspond to an average of measurements performed over 12 frames (instead of 100), these 12 frames being fixed as explained previously. These measurements are valid if DTX has been used by the MS. With these measurements, the MS has to send to the BTS a notification that it has performed DTX or not (uplink DTX status), so that the BTS can choose the average which is valid (RxQual / RxLev Full or Sub) for L1M purposes. This notification is done via the DTX-used bit in the Measurement Report. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 162/629 V17.0 BSS Parameter User Guide (BPUG) 4.11.10 DOWNLINK DTX In the same way as the mobile, the BTS is able to transmit discontinuously (cellDtxDownLink parameter, bts object). The activation of downlink DTX follows depends on : • • • • authorisation for the BSS to use DL DTX, given by the MSC to the BSC at assignment request, dynamically on a call-by-call basis The value of cellDtxDownLink parameter (bts object) The type of radio channel : voice half-rate, voice full-rate, cicuit data The values of certain bits in the bscDataConfig file (bits n°1, n°2 and n°3 of label 64) MSC AUTHORISATION On a call per call basis, the MSC may forbid the BSS to use Downlink DTX. The MSC indicates this to the BSC by including a 1-bit long field called “DTX Downlink Flag” inside BSSMAP Assignment Request (for call setup) or BSSMAP VBS/VGCS Assignment Request (for group call setup, GSM-R only) or BSSMAP Handover Request (for incoming external handover of a call coming from another BSS) : If “DTX Downlink Flag” is present and if DTX Downlink Flag = 1, then the MSC forbids the use of DL DTX for that particular call If “DTX Downlink Flag” is absent or if DTX Downlink Flag is present and DTX Downlink Flag = 0, then the MSC does not forbid the use of DL DTX for that particular call In the second case, the decision to use DL DTX for that call is left entirely up to the BSS and depends on BSS configuration parameters and the type of channel. CELLDTXDOWNLINK If cellDtxDownLink = disabled in the cell, then Downlink DTX is unconditionally turned off in the cell for all types of call (voice and circuit-switched data). So, cellDtxDownLink = enabled is a necessary condition to activate downlink DTX in the cell, but it is not sufficient. It further depends on the type of channel (circuit data, voice half-rate, voice full-rate). Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 163/629 V17.0 BSS Parameter User Guide (BPUG) TYPE OF CHANNEL CIRCUIT-SWITCHED DATA CHANNELS DTX downlink is unconditionally turned off for circuit-switched data channels, even if cellDtxDownLink = enabled. Note : Bit n°1 of label 64 of bscDataConfigfile, called “DTX Downlink in data”, is not used any longer in the software. Whatever its value, and whatever the value of cellDtxDownLink, DTX Downlink is disabled for CS data channels. FULL-RATE VOICE CHANNELS If bit n°2 of label 64, called “DTX Downlink FR”, is equal to 1 : DTX Downlink is unconditionally turned off for FR voice channels. This applies to all types of full-rate codecs supported by the BSS : AMR FR, EFR and FR. If bit n°2 = 0, and if cellDtxDownLink = “enabled” in the cell, then downlink DTX is used on all FR Voice channels, provided that its use has not been explicitly forbidden by the MSC at assignment request stage. By default, label 64 bit n°2 = 0 so by default DL DTX is activated for FR voice calls. HALF-RATE VOICE CHANNELS If bit n°3 of label 64, called “DTX Downlink HR”, is equal to 1 : DTX Downlink is unconditionally turned off for AMR HR voice channels. If bit n°3 of label 64 = 0, and if cellDtxDownLink = “enabled” in the cell, then downlink DTX is used on all AMR HR Voice channels, provided that its use has not been explicitly forbidden by the MSC at assignment request stage. By default, label 64 bit n°3 = 0 so by default DL DTX is activated for FR voice calls. SUMMARY The table below summarises the activation scenarios of DL DTX : DTX DL flag (from MSC) cellDtxDown Link any value disabled enabled enabled enabled enabled enabled enabled enabled enabled Label 64 bit 1 Label 64 bit 2 Label 64 bit 3 DL DTX for CS data DL DTX for FR voice DL DTX for HR voice 1 0 or absent 0 or absent 0 or absent 0 or absent 0 or absent 0 or absent 0 or absent 0 or absent 0 or absent any value any value 0 0 0 0 1 1 1 1 any value any value 0 0 1 1 0 0 1 1 any value any value 0 1 0 1 0 1 0 1 disabled disabled disabled disabled disabled disabled disabled disabled disabled disabled disabled disabled enabled enabled disabled disabled enabled enabled disabled disabled disabled disabled enabled disabled enabled disabled enabled disabled enabled disabled Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 164/629 V17.0 BSS Parameter User Guide (BPUG) 4.12. EMLPP PREEMPTION 4.12.1 PRINCIPLE OF EMLPP DEFINITIONS eMLPP priority : eMLPP priority associated to a call for preemption purposes. The BSC transparently conveys eMLPP priority between the mobile and the NSS. The BSC does not process this eMLPP priority. NSS external priority (also known as BSSMAP priority) : priority associated to a call by the NSS in the assignment or handover procedure. This priority is sent by the NSS to the BSS and may then be used by the BSS for queuing or for preemption. Unlike the eMLPP priority, it is transparent to the mobile. BSS external priority : queuing priority defined via OMC parameter settings. Each type of procedure is associated to a BSS external priority for queuing. This priority is used by the BSS but it is strictly local, therefore the NSS and MS are not aware of it. internal priority : this priority is local to the BSS. Therefore the NSS and MS are not aware of it. It is an output of the allocprioritytable. PRINCIPLE eMLPP is an extension to GSM networks of the existing MLPP service for fixed lines. eMLPP covers 2 basic aspects : • • Resource preemption for mobile originated or mobile terminated call establishment procedures Called party preemption for mobile terminated calls RESOURCE PREEMPTION eMLPP allows the network to preempt resources from ongoing calls (circuits on the A interface and/or radio resources in the BSS) to allocate them to an incoming call of greater priority : o Preemption on the A interface is fully managed (decision and execution), on a per call basis, by the NSS. Preemption on the Radio interface is executed, on a per call basis, by the BSS. However, the decision to allow the preemption comes from the NSS because the NSS is in charge of the Call Control procedures. o Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 165/629 V17.0 BSS Parameter User Guide (BPUG) CALLED PARTY PREEMPTION In the case where the called subscriber has a subscription for eMLPP and for CW (Call Waiting supplementary service), the mobile station shall be informed of the priority of the incoming high priority call together with the CW indication. On reception of the set-up message for the incoming call the compatible mobile station decides on called party pre-emption. If called party pre-emption applies, the mobile station shall automatically accept the incoming waiting call and send a hold message to the network. If a hold acknowledge is received, the waiting call is accepted. CW is mandatory for called party preemption. 4.12.2 END-TO-END PERSPECTIVE eMLPP is an extension to GSM networks of the existing MLPP service for fixed lines. In GSM, eMLPP is a Supplementary Service that is essentially under the control of the NSS. It allows the network to preempt resources (circuits on the A interface and/or radio resources in the BSS) for a particular call. The eMLPP precedence level is selected by the subscriber on a per call basis. The subscriber may select any precedence level up to and including his maximum authorized precedence level. The service provider at the subscriber’s originating exchange ensures that the selected precedence level does not exceed the maximum level assigned to that subscriber. EMLPP PRIORITY eMLPP defines seven priority levels as A, B, 0, 1, 2, 3, and 4 (“A” being the strongest and “4” the weakest priority). Mobile users may subscribe to all priority levels A, B, 0, 1, 2, 3, or 4. However, priority levels A and B may only be used locally, i.e. in the domain of one MSC. The other five priority levels are offered for subscription and may be applied globally, e.g. on interMSC links, and also for interworking with ISDN networks that provide the MLPP service. The precedence level is selected by the subscriber on a per call basis. The subscriber may select any precedence level up to and including his maximum authorized precedence level. The service provider at the subscriber’s originating exchange ensures that the selected precedence level does not exceed the maximum level assigned to that subscriber at subscription. In public GSM, the eMLPP priority is transparent for the BSS. It is meaningful only for the mobile and for the NSS. It is included in the following messages : • By the mobile in the CM SERVICE REQUEST message sent to the NSS, for mobileoriginated call establishment. It indicates to the NSS the eMLPP priority requested by the mobile for the call establishment. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 166/629 V17.0 BSS Parameter User Guide (BPUG) • By the BSS in the PAGING REQUEST type 1, 2 ,3 messages sent to the mobile on the PCH channel. The purpose of including eMLPP priority in paging requests is used by mobiles who are engaged as listeners in a group call to decide to leave the group call or not. By the NSS in the PAGING message sent to the BSS. The purpose of including eMLPP priority in BSSMAP PAGING message is so that the BSS may include it in the Paging Request (see previous bullet point) By the NSS in the SETUP message sent to the mobile for mobile-terminated call establishment. It indicates to the mobile already engaged in a call whether to perform called party preemption or not. By the NSS in the CALL PROCEEDING message by the network to the mobile. This message is sent by the network to the calling mobile station to indicate that the requested call establishment information has been received. In this message, the NSS indicates to the mobile station the eMLPP priority level that the NSS has granted to the call. • • • EMLPP SUBSCRIPTION Two precedence levels are defined by subscriber and stored at the HLR: • • Subscriber’s Maximum Precedence Level. The subscriber may originate a call with a precedence level up to his maximum precedence level Subscriber’s Default Priority Level. In the case no precedence level is sent in the “CM service request” message, this level is used as the priority of the call EMLPP PRIORITY SETTING AT MO CALL SETUP For Mobile Originated point to point calls, the eMLPP priority precedence level is included inside the CM SERVICE REQUEST message sent by the mobile to the network. Its value is set as follows. EMLPP SUBSCRIBER The user may select an eMLPP priority value for the call. If he does not, the precedence is set to its default value by the mobile. The mobile checks that the priority is within the provisioned range. The MSC validates the priority value, and possibly reduces it to the subscriber’s maximum precedence stored in the VLR Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 167/629 V17.0 BSS Parameter User Guide (BPUG) NON-EMLPP SUBSCRIBER A default priority level is set by the MSC. 4.12.3 PREEMPTION ATTRIBUTES OVERVIEW Each call that comes into a BSC from the NSS (via ASSIGNMENT REQUEST or HANDOVER REQUEST) has radio resource preemption capabilities, that have been allocated to it by the NSS. BSS Radio resource Preemption works as follows. In case of a lack of available radio resources, the BSC is capable of allocating currently occupied resources to incoming calls that have a preemption capability, by preempting resources of ongoing calls that are preemptionvulnerable. Only TCH channels in dedicated mode, or PDTCH channels used for a CS call, are subject to preemption. The preemption mechanism of radio resources that is detailed here is based on the “BSSMAP Priority” Information Element carried in ASSIGNMENT REQUEST or HANDOVER REQUEST messages at the BSSMAP layer of the A interface. The BSSMAP priority is the input given to the BSC by the MSC. The “BSSMAP Priority” Information Element contains preemption attributes that are the result of the eMLPP functionality implementation in the NSS. PREEMPTION ATTRIBUTES The BSSMAP priority information element of a given call is optional and contained in ASSIGNMENT REQUEST and HANDOVER REQUEST. It is sent by the NSS to the BSS, and it provides the BSS with the eMLPP preemption capability of the call. IF THE BSSMAP PRIORITY IS PRESENT The BSSMAP priority information element is made up of the following 4 attributes : PCI, PVI, QA and Priority. PCI: preemption capability indicator. The PCI attribute is a flag that specifies whether the call is allowed to preempt another one or not. It is applicable while negotiating the allocation of resources : • • PCI = 0 : this allocation request (resulting from assignment or handover) cannot trigger the preemption procedure. PCI = 1 : this allocation request (resulting from assignment or handover) can trigger the running of the preemption procedure. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 168/629 V17.0 BSS Parameter User Guide (BPUG) PVI: preemption vulnerability indicator. The PVI attribute is a flag that specifies whether the call is allowed to be preempted by another call or not. • • PVI = 0 : this connection is not vulnerable to preemption. PVI = 1 : this connection is vulnerable to preemption. QA: queueing allowed indicator. The QA attribute is a flag that specifies whether the call is allowed to b a queueing procedure or not : • • QA = 0 : queuing is not allowed QA = 1 : queuing is allowed PRIORITY : priority level. The priority attribute is an integer value in the range 1 ... 14 that specifies the level that is applied to the call. Values 0 and 15 indicate “priority not used”. It is built by the MSC thanks to a hardcoded lookup table that maps the eMLPP priority of the call to the BSSMAP priority. eMLPP priority value BSSMAP priority value A (strongest priority) B 0 1 2 3 4 (weakest priority) 1 2 3 4 5 6 7 IF THE BSSMAP PRIORITY IS ABSENT If the BSSMAP priority is absent, the assignment request for that call is treated by the BSS as though the flags were defined as follows : • • • • PCI = 0: no preemption capability; PVI = 0: no vulnerability; QA = 0: queueing not allowed; priority level = 0: no priority. 4.12.4 BSS RADIO RESOURCE PREEMPTION ALGORITHM PROCEDURE Definition : a vulnerable resource is a radio resource whose PVI is defined and equals 1. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 169/629 V17.0 BSS Parameter User Guide (BPUG) Upon receiving an ASSIGNMENT REQUEST or a HANDOVER REQUEST, the BSC follows the following allocation algorithm : • • If there is an available radio resource, the BSC immediately performs the allocation without invoking the preemption procedure; If there is no available radio resource : o If PCI = 1 attribute is set for the request, and if a vulnerable resource (PVI = 1) is available whose priority is strictly weaker than the request’s priority, the BSC triggers the preemption procedure : the BSC starts the release of the active call using this vulnerable resource and starts a specific internal timer (Tpreempt). If the release of the vulnerable resource is completed before expiry of Tpreempt, or if another resource is freed up in the meantime, the assignment is successful. if Tpreempt expires before the resource is freed up, the preemption procedure stops and the BSC declares an assignment failure. No queuing or directed retry is attempted. o If PCI is absent or if PCI = 0 or if no vulnerable resource exists or if the weakest priority of the existing vulnerable (PVI =1) resources is at least as strong as the request’s priority, the BSC does not start a preemption procedure. Instead : If allowed, the queuing and directed retry procedures are started, Otherwise the BSC declares an assignment failure. PREEMPTION TIMER The preemption timer value Tpreempt is computed from T3111 timer (t3111 parameter) as follows: Tpreempt = TdeactAck + (4 x T3111) Tdeactack = 5 seconds (hard-coded). VULNERABLE TCH SELECTION CRITERIA The selection algorithm differs depending on the type of transceiver : DRX and DCU2. To simplify, we assume that only DRX are used (not DCU2). RANKING OF OCCUPIED TCH RESOURCES To be considered a possible candidate for preemption by the BSC, a TCH must first fulfill the following requirements : o the TCH must be occupied by a FR voice call, Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 170/629 V17.0 BSS Parameter User Guide (BPUG) o o and the TCH must be allocated in the large zone in case of concentric cell, and the PVI of the call must be equal to value 1 (preemption possible), Such a TCH is called a “busy TCH”. The BSC puts these potential candidates in 2 separate pools : o o hopping busy TCH pool non-hopping busy TCH pool In each of these pools, the BSC classifies the TCH according to the BSSMAP priority of the call : o o o o o BSSMAP = 0 first (value “0” means “spare” in the GSM specs) Next BSSMAP = 14 (weakest priority) Next BSSMAP = 13 … Finally, BSSMAP = 1 (strongest priority) Busy TCH of equal BSSMAP priority are ranked as follows : 1. TCH allocated to VBS/VGCS initiators are always in front : the most recent ones first, followed by the second most recent etc. The oldest ones are last in the list. 2. TCH allocated to point-to-point calls or to VBS/VGCS listeners come next : the most recent ones first, followed by the second most recent etc. The oldest ones are last in the list. SELECTION ALGORITHM FOR PREEMPTION VOICE CALL ALLOCATION REQUEST For a preemption-capable allocation request concerning a voice call, the BSC selects the TCH timeslot to preempt based on the following algorithm : o Choice of “busy TCH” pool : hopping TCH pool is preferred. If the “hopping busy TCH” pool is empty, the BSC searches instead inside the non-hopping busy TCH pool. Once the correct pool is selected, the BSC chooses the first busy TCH in the list (according to the ranking explained above) whose priority is strictly weaker than the allocation request. o CIRCUIT DATA CALL ALLOCATION REQUEST The only difference with speech concerns the choice of busy TCH pool (hopping or nonhopping) : Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 171/629 V17.0 BSS Parameter User Guide (BPUG) o If the circuit data allocation request concerns the CSD 14.4 service and if the bts object parameter data14-4OnNoHoppingTs = enabled, the preferred “busy TCH” pool is the non-hopping one. If the circuit data allocation request concerns the CSD 14.4 service and if the bts object parameter data14-4OnNoHoppingTs = disabled, the preferred “busy TCH” pool is the hopping one (same a speech allocation request). If the circuit data allocation request concerns CSD services other than 14.4, the preferred “busy TCH” pool is the non-hopping one(same a speech allocation request). o o 4.12.5 ACTIVATION PARAMETER BSS Radio resource preemption must be authorised by a specific O&M parameter : preemptionAuthor : • • • Class 3 signallingPoint object range : forbidden, authorizedWithRelease, authorizedWithForcedHO preemptionAuthor = “forbidden” means that the BSC never performs radio resource preemption, whatever the priority and PCI/PVI flags’ values. preemptionAuthor = “authorizedWithRelease” means that the BSC is allowed to perform radio resource preemption if necessary and if authorised by the MSC.A successful preemption results in the preempted call being released. preemptionAuthor = “authorizedWithForcedHO” means the same thing as preemptionAuthor = “authorizedWithRelease” in the current implementation, despite the different name. 4.12.6 EMLPP PREEMPTION VERSUS PDTCH PREEMPTION PDTCH “preemption” consists in the BSC negotiating with the PCU to be allowed to use (to “preempt”) a PDTCH for a CS call. Although the same word is used, PDTCH “preemption” is not the same as eMLPP preemption. In particular, PDTCH preemption is targeted on a chosen resource, whereas eMLPP preemption is not. PDTCH PREEMPTION o o o The BSC receives an allocation request from the MSC The BSC chooses a radio resource for that particular allocation request. If the chosen resource is a PDTCH, the BSC starts the preemption negotiation with the PCU. No other resource can be used instead, even if a TCH is freed in the meantime. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 172/629 V17.0 BSS Parameter User Guide (BPUG) EMLPP PREEMPTION o o The BSC receives an allocation request from the MSC The BSC chooses a preemptable radio resource and starts the release of the call currently using that resource. In parallel, while the preemption procedure is ongoing, the BSC puts the allocation request that was the cause of the preemption inside a special queue entirely dedicated to preemption-capable allocation requests. The first radio resource that becomes available is allocated to the preemption request that is at the front of the queue. Therefore the radio resource that was preempted originally is not necessarily allocated to the request which initially triggered that particular preemption. o o 4.12.7 INTERWORKING HANDOVER During handover procedures, preemption in best cell is always preferred than fallback to another one. Preemption leads to favour attempting to obtain a radio resource in the first cell of the handover list (ensures better quality, but may cause additional delay to the handover procedure completion), even though a radio resource may be immediately free in a further cell in the list. DIRECTED RETRY If preemption is authorised (i.e. preemptionAuthor = “authorizedWithRelease”), and if no resource is free, the BSC first looks to see, based on the PVI flag and the relative BSSMAP priorities, whether a resource could be preempted. If so, the BSC starts the preemption procedure. Then, either the preemption (and the assignment) succeeds, or the BSC returns an assignment failure. Directed Retry cannot be attempted as a fallback. Therefore, Directed retry may be attempted only after the BSC has decided not to trigger the preemption procedure (due to lack of potential candidate resources, e.g. PVI of all TCH = 0). QUEUING As for Directed retry, queuing may be attempted only after the BSC has decided not to trigger the preemption procedure (due to lack of potential candidate resources, e.g. PVI of all TCH = 0). To solve a congestion issue, preemption is always considered first by the BSC. If a preemption procedure is started and if it fails, queuing may not be attempted as a fallback : the assignment request results in an assignment failure. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 173/629 V17.0 BSS Parameter User Guide (BPUG) Also, the BSS priority table (allocPriorityTable) is not used by the BSS in the preemption procedure. Only the external BSSMAP priority given by the MSC is considered by the BSC in the preemption algorithm, regardless of the corresponding internal priority given by the BSS priority table. RESERVED RADIO RESOURCES Reminder : it is possible to reserve radio resources to assignment requests of internal priority = 0 thanks to the allocPriorityThreshold parameter. When the number of free resources falls below allocPriorityThreshold , these remaining free resources may only be allocated to assignment requests of internal priority = 0. Even preemption-capable assignment requests cannot use these free timeslots if the value of their internal priority is different from 0. They have to preempt ongoing calls on other timeslots and leave these reserved timeslots free. 4.12.8 RESTRICTIONS Network resources (both radio channels and fixed circuits) used by emergency calls (TS12 service) may not be preempted. SDCCH channels may not be preempted. The following TCH channels may not be preempted : o o TCH channels used for signalling (TCH overflow) TCH channels used for HR calls All other TCH, including those used for data calls, are preemptable provided that PVI = 1. In the very first phase of a mobile originated call establishment, in case there are no SDCCH and no TCH available, a Channel Request is not capable of triggering a preemption. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 174/629 V17.0 BSS Parameter User Guide (BPUG) 4.13. PCH AND RACH CHANNEL CONTROL 4.13.1 PAGING COMMAND PROCESS Paging process is triggered by the system when a mobile needs to be found (incoming calls or short messages) in a location area (LA). The paging command is broadcast over all the cells of the LA where the mobile is located. In idle mode, the mobile listens to the broadcast channel (BCCH). Paging messages are carried by the CCCH which is a sub-channel of the BCCH. It is divided into 3 logical channels: • • • Uplink: RACH (Channel Request) Downlink: AGCH (Immediate assignment) Downlink: PCH (Paging command) Four (4) CCCH frames are necessary to transmit a complete paging message due to bursts interleaving. For the mobile, listening to the broadcast channels is battery consuming. Therefore the paging messages broadcast has been optimized. Instead of listening continuously to the paging channel, the mobile waits for specific occurrences of paging message. A set of mobiles are associated to a specific occurrence of the paging channel, they belong to a so-called paging group. In order for a mobile to find its associated paging group among N groups, the following rule is applied: Nb of paging group = (IMSI mod1000) mod N Dimensioning the paging means determining the number of paging groups needed to meet incoming calls requirements inside a specific LAC. Two basic factors are taken into account: • • the number of subscribers the average amount of paging messages per subscriber (or average number of subscribers that receive a paging message at the same time) PAGING CHANNEL CONFIGURATION According to the required number of paging groups, the CCCH configuration is consequently tuned. This configuration depends on the TDMA model and on 2 parameters: • • • TDMA Model: is the BCCH combined or not noOfBlockForAccessGrant: bts object parameter (class 2) noOfMultiframesBetweenPaging: bts object parameter (class 2) Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 175/629 V17.0 BSS Parameter User Guide (BPUG) CONSEQUENCES OF THE TDMA MODEL The number of CCCH occurrences depends on the BCCH model, i.e., if the BCCH is combined or not. If the BCCH is combined, there are less Frames dedicated to the CCCH. BCCH COMBINED CASE BCCH Multiframe representation in combined configuration FCCH SCH BCCH BCCH BCCH BCCH CCCH CCCH CCCH CCCH FCCH SCH CCCH CCCH CCCH CCCH CCCH CCCH CCCH CCCH FCCH SCH SDCCH SDCCH SDCCH SDCCH SDCCH SDCCH SDCCH SDCCH FCCH SCH SDCCH SDCCH SDCCH SDCCH SDCCH SDCCH SDCCH SDCCH FCCH SCH SACCH SACCH SACCH SACCH SACCH SACCH SACCH SACCH IDLE When using a TDMA model with BCCH combined, there are 3 occurrences of CCCH per multiframe of 51 frames. BCCH NOT COMBINED CASE: BCCH Multiframe representation in not combined configuration FCCH SCH BCCH BCCH BCCH BCCH CCCH CCCH CCCH CCCH FCCH SCH CCCH CCCH CCCH CCCH CCCH CCCH CCCH CCCH FCCH SCH CCCH CCCH CCCH CCCH CCCH CCCH CCCH CCCH FCCH SCH CCCH CCCH CCCH CCCH CCCH CCCH CCCH CCCH FCCH SCH CCCH CCCH CCCH CCCH CCCH CCCH CCCH CCCH IDLE When not combined, a BCCH multiframe carries 9 CCCH occurrences. CONSEQUENCES OF NOOFBLOCKSFORACCESSGRANT. From V9, whatever the value of noOfBlocksForAccessGrant, AGCH messages overlap on PCH channels each time AGCH channels are full. The aim was to use when needed the preemption mechanism which is better than booking a specific CCCH for Immediate Assignment. It means that it has been defined to be sure AGCH will be treated as soon as possible in any configuration. In that case, new priorities are applied. This gives the possibility of a higher priority for paging messages repetitions if required on the network. • • • • Priority 1: Immediate assignment message never sent Priority 2: Paging message never sent Priority 3: Paging message already sent Priority 4: Immediate assignment message already sent Note: see chapter Paging Parameters for more information on this parameter advised values. SMS-CB use has some influence on noOfBlocksForAccessGrant value (see chapter Effects of SMS-Cell Broadcast Use on “noOfBlocksForAccessGrant”). CONSEQUENCES OF NOOFMULTIFRAMESBETWEENPAGING: CCCH CONFIGURATION The noOfMultiframesBetweenPaging parameter defines the frequency of a paging group occurrence. For instance, if noOfMultiframesBetweenPaging = 3, 1 multiframe out of 3 will carry an occurrence of a paging group. Using the same example as above with BCCH combined, noOfBlocksForAccessGrant = 1, and noOfMultiframesBetweenPaging = 2, one can see that one out of 2 multiframes won’t Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 176/629 V17.0 BSS Parameter User Guide (BPUG) transmit paging messages for the paging group A. This space is necessary to locate several paging groups. FN0 Block booked for AGCH Paging group nb0 (A) Paging group nb1 FCCH SCH SDCCH SDCCH SDCCH SDCCH SDCCH SDCCH SDCCH SDCCH FCCH SCH SDCCH SDCCH SDCCH SDCCH SDCCH SDCCH SDCCH SDCCH FCCH SCH SACCH SACCH SACCH SACCH SACCH SACCH SACCH SACCH IDLE FCCH SCH BCCH BCCH BCCH BCCH FCCH SCH FN1 Block booked for AGCH Paging group nb2 Paging group nb3 FCCH SCH SDCCH SDCCH SDCCH SDCCH SDCCH SDCCH SDCCH SDCCH FCCH SCH SDCCH SDCCH SDCCH SDCCH SDCCH SDCCH SDCCH SDCCH FCCH SCH SACCH SACCH SACCH SACCH SACCH SACCH SACCH SACCH IDLE FCCH SCH BCCH BCCH BCCH BCCH FCCH SCH FN2 Block booked for AGCH Paging group nb0 (A) Paging group nb1 FCCH SCH SDCCH SDCCH SDCCH SDCCH SDCCH SDCCH SDCCH SDCCH FCCH SCH SDCCH SDCCH SDCCH SDCCH SDCCH SDCCH SDCCH SDCCH FCCH SCH SACCH SACCH SACCH SACCH SACCH SACCH SACCH SACCH IDLE FCCH SCH BCCH BCCH BCCH BCCH FCCH SCH This parameter is deeply involved in the time needed to establish a call when a paging message is coming. For instance, if a paging command is to be transmitted in a paging group P1 just after the paging group P1 occurrence, the paging command will have to wait for at least noOfMultiframesBetweenPaging x 240ms to be transmitted. If noOfMultiframesBetweenPaging = 8, the time waited to transmit a paging message can be of 2 seconds without any other delays. From the configuration, paging group occurences are determined. In the previous example, the paging groups will be split as follows: Nb of Paging groups = (na - nb) x nc • • • na = number of CCCH groups per BCCH multiframe nb = noOfBlocksForAccessGrant nc = noOfMultiframesBetweenPaging Note: see chapter Paging Parameters for more information on this parameter recommended values. noOfMultiframesBetweenPaging has also an influence on mobile battery consumption and on reselection reactivity (see chapter Effects of “noOfMultiFramesBetweenPaging” on Mobile Batteries and Reselection Reactivity). 4.13.2 PAGING COMMAND REPETITION PROCESS (RUN BY BTS) Paging messages are systematically repeated. From V8, three (3) parameters will manage paging message repetitions: • nbOfRepeat defines the number of times a paging message will be repeated by the BTS • delayBetweenRetrans defines the number of occurrence between 2 repetitions of the same paging group • retransDuration defines the maximum time allocated to broadcast a paging message Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 177/629 V17.0 BSS Parameter User Guide (BPUG) The following rule is checked at the OMC-R: retransDuration > (delayBetweenRetrans + 1) x nbOfRepeat This inequality is to insure at least nbOfRepeat paging transmissions when there is no blocking on paging channel. See chapter Paging Parameters and chapter GSM Paging Repetition Process Tuning to find engineering rules to set these parameters. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 178/629 V17.0 BSS Parameter User Guide (BPUG) 4.13.3 REQUEST ACCESS COMMAND PROCESS RACH are used when mobiles request a channel to establish a communication (both terminated and initiated calls, see chapters Mobile Terminating Call and Mobile Originating Call). Request management is configurated (nb of repetitions, time between repetitions...) at the OMC-R thanks to different parameters. 4.13.4 REQUEST ACCESS COMMAND REPETITION PROCESS After sending the initial CHANNEL REQUEST message, the MS starts a timer (T3120) and listens to AGCH logical channel. When this timer expires and number of retransmissions does not exceed maxNumberRetransmission, the MS repeats the CHANNEL REQUEST. See also chapter GSM Paging Repetition Process Tuning. PHASE 1 MOBILES When the timer is started, a random value n is drawn with equal probability between 0 and N-1 where N is: • • for the initial access: max (8, numberOfSlotsSpreadTrans) for next attempts: numberOfSlotsSpreadTrans T3120 is set so that there are n RACH slots between T1 and the expiry of T3120. T1 is a fixed delay thanks to the configuration of the BCCH: • • • before initial access, T1 = 0 after initial access, T1 = 250 ms (for non combined CCCH) after initial access, T1 = 350 ms (for combined CCCH) Fixed delay whose value depends on whether or not the BCCH is combined Variable delay from 0 to numberOfSlotsSpreadTrans – 1 RACCH time Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 179/629 V17.0 BSS Parameter User Guide (BPUG) PHASE 2 MOBILES Rec 04.08 have been modified to avoid double allocation (see chapter Paging Parameters). When the timer is started, a random value n is drawn with uniform probability distribution in the interval [S, S+1, ..., S+T-1]: • • where T is numberOfSlotsSpreadTrans where S depends on the BCCH configuration and on T (see following table). S on non-combined BCCH S on combined BCCH numberOfSlotsSpreadTrans 3, 8, 14, 50 4, 9, 16 5, 10, 20 6, 11, 25 7, 12, 32 55 76 109 163 217 41 52 58 86 115 Fixed delay whose value depends on BCCH configuration and numberOfSlotsSpreadTrans Variable delay set according to numberOfSlotsSpreadTrans time 4.13.5 I MULTIPAGING COMMAND MESSAGE The multipaging command message is a Nortel Specificity. The principle of this implementation is to form group of paging on the Abis interface. Before BSS V14.3.1, for each paging message receives from the MSC; one paging message is sent on Abis interface to a target cell. The aim of this feature is to reduce the congestion and overload messages on Abis interface. In order to achieve this goal, a new BSC timer Called T_Paging_Group was introduced, to define the minimum of time between two occurrences of multi paging command messages on Abis interface. Therefore, at emission of one multi paging command message, the BSC starts T_Paging_Group. If during T_Paging_Group, more than 10 paging messages are received, then only the 10 first messages are stored, thus others messages are discarded. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 180/629 V17.0 BSS Parameter User Guide (BPUG) At T_Paging_Group expiry, either no paging message is received from the MSC or at least more than one paging message is stored and the BSC sends these messages to the BTS. In both cases the BSC restarts the timer. Note: Since BSS V14.3.2 and V15.1 this maximum length is 12 paging messages. From V15.1.1, a multi paging command is sent by the BSC in two cases: • As soon as the 12 first paging are received by the BSC, a paging group message is sent to the BTS leading to avoid discarding paging messages and waiting for T_Paging_Group timer expiry. If T_Paging_Group timer is reached and at least one paging message is received, a multi paging command is sent • Caution! The value of this T_Paging_Group is set to 200ms. Only CS paging use I Multipaging command, therefore the PS pagings are not combined. Thus a single paging I is used for data paging. The following figure illustrates the principles of multipaging command MSC BTS BSC Paging MS1 Paging MS2 Paging MS3 T_Paging_group Multi paging command MS1, MS2, MS3 T_Paging_group Paging MS4 Multi paging command MS4 The two major improvements bring by this feature are: • • a large Lap D bandwidth associated to the BCCH for non-paging messages, which provides a better quality of service, a reduction of the CPU load generated by paging messages at BSC and BTS levels. However, it induces a delay (average=100ms, min=0ms, max=200ms) during the paging management at the BSC level, and the mobile terminated call setup time is lightly increased. CAUTION! Note: As this feature increases the BSS capacity, since BSS V14.3.1 it is activated by default. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 181/629 V17.0 BSS Parameter User Guide (BPUG) 4.13.6 UI MULTIPAGING COMMAND MESSAGE PRINCIPLE Each time a data request message (I frame on LapD) is used to convey a multipaging message to the BTS, the BSC has to wait for an acknowledgement before sending the next multipaging message. Therefore, the paging process is RTD dependent. Using the Unit Data Request message (UI frame on the LapD), no acknowledgement is required before sending the next frame, which decreases the lapd bandwidth associated to the BCCH TRX for paging messages. Hence, whatever is the paging number per second, the quality of service is increased and more especially in case of large location area which generates high number of paging messages or during exceptional events. This feature is introduced in V15.1.1 and it allows, at equivalent paging messages number, to better fill the downlink lapd bandwidth associated to the BCCH for paging messages and to decrease the use of the uplink lapd bandwidth. Hence it increases the lapd bandwidth associated to the BCCH for non-paging messages. SPECIFICATIONS OF THE UI MULTIPAGING COMMAND MESSAGE UI Multipaging command message uses the same mechanisms (to group the paging command messages) as the I Multipaging command message described in below except the ones described here under. In order to build the UI Multipaging message, the BSC timer T_Paging_Group is used, which defines the maximum time between 2 occurrences of UI Multi Paging Command message on the Abis interface. The BSC starts T_Paging_Group at emission of one UI Multi Paging Command message. Until T_Paging_Group expiry, as soon as a MultiPaging command message has stored 12 unit paging command messages, it is transmitted immediately to the BTS. At T_Paging_Group expiry, if one or more than one paging command messages are currently stored: • • the MultiPaging command message is transmitted to the BTS and T_Paging_Group timer is restarted otherwise T_Paging_Group timer is restarted Hence, all paging requests messages accepted by the BSC filter are all sent to the BTS which means up to 105 paging command / second. Note: The value of this T_Paging_Group is set to 200ms and can not be modified even via the bsc data config tool. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 182/629 V17.0 BSS Parameter User Guide (BPUG) The Packet paging message, received from the PCU, are sent by the BSC to the BTS (on the SAPI GSL) whereas the Circuit paging message from MSC are sent to the BTS by the BSC on the SAPI RSL. Therefore PS and CS pagings are not sent into the same multipaging message command. With I multipaging command message the process of combining paging messages into one multipaging command message is supported by CS paging only. The restriction is removed with UI multipaging command feature as it allows combining the packet paging messages before sending them to the BTS. FEATURE ACTIVATION The feature is deactivated by default and can be activated thanks to a build on line. Recommended upgrade steps are the following: • • • Upgrade of the BSC without activation of the UI MultiPaging feature (type 4) Upgrade of the BTS supported by the BSC Activation of the UI Multipaging feature in the BSC (via a build on line) CAUTION! In order to identify bad PCM links and fix it, the operator should monitor the quality of all the PCM links before the feature activation. As soon as the BSCe3 and the TRXs of BTS are able to manage this feature, the BSC sends UI MultiPaging Command messages. The BSC is aware of the BTS capacity for the Circuit Service thanks to the DRX catalog file and especially the bit 8 (from 0 to 31) of the hardware mask defined as follow: • • 0: UI MultiPaging Command message for Circuit Service not supported 1: UI MultiPaging Command message for Circuit Service supported As all types of DRX support this feature (except DCU2), there is no modification of the "display all" feature, in order to know the activation state of this feature. Note: As this feature is not implemented on BSC12000 and due to upgrade constraints, then the BTS has to manage the following types of paging messages: I paging command, I MultiPaging and UI MultiPaging command messages. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 183/629 V17.0 BSS Parameter User Guide (BPUG) 4.13.7 NETWORK MODE OF OPERATION I SUPPORT IN BSS The Network Mode of Operation 1 (NMO1) takes benefit of the Gs interface to exchange messages between the MSC and SGSN in order to coordinate the CS and PS paging management and to optimize some signaling procedures. Note that Gs interface (between SGSN and MSC) is a pre-requesite before using NMO1. The feature should be enabled with gprsNetworkModeOperation (bts object). The parameter is at BTS object but must be consistent at Routing Area level, i.e. activated (or de-activated) in all cells of a given Routing Area. PAGING MANAGEMENT If NMO1 is activated, CS-Paging are managed through Gb interface for any GPRS-attached MS. ClassB MS may be simultaneously attached to GSM and GPRS services but cannot simultaneously perform CS and PS transfer. If the MS is not attached to GPRS services, the CS-Paging procedure is not modified and done through the A interface. If the MS is attached to GPRS, the CS-Paging is sent from the MSC to the SGSN (Gs interface) and then to the PCU (Gb interface): • If the target mobile is in GMM STANDBY state, the PCU transmits the Paging message to the BSC on the SAPI RSL. Therefore the BSC has to broadcast this message on the CCCH of all target cells. If the mobile is in GMM READY state, the PCU sends the Paging on the PACCH of the TBF or on the CCCH of the cell if there is not an established TBF for the target mobile. In case Paging is sent on PACCH, the PCU repeats the paging message 3 times (1 emission + 3 repetitions), with a delay between 2 occurrences equal to 480 ms. This enhances the probability of success of the Paging procedure. • The 3 different cases (MS not GPRS-attached, MS in GPRS STANDY state and MS in GPRS READY state) are illustrated below. Note that the load of some interfaces is impacted by NMO1 activation: • • less paging on A interface more paging on AGPRS interface less load on A interface. more load on AGPRS LAPD TS. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 184/629 V17.0 BSS Parameter User Guide (BPUG) MS attached to GPRS services & standby state SGSN MSC/VLR MS not attached to GPRS services SGSN MSC/VLR MS attached to GPRS services & ready state SGSN MSC/VLR PCU BSC PCU BSC PCU BSC BTS BTS BTS BTS BTS BTS BTS BTS BTS BTS BTS BTS Paging procedure not modified BSC broadcasts paging on CCCH Paging on: • PACCH if TBF established • CCCH if no TBF established COMBINED SIGNALING PROCEDURES Two procedures are combined when using NMO1: • • Combined GSM / GPRS Attach Combined LA / RA update. Each procedure is performed with a single access on packet channels. This is transparent for the PCU, which manages it as usual without any particular action. The SGSN then informs the MSC through the Gs inteface. The following gains are expected: • • • • Notes: • • As the combined procedures are performed on packet channels, it is critical to protect the access to GPRS service and thus set minNbrGprsTs > 0 There is a LAPD impact on Agprs interface due to the addition of cs_paging messages for the data attached mobiles. decrease of SDCCH occupancy less load on A and Abis interfaces less load on BSC faster cell reselection between 2 LA. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 185/629 V17.0 BSS Parameter User Guide (BPUG) 4.13.8 BSS CS PAGING COORDINATION For details please refer to the functional note ([R57] and also to the aPUG document ([A1]). PRINCIPLE When NMO II is used, the network sends all paging messages on the PCH paging channel even if the mobile has been assigned a packet data channel, which might require the MS to leave the packet channel to monitoring the occurrence of paging messages. Compared to NMO II, the BSS CS Paging Coordination is an additional mechanism for handling CS paging. It provides an NMO I-like mechanism (BSS CS Paging Coordination) without involving the packet core and Gs interface. This maximizes the end-user availability for receiving CS calls and the related revenues. While the network is running with NMO II, the BSC sends all CS paging messages received on A interface both to the BTS and, with BSS CS Paging Coordination feature activated, to the PCU as well. The PCU then checks whether the corresponding MS is engaged in a PS session, by checking the IMSI. If so, the PCU sends the CS paging message to the mobile on PACCH channel. BSS CS PAGING COORDINATION MECHANISM ACTIVATION PARAMETER The activation parameter of this feature is bssPagingCoordination (class 3, bts objet). If the network is running in Network Mode of Operation II and if BSC and PCUSN support the BSS CS Paging Coordination feature, the bssPagingCoordination parameter serves to set BSS_PAGING_COORDINATION bit in GPRS Cell Options to “1” to enable the BSS CS Paging Coordination mechanism for all GPRS/EDGE mobiles. Therefore, the behaviour of class B mobiles (from Release 97) is modified when enabling this new BSS CS Paging Coordination in the network, provided that both the BSC and the PCUSN support the feature. SI13 UPDATE The BSC updates the System Information 13 message to indicate the activation/deactivation of the feature and sends PCU BROADCAST INFO MODIFY to provide the updated content of the SI13 to the PCU. DETAILED PAGING COORDINATION MECHANISM Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 186/629 V17.0 BSS Parameter User Guide (BPUG) PCUSN SGSN SPM SPM SPM SPM SPM SPM SPM All CS pages are transferred to the PCUSN MSC/VLR PCUSN CS Pages SPM has found that a TBF is alive for this MS BS C CS Pages broadcast on CCCH CS pages on PACCH BTS BTS BTS BTS BTS TBF alive CS pages on CCCH No TBF alive If the network is running in Network Mode of Operation II, when the BSC receives a CS paging from A interface : • • the BSC broadcasts this paging message in the target cells (as it has always done so far), regardless of bssPagingCoordination parameter value, and, if bssPagingCoordination is enabled on at least one cell of the area, the BSC sends the paging message in a single BSC CS Paging message to the PCU (even if the CS paging addressee is a list of cells) on one of the available Agprs PCM (with a round-robin mechanism to spread the CS paging load on all Agprs PCMs connected to this BSC). When a PCU element receives a CS paging on its Agprs PCM, it broadcasts this message to all PCU elements connected to the same BSC that issued the CS paging message. Each PCU element then checks whether the IMSI value included in the BSC CS Paging message corresponds to one of the existing MS context (i.e. a mobile that is known as currently having an established TBF). In this case : • if the bssPagingCoordination parameter is set to “enable BSS paging coordination” in the corresponding cell, the PCU sends the CS paging on PACCH using the mechanism used for Network mode of Operation I (see §4.13.7). otherwise the paging is discarded. Nortel confidential • PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 187/629 V17.0 BSS Parameter User Guide (BPUG) 4.14. FREQUENCY HOPPING 4.14.1 FREQUENCY HOPPING PRINCIPLES Basically, Frequency Hopping aims at spreading the spectrum of the signal to minimise the impact of potential interferers. Frequency Hopping consists in changing the frequency used by a channel at regular intervals. In GSM, the transmission frequency remains the same during the transmission of a whole burst. Thus, it is possible to have different frequencies on each burst of a frame. The radio interface of GSM uses then slow Frequency Hopping. According to the type of coupler used in the BTS, two (2) main types of Frequency Hopping mechanism can be used: • • Synthesised mode for Hybrid couplers with duplexers: hopping time slots can hop on a large band of frequencies. Baseband mode using Cavity couplers with duplexers: hopping time slots can hop on a set of frequencies limited by the number of TRXs (only available with S4000 BTS). Note: using frequency hopping allows to adapt and maximise the frequency re-use pattern efficiency by maximising the capacity in term of offered Erlang/Mhz/km2. The pattern to use will depend on the available frequency band and the traffic requirement. It is possible (and recommended) to mix different frequency re-use technique, as 4X12 for BCCH and 1X3 or 1X1 for TCH. Indeed, a traditional 4X12 reuse pattern is appropriate to a wide spectrum allocation as for BCCH frequency (only one frequency per cell is needed). However, in order to increase the number of TRX per cell with a given frequency band, while keeping a low interference level, the only solution is to use more restricting reuse pattern, as 1X1 or 1X3. See also chapter General Rules For Synthesised Frequency Hopping. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 188/629 V17.0 BSS Parameter User Guide (BPUG) 4.14.2 MAIN BENEFITS OF FREQUENCY HOPPING • the higher the number of frequencies in the hopping law, the smaller the Fading margin taken into account in the link budget (due to Rayleigh fading). RXLEV cdf versus SFH 100 1 freq 2 freq 4 freq 8 freq % 10 2 8 -2 -1 0 1 2 3 4 1 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 FADING MARGIN (dB) • the smaller the mobile speed and the higher the number of frequencies, the higher the benefit of the frequency hopping. Frame Erasure Rate versus SFH at –104 dBm (DCS) 12.00 10.00 8.00 FER (%) 6.00 4.00 2.00 0.00 1 2 3 4 5 6 7 8 NUMBER OF FREQUENCIES FOR HOPPING 0.5 1.5 2.5 0.5 km/h 1.5 km/h 2.5 km/h 5 km/h 25 km/h 5 25 • the higher the number of frequencies in the hopping law, the narrower the Rxqual distribution. However Rxqual mean remains the same (see figure below). Hence the Frequency Hopping eliminates the number of bad Rxqual samples but it also reduces the number of good Rxqual ones. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 189/629 V17.0 BSS Parameter User Guide (BPUG) cdf RxQual with SFH, at 0.5 km/h, -104 dBm (DCS) 100 90 80 70 60 50 40 30 20 10 0 0 2 4 6 8 10 4 8 1 freq 4 freq 8 freq 16 freq 16 BER % • Increase resistance to Rayleigh fading: re-centred RxQual distribution for slow moving mobiles better stability of the received signal level (smoothing effect) completion of diversity task on uplink and full benefit on downlink high improvement for areas of weaker signal strength (inside buildings and on street level) • Resistance to interference spread of interference over all RF spectrum spread of interference over time highly loaded sites benefit from lower load on adjacent sites more efficient error correction gain from digital processing Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 190/629 V17.0 BSS Parameter User Guide (BPUG) 4.14.3 SYNTHESISED FREQUENCY HOPPING Using synthesised frequency hopping, each TX is associated to one FP (TDMA) and can transmit on all the frequencies. It is used with hybrid coupling systems then more frequencies than TRXs can be used. The main issue is to ensure that the frequency BCCH is transmitted all the time (on all the TS of the TDMA) at a constant power even if there is no call to transmit (no voice or data burst). This is done by a specific configuration which consists in dedicating a TRX to the BCCH frequency (so the TDMA called BCCH does not hop). Generally, the number of frequencies is greater than the number of TRX in order to have the smallest Fading margin in the link budget. TDMA1 TDMA2 TDMA3 TDMA4 MA frequency list TX1 TX2 TX3 TX4 BCCH Freq MAIO The TDMA configurations in case of synthesised frequency hopping are defined as follows: • • F1 is the BCCH frequency. the other two TDMA of the cell have the same MA. HSN and MAIO can be different. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 191/629 V17.0 BSS Parameter User Guide (BPUG) 4.14.4 BASEBAND FREQUENCY HOPPING PRINCIPLE Using baseband frequency hopping, each TX is dedicated to one frequency and is connected to all the Frame Processor (TDMA) via the FH bus. It is used with cavity coupling system. It uses exactly the same number of frequencies as TRXs. The filling is done by the FP according to the configuration of the TDMA (all the parameters for the frequency hopping are static and not per call basis; so even if there is no call the FP knows if it has to transmit on the BCCH frequency). Moreover the TX can have a carrier filling functionality which is not useful for the BCCH frequency (Carrier filling is already done by the FP) but which can be used in case of other frequencies carrier filling with the use of a specific BCF load. FP1 FP2 FP3 FP4 TX1 TX2 TX3 TX4 BCCH Freq Filling burst when there is no information to transmit on the BCCH frequency. If filling is needed on other frequencies, it is managed by the TXs. For a given cell with the previous configuration (4 TRX), one Mobile Allocation should be defined: • MA0 contains all the frequencies except the BCCH frequency (3 frequencies in the exemple). The baseband frequency hopping configuration is the following: • hopping on TCH, no hopping on BCCH Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 192/629 V17.0 BSS Parameter User Guide (BPUG) TS TDMA 0 TDMA 1 TDMA 2 TDMA 3 0 1 2 3 4 5 6 7 F1 MA0 MA0 MA0 F1 MA0 MA0 MA0 F1 MA0 MA0 MA0 F1 MA0 MA0 MA0 F1 MA0 MA0 MA0 F1 MA0 MA0 MA0 F1 MA0 MA0 MA0 F1 MA0 MA0 MA0 MAIO=0 MAIO=1 MAIO=2 MAIO=3 • • • MA: Mobile Allocation (list of hopping frequencies for a TRX) MAIO: Mobile Allocation Index Offset between 0 and (Nb of Freq in MA - 1). F1: BCCH frequency CAUTION! It is not recommended to hop on BCCH frequency when using baseband frequency hopping, because it can lead to some troubles when downlink DTX or downlink power control are enabled. RECONFIGURATION PROCEDURE This procedure is not applicable to BTS that use hybrid coupling. With the baseband frequency hopping mechanism (used only by BTS that have cavity couplers), it is possible to reconfigure the frequencies in certain cases. In case of equipment failure/recovery within a TRX, the BSC starts the reconfiguration process for a Radio Cell which supports frequency hopping and uses the Frequency Management GSM function. This function is supported by the TRX and allows the BSC to configure or to reset a frequency on a TX which is identified by the TEI of the corresponding TRX. The loss of one TX implies the loss of one frequency (which is not the BCCH) and of one TDMA (the one defined with the lowest priority) if no redundant TRX. Two symmetric mechanisms are managed by the BSC to handle the automatic frequency reconfiguration in the case of frequency hopping cavity coupling BTS: • loss of a frequency the cell is stopped and restarted with new set of frequencies. This may lead to release the calls if there is more live TX than btsThresholdHopReconf • recovery of all frequencies an automatic reconfiguration is triggered by the BSC when all the frequencies are recovered. This may lead to release the calls There will be a reconfiguration if the flag bscHopReconfUse is set to “true” (defined at BSC level) and if there are more frequencies than the threshold btsThresholdHopReconf (defined at BTS level). Otherwise the cell is badly configured. When a end of fault occurs if the flag btsHopReconfRestart is set to “true” and if there are more frequencies than the threshold (btsThresholdHopReconf), there is a complete cell reconfiguration. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 193/629 V17.0 BSS Parameter User Guide (BPUG) 4.14.5 AD-HOC FREQUENCY PLAN The Ad-Hoc frequency hopping does not reproduce a pattern all over the network. Frequency planning is done (HSN, MAIO, MA lists) according to the interference matrix. The particularity is that the number of hopping TRX = the number of hopping frequencies in most of the cases. A frequency plan optimizes frequency hopping list of each sector in order to reduce the interferences. The length of the frequency hopping list is variable (it should be at least equal to the number of TRx on the sector). TDMA1 TDMA2 TDMA3 TDMA4 TX1 TX2 TX3 TX4 BCCH Freq MA frequency list: n frequencies for n TRX For ad-hoc frequency planning, an interference matrix or a very intense and accurate drive tests campaign is needed. A frequency planing tool can also be used. For each method the principle is the same: take into account DL BCCH and HO interactions between cells. The frequencies on the list are planned intelligently in order to avoid collision with the neighboring cells, allocating same frequencies on the hopping list to cells which are far in distance or that the interaction between them is the minimum as possible. There is a reduction on the number of frequencies on the frequency hoping list. It is recommended to space the maximum as possible (at least 3 channels) the frequencies used in the same frequency list to maximize frequency hopping gain (fading reduction) Every sector of one site has a different HSN in order to minimize co-channel or adjacent collisions. The main drawback is the cost to maintain the plan since regularly it is recommended to review the plan in order to optimize its performances. Ad-hoc should be considered as a spectral efficiency feature in a constraining bad condition assuming the cost associated. In case of non frequency band constraining conditions, 1x1 has shown a great cost-performance trade-off and is worth to use in the case of a fast growing network in order to minimize operational impacts. In summary Ad-Hoc frequency plan allows good performances if the calculation method is very precise (either Interference matrix, drive tests or frequency planning tool) and number of hopping frequencies per TDMA is sufficicent (at least MA list ≥ 4 frequencies) Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 194/629 V17.0 BSS Parameter User Guide (BPUG) 4.15. BSC OVERLOAD MANAGEMENT MECHANISMS The aim of such a feature is to avoid BSC restart or crash because of overload conditions. Without defense mechanism, an overload of one of the BSC boards will imply a suicide of the active chain, a switch to the passive chain and at last a suicide of the new active chain. This implies a suppression of all the communications and an interruption of service. For further details on this feature please refer to BSS Engineering Rules in chapter Reference Documents 4.15.1 BSC12000 OVERLOAD MANAGEMENT This overLoad management mechanism is based on the following principles: • • • • Current CPU load for MPU / BIFP / OMU / SICD and memory resources are supervised (including also OMU-SUP-SWC chained boards) Resources fluctuation trends are analysed and taken into account for anticipation purpose Each board monitors its own load and neighboring involved board load, and makes decisions dependent of all others Decisions are taken only on traffic stimuli, not O&M stimuli Such a mechanism is able to take into account not only traffic CPU load but O&M CPU load and to trigger an upstream or downstream protection (but based only on traffic stimuli). BSC12000 DIMENSIONING RULES LOCAL CARD SYNTHETIC LOAD A local card “synthetic” load is generated each second by each board. This synthetic load is given as the result of: • • • the CPU load occupancy, the memory resource occupancy, the resources fluctuation trends (only positive variations of CPU/memory occupancy values according to the previous one are taken into account for anticipation purpose) Note: CPU or memory resource occupancy is corrected to give the higher weight to the more critical factor (i.e. a lack of timer may lead to a BSC switchover, thus timers have a weighting factor more important than CPU load). LOCAL CARD OVERLOAD LEVEL This local card synthetic load, compared with the overLoad threshold value associated with current board, is converted into a local card overLoad level [levels 0..3] and sent to a centralized overLoad control task located on the OMU board. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 195/629 V17.0 BSS Parameter User Guide (BPUG) OMU-SUP-SWC CHAINED BOARDS By the same way, the OMU-SUP-SWC cain is monitored in order to generate an associated overload level. GSM OBJECT & OPERATION OVERLOAD LEVEL Thus firstly, this centralized task collects and computes different overLoad levels to determine: • the overLoad level of each cellGroup, showing the overLoad level of each BIFP board (used for instance by TMG to select BIFP board to “propagate” a pagingRequest from A-I/F or an incoming external handover) the overLoad level of each CELL, showing the highest overLoad level between SICD boards handling this GSM object instance the overLoad level of each SITE, showing the highest overLoad level between SICD boards handling this GSM object instance the overLoad level of each TCU, showing the highest overLoad level between SICD boards handling this GSM object instance • • • COMPUTED INFORMATION REDISTRIBUTED Then secondly, this centralized task collects and computes different overLoad levels to determine the overLoad level of the operation family (i.e Paging Request, Network Access, Location Updating...) indicating the highest overLoad level between potentially impacted boards OMU / MPU / SICD / BIFP / OMU-SUP-SWC. OVERLOAD LEVEL CONTROL Lastly, before processing any operation, each board (i.e. each applicative task located on this board, impacted by this operation) must check: • • • its local overLoad level, the overLoad level associated to the current operation, the overLoad level of the impacted object instances Example: Before processing a pagingResponse at BIFP level, TMG (TMG-RAD and TMG-CNX located on BIFP board) checks: • • • its local overLoad level (i.e.its own overlLoad level... at BIFP level) the overLoad level of the “network access” operation family (i.e. overLoad levels of OMU-SUP-SWC, OMU and MPU boards involved) the overLoad level of the each CELL impacted by this operation (i.e. over-Load levels of the impacted SICD board) List of the operations to be filtered Despite the fact, this mechanism is defined as a “centralized” overLoad control method, actions are triggered at local level (i.e. by each board). Following actions can be done only on traffic reduction purpose according overLoad level and operation type: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 196/629 V17.0 BSS Parameter User Guide (BPUG) • overLoad level 1: traffic reduction around 33% by filtering 1 request out of 3 of the following messages: Paging Request, Channel Request with cause different from “Emergency call”, All First Layer 3 messages with cause different from “Emergency call”, HandOver for traffic reason, HandOver for O&M reason, Directed Retry. • • overLoad level 2: traffic reduction around 66% by filtering 2 requests out of 3 of the previous messages. overLoad level 3: no new traffic is accepted by screening all previous and following messages: All First Layer 3 messages, All Channel Request (including causefor “Emergency Call”), All Handover Indication, All Handover Request. Note: when communications need to be filtered to reduce the load of the BSC, it can be done for all the BTSs or CELLs supported by the overLoaded board ! PROTECTION AT STARTING OR SWITCHING During the first 30mn of a BSC restart, all thresholds are decreased by 30%, in order to give more power to the O&M operations. When a BSC is in simplex mode, all thresholds are decreased by 20%, in order to reduce the risk of outage in this phase. CHOOSING PARAMETERS The internal overload parameters have been .validated in R&D for V12 and upper releases and must not be changed. Refer to the processorLoadSupConf parameter. CAPACITY IMPACT As overLoad mechanism is based on real measurement, robustness has been increased as rejected rate for incoming calls. In other terms, same traffic can be carried by the BSC but with higher rejected rate for incoming calls in case of overload. ALARM NOTIFICATION Alarm notification number is 1490 “BSC OverLoad”. This alarm is triggered for the first card which is in overLoad level 3 for 5sec at less and ended when all cards are under the OverLoadLevel 3 for 5sec at less. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 197/629 V17.0 BSS Parameter User Guide (BPUG) 4.15.2 BSC3000 OVERLOAD MANAGEMENT The Overload software manages the board load and the global load of the system so as to avoid the crash in case of overload. On the BSC sub-system an overload situation is mainly due to the traffic management which is computed on the TMU module. The overload software uses system indicators to calculate overload levels that allow applications to decrease the load level. BSC3000 DIMENSIONING RULES The BSC is responsible for accepting or rejecting sites creation or reparenting in order to ensure that the hardware capacity is sufficient to handle the traffic. The maximum dimensioning of a BSC 3000 is 3000 Erlang, 500 Sites, 600 Cells, 1000 TRX, 16 SS7 links, 567 LAPD links. A good dimensioning lead to the following relations: Carried Traffic ≤ BSC hardware capacity (number of TMU) Offered Traffic ≤ BSC hardware capacity (number of TMU) CARRIED TRAFFIC The carried traffic (or real traffic) is the number of simultaneous voice communication a BSC handles at the busy hour. The carried traffic is given by the customer for an area or can be observed with monitoring. It is necessary to consider a margin carried traffic for a lot of reasons (GPRS traffic is increasing lightly the load on the TMU, Load balancing algorithm shares fairly the load between TMU, The operator wants to be able to absorb additional traffic in case of special Event). As a consequence it is recommanded to use a margin of about 20-25 % when considering the carried traffic. Moreover AMR handset penetration should be considered if half rate vocoder is used on a network since it increases offered capacity on radio sites. OFFERED TRAFFIC The offered traffic in a cell is the number of simultaneous users that can use a resource with a target quality of service objective (blocking rate). This step will consist in determining the values of table ERLANG_PER_N_TRX_CELL in order to let the BSC computes the most adapted offered erlang. TMU NUMBER To set the appropriate number of TMU boards please refer to the BSS Engineering Rules (Reference Documents). Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 198/629 V17.0 BSS Parameter User Guide (BPUG) BSC3000 OVERLOAD MECHANISM The overload mechanism only applies to TMU boards. TMU boards are SBC and PMC, from V16.0 a new TMU was introduced:TMU2 . This new TMU has only one board, the SBC one. OMU and interface node overload are not managed. This overload mechanism is based on the following principles: • Decisions are only taken on traffic stimuli, not on O&M stimuli. On the BSC subsystem, an overload situation is mainly due to the traffic management, which is computed on the TMU module Each TMU monitors its overload level and decisions will be applied to all the cellgroups it manages. • The overload management concerns overload levels of two boards of the TMU: • • SBC board (based on CPU usage, memory and waiting time of messages in the mailbox) PMC board (based only on CPU usage). For TMU2 the overload management concerns one board only (therefore the monitoring counter pegged is the one associated to SBC ) Overload architecture is hierarchically organized: • • • 1) the elementary overload level is returned from SBC and PMC by comparing their level of CPU, memory and mailbox resources to specific thresholds 2) the maximum of these elementary overload level gives the local overLoad level 3) for each new local overload level received, each TMU computes its TMUOvLevel(i) as the maximum of all the local overload levels of the boards it manages. TMUOvLevel(i) is then sent to a centralized overload control task located on the OMU that will trigger the appropriate action for TMU(i). The actions are triggered at TMU level, as TMU are rather independent one from the other in terms of overload handling. When a TMU is in overload, it will filter partially the new coming traffic requests related to the cell-groups it manages. LIST OF OPERATIONS TO BE FILTERED • Overload level 1: filtering 33,33% requests of the following messages: Paging request Channel request with cause different from “Emergency call” All first layer 3 messages with cause different from emergency call Handover for traffic reason Directed retry • • Overload level 2: filtering 66,66% requestsof the messages described above Overload level 3: no new traffic is accepted by filtering all previous and following messages All first layer 3 messages All handover indication All handover requests Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 199/629 V17.0 BSS Parameter User Guide (BPUG) PARAMETERS No specific new counters or configuration parameters are introduced with this feature. 4.15.3 LOAD BALANCING The Load Balancing is a mechanism that allows a distribution as balanced as possible (from the traffic weight point of view) of the Cell Groups (CG) among the existing TMUs (See chapter BSC Boards Management) during the initialization phase. It also allows a redistribution of the CG on the TMUs (if all the CG are duplex), without disturbing the established calls when: • • A TMU module fails or comes into operation (for hardware or operator reasons) An imbalance of the TMU loads is detected by the BSC (on online operations such as new TMU board, new BTS, or new TRX). In this case, the load balancing can be manually started. For further details on this feature please refer to the corresponding chapter in the BSS Engineering Rules (chapter Reference Documents). 4.15.4 V15.1 EVOLUTION OF LOAD BALANCING In V15.1 some evolutions are introduced in the Cell Group Management and Load Balancing algorithms used by the BSCe3. These evolutions are made in order to take into account the introduction of new TMU boards (TMU2), to better introduce new big site configurations. MAIN EVOLUTIONS Global dimensioning constraints for the BSC remain unchanged: the BSC capacity is, as in V14.3, V14.3.1 and V15.0 limited by the following maximum number of managed objects: • • • • • • Maximum of 1000 TRX per BSC Maximum of 600 Cells per BSC Maximum of 500 Sites per BSC Maximum of 1 PCUSN per BSC Maximum of 2 TCUe3 per BSC Maximum of 32 TCU2G per BSC Concerning the maximum site configuration supported in V15.1, the limitations are the following: • • Maximum of 16 TRX per Cell Maximum of 48 TRX per Site Moreover, the maximum capacity of the BSC remains 3000 Erlang. The rules to respect the same dimensioning constraints for the TMU and TMU2 boards are defined in the BSS Engineering Rules (see chapter Reference Documents), as well as those existing for the Cell Group definitions. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 200/629 V17.0 BSS Parameter User Guide (BPUG) PACKAGING OF CG IN ERLANG The previous packaging of site in CG was previously based on the number of TRX. The addition of a site of N TRX in an existing CG was roughly done if the CG had no more than 16N TRX, else an empty CG was chosen. The maximum number of TRX per CG (48) could be an issue in the case of site extension or big site introduction in V15.0.1 (with more than 40 TRX). In V15.1, the packaging of sites in CG is now based on a target in Erlang. The weight of each site is estimated and this estimation is used for the packaging of the CG: the objective is to have a target of 84 Erlang per CG. So the principle of the algorithm remains the same: the addition of a site with N TRX in an existing CG is roughly done if this one has no more than 84 Erlang. If no more empty CG remains, the site is added in the existing CG with a maximum constraint of 10 sites per CG. A site created on line is considered with a value of Erlang corresponding to a site of one Cell with 8 TRX. ESTIMATEDSITELOAD PARAMETER In V15.1 is introduced a new parameter called estimatedSiteLoad. This parameter (applicable to the btsSiteManager object) allows specifying the value in Erlang for a given site. This parameter is optional (default value 0). If this parameter is not specified (value of 0), the BSC will use the ERLANG_PER_N_TRX table for the estimation of the site’s weight, else it is the estimatedSiteLoad value that is used. This weight will be considered for the placement of the site into a CG and naturally also for the CG distribution on the TMU. This parameter is a class 3 parameter. Thus, this one may be used at site creation (off line or on line) but may also be changed at any moment while the site is operational. On an online change of this parameter, the BSC will regenerate the site weight estimation (and the CG weight estimation) and will perform a new CG re-balancing if needed (as in case of a TRX addition for instance: the packaging of sites in CG are not re-performed, but the distribution of the CG according to new CG weight will be reconsidered: if the capacity of the TMU hosting the active CG or the passive CG reach their limits, the algorithm considers if it can move these CG to other TMU. Otherwise, it suppresses the CG that can not fit). Please refer to the BSS Engineering Rules (see chapter Reference Documents) for further informations on the use of that parameter. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 201/629 V17.0 BSS Parameter User Guide (BPUG) 4.16. CABINET OUTPUT POWER SETTING This section aims at describing the way to determine the output power of a BTS knowing its coupling and its associated parameter setting. As described in following figure, two OMC parameters are involved: bsTxPwrMax (powerControl object) and from V9, attenuation (btsSiteManager object). 4.16.1 CABINET POWER DESCRIPTION There are three steps in the cabinet output power evaluation. OMC attenuation (since V9) DLU attenuation (until V8) OR bsTxPwrMax SUM Pc Tx Tx Pr translation translation table table Coupling Coupling system system Ps Pc: bsTxPwrMax + DLU/OMC attenuation Pr: given by a translation table Ps: Cabinet output power Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 202/629 V17.0 BSS Parameter User Guide (BPUG) 4.16.2 PR COMPUTATION S8000/S12000 FAMILY This is the table mapping the bsTxPwrMax and the Pr for S8000 and S12000 products (in function of the coupling system). BTS Coupling system ⇒ DLU attenuation or OMC attenuation ⇒ Duplexor & Tx filter 1 Pr ⇓ S8000 (In/Out) & S12000 (In/Out) H2D 4 Pr ⇓ H4D 8 Pr ⇓ BsTxPwrMax ⇓ PA / ePA HePA PA / ePA HePA PA / ePA HePA 51 50 49 48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 0 Nack Nack Nack Nack Nack Nack Nack Nack Pmax Pmax Pmax -2 Pmax -2 Pmax -4 Pmax -4 Pmax -6 Pmax -6 Pmax -8 Pmax -8 Pmax -10 Pmax -10 Pmax -12 Pmax -12 Nack Nack Nack Nack Nack Nack Nack Nack Nack Nack Nack Nack Nack Pmax Pmax Pmax -2 Pmax -2 Pmax -4 Pmax -4 Pmax -6 Pmax -6 Pmax -8 Pmax -8 Pmax -10 Pmax -10 Pmax -12 Pmax -12 Nack Nack Nack Nack Nack Nack Nack Nack Nack Nack Nack Nack Nack Nack Nack Nack Nack Nack Nack Nack Nack Nack Pmax Pmax Pmax -2 Pmax -2 Pmax -4 Pmax -4 Pmax -6 Pmax -6 Pmax -8 Pmax -8 Pmax -10 Pmax -10 Pmax -12 Pmax -12 Nack Nack Nack Nack Nack Nack Nack Nack Nack Nack Nack Nack Nack Pmax Pmax Pmax -2 Pmax -2 Pmax -4 Pmax -4 Pmax -6 Pmax -6 Pmax -8 Pmax -8 Pmax -10 Pmax -10 Pmax -12 Pmax -12 Nack Nack Nack Nack Nack Nack Nack Nack Nack Nack Nack Nack Nack Nack Nack Nack Nack Nack Nack Nack Nack Nack Nack Pmax Pmax Pmax -2 Pmax -2 Pmax -4 Pmax -4 Pmax -6 Pmax -6 Pmax -8 Pmax -8 Pmax -10 Pmax -10 Pmax -12 Pmax -12 Nack Nack Nack Nack Nack Nack Nack Nack Nack Nack Nack Nack Nack Pmax Pmax Pmax -2 Pmax -2 Pmax -4 Pmax -4 Pmax -6 Pmax -6 Pmax -8 Pmax -8 Pmax -10 Pmax -10 Pmax -12 Pmax -12 Nack Nack Nack Nack For more details on the Pmax per products, please refer to the Engineering Rules (ref. [R47] to ref. [R56]). Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 203/629 V17.0 BSS Parameter User Guide (BPUG) CAUTION! There is no exact match between the power emitted with a PA/ePA (even power) and the power emitted with a HePA (odd power) BTS18K/6K FAMILY This is the table mapping the bsTxPwrMax and the Pr for BTS6000 & BTS18000 product (in function of the configuration). Note: That H4 is not used for BTS6000 Configuration attenuation Pmin-Pmax bsTxPwrMax 51 -> 48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 ≤ 22 D 1 RM 30W H2 H3 4 6 31-44 Nack Nack Nack Nack Nack Nack Nack Nack Pmax Pmax Pmax -2 Pmax -2 Pmax -4 Pmax -4 Pmax -6 Nack Nack Nack Nack Nack Nack Nack Nack Nack Nack Pmax Pmax Pmax -2 Pmax -2 Pmax -4 Pmax -4 Pmax -6 Pmax -6 H4 8 D 1 RM 40W H2 H3 4 6 33-46 Nack Nack Nack Nack Nack Nack Pmax Pmax Pmax -2 Pmax -2 Pmax -4 Pmax -4 Pmax -6 Nack Nack Nack Nack Nack Nack Nack Nack Pmax Pmax Pmax -2 Pmax -2 Pmax -4 Pmax -4 Pmax -6 Pmax -6 H4 8 D 1 RM 50W H2 H3 4 6 34-47 Nack Nack Nack Nack Nack Pmax Pmax Pmax -2 Pmax -2 Pmax -4 Pmax -4 Pmax -6 Nack Nack Nack Nack Nack Nack Nack Pmax Pmax Pmax -2 Pmax -2 Pmax -4 Pmax -4 Pmax -6 Pmax -6 H4 8 RM 60W – HPRM 60W D H2 H3 H4 1 4 6 8 34-47 Nack Nack Pmax Pmax Pmax -2 Pmax -2 Pmax -4 Pmax -4 Pmax -6 Pmax -6 Pmax -8 Pmax -8 Nack Nack Nack Nack Nack Pmax Pmax Pmax -2 Pmax -2 Pmax -4 Pmax -4 Pmax -6 Nack Nack Nack Nack Nack Nack Nack Pmax Pmax Pmax -2 Pmax -2 Pmax -4 Pmax -4 Pmax -6 Pmax -6 Nack Nack Nack Nack Nack Nack Nack Nack Nack Pmax Pmax Pmax -2 Pmax -2 Pmax -4 Pmax -4 Pmax -6 Pmax -6 Nack Nack Nack Nack Nack Pmax Pmax Pmax -2 Pmax -2 Pmax -4 Pmax -4 Pmax -6 Pmax -6 Pmax -8 Pmax -8 Nack Nack Nack Nack Nack Nack Nack Nack Nack Nack Nack Nack Pmax Pmax Pmax -2 Pmax -2 Pmax -4 Pmax -4 Pmax -6 Pmax -6 Nack Nack Nack Pmax Pmax Pmax -2 Pmax -2 Pmax -4 Pmax -4 Pmax -6 Pmax -6 Pmax -8 Pmax -8 Nack Nack Nack Nack Nack Nack Nack Nack Nack Nack Pmax Pmax Pmax -2 Pmax -2 Pmax -4 Pmax -4 Pmax -6 Pmax -6 Nack Nack Pmax Pmax Pmax -2 Pmax -2 Pmax -4 Pmax -4 Pmax -6 Pmax -6 Pmax -8 Pmax -8 Nack Nack Nack Nack Nack Nack Nack Nack Nack Pmax Pmax Pmax -2 Pmax -2 Pmax -4 Pmax -4 Pmax -6 Pmax -6 Pmax -10 Pmax -6 Pmax -10 Pmax -8 Pmax -12 Pmax -8 Nack Nack Nack Nack Pmax -10 Pmax -6 Pmax -10 Pmax -8 Pmax -12 Pmax -8 Nack Nack Nack Pmax -10 Pmax -6 Pmax -10 Pmax -8 Pmax -12 Pmax -8 Nack Nack Nack Nack Nack Pmax -10 Pmax -6 Pmax -10 Pmax -8 Pmax -12 Pmax -8 Nack Nack Nack Nack Nack Nack Nack Nack Pmax -12 Pmax -10 Pmax -8 Pmax -10 Pmax -8 Pmax -12 Pmax -10 Pmax -8 Pmax -10 Pmax -8 Pmax -12 Pmax -10 Pmax -8 Pmax -10 Pmax -8 Pmax -12 Pmax -10 Pmax -8 Pmax -12 Pmax -10 Pmax -8 Nack Nack Nack Nack Nack Nack Nack Nack Pmax -12 Pmax -10 Pmax -8 Pmax -12 Pmax -10 Pmax -8 Nack Nack Nack Nack Nack Nack Nack Nack Pmax -12 Pmax -10 Pmax -12 Pmax -10 Nack Nack Nack Nack Nack Nack Pmax -12 Pmax -12 Nack Nack Nack Nack Pmax -12 Pmax -10 Pmax -8 Pmax -10 Pmax -8 Pmax -12 Pmax -10 Pmax -8 Pmax -12 Pmax -10 Pmax -8 Nack Nack Nack Nack Nack Nack Nack Pmax -12 Pmax -10 Nack Pmax -12 Pmax -10 Nack Nack Nack Nack Nack Nack Nack Pmax -12 Nack Pmax -12 Nack Nack Nack Nack Nack Nack Nack Nack Nack Pmax -12 Pmax -10 Pmax -8 Pmax -12 Pmax -10 Pmax -8 Nack Nack Nack Nack Nack Pmax -12 Pmax -10 Nack Pmax -12 Pmax -10 Nack Nack Nack Nack Nack Nack Pmax -12 Nack Pmax -12 Nack Nack Nack Nack Nack Nack Nack Pmax -12 Pmax -10 Nack Pmax -12 Pmax -10 Nack Nack Nack Nack Pmax -12 Nack Pmax -12 Nack Nack Nack Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 204/629 V17.0 BSS Parameter User Guide (BPUG) 4.16.3 PS COMPUTATION Then, the effective cabinet output power is: Ps = Pr - cablesLoss - couplingLoss Pr is derived from Pc (where Pc = bsTxPwrMax + OMCattenuation or DLU attenuation) based on the translation table (§ 4.13.2). Pr can only be equivalent to Pmax in case when the operator has chosen the maximum value for bsTxPwrMax for a given coupling system. POWER AMPLIFIER 30W The nominal output power output for PA is 44.8 dBm (+/- 0.5dBm). This nominal output is the same for all frequencies. HIGH POWER EDGE POWER AMPLIFIER (HEPA) The nominal power output for HePA depends on the frequencies and on the product. Please note that not all product support HePA for all the frequency bands. For more details on HePA output power as a function of the product and the frequency band, please refer to the appropriate Engineering rules document ([R47] to [R56]).. COUPLING SYSTEM To know the input power, it is important to factor in the system coupling losses. Please refer to the appropriate Engineering rules document ([R47] to [R56]). CABLE LOSS For the values of the losses depending on the BTS configuration and frequency band, please refer to the appropriate Engineering rules document ([R47] to [R56]). RF/IO CABLE It is the RF cable connecting the Antenna connector of the duplexer to the output connector (to connect the antenna feeder). Each cable is specifically dedicated to a frequency band. This particularity is due to the quarter wave lightning protector which must be adapted to the frequency band. S8000 Example: Maximum insertion attenuation (guaranted): • GSM 900: 0.2 dB Outdoor BTS, 0.25 dB Indoor BTS Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 205/629 V17.0 BSS Parameter User Guide (BPUG) • • • • GSM1800&1900: 0.3 dB Outdoor BTS, 0.35 Indoor BTS Characteristic impedance: 50 Total length: 290 mm Maximum cable diameter: 7 mm CABLE BETWEEN PA AND COUPLING SYSTEM It is the RF cable connecting the PA (Power Amplifier) output connector to the input connector of the Hybrid combiner. S8000 Example: Maximum insertion attenuation (guaranted): • • • • • Cable total length: L ≤ 305 mm GSM 900: 0.25 dB Outdoor BTS, 0.35 dB Indoor BTS GSM1800&1900: 0.40 dB Outdoor BTS, 0.5 dB Indoor BTS Characteristic impedance: 50 Maximum cable diameter: 5.5 mm PS COMPUTATION EXAMPLE Calculation for S8000 Outdoor coupling duplexor, GSM 900 band : • • • • Pr = 44.8 dBm +/- 0.5 dB PA-coupling system cable loss = 0.25 dB RF/IO cable loss = 0.2 dB Duplexor loss = 1.0 dB Therefore : Ps = 44.8 (+/- 0.5dB) – (0.2+0.25) – 1= 43.35dB (+/-0.5dB) Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 206/629 V17.0 BSS Parameter User Guide (BPUG) 4.17. SYSTEM INFORMATION MESSAGES RELATED FEATURES 4.17.1 DUAL BAND HANDLING The purpose of this feature is to allow an operator with licenses in several frequency bands to support the use of multiband mobile stations in all its bands. In addition, it also allows the operator to support the use of single band mobile stations in each band of the license. The specification indicates that GSM900 and GSM1800 frequency bands can be combined. No frequency band is treated as the primary band. However, parameter setting can help multiband MS to give a higher priority to one of the bands. CAUTION! It has been experimented that with some mobile brands a delay in the other band neighbor cells reports occurs, i.e. a minimum time is necessary for those mobiles to send measurements from neighbors transmitting of the other band to the current cell. MULTIBAND MOBILE STATION A multiband mobile station is a mobile station which: • • supports more than one band has the functionality to perform handover, directed retry, channel assignment, cell selection and cell reselection between the different bands in which it can operate (within the PLMN) has the functionality to make PLMN selection in the different bands in which can it operate has 2 receivers, one specific to each band has 2 transmitters, one specific to each band • • • MODIFIED SYS INFO 3 Two new fields have been added to SYS INFO 3: EARLY_CLASSMARK_SENDING_CONTROL It indicates if multiband MS is authorized to send the early Classmark Change message to the BSC via the BTS. This allows the MSC to receive as soon as possible the multiband information and to pass it to the target BSC. It will speed up call set-ups and allows to perform Handover and directed retry when needed. The Classmark Change indicates the frequency bands supported by the MS and MS power classes to perform HO procedures in the best conditions. The corresponding parameter is the class 3 attribute early classmark sending belonging to bts objects. If it is set to “enabled”, the Classmark_Change message is sent just after the SABM and UA frames exchange on the Immediate_Assignment procedure. This message makes interband handover procedures possible. Moreover this parameter allows the mobile to send its capacity downlink Advanced Receiver performance. That helps to have SAIC mobile penetration Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 207/629 V17.0 BSS Parameter User Guide (BPUG) In single band networks, early classmark sending will be set to “disabled”. Note: indeed monoband network may forbid a dual band mobile to use the Early Classmark sending procedure in order to prevent phase 2 mobiles to send useless information to the network, and to cope with any potential problems with this feature in the mobiles. SYS_INFO_2TER_INDICATOR It is used to inform multiband MS that SYS INFO 2ter information is available. NEW SYS INFO MESSAGES The neighbouring cell lists for handover and cell reselection are broadcast towards multiband and single band mobile stations. The frequencies of neighbouring cells in other frequency bands than the current cell will be carried by new SYS INFO messages: • • SYS INFO 2ter for reselection neighbours. SYS INFO 5ter for handover neighbours. A single band mobile station will only use frequencies from SYS INFO 2 and 5 and if necessary, 2bis and 5bis for reselection and handover purposes, i.e. frequencies from the frequency band it supports. The BSC selects neighbour cells from the other band out of the neighbour list and sends them in SYS INFO 2ter and 5ter (see table below). Sys info 2 Sys info 5 GSM900 cell GSM 1800 cell Sys info 2bis Sys info 5bis Sys info 2ter Sys info 5ter GSM900 nei list GSM1800 nei list GSM1800 nei list GSM1800 nei list GSM900 nei list NEIGHBOUR CELL LIST IN SYS INFO The new SYS INFO 2ter and 5ter messages carry parameters which are needed by multiband mobile stations to perform respectively cell reselection (2ter) and handover (5ter) towards cell from another band: • Multiband Reporting: indicates to multiband MS the minimum number of cells to report in their measurement report outside the current frequency band. Its value is equal to the Multiband reporting parameter in the SYS INFO 5ter message. Neighbouring Cells List: coding of the frequencies of neighbouring cells. • CAUTION! Some single band mobiles are disturbed by the receipt of SYS INFO 5ter. They react by sending an RR status message, that can load the BSC. To avoid this, the sending of these messages is controlled by the BTS. On the opposite, single band mobile stations are not disturbed by 2ter messages because they ignore them. No field called ‘Sys_Info_5ter_Indicator’ exists. To know if 5ter messages are sent, SACCH filling messages are used. The parameter cellBarQualify is not used by some dual band MS in selection and reselection algorithms. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 208/629 V17.0 BSS Parameter User Guide (BPUG) MULTIBAND REPORTING Multiband mobile stations report cells from different frequency bands according to Multiband Reporting parameter (corresponding to class 3 attribute ‘multi band reporting’ of bts objects) broadcast in SYS INFO messages: • • the six strongest cells: default value. The multiband MS reports the six strongest allowed cells regardless of the frequency band. 1, 2, 3: the multiband MS reports the strongest or the two, three strongest allowed cells outside the current frequency band. The remaining space in the report is used to give information about cells in the current frequency band. If there are still some remaining positions (not enough neighbours in the current frequency band), these positions are used to report cells outside the current frequency band. CAUTION! A maximum of six cells will be reported. Only a maximum of n ”best” cells (according to the L1M algorithm) will be transmitted to the BSC by the L1M in a Handover_Indication message (n = 3 before V12 ; n = 6 from V12). OHER PROCEDURES The handling of multiband MS did not need specific changes in L1M. Main changes are on MS side. However, main procedures can be reviewed with the differences that occur in V10. • • PLMN selection: a single band MS only selects a PLMN from its frequency band. A multiband MS can select PLMNs of both bands. Cell selection & reselection: a single band MS only selects or re-selects cells from its frequency band. A multiband MS can select or re-select cells of both bands. Priority can be given to one band (see chapter Selection, Reselection Algorithms). Handovers: a new attribute is introduced in both adjacentCellReselection and adjacentCellHandover objects. Its name is standardIndicator Adjc and tells the type of network where the neighboring cell operates (“gsm” or “dcs” or “gsmdcs” or “dcsgsm”). A single band MS only performs handovers towards cells from its frequency band. A multiband MS can perform handovers towards cells of both bands if classmark 3 is supported on NSS side. • If local mode directed retry is chosen, as it is performed towards a specific neighbour, one type of single band MS (the one which does not support the frequency band of adjacent cell umbrella ref) will not use this feature. For multiband MS, formulas like PBGT or thresholds are the same as single band ones, their power class is replaced according to the band of the cell they are in (se chapter General formulas). Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 209/629 V17.0 BSS Parameter User Guide (BPUG) 4.17.2 SI2QUATER & SI13 ON EXTENDED OR NORMAL BCCH PRINCIPLE This feature has been designed to allow configuring the sending of System Information 13 (SI13) and System Information 2Quater (SI2Quater) messages either on normal or extended BCCH. This configuration is possible on a per BSC basis and done via the BSC Data Config tool. That feature is avalaible from V15.1 for BSC3000 and BSC12000. 3GPP recommendations gives: SI2QUATER It is sent if needed, as determined by the system operator. If sent on BCCH Norm, it shall be sent when TC = 5 if neither of SI2bis and SI2ter are used, otherwise it shall be sent at least once within any of 4 consecutive occurrences of TC = 4. If sent on BCCH Ext, it is sent at least once within any of 4 consecutive occurrences of TC = 5. SI13 It is only related to the GPRS service. SI13 need only be sent if GPRS support is indicated in one or more of System Information Type 3 or 4 or 7 or 8 messages. These messages also indicate if the message is sent on the BCCH Norm or if the message is transmitted on the BCCH Ext. In the case that the message is sent on the BCCH Norm, it is sent at least once within any of 4 consecutive occurrences of TC = 4. Today SI13 and SI2Quater are allocated on Norm BCCH. FCCH SCH BCCH BCCH BCCH BCCH CCCH CCCH CCCH CCCH FCCH SCH CCCH CCCH CCCH CCCH CCCH CCCH CCCH CCCH FCCH SCH CCCH CCCH CCCH CCCH CCCH CCCH CCCH CCCH FCCH SCH CCCH CCCH CCCH CCCH CCCH CCCH CCCH CCCH FCCH SCH CCCH CCCH CCCH CCCH CCCH CCCH CCCH CCCH IDLE The feature allows configuring separately SI2Quater and SI13 per BSC either on Norm BCCH or Ext BCCH. FCCH SCH BCCH BCCH BCCH BCCH BCCH BCCH BCCH BCCH FCCH SCH CCCH CCCH CCCH CCCH CCCH CCCH CCCH CCCH FCCH SCH CCCH CCCH CCCH CCCH CCCH CCCH CCCH CCCH FCCH SCH CCCH CCCH CCCH CCCH CCCH CCCH CCCH CCCH FCCH SCH CCCH CCCH CCCH CCCH CCCH CCCH CCCH CCCH IDLE As a consequence, SI3 message has been updated in order to indicate to the mobile: • • whether or not SI2quater and SI13 is broadcast if broadcast is done on Normal or Extended BCCH PERFORMANCES The BCCH channel has a repeat period of 8 multi-frames. One multi-frame has 51 frames and one frame is approximately 4,615ms long. Therefore, the BCCH repeat period is 8*51*4.615ms, or 1,88 seconds. Each period of the BCCH channel is given a number in the Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 210/629 V17.0 BSS Parameter User Guide (BPUG) range 0 to 7. This number is called TC. The 3GPP specifications define in which BCCH repeat period (TC value) a specific SYS INFO message can be sent. SI2Ter, SI13 and SI2quater can be sent when TC=4. This means that: • • • if 1 of SI2Ter, SI13 and SI2Quater messages has to be sent, it will be sent every 1.88 seconds. if 2 of SI2Ter, SI13 and SI2Quater messages has to be sent, each will be sent every 3.76 seconds. if all of SI2Ter, SI13 and SI2Quater messages has to be sent, each will be sent every 5.64 seconds. Redirection procedure duration is directly linked to the time the MS needs to read system information messages. On the contrary, the sending of system information on extended BCCH increase load on AGCH/PCH channel. BENEFITS Customers are facing MS issues: • Devices being unable to read SI13 messages when these are sent on the Extended BCCH. The impact of the failure to read this message was that the device is partially or completely unable to connect to GPRS services. Devices seeing valid SI messages containing 3G NCells (SI2Quater) as “corrupted” when sent on the Normal BCCH; continued reception of these messages resulted in the device rebooting or failing to set up CS calls. • So if customers don’t wish to recall affected MS the feature allows to modify the allocation of SI2Quater and SI13 messages SI2Quater and SI13 on Ext BCCH allow as well speeding up 3G toward 2G cell reselection (see chapter Mobility 2G - 3G Reselection). The drawback is a PCH / AGCH capacity lost. CAUTION! When this feature is enabled, e.g. if SI2Quater and/or SI13 on extended BCCH features are activated, the parameter noOfBlocksForAccessGrant has to be greater than 0. 4.17.3 SUMMARY OF SYSINFO SCHEDULING For each multi-frame, the BCCH block is used to transmit a BCCH system information. TC defines the index of the multiframe in which the Sysinfo message is sent by the network. The broadcast cycle is 8 multiframes therefore the TC index ranges from TC = 0 to TC = 7. In the absence of option SYSINFO messages, the basic cycle is : SYSINFO 1, SYSINFO 2, SYSINFO 3, SYSINFO 4, SYSINFO 1, SYSINFO 2, SYSINFO 3, SYSINFO 4. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 211/629 V17.0 BSS Parameter User Guide (BPUG) TC5 may be preempted by the optional SYSINFO 2x that has the highest priority, where 2bis priority > 2ter priority > 2quater priority. TC4 is shared by remaining optional SYSINFO messages one after the other in the following order : SYSINFO 2ter, SYSINFO 2quater and SYSINFO 13. Optional SYSINFO to broadcast None 2bis only or 2ter only or 2quater only 13 only 2bis & (2ter or 2quater or 13) 2ter & (2quater or 13) 2quater & 13 2bis & 2ter & (2quater or 13) 2bis & 2quater & 13 2ter & 2quater & 13 TC=0 TC=1 TC=2 TC=3 TC=4 TC=5 TC=6 TC=7 (Si n°) 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 (SI n°) 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 (SI n°) 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 (SI n°) 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 (SI n°) 1 1 13 2ter or 2quater or 13 2quater or 13 13 2ter 2quater or 13 2quater 13 2quater 13 2ter 2quater 13 (SI n°) 2 2bis or 2ter or 2quater 2 2bis 2ter 2quater 2bis 2bis 2bis 2bis 2ter 2ter 2bis 2bis 2bis (SI n°) 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 (SI n°) 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 2bis & 2ter & 2quater & 13 Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 212/629 V17.0 BSS Parameter User Guide (BPUG) 4.18. INTERFERENCE CANCELLATION Note : to activate interference cancellation feature, it is necessary to have receive diversity enabled. Interference cancellation is a very important feature in a mobile network, especially when capacity is a critical issue and aggressive frequency reuse schemes are applied to maximize it. Experience has shown gains with an adhoc frequency plan. Preliminary studies had indicated that in a 1X3 reuse frequency pattern network, capacity could be limited by uplink interferers. In general, even if capacity is not limited by uplink interferers, it is essential to mitigate their effect for quality improvement. Moreover it has been experienced that even if capacity is not UL limited, Interference Cancellation ensures improvements on data performance in UL, vocal quality in UL and measurement reports in UL, which improve mobility management. This results in a descreasing number of radio drops (study done with half MS quite UL weak, half MS quite DL weak). A BTS-based interference cancellation algorithm is of great interest. Nortel has designed a proprietary signal processing scheme aimed at cancelling the interferers. It works on the Base Stations equipped with all DRX S8K/S12K and with BTS18000. The effect of the feature depends on diversity: on a site without diversity, the feature Interference Cancelation will have no benefit. The algorithm works as well with or without frequency hopping and it can remove any kind of interferer that has some spatial or temporal coherence (co-channel, adjacent channel, CDMA signal leaking in the PCS band, TV transmitter, etc..). It can be viewed as a digital beam-forming technique in which a null of the radiation pattern is pointed towards the interferer. 8 interfering MS ’s on the 8 TS ’s of F0 BS#2 BS#1 call drop: too high C/I MS driving away from serving BS The algorithm is based on the use of the Maximum Ratio Combining diversity technique and the midamble in the GSM burst that is used to gain some indication of the channel characteristics, and hence an estimate of the noise present. This noise is approximately made up of interference and thermal-noise. The midamble is a known sequence of bits, which undergoes changes after propagation. The interference estimation is necessarily biaised since it is estimated on a short period of time (22 Tsymbol compared to the 148 Tsymbol) and the interference cancellation in the absence of interference will result in decreasing the SNR ratio. To avoid this problem, a parameter ρ is introduced. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 213/629 V17.0 BSS Parameter User Guide (BPUG) Thus, it is better not to try to estimate the noise but to put as ’an a priori information’ that there is only white noise. However when there are interferers, it is necessary to estimate them and the algorithm can do it only on the 22 signal samples where the useful signal is known. The ρ parameter is the interferer cancel algo usage parameter that can be set from the OMC. The ρ parameter is a compromise parameter that can trade-off the pure noise performances against the dominant interferer case. The algorithm finds the maximum of the modified signalto-noise ratio: • ρ = 0 implies that we have a constant term at the denominator, the noise energy, and the processing finds the linear combination that maximizes the signal (under the constraint that |a|2+|b|2=1), i.e. it performs the maximal ratio combiner (MRC). ρ = 1 (100%) means that we remove the constant term i.e. the a priori information on the noise. When there is no interference an approximate MRC combiner is performed. other ρ values like e.g. .5 (50%) mean that a compromise is made between performances at high interference and at pure noise situations. • • MRC is Nortel equipment’s diversity combining technique which is known to be the linear combination of signals received on the two antennas, that maximises the S/N ratio when there is only thermal noise (for example it is 1.5dB better than selection combining). It suffers about 2dB loss when there are strong interferers. Simulations have been carried out to show how with the use of MRC, the required Carrier-to-Int+Noise ratio (C/(I+N)) to maintain a particular BER reduces, as the presence of synchronus/asynchronus interferers increases. Although following the same trend, ICA simulation showed the use of a lower C/(I+N) to maintain the same BER as opposed to only using MRC. Before V15.1.1, gain of interferer cancellation was not optimal in case of low Rxlev. Since V15.1.1 interferer cancellation algorithm has been improved to take into account all range value for parameter "interferer cancel algo usage" (called rejection factor ρ) for all RxLev range Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 214/629 V17.0 BSS Parameter User Guide (BPUG) 4.19. EXTENDED CCCH This V12 feature consists in the implementation of the extended CCCH feature The need of this feature has been identified in some configuration where only one CCCH is not sufficient, due to a high rate of paging and immediate assignment. 4.19.1 CUSTOMER/SERVICE PROVIDER BENEFITS This feature allows increasing the rate of paging and immediate assignment messages related to a cell and thus: • • • Allows managing large location area with up to 16 TRX per cell, Gives the ability to manage multi-layers networks Allows managing GPRS traffic. 4.19.2 FEATURE FUNCTIONAL DESCRIPTION Up to V.11, only one CCH could be configured at the OMC-R. From V12 you can allow the configuration of extended CCCH on TS 2, 4 and 6 of the BCCH TDMA. The following CCCH configurations are now available : • CCCH_Conf = 0: TS 0 = FCCH+SCH+BCCH+CCCH • CCCH_Conf = 1: TS 0 = FCCH+SCH+BCCH+CCCH+SDCCH/4+SACCH/4 • CCCH_Conf = 2: TS 0 = FCCH+SCH+BCCH+CCCH TS 2 = CCCH • CCCH_Conf = 4: TS 0 = FCCH+SCH+BCCH+CCCH TS 2 = CCCH TS 4 = CCCH • CCCH_Conf = 6: TS 0 = FCCH+SCH+BCCH+CCCH TS 2 = CCCH TS 4 = CCCH TS 6 = CCCH Note: By increasing the number of CCCH, we decrease the number of TCH, so it leads to reduction of the capacity. For example, an O8 with 1 BCCH has a capacity of 48,65 Erlangs (with 2% of blocking rate); with 4 CCCH its capacity drops to 45,88 Erlangs. To configuration of a CCCH block on a TS the channelType parameter must be set to “cCH’. See also chapter SDCCH Dimensioning an TDMA Models. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 215/629 V17.0 BSS Parameter User Guide (BPUG) 4.20. PCM ERROR CORRECTION This feature, introduced in v12, is no longer supported as of v17. It is automatically deactivated by the OMC-R v17 : • • enhancedTRAUFrameIndication parameter is automatically set to value “not available” by the OMC-R v17 the value 1 for pcmErrorCorrection parameter is automatically forbidden by the OMCR v17. Therefore, the following sections (§4.20.1, §4.20.2, §4.20.3) are applicable only to BSS releases prior to V17. 4.20.1 FEATURE PRINCIPLE (applicable only to releases before V17) This feature had been introduced in V12 to reduce the number of errors due to PCM. The principle of this feature is quite simple; it is to replace the ETSI TRAU frames and to define a new frame (ETF) by introduction of a CRC on the uplink and the downlink path in order to detect and correct erroneous frames due to PCM error rate. The ETF can be used for the following frames: • • • Full rate, Enhanced full rate, Data up to 14.4 kbit/s The CRC is designed for three functions: • • • Firstly, it synchronizes the ETF (CRC 26), Then, it detects errors on the received ETF, And it corrects them until 2 pairs of bits. According to the frame transmission direction (downlink or uplink), the functions of the BTS and the TCU are different: • On uplink direction: the BTS(DRX boards) build the frame(ETF) while the TCU (TCB2 boards) synchronizes, detects, corrects and monitors the frame. If an error is not corrected, the TCU mutes the frame. At the end of the communication, the RF_channel_Release_Ack message carries the synthetic information about the PCM link status. On downlink direction: the BTS(DRX boards) synchronizes, detects, corrects and monitors the frame while the TCU builds the frame. If an error is not corrected, the BTS sends a filled frame to the MS. • During a BSC HO, if the TCU losses the frame synchronization, the communication is cut until the synchronization is found back (duration around 1 or 2 frames: it means around 20 or 40 ms). Moreover, if the BSC manages different frame formats (ETSI TRAU 8.620, ETF), the PCM error correction performance on the voice depends on the transmission direction: • On uplink direction: no degradation in relation to the current state Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 216/629 V17.0 BSS Parameter User Guide (BPUG) • On downlink direction: 60 ms of supplementary muting 4.20.2 FEATURE BENEFITS (applicable only to releases before V17) For users, the benefits of this feature are: • • Improvement of the voice quality, Better data transmissions. 4.20.3 FEATURE ACTIVATION (applicable only to releases before V17) This feature needs to be activated at two levels: the BSC one and the BTS one. At the BSC level, the parameter enhancedTRAUFrameIndication is set to “available”, only if the transcoder boards of all the related TCUs are on TCB2 boards type with V12 software. Since V14.3 the feature is available for TC3000 Moreover, at the BTS level pcmerrorCorrection must be set to “1” (but it can only be set to 1 if the enhancedTRAUFrameIndication is set to available). CAUTION! Some simulations with FR and different PCM error rate have shown that pcm error correction feature is efficient on FR whatever the PCM quality. But with EFR, according to the PCM quality the activation of PCM error correction may lead to a worst voice quality: • • • Good PCM: pcm error correction for EFR is useless Not too bad PCM: pcm error correction may be useful Bad PCM: no pcm error correction activation is better for EFR. As a result PCM error correction feature is efficient with: • • EFR when PCM quality is not too bad FR whatever the PCM quality For the other codec: PCM error correction feature is not available on data circuit codec. Furthermore, Nortel has not designed this feature for AMR codec as this feature is useless for AMR calls, moreover, in case of activation with AMR, the feature gain decrease when AMR penetration increases. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 217/629 V17.0 BSS Parameter User Guide (BPUG) 4.21. CELLULAR TELEPHONE TEXT MODEM (TTY) Deaf, hard of hearing, and speech-impaired persons have been using specific Text Telephone (referred to as TTY in North America) equipment in the fixed network for many years to transmit text and speech through ordinary speech traffic channels. To answer US FCC requirements, NORTEL V12.4 (or V14.3 with BSC/TCU 3000 introduction) BSS includes now the Cellular text Telephone Modem (CTM) solution for reliable transmission of a Text Telephone conversation via the speech channel of cellular or PSTN networks. 4.21.1 TTY PRINCIPLE Data transmission methods exist in the wireless services, but for various reasons, a text telephone transmission method for the speech path is desired. Two reasons are: • • text telephony is acknowledged as a way to contact the emergency services, and emergency services in wireless networks are so far only defined for speech calls. alternating speech and text in a call is desired, and one simple way to accomplish that without special service support (like multimedia) is by alternating the use of the speech channel. CTM allows reliable transmission of a text telephone conversation alternating with a speech conversation through the existing speech communication paths in cellular mobile phone systems. This reliability is achieved by an improved modulation technique, including error protection, interleaving and synchronization. The CTM is intended for use in end terminals (on the mobile or fixed side) and within the BSS network for the adaptation between CTM and existing traditional text telephone standards. The signal adaptation Baudot CTM is localized in the TCU-TCB2 in a pool TCB2 boards (or in the TCU 3000 in each TRM board). NORMAL CASE “SPEECH/DATA INDICATOR” = “SPEECH + CTM” If an ASSIGNMENT REQUEST or HANDOVER REQUEST message is received from the MSC with: • • • Circuit Identity Code compatible with TCB2 (or TRM_DSP) capability (FR+CTM) “Speech/data indicator” = “Speech + CTM” and “permitted speech version identifiers” = EFR & FR, an ASSIGNMENT COMPLETE or HANDOVER COMPLETE message will be sent to the MSC with Speech Version (Chosen) = FR (or EFR). Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 218/629 V17.0 BSS Parameter User Guide (BPUG) “SPEECH/DATA INDICATOR” = “SPEECH” If an ASSIGNMENT REQUEST or HANDOVER REQUEST message is received from the MSC with: • • • • Circuit Identity Code compatible with TCB2 (or TRM_DSP) capability (FR+CTM) “Speech/data indicator” = “Speech” and “permitted speech version identifiers” = EFR & FR or FR (or EFR & FR) and unavailable archipelago EFR and FR resource (SPU) an ASSIGNMENT COMPLETE or HANDOVER COMPLETE message will be sent to the MSC with Speech Version (Chosen) = FR (or EFR). ABNORMAL CASE On reception by the BSC of an ASSIGNMENT REQUEST or HANDOVER REQUEST message with: • Circuit Identity Code incompatible with TCB2 (or TRM_DSP) capability (the circuit pool implied by the CIC information element is incompatible with the channel type indicated) “Speech/data indicator” = “Speech + CTM” and “permitted speech version identifiers” = EFR & FR and unavailable archipelago EFR_CTM resource (SPU) • • • In a first step an ASSIGNMENT FAILURE or HANDOVER FAILURE message will be sent to the MSC. In a second step an ASSIGNMENT COMPLETE or HANDOVER COMPLETE message will be sent to the MSC with Speech Version (Chosen) = EFR (or FR according to the archipelago resource availability). 4.21.2 TTY IMPACT TCU-TCB2 The TCU-TCB2 capacity is not impacted by the CTM implementation. The TCU-TCB2 performances are the following: Manage up to 8 TCB2 boards and 4 A interface PCM (24 TS available on PCMA 0-1-2 and only 20 TS available on PCMA 3 fir ss#7, X25 or circuit) Each TCB2 board is downloaded with either the FR + EFR load and FR + CTM load Each TCB2 manages 12 communications whatever the associated CODEC type (FR + EFR and FR + CTM) exept for the #7 TCB2 which manages 8 communications. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 219/629 V17.0 BSS Parameter User Guide (BPUG) TCU 3000 The TCU 3000 capacity is affected by the CTM implementation according to the configured archipelagos EFR_CTM number. TCU 3000 architecture supports until 10 TRM max: (9+1 for redundancy)) Each TRM manages 3 archipelagos i.e. 36 SPU: • • • • FR codec: up to 6 communications corresponding to 72 calls per archipelago EFR codec: up to 6 communications corresponding to 72 calls per archipelago EFR_CTM codec: up to 4 communications corresponding to 48 calls per archipelago AMR: up to 5 communications Each TRM2 (introduced in V16.0) manages 3 archipelagos: • FR codec: up to 96 calls per archipelago • EFR codec: up to 96 calls per archipelago • EFR_CTM codec: up to 84 calls per archipelago • AMR: up to 96 calls per archipelago The TCU 3000 capacity can be formulated on maximum of communications. If X = number of configured archipelago FR If Y = number of configured archipelago EFR If Z = number of configured archipelago EFR_CTM Capacity = X*72 + Y*72 + Z*48 = 2138 No new parameters or counters are introduced with this feature. However, new information is available through the “Channel Type” message, and the field “Speech / data indicator”. We have the new request: “Speech + CTM Text Telephony”. CAUTION! CTM provides a solution that: • • • works with EFR and FR codecs (for example AMR) allows roaming between networks of different operators allows the users to transmit speech and text alternately (“Voici Carry Over VCO / Hearing Carry Over HCO) Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 220/629 V17.0 BSS Parameter User Guide (BPUG) 4.22. LOCATION SERVICES The objective of this feature is to allow the GSM network to geographically position Mobile Stations with BSC12000 (this BSS feature is available from V13.2) and BSC3000. The position of the MS is obtained using handset-based methods, namely EOTD and Network Assisted GPS. Additionally, the Cell Id and Timing Advance methods may be used as fallback methods. The determination of the positioning method is done outside the BSS at Mobile Location Center level. 4.22.1 PRINCIPLE The Enhanced Observed Time Difference (EOTD) positioning method combines the relative time of arrival of the signals from several BTSs reported by the target MS with the signals received by a fixed measuring point known as the Location Measurement Unit (LMU) whose location is known. Typically one LMU is needed for every 3 to 4 BTS sites. Note that there are two possible types of LMU: • Type A LMU communicates with the BTS over the air, it requires an additional antenna for this purpose. This is known as the ‘GSM Tx/Rx’ antenna. The signaling protocol for the LMU to SMLC interface is known as the LMU LCS Protocol (LLP) and is described in GSM 04.71. Type B LMU communicates with the BTS over a dedicated wired interface. The Type B interface uses the serial communications port on the LMU and will require a proprietary connection to the BTS (such as the Q1 bus or similar). • The Network Assisted GPS solution uses the GPS information measured by the MS if it supports this functionality. To ensure efficient service, assistance data needs to be sent by the network to the MS. Nortel has adopted a NSS-based architecture and will provide a combined Gateway Mobile Location Center and Serving Mobile Location Center (GMLC/SMLC) into a single platform, the Mobile Location Server. This server is therefore connected to the MSC. The BSS acts as a relay between the mobiles and the LMUs on one side and the Mobile Location Server on the other. Location Measurements Units (LMUs), if required (EOTD method), are wireless devices (type A) provided by a third party. It should be noted that the positioning accuracy is dependant on many factors, but mainly the algorithms implemented in the MS and in the SMLC. Therefore, the BSS is not responsible for the final location accuracy. Interface Lb is introduced for BSS based solution in V16.0 (see Engineering rules [R37]). 4.22.2 PERFORMANCES New signaling messages are introduced for this feature management: • • • RR Layer: Application Information message BSSMAP Layer: Connection Oriented Information message New BSSLAP Layer, including 7 messages needed for signaling between SMLC and BSC. Note: the class 3 parameter early classmark sending of the bts object class must be set to “allowed” by the OMC-R user. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 221/629 V17.0 BSS Parameter User Guide (BPUG) 4.23. SMS-CELL BROADCAST The objective of this feature is to support new broadcast services as advertising or information’s with BSC12000 and BSC3000 (this BSS feature is available from V14.2) The goal is to offer an interface for the SMS-CB that allows to send easily the same message on every cell of a list of BSCs and so that the system can update all the cells in a quicker time. BS OMC BS Cell Broadcast Center SMS-CB manager BSC BS BS BSC BS 4.23.1 PRINCIPLE In the Nortel network’s structure of Cell Broadcast Service a Cell Broadcast Center is interfaced with the OMC via a non Q3 interface. The OMC act as the SMS-CB manager and broadcast SMS over all the BSCs placed under its control. The new requirements concern: • • • • • the broadcast of the same short messages on all the cells which are managed by an OMC-R or a BSC list. the change rate of these short messages: 13 seconds are required; The current implementation about the short message broadcast involves several limitations and OAM constrains which should be raised: CBC/OMC-R interface throughput which must be compliant with the user activity performance. OMC-R/BSC interface throughput which must be compliant with the number of message (TGE) to be processed by the BSC (from 1 up to 2 TGE/sec for all transactions). Heavy OAM constraint to update the data base CBC when network (re) configuration occurs. Nortel confidential • PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 222/629 V17.0 BSS Parameter User Guide (BPUG) 4.23.2 PERFORMANCES The following table depicts the number of messages: CBC / OMC / I/F Messages Create short message Start broadcast (first time) Set short message (continued) Stop broadcast (continued) Start broadcast (continued) Stop broadcast (last) Periodic MMI commands number Periodic TGEs number OMC / BSC / I/F Old 1 X*Y 1 X*Y X*Y X*Y (1+2*X*Y)*n New 1 1 1 0 1 1 2*n Old Y Y Y Y New 1 0 1 1 2*y*n 320*n max or 1200*n max n X: BSC number [1:30] Y: Cell number / BSC12000 [1:160] X*Y: Cell number / OMC [1:2400] n: Number of updates of messages With this solution, SMS-CB has been dimensioned for following capacities: • • • 5 messages maximum per cell (broadcast in loop) message format: 1 page / 93 characters broadcast periodicity (30 sec, 1 mn, 2mn, 4 mn, 8 mn or 16 mn), 2 sec (1 message / cell) corresponding to the CBCH maximum capacity The whole users activity can be: • • on an average: 1 MMI command every 10 sec. for the whole set of users. Or, 1 MMI unitary command every 160 sec. per users, with a maximum of 16 users. on a maximum: 1 MMI unitary command every 2 sec. for the whole set users, during 2 hours maximum. Or 1 MMI unitary command every 32 sec. per users, during 2 hours maximum, with a maximum of 16 users. The CBC can be associated to n users among 16 ones: then the number of MMI commands on the CBC / OMC interface is n every 32 sec. Every short message modifications involves 2 MMI unitary commands (set short message & start broadcast) the short message change rate is 32*2n. Note: When the OMC-R receives one command for all the cells of one or several BSC, it checks for each cell if there is a CBCH channel and if the limit of 5 short messages is not exceeded. That defines a “compliant” cell. It then checks if a threshold S (per BSC) corresponding to a max of tolerated non compliant cells is reached. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 223/629 V17.0 BSS Parameter User Guide (BPUG) If the limit of 5 messages is exceeded for one or several cells and if the number of non compliant cells exceeds the threshold S for one or several BSC, the OMC-R rejects the command and does not sent the TGEs. The TGEs will not be sent for these BSC(s), but will be sent for the others. The response (FAILED) to the CBC will report per BSC the non compliant bts identities (up to the first S bts identities per BSC). If the number of non compliant cells does not exceed the threshold S for any BSC, the OMC-R accepts the command and sends the TGEs. The response (SUCCEEDED) to the CBC will report per BSC the non compliant bts identities (up to S bts identities per BSC). CBCH CHANNEL RECOMMENDATION On the air interface the CBCH channel takes 4 TS bursts (4*0.577 ms) on one 51 multiframe. The CBCH channel takes the place of one SDCCH channel. The SDCCH channel can be mapped on two different ways on TDMA: with BCCH combined (SDCCH/4) or on one reserved TS for SDCCH (SDCCH/8). Thus it is the same thing for CBCH. The CBCH is not using the radio resources of the CCCH. It is using the radio resources of one SDCCH channel. The activation and the use of the SMS-CB will not impact the load on the CCCH. The activation of the CBCH will take 1 SDCCH channel and so will increase the SD congestion. After the activation of the CBCH one needs to follow the SDCCH congestion and maybe if necessary on some cells to increase the number of SDCCH channels. Once defined on the cell the CBCH channel can only be used to send SMS-CB. Thus the quantity of SMS-CB sent will not impact the load of the radio channels other than the CBCH. Throughput calculation: The CBCH (idem to SDCCH) offers 184 bits for a block message (or 4TS). The corresponding throughput offered by the CBCH carried on 51 multitrame: Throughput = 184 * 4 / 4.615 ms / 51 = 781 b/s The limitations described in the FN are: • • • SMS of 88 bytes 5 messages per cell 2 seconds between each message. This means a throughput of: 88 * 8 * 5 / 2= 1760 b/s, which is more than 2 times the max throughput of the CBCH channel. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 224/629 V17.0 BSS Parameter User Guide (BPUG) 4.24. BSC/TCU 3000 INTRODUCTION With the BSC3000 introduction (this BSS equipment is available from V14.3), a lot of new features will be implemented: • • • • • Automatic handover adaptation (see HO adaptation feature TF 1216 in chapter Automatic handover adaptation) Protection againts Intracell HO Ping-pong (see HO Ping-pong feature TF 1217 in chapter Protection against intracell HO Ping-pong) TTY Support on TCU 3000 (see TTY feature in chapter CELLULAR TELEPHONE TEXT MODEM (TTY)) BSC 3000 overload (see chapterBSC3000 Overload Management) AMR HR/FR ( see AMR feature SV885/SV713 in chapterAMR - Adaptative Multi Rate FR/HR) Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 225/629 V17.0 BSS Parameter User Guide (BPUG) 4.25. AMR - ADAPTATIVE MULTI RATE FR/HR Nortel BSS has evolved to introduce sophisticated traffic management features dealing with call quality management and capacity improvements. This feature manages AMR services, which allow high gains and good trade-off between these 2 objectives. 4.25.1 BASICS AND SPECIFIC TERMINOLOGY In GSM, speech is transmitted on a radio channel (using a speech coder also called source coder) which has a fixed raw bit rate. The coder delivers speech frames every 20 ms. From that standpoint, speech quality tends to improve when the source coder bit rate is increased. If we use a high coder rate, the speech quality will be very good in excellent radio conditions, as long as speech frames can be decoded properly. But in bad radio conditions, a high proportion of speech frames will not be decoded, in which case some interpolation will be done by the decoder, and speech quality actually drops. If we use a low coder rate, speech quality will be medium or low, but will resist very well to radio channel impairments, due to the high level of redundancy. Consequently, present techniques like FR or EFR are the result of compromises between the source coder rate, and the channel coding, within the boundaries of the raw bit rate of a GSM channel. AMR techniques are adaptive, and multirate. It means that it allows adapting the compromise between source coder rate and channel coding/redundancy to actual radio conditions. AMR may operate in full rate channels, or half rate channels. This is called the “channel type” (TCH/FR or TCH/HR). Uplink and downlink always apply the same channel type. Basis of AMR is that within the channel (FR or HR), there is a set of voice coders, along with associated channel coding, among which the best combination can be selected to maximize speech quality according to conditions met on the radio link. This is “codec mode adaptation”. For codec mode adaptation the receiving side performs link quality measurements of the incoming link. The measurements are processed yielding a Quality Indicator. For uplink adaptation, the Quality Indicator, as measured in the BTS is compared to certain thresholds and generates, also considering possible constraints from network control, a Codec Mode Command (CMC) indicating the codec mode to be used on the uplink. The Codec Mode Command is then transmitted inband to the mobile side where the incoming speech signal is encoded in the corresponding codec mode. For downlink adaptation, the DL Mode Request Generator within the mobile compares the DL Quality indicator with certain thresholds and generates a Codec Mode Request (CMR) indicating the preferred codec mode for the downlink. Both for uplink and downlink, the presently applied codec mode is transmitted inband as Codec Mode Indication (CMI) together with the coded speech data. At the decoder, the Codec Mode Indication is decoded and applied for decoding of the received speech data. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 226/629 V17.0 BSS Parameter User Guide (BPUG) The following figure provides the AMR data flow from a "CMR, CMC and CMI" point of view and explains the CMI, CMC and CMR period. MS CMI 20ms 40ms BTS CMI CMR CMC CMI CMI CMR CMC 20ms 40ms AMR is introduced to choose in real time the repartition between rate of the source vocoder and channel protection: Half Rate Source coding Global throughput = 11,4 kBits/s Channel coding Full Rate Global throughput = 22,8 kBits/s • • when the transmission is good, a high rate vocoder is chosen and the number of bits dedicated to the channel protection is low, in case of degraded radio conditions, the vocoder rate is decreased, in order to provide a better channel protection and allow a better voice quality. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 227/629 V17.0 BSS Parameter User Guide (BPUG) 4.25.2 AMR MECHANISMS AMR introduces algorithms based on requested codec mode, which are fixed using an approximation of C/I and a set of thresholds and hysteresis. Depending on the channel used, the set of codec mode is different: • • For AMR FR, 5 codec modes can be requested: 12k2, 10k2, 6k7, 5k9, 4k75 (12k2 is a virtual mode) For AMR HR, 4 codec modes can be requested: 7k4, 6k7, 5k9, 4k75 (7k4 is a virtual mode) CODEC MODE ADAPTATION The purpose of AMR codec mode adaptation is to provide the "best" compromise between data rate of codec mode and channel protection, according to the link quality. This adaptation is done for uplink and downlink and there is no interdependence between the 2 links, but both sets of codec have to be identical. Each 40ms, according to the requested codec mode and the applied codec mode, the BTS: • • • increases by one step the rate of the codec mode, if the requested codec mode (CMR) is greater than the applied codec mode, decreases by one step the rate of the codec mode, if the requested codec mode (CMR) is lower than the applied codec mode, keeps the same codec mode, if the requested codec mode (CMR) is equal to the applied codec mode. DOWNLINK REQUESTED CODEC MODE A comparison of the estimated uplink C/I is then made with the network parameters to see to which codec mode the C/I corresponds. C/I Codec Mode 4 Thresold_3 + Hysteresis_3 = Threshold_Max_Up(3) Thresold_3 = Threshold_Max_Dn(4) Thresold_2 + Hysteresis_2 = Threshold_Max_Up(2) Thresold_2 = Threshold_Max_Dn(3) Thresold_1 + Hysteresis_1 = Threshold_Max_Up(1) Thresold_1 = Threshold_Max_Dn(2) Codec Mode 3 Codec Mode 2 Codec Mode 1 Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 228/629 V17.0 BSS Parameter User Guide (BPUG) UPLINK REQUESTED CODEC MODE The BTS computes for each burst the SNR criteria, which provides a good approximation of C/I. In order to have a smooth variation of these criteria, the BTS applies the following filter: (SNR)(k) = ß * (SNR)(k) + (1 - ß) * (SMR)(k - 1) Where ß is equal to: • • • • 0.05 in case of FR no frequency hopping channel and slow moving mobile, 0.1 in others cases of FR channels, 0.1 in case of HR no frequency hopping channel and slow moving mobile, 0.2 in others cases of HR channels. In case of DTX, the BTS cannot evaluate the SNR criteria, thus during the DTX period, the last value of (SNR)k is taken into account and at the end of the DX period, a time exponential filter is used in order to increase the weight of the new measures and keep the same period of filtering. This filtered SNR is compared to a set of thresholds and allows determining the requested codec mode. If no uplink correct frames is received, the BTS has no way to evaluate the quality of the downlink path, the BTS decreases the applied downlink codec mode of one step each 40ms. This procedure is repeated until an uplink frame is correctly received or the 4k75 codec mode is selected for the downlink path. CAUTION! Before V16.0 there was a limitation on UL SNR in order to have homogeneous behavior for AMR calls with every kind of DRX. From now, UL SNR measurements are truncated at 24dB (48 in 0.5dB) at SDO level, whatever hardware is used. The 48 value given from the BTS corresponds to 24dB and more. This new implementation improves the power control reactivity. That impacts on the AMR metric. Therefore C/I metric values for both AMR and EFR calls cannot be compared. PARAMETERS For each mobile, the following set of parameters has to be defined: • • for each link direction (upLink or DownLink), one threshlod per subsequent codec in the defined Active Codec Set (ACS), one hysteresis (the same value is used for each codec mode, but one for FR and another one for HR channel). But these parameters are linked to a set of factors, some of them being determined by the BTS (frequency hopping, MS speed), others being network dependent (environment profile…). The following table is implemented in the BSS: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 229/629 V17.0 BSS Parameter User Guide (BPUG) 5k9 to 4k75 6k7 to 5k9 FR thresholds 10k2 to 6k7 12k2 to 10k2 FR hysteresis 5k9 to 4k75 HR thresholds 6k7 to 5k9 7k4 to 6k7 HR hysteresis slow MS no FH 81 82 83 84 85 86 87 88 89 uplink downlink ideal FH fast MS SFH 900 < 4 FH (>= 4 freq) no FH TU3 90 99 108 117 91 100 109 118 92 101 110 119 93 102 111 120 94 103 112 121 95 104 113 122 96 105 114 123 97 106 115 124 98 107 116 125 According to the network configuration, and for each combination of codec mode and link direction, the operator selects the appropriate thresholds by using the parameters amrUlFrAdaptationSet, amrUlHrAdaptationSet, amrDlFrAdaptationSet, amrDlHrAdaptationSet (or the single parameter amrAdaptationSet before V15.1.1). These parameters allow to choose between 3 sets of pre-defined tables (optimistic, pessimistic and typical settings) plus one set of tables which is user-defined The BSS using the TS configuration and the MS speed applies the appropriate column for the uplink path. As specifed in the GERAN recommendations (05.09) the mobile shall use the downlink thresholds provided by the BSS defined for a reference environement: Typical Urban 3 km/h with ideal frequency hopping at 900 MHz. The MS shall then apply a normalization factor to normalize with respect to different channel types. The normalization factor is mobile dependant. See also chapter AMR Field Feedback for further informations on the codec adaptation table. RATSCCH MANAGEMENT This new channel is used in order to change the set of codec modes (see "L1m" section), and has the following main characteristics: • • • • • frame stealing (1 speech frame for a FR channel, 2 speech frames for a HR channel), priority of RATSCCH frames is lower than FACCH priority, a RATSCCH message has to be acknowledged in the next 3 frames by the MS, the content of RATSCCH message is applicable 12 frames after this message, in case of failure (ACK_ERR message), a RATSCCH procedure is repeated twice. If the procedure completely fails, the MS and the BTS use the previous set of codec modes. When amrReserved1 is set to enabled, this procedure is used by the L1m to modify the set of codec modes, for a FR channel and in case of handover failure with return on the old FR channel, in order to avoid inconsistency between the BTS and the MS (the BTS sends the AMR_CONFIG_REQ message). Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 230/629 V17.0 BSS Parameter User Guide (BPUG) For TCH/FR, the default transmission phase shall be such that Codec Mode Indications are sent aligned with TDMA frame 0 in the uplink and with TDMA frame 4 in the downlink. For TCH/HR, the default transmission phase shall be such that Mode Indications are sent aligned with TDMA frame 0 or 1 depending on the subchannel in the uplink and with TDMA frame 4 or 5 depending on the subchannel, in the downlink. If at call setup or after a handover, the Codec Mode Indication is not aligned, an Ater procedure is engaged in order to change the default phase in downlink direction. PRINCIPLES The RATSCCH as the FACCH shares the dedicated channel of the TCH. Contrarily to the FACCH the RATSCCH is time synchronous. The RATSCCH allows modification of the AMR configuration (CMI/CMC phasing, Adaptation Thresholds, ACS). From V14, the introduction of the AMR, Nortel Networks BTS will support the RATSCCH (All Nortel’s BTS from the S4000 DCU4 to the most recent BTS will support the AMR speech service.) The RATSCCH message is composed of a preamble and of a message part. Several messages have been defined. These messages correspond to different procedures. At the moment the following have been defined: • • Changing of the Active Codec Set Changing of the thresholds and hysteresis PRE-HANDOVER In case of intracell or intercell handover, the adaptation mechanism has to be frozen to the ICM. For this result, the BTS has to intercept: • • the Assignment Command in case of intracell, the Handover Command in case of intercell handover, and to perform up to 2 codec mode adaptations, in order to activate the initial codec mode (5k9 kbits in all cases) and to stop the adaptative mechanism. This induces: • • an increase of around 150ms on the handover duration from the BSS point of view, a delay of around 150ms on the handover starting time from a MS point of view, but no impact for the end-user in term of voice quality (i.e. same speech gap). In case of handover failure when the MS returns on the old channel, the adaptation mechanism is restarted by the BTS at reception of the Start Measurement message 4.25.3 TRAFFIC MANAGEMENT MECHANISMS CHANNEL ALLOCATION TCH channel allocation is triggered by the reception of an Assignment request or a Handover request message from the MSC, or in case of an intraBSC handover. The BSC should Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 231/629 V17.0 BSS Parameter User Guide (BPUG) determine whether AMR is to be used, and select between FR or HR. This mechanism is based on proprietary algorithms, which provide to the operator a full control of the allocation. These decisions are made based on several criteria: • • • OAM flags which indicate if the BSC, the TCU, and the cell support AMR, and strategy selected MS capability, which is reported by the MSC in Assignment request or Handover request messages radio context, for instance as evaluated during the SDCCH phase. The BSC also has to control the BSS version: an AMR channel is activated only if all nodes managing the call are at least in V14. FLAG MANAGEMENT We use the two following parameters: • • coderPoolConfiguration (AMR, fullrate, enhancedfullrate) attribute. This attribute indicates enumerated speech coding algorithms supported by the TCU. speechMode (halfRateAMR, fullRateAMR, fullrate, enhancedfullrate) attribute. This attribute indicates speech coding algorithms supported by the cell. CHANNEL TYPE MANAGEMENT In order to select the channel type associated to the connection, the BSC uses the channel rate and type and permitted speech version information, in order to know the MS capability in term of: • • FR/HR management Speech codec But the chosen channel type is fixed according to radio criteria and some O&M parameters, and the BSS has the possibility to modify the channel type during the connection, in all cases. So at reception of the Assignment Request or Handover Request, the following mediation is done on the Channel Type octet 4: IF Target TCH = FR TCH THEN the BSC always allocates a FR TCH IF Target TCH = HR TCH AND IF AMR HR is allowed in the cell THEN the BSC allocates a HR TCH ELSE the BSC allocates a FR TCH. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 232/629 V17.0 BSS Parameter User Guide (BPUG) CELL LOAD STATE The cell load state is used in order to choose between a FR or a HR channel, and is defined using following parameters: • • • hrCellLoadStart hrCellLoadEnd filteredTrafficCoefficient Previously to V15.1.1, if hrCellLoadStart = 0, then FR radio channel is always allocated to the MS, and if hrCellLoadStart > 0, then HR radio channel is allocated to the MS, according to its radio conditions. For one call, the cell load state is evaluated at the first TCH allocation in the cell, thus in case of intracell handover, the cell load state is not reevaluated. In V15.1.1, the feature AMR based on traffic is introduced. The goal is to enhance the HR allocation in order to take into account the cell load: AMR HR channels are allocated only during loaded period. The cell load state is evaluated every 10s (see Filtered Erlang traffic and cell load state) ASSIGNMENT In case of assignment, according to: • • • the speechMode parameter value TranscoderBoard + bts parameters) the cell load of the target cell the radio condition of the MS of the target cell (signalingPoint + the BSC selects the target Channel Type. To know the radio conditions, the BSC sends to the BTS a Connection State Request and in the Connection State Ack the BTS gives the following bit map: • • • “small zone” bit indicates if the small zone of the serving is eligible in case of multizone cell “HR large” bit indicates if the MS has sufficient radio conditions to manage a HR channel in the large zone of a mullti-zone cell or in normal cell “HR small” bit indicates if the MS has sufficient radio conditions to manage a HR channel in the small zone of a mullti-zone cell or in normal cell Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 233/629 V17.0 BSS Parameter User Guide (BPUG) Using these bits and the following priority order between channel type and zone: Priority ++ + -Preferred zone HR small zone HR large zone FR small zone FR large zone the BSC selects the channel type and the zone for the MS. RADIO ALLOCATOR The radio allocator is improved in order to manage AMR calls. Due to intrinsic quality of FR AMR and HR AMR, 2 new parameters are created on the transceiver object, in order to give an AMR priority to each TDMA: • • where • • • Priority 0 is given to a high priority TDMA Priority 1 is given to a low priority TDMA Priority 2 disables this service on the TDMA frAMRprioriry hrAMRPriority Thus according these new parameters, the BSC chooses the radio TS using the following order: • • • • Interference level, TDMA priority, TDMA number (from the smallest to the biggest: 0 to n), TS number (from the biggest to the smallest: TS7 to TS0). In case of HR request, the BSC applies the following rules: • • • • • Always fill the holes in term of tree half (between 2 holes, the BSC uses priority rules previously defined If there is no hole, then the BSC allocates the highest priority TS using the rules previously defined This radio allocator is not improved in order to manage AMR calls, thus if an AMR request occurs and this radio allocator is selected, then: an other vocoder (EFR or FR) is selected using priority order given in the channel type element the allocated channel type is always a full rate TCH. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 234/629 V17.0 BSS Parameter User Guide (BPUG) 4.25.4 AMR L1M Up to V14, L1m algorithms are common for all types of dedicated channel, but due to performances of AMR channels: • • A FR AMR channel, specially with low codec mode, is more resistant than the normal FR channel A HR AMR channel, is more sensitive to interference than the normal FR channel Some new mechanisms dedicated for AMR channels based on "requested codec mode" in uplink and downlink paths, which are the best representation of the quality in this case, are designed. For this reason, RxQual criterion is not used in AMR L1m algorithm, dealing with AMR channel. 12K2 AND 7K4 CODEC MODE FALSE ACTIVATION As seen before following codec mode sets are implemented in the BTS: AMR FR AMR HR 10k2 6k7 5k9 4k75 6k7 5k9 4k75 In AMR L1m mechanisms, the main criterion for L1m is the requested codec mode provided by the MS or the BTS. With this set of codec modes, it is impossible to detect if the quality is good or very good (in both cases the MS and the BTS provide the 10k2 or 6k7 codec mode according to the channel type). In order to solve this problem, for an half rate channel, a fourth codec mode (7k4) is added to the list allowing to distinguished between good and very good radio conditions. Thus the half rate codec mode set becomes: AMR HR 7k4 6k7 5k9 4k75 For a full rate channel: • if the radio conditions are good for uplink and downlink, then the 12k2 kbits codec mode is configured and the 4k75 discarded allowing to distinguish between good and very good radio conditions (using RATSCCH channel). if the radio conditions are bad for uplink or downlink, then the 12k2 kbits codec mode is removed and the 4k75 is set back (using RATSCCH channel). • Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 235/629 V17.0 BSS Parameter User Guide (BPUG) Thus the codec mode set becomes: AMR FR AMR FR 12k2 10k2 6k7 5k9 10k2 6k7 5k9 4k75 The following algorithm details the way of changing the codec mode set, for both paths: 1) initial state: the active codec mode set is {12k2, 10k2, 6k7, 5k9} 2) during the last 480ms period, at least one 4k75 code mode or 3 * 5k9 codec mode are requested for uplink or downlink paths, then the active codec mode set is change to {10k2, 6k7, 5k9, 4k75} 3) if the active code mode set is {10k2, 6k7, 5k9, 4k75} and during the last 2*480ms period, no 5k9 nor 4k75 code mode is requested for uplink and downlink paths, then the active codec mode set is change to {12k2, 10k2, 6k7, 5k9}. POWER CONTROL The Power Control feature reduces the average interferences level on the Network and saves mobile batteries. Power control algorithms are redesigned for AMR calls, in order to take into account the requested codec mode. With the following parameters (powerControl object), the operator defines the target codec mode of each channel type: Uplink target codec • • hrPowerControlTargetMode frPowerControlTargetMode Downlink target codec • • hrPowerControlTargetModeDl frPowerControlTargetModeDl For the uplink path, SNR and CMR criteria are available, but the SNR is more accurate than the CMR. For the downlink path only the CMR is available. Thus the AMR power control does not apply same principles for both paths. This new power control mechanism is also controlled by the 2 classical power control parameters: • • bsPowerControl for the downlink path, uplinkPowerControl for the uplink path. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 236/629 V17.0 BSS Parameter User Guide (BPUG) UPLINK POWER CONTROL For the uplink path, the criterion is the SNR, averaged on 2 measurement periods. As this mechanism shall guarantee a voice quality, the target SNR is the upper threshold of the adaptation mechanism: Note: for the 12k2 (or 7k4) value, the BTS takes into account the 10k2 (or 6k7) value plus the FR (or HR) hysteresis. At each measurement period, the BTS calculates the new MS power using the following formula: IF (Filtered_SNR – Target _SNR) > 0 THEN MS_txpwr(N) = MS_txpwr(N-1) – 0.7*( Filtered_SNR – Target _SNR) ELSE IF THEN MS_txpwr(N) = MS_txpwr(N-1) + 1.4*( Target _SNR -Filtered_SNR) Note: From V 16, the reactivity of UL power control is improved as UL SNR measurements limited to 24 dB (48 in 0.5 dB) are taken out. DOWNLINK POWER CONTROL The power control principle is: • • To decrease the power level of one step if the last requested codec mode of the 480 ms is greater than the target codec mode, To increase the power level of one step if the last requested codec mode of the 480 ms is lower than the target codec mode Note: in AMR like in EFR, the parameter lRxLevDLP indicates the threshold below which power control is inhibited. HANDOVER MECHANISMS The following table describes which handover mechanisms are impacted by the AMR introduction Handover type uplink and downlink quality uplink and downlink strength distance power budget uplink and downlink intra-cell handover capture inter-zone directed retry Traffic modified yes no no no yes no yes no no Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 237/629 V17.0 BSS Parameter User Guide (BPUG) PRINCIPLE These 4 handovers are based on "(n,p) voting" principle, using the requested codec mode. The (n,p) voting principle considers the last p requested codec modes, it compares them to two parameters: a codec mode threshold defined for the procedure and the specific n value pRequestedCodec t Handover decision used for the procedure. If p is set to 2 SACCH periods (2*12), n is set to 10, the target codec mode is the green one, and then a handover is triggered in the following example: This principle applies in uplink and downlink direction independently. This mechanism is managed by the L1m and triggered at the end of each period of measurement, thus p has to be a multiple of the number of requested codec mode in one measurement period (i.e. 480 / 40 = 12). The following parameters are defined in the handOverControl object: • • • pRequestedCodec nHRRequestedCodec nFRRequestedCodec If the n parameter is set to a value greater than the p parameter, then all associated features are deactivated. If the target codec mode is the smallest, then the associated feature is deactivated. INTERBSC HANDOVER In case of interBSC handover, according to: • • • • the speechMode parameter value transcoderBoard + bts parameters) the cell load of the target cell the Current Channel element the Cause element of the target cell (signallingPoint + the BSC selects the target Channel Type: • • if one out of these last 2 optional A interface elements is not set in the Handover Request message, the chosen channel type is FR if these 2 elements are present and the half rate is allowed in the target cell, then the following table is applied: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 238/629 V17.0 BSS Parameter User Guide (BPUG) Current Channel type 1 Cause uplink quality uplink strength downlink quality downlink strength Distance O&M intervention Better cell Directed retry Traffic HR FR FR FR FR FR FR FR HR FR HR FR FR FR FR FR FR FR FR FR In all other case, a FR channel is allocated. INTRABSC INTERCELL HANDOVER In case of intraBSC handover, following transitions are defined in order to determine the target channel type: Initial Channel type Handover cause AMR quality DISTANCE PBGT TRAFFIC Forced HO Capture Directed retry HR AMR FR AMR FR AMR FR AMR HR AMR HR AMR FR AMR FR AMR FR AMR FR AMR FR AMR FR AMR FR AMR FR AMR FR AMR FR AMR The speechMode parameter value of the target cell and the cell load are also checked in order to verify that the half rate is allowed in the cell. With AMR calls, RxLev and RxQual criteria for uplink and downlink are not used and replaced by an algorithm based on "(n,p) voting" principle, using the requested codec mode. Following parameters are introduced in order to specify the target requested codec mode for FR and HR AMR channel: • • amrHRIntercellCodecMThresh amrFRIntercellCodecMThresh In order to manage the eligible cell list, a new handover margin is introduced in the adjacentCellHandOver object: hoMarginAMR this parameter is used in order to calculate the Exp2 (this expression is used to evaluate the PBGT criteria for each cell and to classify eligible cells, please refer to chapter EXP2). Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 239/629 V17.0 BSS Parameter User Guide (BPUG) IF N(Uplink) ≥ nXXRequestedCodec OR N(Downlink) ≥ nXXRequestedCodec THEN the Handover is triggered With N the number of requested codec mode for the uplink or the downlink strictly lower than AMRXXIntercellCodecModeThreshold (XX stands for HR or FR) INTRABSC INTRACELL HANDOVER In order to select the channel type, the BSC applies the following table: Handover cause normal intra-cell Small to large zone large to small zone large to small zone tiering FH to no FH tiering FH to no FH tiering no FH to FH tiering no FH to FH AMR FR to HR AMR HR to FR original channel type target channel type FR FR or HR FR HR FR HR FR HR FR HR FR FR FR or HR according to radio conditions* HR** FR FR FR HR HR FR *The radio conditions are given by the BTS to the BSC using the Current Cell Add information element in the Handover Indication message. **If radio conditions are not sufficient in the small zone to manage this HR MS, the MS remains in the large one, due to the HR priority. Intracell handover principle is to give to the mobile a better resource in term of interference, if its C/I is low, with a high C value. This principle is only applicable to FR AMR mobiles, due to interaction with HR >FR handover: in these radio conditions, it is really more efficient to allocate a FR radio TS to a HR AMR mobile, than to perform a handover from an HR TS to a HR TS. This intracell handover is triggered only if the intracell parameter of handovercontrol object is set to enable. The following parameter is introduced on the handoverControl object, in order to specify the target requested codec mode for FR AMR channel: • amrFRIntracellCodecMThresh The minimum level to perform an AMR intracell handover is defined by following parameters on the handoverControl object: • • amriRxLevDLH amriRxLevULH Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 240/629 V17.0 BSS Parameter User Guide (BPUG) So the intracell handover uses the following criteria: IF N(Uplink) ≥ nFRRequestedCodec AND RxLevUL > amriRxLevULH OR N(Downlink) ≥ nFRRequestedCodec AND RxLevDL > amriRxLevDLH THEN the handover is triggered. With N the number of requested codec mode for the uplink or the downlink strictly lower than amrFRIntracellCodecMThresh for the uplink or the downlink INTRACELL HANDOVER AMR FR AMR HR This handover is used to change the channel type of a mobile from FR to HR if the quality is sufficient. Due to the high C/I requirement for HR channel, the requested codec mode of "(n,p) voting" mechanism is fixed by default to 12k2 kbits/s and a dedicated "n" parameter allows to set the trade-off between quality and capacity: • nCapacityFRRequestedCodec The handover is triggered if the "(n,p) voting" principle is fulfilled in both directions. Note: • • this mechanism is not linked to the intracell parameter of handovercontrol object. this mechanism is deactivated if nCapacityFRRequestedCodec is greater than pRequestedCodec. So the handover AMR FR to HR uses the following criteria: IF N(Uplink) ≥ nCapacityFRRequestedCodec AND N(Downlink) ≥ nCapacityFRRequestedCodec THEN the capacity handover is triggered. With N the number of requested codec mode for 12k2 in the p requested codec mode for the uplink and the downlink path, INTRACELL HANDOVER AMR HR AMR FR This handover is used to change the channel type of a mobile from HR to FR if the quality is not sufficient. The handover is triggered if the "(n,p) voting" principle is fulfilled in one direction. The following parameter is introduced on the handoverControl object, in order to specify the target requested codec mode for this handover: • amrHRtoFRIntracellCodecMThresh Note: this mechanism is not linked to the intracell parameter of handovercontrol object, and it is deactivated if amrHRtoFRIntracellCodecMThresh is set to 4k75. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 241/629 V17.0 BSS Parameter User Guide (BPUG) DIRECT HALF RATE TCH ALLOCATION In order to avoid some unnecessary handover from FR to HR channel, it is mandatory to evaluate the radio conditions at following stages: • • • • primo allocation: SDCCH to TCH in a normal cell, primo allocation: SDCCH to large zone TCH in a multi-zones cell, primo allocation: SDCCH to small zone TCH in a multi-zones cell, inter-zone handover from large to small in a multi-zones cell. and allocate immediately a HR channel if radio conditions are sufficient. The principle of this mechanism is to compare the RxLev uplink and downlink to dedicated thresholds, in order to estimate the MS HR capability. Following parameters are introduced on the handoverControl object, in order to specified RxLev thresholds for this handover: • • • • amrDirectAllocIntRxLevDL amrDirectAllocIntRxLevUL amrDirectAllocRxLevDL amrDirectAllocRxLevUL So the direct half rate TCH allocation uses the following criteria: In a normal cell or in the large zone: IF RxLevDL > amrDirectAllocRxLevDL and RXLevUL > amrDirectAllocRxLevUL THEN the direct HR TCH allocation is eligible In a small zone: IF RxLevDL > amrDirectIntAllocRxLevDL and RXLevUL > amrDirectIntAllocRxLevUL THEN the direct HR TCH allocation is eligible In v17.0, the Direct TCH Allocation mechanism has been improved to take into account the case where only a short, not fully reliable, measurement average is available. In that case, all algorithm criteria are tightened by adding the hoMarginBeg parameter to the appropriate thresholds (amrDirectAllocIntRxLevDL, amrDirectAllocIntRxLevUL, amrDirectAllocRxLevDL, amrDirectAllocRxLevUL). Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 242/629 V17.0 BSS Parameter User Guide (BPUG) SUMMARY The following table presents a summary of all new L1m decisions: HO decision channel type p value for (n,p) voting n value for (n,p) voting target codec quality intercell UL / DL TCH FR TCH HR FR HR FR FR FR HR TCH FR TCH HR TCH FR pRequestedCodec pRequestedCodec pRequestedCodec pRequestedCodec pRequestedCodec channel type nFRRequestedCodec nHRRequestedCodec quality intracell UL / DL amrFRIntercellCodecMThresh amrHRIntercellCodecMThresh amrFRIntracellCodecMThresh amrHRtoFRIntracellCodecMThresh fixed to FR codec 12k2 thresholds nFRRequestedCodec nHRRequestedCodec capacity intracell nCapacityFRRequestedCodec averaging window Direct HR TCH allocation outer zone inner zone SDCCH SDCCH TCH FR TCH HR 1 … rxLevHreqt* rxLevHreqave 1 … rxLevHreqt* rxLevHreqave amrDirectAllocRxLevDL amrDirectAllocRxLevUL amrDirectAllocIntRxLevDL amrDirectAllocIntRxLevUL * in this case, all available measures, up to rxLevHreqt are taken into account.0 Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 243/629 V17.0 BSS Parameter User Guide (BPUG) Following figures illustrate all possible transitions for an AMR call, in a multi-zones cell environment: INTRACELL HANDOVERS ON QUALITY Tiering BCCH to FH FR Tiering BCCH to FH HR FR Intracell FR or HR FR FR Interzone FR or HR Intracell FR or HR FR INTRACELL HANDOVERS ON CAPACITY Tiering BCCH to FH FR Tiering BCCH to FH HR Interzone FR Interzone HR Capacity FR HR FR or HR FR or HR HR Capacity FR HR FR or HR Direct TCH allocation FR HR HR Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 244/629 V17.0 BSS Parameter User Guide (BPUG) INTERCELL HANDOVERS: FR FR Target Cell HR HR FR FR PBGT Traffic HR HR FR FR HR Alarm Capture Source Cell FR FR HR FR FR Directed Retry 4.25.5 LEGACY L1M Type of power control and quality handover can be chosen via the parameter amrReserved2. While legacy L1m bases its decision on RxQual/RxLev measurements (please refer to chapter Measurement Processing), AMR L1m base trigger its algorithms on C/I estimations (please refer to chapter AMR L1m). The choice between legacy or AMR power control or handover management is up to the operator’s strategy. 4.25.6 PDTCH PREEMPTION BY AMR FR OR HR CALLS The GSM/GPRS TS sharing feature allows the BSC to preempt some GPRS radio resources, in case of lack of circuit radio resources. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 245/629 V17.0 BSS Parameter User Guide (BPUG) AMR FR REQUEST In case of AMR FR request, there is no specific mechanism. The request is granted in the same conditions as for a non-AMR circuit-switched call. AMR HR REQUEST Before v17.0, in case of an AMR HR request, if a preemption has to be done, then the allocated channel following preemption is an AMR FR channel. From v17.0, if the “AMR-HR on preempted pDTCH” feature is activated (v17 parameter gprsPreemptionForHr = enabled), then the BSC is able to preempt a shared GPRS timeslot to serve an AMR-HR request. The algorithm is as follows : When the BSC receives an assignement or a handover request for a half-rate speech channel, the BSC searches for an available HR channel in the following order of preference : • free half-rate channel of a TCH physical channel whose other half-rate channel is already allocated to a voice AMR HR call (no dialog between BSC and PCU is needed) free TCH physical channel (no dialog between BSC and PCU is needed) free half-rate channel of an already preempted PDTCH whose other half-rate channel is already allocated to a voice AMR HR call (no dialog between BSC and PCU is needed) half-rate channel of a newly preempted PDTCH (BSC and PCU must negotiate) • • • This feature for AMR-HR preemption may have an impact on the AMR based on Traffic threshold settings, see 4.23.7 Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 246/629 V17.0 BSS Parameter User Guide (BPUG) 4.25.7 ENGINEERING RULES QUEUING/PRIORITY 0 • • queuing is not possible for an HR only request, for a FR or HR request in queue, only a FR TCH can be allocated. The number of priority 0 TS takes into account only radio TS which are completely free (i.e. a free half rate TS is count for 0). TCH SIGNALLING A signaling half rate TCH can not be activated at reception of Channel Required. If a “signaling” Assignment Request (channel type: “speech/ data indicator” field), for a mobile using a half rate TCH, an assignment procedure is triggered to a SDCCH channel and the associated CIC is released (this case occurs at the end of a speech call, if a SMS procedure is started and not finished). If a “signaling” Assignment Request (channel type: “speech/ data indicator” field), for a mobile using a full rate TCH, a channel mode modify procedure is triggered to a signaling TCH channel and the associated CIC is released (this case occurs at the end of a speech call, if a SMS procedure is started and not finished). If an AMR HR or FR Assignment Request is received for a mobile using a signaling FR TCH, the BSC modifies the current signaling FR TCH to a AMR FR TCH and later, if radio conditions are sufficient, then a handover from AMR FR to AMR HR will be triggered by the BTS (see section “Principles/ L1m/Handover mechanisms/ handover HR->FR”). AUTOMATIC CELL TIERING In V12.4, according to PWCI distribution and hopping TCH percentage, the BTS is able to automatically set the used threshold in order to trigger tiering handover. In V14, this mechanism has to be enhanced as show below, in order to take into account AMR HR calls: • in V12.4: P% is evaluated as: P%= • Number of non hopping TCH - nbLargeReuseDataChannel Total number of TCH in the cell - nbLargeReuseDataChannel in V14: P% is evaluated as: P%= (Number of non hopping TCH – nbLargeReuseDataChannel) * (1 + Non_FH_HR%) (Total number of TCH in the cell – nbLargeReuseDataChannel) * (1 + HR%) • • FH_HR% is the percent of HR calls managed by the hopping pattern in the cell, HR% is the percent of HR calls managed in the cell. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 247/629 V17.0 BSS Parameter User Guide (BPUG) These 2 percentages are calculated by the BTS. GENERAL PROTECTION AGAINST HO PING PONG Due to AMR L1m introduction, a new cause value is added in hoPingPongCombination: AMRquality. This value is used in case of AMR handover triggered for alarm purpose. In case of interBSC handover, in order to distinguish between RxQual handover and AMR quality handover, the BSC uses following rules: • • If the handover cause = RxQual and the speech version <> AMR then the Handover cause = RxQual. If the handover cause = RxQual and the speech version = AMR then the Handover cause = AMR quality. HANDOVER EFR/FR - AMR For handover from an AMR cell to a non-AMR cell it is performed via the A interface using external handover mechanism, in order to allow the fallback to EFR or FR channel (according to Assignment Request order). For handover from a non-AMR cell to an AMR cell, in order to decrease the MSC load, the call is not upgraded to AMR and a normal EFR handover occurs. Note that interBSC procedure may increase the number of dropped call, so it is recommended to minimize that trnasition period. TDMA CONFIGURATION Due to the half rate channel introduction and to limit the number of contexts in the BSC, the number of SDCCH per TDMA is limited as following: normal cell: • • • Maximum number of SDCCH per TDMA: 2, only one SDCCH TS managed by odd TS per TDMA, only one SDCCH TS managed by even TS per TDMA. extended cell: • Maximum number of SDCCH per TDMA: 1. CAUTION! It is highly recommended to respect that TDMA configuration in case of activation of AMR. AMR HR-FR INTERWORKING In case of deactivation of AMR FR service, following points have to be highlighted: • • direct HR TCH allocation is available, even if AMR FR is not configured in the cell, handovers from FR radio TS to AMR HR are triggered on “requested codec mode” criterion, but this criterion is available only for AMR calls, thus this kind of Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 248/629 V17.0 BSS Parameter User Guide (BPUG) handover is not possible from a FR or EFR channel and decreases the AMR HR efficiency, handovers from (or to) an AMR HR channel to (or from) EFR channel are performed using an external handover procedure and thus induce: more load on the MSC, more perturbations on the voice quality, thus it is mandatory to activate AMR FR service, in case of AMR HR activation. • • • 4.25.8 AMR BASED ON TRAFFIC PRINCIPLE Previously to V15.1.1, the choice between an half rate and full rate channel was based only on radio criteria, thus in order to guarantee the voice quality at any time the operator had to tune the network with conservative values. With the introduction of AMR based on traffic, AMR HR channels are allocated only during loaded period, so the operator could choose more aggressive radio thresholds and then get more radio capacity for the same number of TRX. In order to minimize impacts of this strategy, this feature tunes the half rate penetration according to the cell load: HR capacity FR capacity HR FR This feature is based on a smooth mechanism, which allows anticipating the cell load and switching the allocation into HR mode, when an Erlang threshold is reached. The following picture illustrates the interworking between these 2 kinds of mechanisms over 24 hours: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 249/629 V17.0 BSS Parameter User Guide (BPUG) Traffic Max HR capacity Number of allocated TCH Blocking managed thanks to directed retry and HO traffic Half rate area Max FR capacity FR->HR threshold Blocking managed thanks to directed retry and HO traffic Full rate area Avg Erlang 24 hours t Two typical periods are observed: • • Low traffic: all calls are allocated in full rate mode and the blocking is managed thanks to directed retry and traffic handovers features. High traffic: call are allocated in half or full rate modes, according to radio conditions of each calls and the ultimate blocking is managed thanks to directed retry and traffic handovers features. FILTERED ERLANG TRAFFIC AND CELL LOAD STATE busy_TCH_TS + (1 - a)* Filtered_TCH_ration-1 available_TCH_TS Filtered_TCH_ration = a* where: • • • • Filtered_TCH_ration is the busy TCH ratio managed by the cell at period n. α is the filter coefficient (filteredTrafficCoefficient parameter). busy_TCH_TS is the number of TCH TS allocated to a FR or a HR TCH call (in case of multi-zones cell, traffic of both zones is taken into account). Available_TCH_TS is the number of TCH TS configured and available in the cell (in case of multi-zones cell, traffic of both zones is taken into account). The initial value of Filtered_TCH_ration is set to 0. This filtered busy TCH ratio is then compared to the 2 thresholds HRCellLoadStart and HRCellLoadEnd in order to determine the cell load state: • If (Filtered_TCH_ration < HRCellLoadEnd), Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 250/629 V17.0 BSS Parameter User Guide (BPUG) then Cell_Load_Staten = min(max (0, Cell_Load_Staten-1 -1); nb of in service DRX) • Else if (Filtered_TCH_ration >= HRCellLoadStart), then Cell_Load_Staten = min(nb of in service DRX, Cell Load_Staten-1 +1). • Else Cell_Load_Staten = min(Cell_Load_Staten-1; nb of in service DRX) The initial value of this Cell_Load_Staten is set to 0. This mechanism is activated whatever values of all associated parameters (AMR FR and / or HR activated or not, HRCellLoadStart, HRCellLoadEnd …), in order to allow the monitoring at the OMC-R level of this mechanism. PDTCH TS (preempted or not) are not taken into account in this mechanism in order to decrease PDTCH preemption. In case of TDMA / TRX defense mechanism, the BSC has to take into account the new number of DRX in service at the next period, in order to evaluate the cell load state. TRAFFIC MANAGEMENT PRINCIPLE The 3 algorithms used to allocate a HR channel to a mobile are tuned in order to be adapted to the cell load. DIRECT HALF-RATE ALLOCATION Direct half rate allocation: the range between the OMC-R RxLev threshold and -48dBm (the deactivation value) is divided in N sub-range, thus new subthresholds are dynamically created by the BSC. At each cell load state modification, appropriate sub-thresholds is used by the BTS: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 251/629 V17.0 BSS Parameter User Guide (BPUG) Cell load state Smax S4 S3 S2 S1 S0 RxLev distribution -110 amrDirectAlloc RxLev4 (Int)RxLevxx RxLev3 RxLev2 RxLev1 -48 dBm The principle is for the BSC to adapt the following OMC-R parameters according to the cell load state: • • • • AMRDirectAllocRxLevUL AMRDirectAllocRxLevDL AMRDirectAllocIntRxLevUL AMRDirectAllocIntRxLevDL The threshold associated to the cell load state i is evaluated according to the following formula: ⎡ Nb_DRX-i ⎤ Threshold_i = int ⎢ AMRDirectAllocyyRxlevxx + (-48 - AMRDirectAllocyyRxlevxx)* Nb_DRX ⎥ ⎣ ⎦ Where: • • xx is used for UL or DL, yy is used for int or nothing. Every 10 seconds if needed, new thresholds are sent to all DRX. The initial value of this mechanism is the threshold_0 (-48dBm), At the end of a defense TDMA procedure, current thresholds are sent to the BTS. This mechanism is activated only if: • • at least one OMC-R threshold is not equal to -48. The AMR HR service is activated in the cell (speechMode parameters of the BSC & cell object) In case of modification of one AMRDirectAllocyyRxlevxx parameter, the new value is taken into account at the next period. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 252/629 V17.0 BSS Parameter User Guide (BPUG) FR TO HR HANDOVER FR to HR handover: this handover is activated DRX per DRX according to the cell load state: • • S0: no DRX is configured in order to allow the FR to HR handover Si: i DRX are configured in order to allow the FR to HR handover and N-i-1 are configured in order to deactivate this handover. The BSC chooses the i DRX in the cell according to the AMR FR radio allocator priority. Highest priority TDMA are switched in FR->HR mode in first. Every 10 seconds if needed, new parameters are sent to all DRX. The initial is no DRX activated, especially at the end of a defense TDMA procedure. In case of modification of any AMR FR to HR handover parameter, the new value is taken into account at the next period. All Handover Indication messages sent by the BTS, have to be managed by the BSC whatever the cell load state. This mechanism is activated only if: • • nCapacityFRRequestedCodec not greater than pRequestedCodec. The AMR HR service is activated in the cell (speechMode parameters of the BSC & cell object) HR TO HR INTER-CELL HANDOVER HR to HR inter-cell handover: this half rate allocation is full deactivated in case of S0 cell load state and fully activated in all others cases. This mechanism is activated only if the AMR HR service is activated in the cell (speechMode parameters of the BSC & cell object) IMPACT ON ABOT OF “HR CHANNEL ALLOCATION ON PREEMPTED PDTCH (V17)” The cell load that is used to set thresholds for the AMR based on traffic feature is defined by the number of busy TCH versus the number of free TCH. The formula does not take into account the pDTCH channels which, thanks to pDTCH preemption for HR channels feature, could be preempted for HR. When PDTCH preemption for HR channels (V17) is activated, operators may want to increase the number of pDTCH defined in the cell, at the expense of TCH, because this increase in pDTCH will come at no voice capacity cost (HR may preempt these channels) while increasing the maximum throughput available for data traffic. As the number of TCH changes, so will the cell load used in AboT, and therefore Direct HR allocation may occur for a lower cell load than is strictly necessary. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 253/629 V17.0 BSS Parameter User Guide (BPUG) 4.25.9 REPEATED DOWNLINK FACCH The purpose of the feature ‘Repeated downlink FACCH’ is to secure the handover procedure in poor radio condition (with AMR FR) by retransmitting the FACCH frames in downlink after about 40ms, i.e. without waiting for the mobile acknowledgement Thanks to this feature end-users will experience a better call retainability in badly covered or interfered area. Acceptable voice quality will be maintained thanks the robust AMR/FR codec usage. On the other hand voice quality being slightly degraded during handover procedures due to repeated frame stealing; the preventive retransmission scheme should be triggered only in bad radio conditions. PRINCIPLE OF THE FEATURE The Repeated Downlink FACCH functionality is applicable when sending LAPDm command frames on the TCH/F channel. The BSS uses the Repeated Downlink FACCH functionality when AMR FR codec used is less than a defined threshold (settable at OMC-R) and when the first transmission fails (T200 expires). A repeated FACCH block is sent in such a way that, if the first burst of the downlink FACCH block containing the first instance of a LAPDm frame is sent in TDMA frame M, the first burst of the downlink FACCH block containing the repeated instance of the LAPDm frame is sent in TDMA frame M+ 8 or M+ 9 (the latter corresponding to the case where the two FACCH blocks are separated by either a SACCH frame or an idle frame). The MS shall, when receiving a downlink FACCH block, always attempt to decode it without combining with any previously received FACCH block If the current FACCH block is successfully decoded and an identical FACCH block was previously received (successfully decoded and spaced in time from the current FACCH block as specified here-above): • • The MS (Release 6 and subsequent) shall not send the LAPDm frame of the current FACCH block to the LAPDm entity. Pre-release 6 MS may send a REJ message upon receiving repeated frame, but this does not prevent this MS to get the benefit from the repetition mechanism. If the current FACCH block is successfully decoded and there was no such previously received identical FACCH block, the LAPDm frame of the current FACCH block is sent to the LAPDm entity. FEATURE ACTIVATION A dedicated cell class 2 parameter, enableRepeatedFacchFr, is used to enable the feature by chosing a codec threshold or to disable the support of Repeated FACCH in each cell. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 254/629 V17.0 BSS Parameter User Guide (BPUG) MECHANISM OF THE FEATURE When the Repeated FACCH feature has been enabled on the cell, each time the AMNU entity needs to re-transmit an I-frame on FACCH due to T200 expiry, it sends this frame again to the SPU entity (with a flag related to the retransmission). The SPU entity sends first the I-frame on FACCH in TDMA frame M as it does when the feature is disabled. And if the selected CODEC is lower than the threshold set to activate the feature, it stores the LAPDm frame to be repeated in TDMA frame M+ 8 or M+ 9 When repeating FACCH messages, T200 is started when transmitting the subsequent FACCH (~ 40 ms later) to cope with the case where an MS fails to decode the downlink FACCH block used to send the first instance of a repeated LAPDm frame. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 255/629 V17.0 BSS Parameter User Guide (BPUG) PERFORMANCE When repeating a frame, the applicable T200 duration is increased by about 40 ms (~20%). This induces a longer time for drop call detection with T200 mechanism because N200 cannot be modified. In addition, a new MS shall soft combine the frames to optimize the decoding probability whereas legacy mobile will simply see an increased probability of decoding Lapdm frame. The expected benefit for mobiles using soft combining is about 4 dB gain and about 2 dB gain for legacy mobiles. This graph presents the expected benefits on softcombining MS and lecacy MS. Legacy MS gain Soft combining gain Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 256/629 V17.0 BSS Parameter User Guide (BPUG) 4.25.10 TX POWER OFFSET FOR SIGNALING CHANNELS In order to increase the signaling channels (FACCH and SACCH) robustness in downlink, BTS may use a power offset (above the Tx power applicable for speech) to transmit the signaling bursts. The benefit in term of C/I is depending on the power offset for the signaling robustness and allows the operator increasing the fractional load and thus the spectrum efficiency. Voice quality can be still acceptable thanks to the use of robust AMR codec. PRINCIPLE OF THE FEATURE The Tx Power Offset for Signaling Channels is applicable to: • The first transmission of HO COMMAND and ASSIGNMENT COMMAND for all AMR calls in order to maximize the likelihood of decoding these messages from the first instance, Every re-transmission of I-frame on FACCH for all AMR calls (HR and FR) in order to maximise the likelihood of decoding these messages. Every RR and REJect frame on FACCH corresponding to an uplink retransmission for all AMR calls (HR and FR) in order to improve the two-ways robustness. Every UA (respectively DM) frame on FACCH corresponding to an uplink retransmission of SABM (respectively DISC) frames for all AMR calls (HR and FR) in order to improve the two-ways robustness. The transmission of all SACCH frames for AMR FR 4.75 kbps, 5.9 kbps and 6.7 kbps calls (tunable with an OMC-R parameter) in order to avoid radio link time-out (that leads to drop calls. • • • • On theses messages a power offset (tunable from the OMC-R) is applied up to the nominal Tx power. Note: The power offset applies (up to the nominal Tx power of the BTS) on BTS18000, ecell, as well as S8000 and S12000 fitted with e-DRX or DRX-ND3. For other BTS hardware, the feature does not apply. In addition this feature is not applicable on BCCH TRX (PA is always transmitting with Pmax and transmitting power should not fluctuate). Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 257/629 V17.0 BSS Parameter User Guide (BPUG) FEATURE ACTIVATION This feature is activated at cell level; dedicated class 2 parameters are used to enable/disable the feature in each cell. The parameters related to tune the feature are the following: • • • facchPowerOffset sacchPowerOffset sacchPowerOffsetSelection Note: If the BTS hardware (DRX or RM) does not support the signalling offset mode (up to Pnominal), the facchPowerOffset and sacchPowerOffset provisioning is not considered and the DRX or RM behaves as it behaves when facchPowerOffset and sacchPowerOffset are set to 0 dB. FEATURE DESCRIPTION The Tx Power Offset for Signaling Channels is applicable to different type of message; hereafter the process for each specific handling: SPECIFIC HANDLING OF HO COMMAND AND ASSIGNMENT COMMAND For all AMR calls, these messages are transmitted with the maximum power (considering facchPowerOffset) from the first instance in order to maximize the likelihood of decoding these messages with no LAPDm repetition at all, and therefore avoid as far as possible the drop calls during (inter-cell or AMR triggered) handover procedure. Since these messages can be segmented, the power offset applies on all segments: the level 3 entity flags all frames of the HO COMMAND and ASSIGNMENT COMMAND messages then SPU entity checks this flag in each I-frame to apply (or not) the power offset (facchPowerOffset) on the transmitted frame. When applying the power offset, First case: IF PWR + facchPowerOffset ≤ Pnominal THEN SPU modifies the dynamic power control in accordance with PWR + facchPowerOffset Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 258/629 V17.0 BSS Parameter User Guide (BPUG) Second case: IF PWR + facchPowerOffset > Pnominal THEN SPU set the dynamic power control to: 0 BTS transmits the frame at Pnominal Note: PWR is the BTS transmit power computed by L1M power control algorithm and applicable for speech and Pnominal is the BTS Tx power set by the static power control SPECIFIC HANDLING OF RE-TRANSMITTED I-FACCH FRAMES, RR AND REJECT CORRESPONDING TO RE-TRANSMITTED UPLINK FACCH FRAMES AND UA CORRESPONDING TO RE-TRANSMITTED SABM OR DM For all AMR calls, every re-transmission of FACCH frames as well as: • • UA (with F bit set to 1) corresponding to a retransmitted SABM or Disconnect Mode, and RR and REJect frames on FACCH (with F bit set to 1) corresponding to an uplink retransmission of a FACCH frame are transmitted with the maximum power in order to maximise the likelihood of decoding these messages and therefore avoid as far as possible the drop calls due to N200 overrun. The BTS LAPDm entity flags each FACCH frame mentioned here-above then SPU entity checks this flag and apply (or not) the power offset (facchPowerOffset) on the re-transmitted frame. When applying the power offset: SPU (as describes for HO command and assignment command) either modifies the dynamic power control in accordance with PWR + facchPowerOffset or set this power control to 0 leading the BTS to transmit the frame at Pnominal. SPECIFIC HANDLING OF SACCH FRAMES For AMR calls, depending on sacchPowerOffsetSelection provisioning, the transmission of SACCH frames for AMR FR 4.75 kbps, 5.9 kbps and 6.7 kbps calls are transmitted with the maximum power (considering sacchPowerOffset) in order to avoid radio link time-out (that leads to drop calls) and the drop calls due to N200 overrun (for re-transmission). For SACCH transmission, SPU entity, according to the last selected AMR CODEC and sacchPowerOffsetSelection provisioning, applies (or not) the power offset (sacchPowerOffset) on the transmitted bursts. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 259/629 V17.0 BSS Parameter User Guide (BPUG) When applying the power offset: First case: IF PWR + sacchPowerOffset ≤ Pnominal THEN SPU modifies the dynamic power control in accordance with PWR + sacchPowerOffset Second case: IF PWR + sacchPowerOffset > Pnominal THEN SPU set the dynamic power control to: 0 BTS transmits the frame at Pnominal Note: Correction of RxLev (to remove the impact of the power offset on Tx power control mechanism) can be approximated by SPU entity and conveyed to the L1m. In another hand, correction of CMR is not possible since BTS does not have the SNR info from MS. The impact on the choice of AMR CODEC cannot be by-passed see [R36] Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 260/629 V17.0 BSS Parameter User Guide (BPUG) ENHANCEMENT OF AMR POWER CONTROL MECHANISM Since this feature improves the downlink robustness, new parameters are introduced to define dedicated target for uplink and downlink AMR CODEC. The existing parameters (hrPowerControlTargetMode and frPowerControlTargetMode) still apply on uplink and two new parameters are introduced for downlink targets: • • hrPowerControlTargetModeDl: downlink AMR codec target to define the downlink power control threshold for HR AMR calls, frPowerControlTargetModeDl: downlink AMR codec target to define the downlink power control threshold for FR AMR calls, With setting a lower codec as a Downlink Power control target: • • A more protected AMR speech codec is used in downlink, Overall BS attenuation is higher and the overall interference level is decreased accordingly. So, in poor radio condition, the transmission power for signaling burst may stay identical thanks to the Power offset while interference level has decreased. Since the low target codec for Downlink Power control cannot be reached if the RxLev Power control threshold limits the BS attenuation and if the Tx Power Offset for Signaling Channels feature is enabled, lRxLevDLP for AMR communication is set to: LRxLevDLP - min (facchPowerOffset, sacchPowerOffset). Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 261/629 V17.0 BSS Parameter User Guide (BPUG) 4.26. WPS - WIRELESS PRIORITY SERVICE The current United States industry focus in support of National Security and Emergency Preparedness telecommunications services is to specify the requirements for Wireless Priority Services. The initial deployment of WPS is intended to allow qualified and authorized NS/EP users to obtain priority access to radio traffic channels during situation when Commercial Mobile Radio Service (CMRS) network congestion is blocking call attempts. WPS is intended to facilitate emergency response and recovery operations in response to natural and man-made disasters and events, such as floods, earthquakes, hurricanes, and terrorist attacks. WPS is also intended to support both national and international emergency communications. 4.26.1 PRINCIPLE If a Service user invokes WPS (Wireless Priority Service) and no radio traffic channel is available in the cell, the WPS request shall be queued according to the WPS priority, the call initiation time and the state of the queue for the cell. This feature is an improvement of the queuing services available to WPS users. The WPS queuing principle is the following: • • The eight (8) current queues are kept unchanged Five (5) new queues are added an dedicated to WPS request For public queue management and related parameters, refer to chapter Queuing. 4.26.2 WPS – QUEUING MANAGEMENT The new queuing management of WPS requests is activated when queuing is driven by the MSC (bscQueuingOption parameter is set to “allowed”) and WPS management is activated (wPSManagement parameter is set to “enabled”) CAUTION! The bscQueuingOption is a class 1 parameter, which means that parameter can be set only when the parent bsc object is locked. It is important to underline that the internal queues associated with WPS requests and the internal queues associated with public requests are treated in completely separate ways. CHARACTERISTIC OF THE WPS QUEUE Each WPS queue is defined with: • • • Its associated priority Pi Its queue size Ni, the maximum number of WPS call requests (of priority Pi or higher) which can be queued simultaneously Its own T11 timer value, which represents the maximum time a WPS call request of a given priority Pi can remain in queue Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 262/629 V17.0 BSS Parameter User Guide (BPUG) The priority Pi is received from the MSC in the assignement request message. The size Ni of a given WPS queue is set according to the allocWaitThreshold parameter. In order to be in accordance with the WPS industry requirement and configuration, each queue size threshold Ni (with 8< i <12) should be equal (N8=N9=N10=N11=N12) and equals the maximum number of WPS requests allowed in the WPS queues. The timer T11 for a given queue can be defined with the allocPriorityTimers parameter. It is understood that the request will immediately be denied with a cause “no radio resource available” if this timer is set to “0”. PROCEDURE TO QUEUE SERVICE REQUEST USER WPS FIRST CASE: MS IS PUT IN QUEUE As no radio channel is available, and as the queue size threshold Ni of the queue corresponding to the WPS priority Pi is not reached, the WPS call request is put in queue i. A queuing indication message is sent to the MSC. SECOND CASE: MS IS DENIED (QUEUE FULL) As no radio channel is available, and as the queue size threshold Ni of the queue corresponding to the WPS priority Pi is reached, the WPS call request is denied. An assignement failure message with cause “no radio resource available “is returned to the MSC. THIRD CASE: MS IS PUT IN QUEUE TAKING THE PLACE OF AN OTHER MS As no radio resource is available, if the queue size threshold Ni corresponding to the WPS priority Pi is not reached, but if adding the call request to queue i would cause the threshold Nj of another internal WPS queue j to be violated, and if the WPS request priority (Pi) is higher than at least one WPS request (Pk) already in queue in the cell, the BSS takes the following actions: • the BSS shall remove the WPS request with the lowest priority (Pk) and the most recent initiation time from the queue. It sends an assignment failure for this removed WPS request with the cause “no radio resource available”. the BSC shall place the newly arrived WPS request in the queue i according to the initiation time and the priority level. • A queuing indication for the WPS call request of priority Pi and an assignement failure for the WPS call request of priority Pk are sent to to the MSC. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 263/629 V17.0 BSS Parameter User Guide (BPUG) MANAGEMENT OF SERVICE REQUEST USER WPS PUT IN QUEUE RESOURCE AVAILABLE If a radio traffic channel becomes available when there are WPS requests in queue, the process of ressource allocation decribed in the WPS – Public access bandwith protection (see chapter WPS – Public access bandwith protection below) has to be followed. T11 EXPIRY If the WPS request is in queue i for a radio traffic channel and the maximum time allowed for that queue expires, the WPS request is removed from the queue and the call is cleared. A clear request with the cause “no radio resource available” is then sent to the MSC. RADIO CONTACT WITH THE MS IS LOST If the WPS request is in queue for a radio traffic channel but radio contact with the mobile is lost (detected by the BTS which informs the BSC), the WPS request is removed from the queue and the call cleared. A clear request with the cause “Radio Interface Failure” is sent to the MSC. MS DISCONNECTS THE CALL If the MS decides to disconnect the call while the WPS request is queued, the BSC receives a clear command message from the MSC and processes the release of the call including the request removing from the WPS queue. FEATURE ACTIVATION If the bscQueuingOption parameter is set to “not allowed” then queuing is not performed, i.e. no request goes into any of the queues 0 to 12, whatever the wPSManagement value is. In all the following cases, the bscQueuingOption flag is considered as “allowed (MSC driven)”. One has to well understand the two levels of queuing in “MSC Driven” queuing mode: • At the MSC level the call request is described by two fields in the assignement request message: “queuing allowed” set to allowed / not allowed, and “priority level” (14 are defined) At the BSC level the queuing management of the call requests is set to allowed, so the BSC takes into account the 2 fields described above • WPS queuing is so done according both to the “queuing allowed” field value set in the assignment request message sent by the MSC (if this field value is set to “queuing not allowed”, then there is no queuing) and the WPS priority (1 to 5). In all the following cases, this field value is considered as “queuing allowed” for all WPS and public call requests. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 264/629 V17.0 BSS Parameter User Guide (BPUG) WPSMANAGEMENT FLAG IS ENABLED The WPS request is queued according to the mapping (GSM 08.08 priority / internal priority) done by the customer at the OMC-R. Internal priorities correspond to the queues 0 to 7 for public requests, and queues 8 to 12 for WPS requests. When the wPSManagement flag is enabled, a recommended mapping of the allocPriorityTable has to be respected. When the wPSManagement flag is turned on, it also enables the PURQ AC algorithm feature. (see chapter WPS – Public access bandwith protection below) WPSMANAGEMENT FLAG IS DISABLED It is recommended that the customer sets the mapping (GSM 08.08 priority / internal priority) at the OMC-R, so that only internal priority 0-7 are used when the wPSManagement flag is disabled. In this case, if a WPS request is received by the BSC, the request will be managed like a public call since it will be queued in the public queues. If no mapping is specified by the customer, the default mapping is done to the internal queue 0. 4.26.3 WPS – ACCESS CLASS BARRING WITH CLASS PERIODIC ROTATION In normal conditions, the number of WPS Users should be sufficiently small that there is little likelihood of them having a significant impact on public use. But in case of exceptional events, the number of initial access is dramatically increased and can induce a full blocking of the system. In V9, a feature called "access class barring" was designed in order to avoid this kind of problem, thanks to a dynamic barring of a significant part of users. An enhancement of this feature has been designed, in order to allow users to access periodically to the network, without huge network congestion. To synthesize, one can say that this feature allows users to access the network periodically during network congestion by modifying the number of barred access classes in function of the congestion state of the cell, and by periodically changing which access classes are barred. There are no specific access class parameters that can be tuned in order to optimize WPS use. For further details about this change of access class baring, see chapter Barring of access class. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 265/629 V17.0 BSS Parameter User Guide (BPUG) 4.26.4 WPS – PUBLIC ACCESS BANDWITH PROTECTION The public access bandwidth protection is required in case of cell congestion with WPS users in the cell. Assuming that the number of WPS users is less important than public users, and taking into account that WPS users are priority users, this feature ensures that a radio network bandwidth is available to public users during cell congestion (lack of radio resources). PRINCIPLE The idea of the algorithm is to allocate a specified portion of the traffic channels (as they become free) with preference to public calls, and to allocate a second portion of the traffic channels (as they become free) with preference to WPS calls. The BSC radio resource allocator processes the algorithm which favors WPS calls 1 out of wPSQueueStepRotation times and then process the algorithm which favors public calls P out of wPSQueueStepRotation times (P = wPSQueueStepRotation – 1). With this choice, 1 out of wPSQueueStepRotation of the call capacity can be allocated for WPS users, wPSQueueStepRotation being 1,2, …,10. (recommended value is 4 and hence 25% can be allocated with preference to WPS requests) PURQ-AC ALGORITHM WITH SUPERCOUNT PURQ-AC stands for Public Use Reservation for Queuing - All Calls This algorithm is only activated if If the wPSManagement flag (BSC level) authorizes the WPS requests management When the algorithm is turned on (i.e at the startup of a BSC or after a lock/unlock of the cell), the priority is given to a WPS call request (1 out of wPSQueueStepRotation times), the algorithm proceeds to some checks about the state of the WPS queues (left side on the schema below), then the priority is given to public call requests (P out of wPSQueueStepRotation times) and the algorithm proceeds also to some checks about the state of the WPS queues (right side of the schema below). The aim of the supercount is to allow “10 call running deficit” over allocation, and enhanced small cell performances. It smoothes out short term variations, and decreases delay. The Supercount tigger value of 10 is a fixed value. Supercount is initialised to 0 and is reset to 0 when a lock/unlock action is done on the cell for instance. FEATURE ACTIVATION If the wPSManagement flag (BSC level) is disabled but queuing indications in the assignement request message still give the priority to WPS call requests, in case of cell congestion, the WPS users may use all the cell bandwidth (due to their priority) and public users may not have an access to the network. However that case could only occur if WPS queues are mapped on internal queues 0-7 instead of the queues dedicated for WPS, because only internal queues 07 are evaluated to serve a queued request when wPSManagementFlaf is turned off. The new algorithm has a cell based internal management that does not impact any other cells in term of traffic management. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 266/629 V17.0 BSS Parameter User Guide (BPUG) This feature is linked with the queuing management (public and WPS requests) and hence parameters related to the queue management have to bet set in order to take advantage of the benefits provided by the PURQ AC algorithm. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 267/629 V17.0 BSS Parameter User Guide (BPUG) 4.27. SATELLITE ABIS INTERFACE From V15.1 the use of Satellite Abis links will be possible to allow the connection between BSC and BTS. BSC Abis Agprs Abis BTS Ater BTS Abis In some network areas, there is no earth terrestrial transmission infrastructure between the BSC and the BTS. This feature solves this problem thanks to a satellite link between these 2 nodes. To get detailed information about the implementation of this feature, please refer to document [R31]. 4.27.1 PRINCIPLE The principle of this feature is to allow the implementation of satellite links, instead of terrestrial links on the Abis interface. The main issue is to take the propagation delay between BSC to BTS which changes of some ms to about 240 ms (2*36000 km/300.000 km/s): • • The Abis link has to be modified, in order to take into account this supplementary delay The channel Request / Immediate Assignment has to be improved in order to allow an efficient channel allocation. Details on how these changes are done are fully detailled in the Functional Note. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 268/629 V17.0 BSS Parameter User Guide (BPUG) 4.27.2 FEATURE ACTIVATION To activate this feature on a given BSS, some appropriate parameters will have to be specified. These parameters will be provided through the “BSC data config” functionality. They are presented in document [R31] and correspond: • • to the LAPD T200 timer value and anticipation window size to be used for Abis LAPD Data Links to the type of Abis configuration concerned (terrestrial or satellite) at a BTS level Thus a dedicated build will be needed to activate this feature with the corresponding parameters. At the BTS site, installation has to be done with software release compatible with satellite links. Else it will not be possible to switch in service these equipments. The introduction of this feature will also imply specific engineering rules mainly due to very big transmission delays induced by satellite links usage and due to specific implementation choices. The current document will not focus on engineering rules related to this feature as they are described in detail in the Satellite Abis Interface - Engineering Guideline (refer to document [R32]). CAUTION! The applicable BSS Engineering rules presented on document [R7] may be overwriten by the specific rules applicable to the case where Abis satellite links are used. 4.27.3 FEATURE INTERWORKING INTERWORKING WITH NON SATELLITE EQUIPMENTS The system behaviour is not guaranteed if: • • • • a satellite BTS is equipped with a DRX, which is not a eDRX, a satellite BTS is equipped with a CMCF phase 1, a satellite BTS is connected to a non satellite BSC, a non satellite BTS (i.e. this type of BTS or the BTS release do not support this feature) is connected to a satellite BSC. COMBINED BCCH It is recommended to not use a combined BCCH for a satellite cell because of: • Channel Request: the MS timer between Channel Request and Immediate Assignment is shorter, in case of combined BCCH, thus the risk of triple Channel Request is increased Lapd load: in order to distribute the signaling load over all DRX. • More details on recommended parameter associated to feature restrictions are given in the Satellite Abis Interface - Engineering Guideline (refer to document [R32]) Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 269/629 V17.0 BSS Parameter User Guide (BPUG) 4.28. NETWORK SYNCHRONIZATION 4.28.1 GLOBAL DESCRIPTION ASYNCHRONOUS NETWORK When NW synchronization is not applied (asynchronous network), cells get their time base through the PCM time. As PCM of different cells are not correlated, it can be considered that, comparing to the hypothetical network time reference, the not co-site cells have on a site basis: • • • Random time bit offsets (from 0 to 156,25) Random time slot offsets (integer from 0 to 7) Random frame numbers offsets (integer from 0 to 2 715 647). Consequently, as shown in the figure below, between two not co-site cells there are random: • • • Δtime bit offsets Δtime slot offsets Δframe numbers offsets FN x-1 FN x-1 FN x-1 FN x FN x FN x FN x FN x FN x cell 1 5 6 7 0 1 3 4 5 6 Δ time bit offset (random) Δ time slot offset (random) FN y FN y FN y FN y-1 FN y FN y FN y FN y FN y cell 2 7 0 1 2 3 4 5 6 7 Δ frame number offset = y-x (random) General case of non synchronization It has to be noted that a MS computes - using its timebase counter - the time offset by measuring the time from the beginning of TS0 on its BCCH carrier and the beginning of the first TS0 on a neighbor BCCH carrier. Also, the data found on these 2 TS0 may be used for calculating the FNOffset between its cell and the neighbor cell. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 270/629 V17.0 BSS Parameter User Guide (BPUG) SYNCHRONIZED NETWORK With NW synchronization feature, all cells of a network could be synchronized on the same clock, the GPS clock, through an additional external GPS receiver. There are 2 ways this can be implemented: • • Burst synchronization in which all burst are aligned to the GPS clock Time synchronization in which all burst are aligned to the GPS clock and also a absolute time (or a way to deduce it) is provided, as well, to all the equipments FN x-1 FN x-1 FN x-1 FN x FN x FN x FN x FN x FN x cell 1 5 6 7 0 1 3 4 5 6 Δ time slot offset (random in burst synch) (known&controlled in time synch) FN y-1 FN y FN y FN y FN y FN y FN y FN y FN y cell 2 7 0 1 2 3 4 5 6 7 Δ frame number offset = y-x (random in burst synch) (known&controlled in time synch) General case of synchronization Both type of synchronizations are implemented in Nortel’s portfolio and are supported by addition of equipments (TMU) and parameters. BURST SYNCHRONIZED NETWORK In a burst synchronized network, it can be considered that, comparing to the hypothetical network time reference, the not co-site cells have on a site basis: • • • Time bit offsets = 0 Random time slot offsets (integer from 0 to 7) Random frame numbers offsets (integer from 0 to 2 715 647). It has to be noted that in a burst synchronized network these time slot offsets and frame number offsets cannot be controlled and that every time a site is locked-unlocked these offsets change randomly. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 271/629 V17.0 BSS Parameter User Guide (BPUG) Consequently, see general case of synchronization figure on previous page, between two not co-site burst synchronized cells there are: • • • Δtime bit offsets = 0 Random Δtime slot offsets Random Δframe numbers offsets As in the case of an asynchronous network, the co-site cells have the same time bit offsets, time slot offsets and frame number offsets. TIME SYNCHRONIZED NETWORK In a time synchronized network, it can be considered that, comparing to the hypothetical network time reference, the not co-site cells have on a site basis: • • • Time bit offsets = 0 Known & controlled time slot offsets Known&controlled frame numbers offsets Also, similar to the asynchronous network, the co-site cells have the same time bit offsets, time slot offsets and frame number offsets. Consequently, see general case of synchronization figure on previous page, between two not co-site time synchronized cells there are: • • • Δtime bit offsets = 0 Known & controlled Δtime slot offsets Known&controlled Δframe numbers offsets It has to be noted that the main difference between a time synchronized and a burst synchronized network is that time slot offset planning and frame number offset planning are possible only in a time synchronized network. 4.28.2 FEATURE ACTIVATION The parameters related to tune the feature are the following: • • • • btsSMSynchroMode tnOffset, fnOffset masterBtsSmId Note: Other network existing parameters may have a significant impact on network performances when network synchronization is applied: • baseColourCode TSC (TSC=BCC) planning and therefore whole BSIC (NCC& BCC) planning. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 272/629 V17.0 BSS Parameter User Guide (BPUG) • • Hopping laws parameters (HSN, MAIO, MA list) dARPPh1Priority Also, it has to be noted that more parameters (for handovers, location services etc…) may have to be eventually retuned for an optimal functioning when network synchronization feature is deployed. 4.28.3 FEATURE IMPACTS EXPECTATIONS Network synchronization simple deployment may have positive impact on location services as the location precision will improve with a better synchronization of the network elements. However, synchronizing all BTS in a network, meaning synchronizing interferers and their victims, doesn’t provide alone any gain of RF quality or RF capacity. On the contrary, the network synchronization may degrade the network RF performances if no additional feature or engineering solution is applied. (The main degradation is mainly due to the eventual TSC collisions if a traditional BSIC -NCC/BCC- planning as for an asynchronous network is used) Therefore, for improving the RF quality and capacity, a network synchronization deployment must be accompanied by additional features and significant engineering parameter planning. Please refer to chapter Network synchronization engineering planning methodologies. After Activing NW synchronization significant modifications of the NW behavior may occur at various levels: • Quantity of interferences: being able to control cell FN Offsets, it may be possible to use some carefully chosen of hopping laws (HSN, MAIO, MA list, FN) in order to decrease the collision probability between one or more couples of cells being able to control cell TN and FN Offsets, it is possible to completely avoid the collisions between two cells which are not co-site when using a fractional reuse frequency plan Note: all this eventual control of the quantity of interferences is possible only when time synchronizing the network as it is required to control and plan the FN Offsets (and TN Offsets as well); • Impact of interferences: the various features of interferences cancellation and noise cancellation for both BTS and MS are expected to work optimally (or better) when synchronizing the network • Others HO reactivity, LCS precision … Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 273/629 V17.0 BSS Parameter User Guide (BPUG) 4.29. NOVEL ADAPTIVE RECEIVER 4.29.1 PRINCIPLE This v17.0 feature introduces a novel digital processing approach developed by Nortel Networks for improving reception performances of GSM and EDGE radio communications. It has been developed to enhance performances in real radio conditions (multipath profiles), with a particular focus on interference from other radio channels (a major cause of disturbance for reception performances). Usual reception schemes are optimal under one specific noise assumption only, basically thermal noise. However, digital communication faces in practice other noise sources, namely adjacent channel and/or co-channel interferences, the statistics of which strongly differ from thermal noise. The consequence is lower reception performances in presence of interferers, leading to a poorer speech quality or lower throughput for the end-user. The approach developed by Nortel consists in a scheme that adapts itself to the interference condition affecting each received burst. In addition, a new filter design strategy has been developed in order to come out, for each basic noise situation, with a filtering process yielding the minimal BER. This new method calls, prior to processing the burst, for an estimation of the noise situation. This is achieved by a filter bank detector for the adjacent interferers; co-channels interferences are taken into account later on, after channel sounding. According to the adjacent interference noise estimated by the detector, a filter matching the noise situation is designed and applied to the current burst. Reception performance is significantly improved in most situations, especially with adjacent interference conditions. These benefits apply both to GMSK and 8PSK modulations, traffic and data applications. It thus provides the end-user with an increased throughput for data transmission as well as an improved quality of service for voice calls. For more details, please refer to the Functional Note ([R45]). 4.29.2 HW/SW DEPENDENCE This feature is applicable to : • • Hardware : BTS 6000/BTS18000 Radio Modules, 1900 MHz band only Software : v17.0 release. 4.29.3 ACTIVATION GUIDELINES O&M PARAMETER adaptiveReceiver is a new Class 2, transceiver object, parameter that serves to activate or deactivate the Novel Adaptive Receiver. It can take two values : Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 274/629 V17.0 BSS Parameter User Guide (BPUG) • • “enabled” : use of the Novel Adaptive Receiver “disabled” : use of the legacy signal processing RECOMMENDATIONS HILLY TERRAIN PROFILES For cells operating under very specific radio conditions, namely hard Hilly Terrain profiles, the Novel Adaptive Receiver structure may possibly cause a slight performance loss compared with the initial processing. Therefore, it is recommended to disable the adaptive receiver for these cells. : adaptiveReceiver = disabled INTERWORKING WITH RX DIVERSITY If Rx diversity is used, best receiver performance is achieved by activating both Joint diversity and Novel Adaptive Receiver features : adaptiveReceiver = enabled; diversity = enhancedDiversity. INTERWORKING WITH EXTENDED CELL Novel Adaptive Receiver does not interwork with the Extended Cell feature. Therefore, for extended cells, the Novel Adaptive Receiver must be deactivated : adaptiveReceiver = false. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 275/629 V17.0 BSS Parameter User Guide (BPUG) 4.30. A5/3 ENCRYPTION ALGORITHM 4.30.1 PRINCIPLE For details, please refer to the Functional Note ([R41]). PURPOSE OF THE FEATURE Before v17.0, the only available encryption algorithms available in the BSS were : • • • No encryption Encryption algorithm version 1, also called A5/1 Encryption algorithm version 2 (also called A5/2). A5/2 was removed from the GSM networks at the end of 2006 in compliance with the 3GPP recommendations, as a consequence of the published attacks against A5/2. This v17.0 feature provides a new encryption algorithm in the BSS called A5/3. Also, this feature changes the class of the existing parameter encryptAlgorSupported from class 0 to class 3 to limit service disruption when changing its setting. A5/3 ALGORITHM OVERVIEW The A5/3 algorithm is stream cipher that is used to encrypt/decrypt blocks of data under a confidentiality key Kc. The algorithm is based on the KASUMI algorithm, which is specified in 3GPP TS 35.202. KASUMI is a block cipher that produces a 64-bit output from a 64-bit input under the control of a 64-bit ciphering key. 4.30.2 HARDWARE DEPENDENCE A5/3 is supported on : • • • DRX ND3 eDRX RM. 4.30.3 CIPHERING ACTIVATION RULES BSS PARAMETERS ENCRYPTION ALGORITHM ACTIVATION The BSS can select A5/3, on MSC request, for a call, assuming that : • • A5/3 is supported by the TRX A5/3 is supported by the mobile Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 276/629 V17.0 BSS Parameter User Guide (BPUG) • A5/3 is configured at the O&M level as the preferred encryption algorithm in the BSS Since the A5/3 encryption algorithm is neither supported by all types of TRX nor by all mobiles, and more especially by legacy mobiles already deployed by the operators, a fallback encryption algorithm needs to be available whenever the A5/3 encryption algorithm is requested by the MSC. In such a case, based on the value of the O&M parameter encryptAlgorSupported , either “no encryption” or “A5/1” may be defined at O&M level as the fallback encryption algorithm to be used by the BSS. The encryptAlgorSupported parameter is an existing parameter which has been modified in v17.0 as follows : • • The class is changed in v17.0 from class 0 to class 3. Thus, no BDA build is necessary when changing the value of this parameter : no interruption of service The range of values has been expanded and now includes the following values : o o “None” : the BSS will not cipher any calls “gsmEncryptionV1” : all the BTS of the BSS will use A5/1 for ciphering, if requested and allowed by the NSS (new value) “gsmEncryptionV3FallbackNoEncryption” : A5/3 is the preferred algorithm for the BTSs of the BSS, but if this algorithm cannot be used for a specific call in a specific cell (due to mobile capability limitation or TRX capability limitation or MSC request), the BSS will not cipher the call (new value) “gsmEncryptionV3FallbackV1” : A5/3 is the preferred algorithm for the BTSs of the BSS, but if this algorithm cannot be used for a specific call in a specific cell (due to mobile capability limitation or TRX capability limitation or MSC request), the BSS will attempt to use A5/1 instead. o o BSSMAP MESSAGES CONFIGURATION PARAMETERS With a Nortel BSS supporting the A5/3 feature, the NSS must be able to understand ciphering information fields conveyed by the BSS to the NSS in the following BSSMAP messages : • • • • • CIPHER MODE REJECT ASSIGNMENT COMPLETE HANDOVER PERFORMED HANDOVER REQUEST ACKNOWLEDGE CIPHER MODE COMPLETE. Today (2007), all NSS software on the market supports these messages. Therefore, these BSSMAP messages and fields must be enabled on the BSS side, otherwise the BSS will not send them to the NSS, and this risks causing the ciphering procedure to operate in a lessthan-optimal manner. To prevent this happening, the following BSS parameters must be set to value “true” : • cypherModeReject Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 277/629 V17.0 BSS Parameter User Guide (BPUG) • • • • • encrypAlgoAssComp encrypAlgoCiphModComp encrypAlgoHoPerf encrypAlgoHoReq layer3MsgCyphModComp NSS PARAMETERS A5/3 is supported by the NSS Nortel since GSM07 by feature AD8028. A5/3 is datafilled in the MSC by setting the following Office Parameters : • GMSC_CIPHERING (OFCOPT table) : enables ciphering and deciphering of the radio interface control between the MSC and the radio network subsystem (RNS) for the transmission of user data or confidential network parameters. GSM_CIPHER_ALGORITHM_SUPPORTED” (OFCENG table) : indicates which GSM ciphering algorithms are supported, in addition to the “no” encryption option. There are seven defined algorithms (A5/1, A5/2, A5/3, A5/4, A5/5, A5/6, and A5/7). • 4.30.4 PERFORMANCE IMPACT BTS PROCESSING TIME The ciphering processing time of the A5/3 encryption algorithm is not degraded compared to the A5/1 processing time inside the BTS. CALL SETUP TIME On the other hand, since the “ciphering mode setting field” may be included in the Radio Interface ASSIGNMENT COMMAND message, adding 1 byte, the BSS may need to send an additional frame on the radio interface SDCCH channel in case the existing frame is already full without this field. This additional frame could lead to 235 ms additional delay at the call setup. HANDOVER DURATION In the same way, since the “ciphering mode setting field” may be added in the Radio Interface HANDOVER COMMAND message, adding 1 byte, the BSS may need to send an additional frame on the radio interface dedicated channel in case the existing frame is already full without this field. This additional frame could lead to 235 ms (handover on SDCCH) or 20 ms (handover on TCH) additional delay during the handover. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 278/629 V17.0 BSS Parameter User Guide (BPUG) 4.31. BTS SMART POWER MANAGEMENT 4.31.1 DEFINITIONS Several definitions will be used in this section : • Configured TRX : TRX that is mapped to a TDMA. The state of a configured TRX’s PA depends on whether the TRX is active or idle (see definitions below) and on the circumstances. Unconfigured TRX : transient state of the TRX that exists while the TRX has not yet received the “current cell parameters” from the BTS Deconfigured TRX : state of a TRX that exists after having received a “clear config” command from the BTS Spare TRX : TRX that is not mapped to a TDMA. The PA of a spare TRX may be in state “ON” or state “OFF” depending on the circumstances, as explained in what follows. Active TRX : configured TRX that is being used by signaling or traffic on at least one of the TDMA’s radio timeslots. The PA of an active TRX is always “ON”. Idle TRX : configured TRX whose TDMA is not currently carrying any ongoing traffic or signalling. The PA of an idle TRX may be in state “ON” or state “OFF” depending on the circumstances, as explained in what follows. • • • • • 4.31.2 PRINCIPLE This feature switches off the PA after the TRX has been idle for a certain amount of time (configurable via an O&M parameter). The PA is automatically switched back on again when a circuit call is set up on one of its timeslots. The PA can be switched “OFF” or “ON” thanks to an electronic switch. This switch can be set to “ON” or “OFF” by software, thanks to a dedicated new TX firmware function. 4.31.3 PRE V17 BEHAVIOUR Before v17.0, the BTS behaviour is the following : When the TRX restarts (BTS start up, TRX lock/unlock, TRX trap … ) the PA is in an unpowered state. It remains un-powered until it has received an RF Trans message from the BSC. Once the PA has been powered on, it remains so until the next reset or lock of the TRX. This behaviour applies to all TRX regardless of their state : • • configured TRX (by definition, a configured TRX is mapped to a TDMA), spare TRX (by definition, a spare TRX is not mapped to a TDMA) Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 279/629 V17.0 BSS Parameter User Guide (BPUG) 4.31.4 POST V17 BEHAVIOUR FEATURE DEACTIVATED CASE OF CONFIGURED TRX In v17.0, if the feature is deactivated, the TRX behaves as before v17.0. CASE OF SPARE, UNCONFIGURED OR DECONFIGURED TRX The feature cannot be activated on a spare, unconfigured or deconfigured TRX. However, the behaviour has been modified between v16.0 and v17.0 so that a spare or unconfigured or deconfigured TRX is systematically switched off after a certain time For this, a 30 second internal timer is started when the “enable TRX procedure” (RF Trans un-configuring) is performed. When this timer expires, if no TDMA has been configured on the TRX, the PA is switched off and its display hardware state is set to “OK – OFF cause SmartPowerManagement” As soon as the TRX is configured with a TDMA, this PA will be switched on. FEATURE ACTIVATED CASE OF TRX CONFIGURED WITH SPECIFIC TDMA The TRX that are mapped to specific TDMA configurations are not allowed to turn off their PA. The feature, even if it is activated, does not apply to them. These TDMA configurations are the following : • • • • • TDMA containing a BCCH channel TDMA containing a combined BCCH/SDCCH channel without CBCH TDMA containing a combined BCCH/SDCCH channel with CBCH TDMA containing a non-combined SDCCH/8 channel with CBCH channel TDMA containing a pDTCH channel ALL OTHER CASES OF CONFIGURED TRX For all other configured TRX whose TDMA is not in one of the above categories, if the feature has been activated, the TRX automatically switches its PA OFF after the TDMA has been idle a certain amount of time (configurable timer). The TRX switches its PA on again when a channel is activated on the TDMA for a circuit-switched call establishment or for an incoming handover. More precisely : • when the BTS receives a channel activation message from the BSC : o If the PA had been switched off, it is switched back on. PA hardware state is set to OK (or KO). Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 280/629 V17.0 BSS Parameter User Guide (BPUG) o • If the PA is still on but the TRX is idle, meaning that the smart Power SwitchOff timer is running, then this timer is immediately stopped. when the BTS receives a channel release message from the BSC : if there are no more ongoing circuit-switched calls on the TRX (TRX has become idle), the countdown of the smart Power Switch-Off timer is started. The fact that the PA is switched off has no impact on the TRX operational state : the TRX remains in the “in service” state. The PA switching off has no impact on the TRX receive chain. CASE OF SPARE TRX The feature does not operate on a spare, unconfigured or deconfigured TRX, even if the feature is activated on the cell. However, the behaviour has been modified between v16.0 and v17.0 so that a spare, unconfigured, or deconfigured TRX is systematically switched off, regardless of the activation or deactivation of the smart power management feature. For this, a 30-second internal timer is started when the “enable TRX procedure” (RF Trans un-configuring) is performed. When this timer expires, if no TDMA has been configured on the TRX, the PA is switched off and its display hardware state is set to “OK – OFF cause SmartPowerManagement” As soon as the TRX is configured with a TDMA, it ceases to be a spare, unconfigured or deconfigured TRX and its PA will be switched on. 4.31.5 HARDWARE DEPENDENCE This feature is applicable to RM family only. 4.31.6 ACTIVATION GUIDELINES O&M PARAMETERS ACTIVATION PARAMETER This feature is activated thanks smartPowerManagementConfig : • • • Class 3 object : powercontrol range : “enabled”; “disabled” to a new v17.0 BSS parameter called Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 281/629 V17.0 BSS Parameter User Guide (BPUG) POWER SWITCH-OFF TIMER A timer can be configured to delay the switching off for a certain time after the TRX has become idle. The start value of this timer is defined by setting the parameter smartPowerSwitchOffTimer : • • • Class 3 Object : powercontrol range : 5 to 255 minutes The timer is used as follows : • • • start condition : last active channel managed by this TRX is released stop condition : a channel for a new call or an incoming handover is allocated on the TRX action on expiry : PA is switched off. RECOMMENDATIONS CONFIGURATION OF LOGICAL CHANNELS ON TDMA As the TRX supporting pDTCH never switches off its PA, to take full benefit of this feature, it is recommended not to configure more pDTCH than are strictly necessary. As TDMAs that carry BCCH, SDCCH or pDTCH are never switched off, it is recommended to collect these channels as far as possible on the same TDMA rather than spread them onto several TDMAs. MINIMUM TIMER VALUE In the current BTS behaviour (without the feature), if there is no call on a TRX for 5 minutes at least, the VVA consign of the PA is reduced by 2 dB. The aim is to avoid untimely a “high current” alarm when the PA starts transmitting again after a while without transmission. Such an alarm could occur if the PA gain, which depends on the VVA consign, is not consistent with the “new” temperature of the PA when it starts transmitting again (temperature goes down when PA stops transmitting). With the “smart power management” feature activated, the temperature will fall all the more as, on top of not transmitting, the PA is actually completely switched off. Moreover, this “off” state may last the whole night causing even further temperature drop. Therefore, before a PA is switched off, it is vital that the VVA consign should have been reduced by 2dB so that when the PA is switched back on again, there are no high current alarms. To ensure this VVA is reduced by 2dB, as explained above, 5 minutes must elapse after the last call on the TDMA has been released. If the smart power timer is less than 5 minutes, the PA would be switched off before a VVA consign reduction cpuld be applied. So, when the PA is switched back on again, it will apply the old consign corresponding to a high Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 282/629 V17.0 BSS Parameter User Guide (BPUG) temperature, whereas the PA will have significantly cooled down. This risks triggering an alarm ans dpossibly damaging the PA. To prevent this, the smart power swicth off timer minimum value has, by design, been set to 5 minutes. OPTIMUM TIMER VALUE The smaller the switch-off timer : • • • the more reactive the power management will be to the minute-by-minute changes to the call profile as the day progresses towards quieter moments the more power is likely to be saved as a result. but the more frequently the PA is likely to go through off/on cycles, especially at the transition from busy hour to quieter hours, thus possibly impacting its life expectancy. Furthermore, the more TRX per cell, the more TRX are eligible for switch-off, and therefore the more the feature is expected to make a difference to the power consumption. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 283/629 V17.0 BSS Parameter User Guide (BPUG) 5. 5.1. ALGORITHM PARAMETERS INTRODUCTION This chapter lists parameters, sorted according to their group, as they were defined in the previous Chapter. The following information is provided for each parameter: • • • • • • • • • • a brief description value range and unit the recommended value: takes the best benefit of the feature in a standard network configuration and environment. process in which it is used (see Chapter 2) some engineering rules that must be considered for the parameter setting the object that contains this parameter the default value. Most of the time, the default value inhibits the feature characterized by this parameter corresponding GSM name GSM Recommendation parameter type and OMC-R class (see note below) Note: The recommended value is established from Nortel experience and studies. This value has to be adapted according to the network specificities. For the recommended value in GSM 900, it is the same value for eGSM and GSM-R when nothing else is recommended for these two networks. This value is not contractual, and it could change with Nortel new studies results and experience growth. The following types of parameters can be distinguished: • Customer engineering parameters: Addressing: relative to an object Design: contract characteristic Optimization:network tuning Operation: network operation • Manufacturer parameters: System: modifying such a parameter seriously impacts system behaviour Product: parameters related to the current system release DP: stands for permanent data OMC-R class gives rules to be followed when modifying a parameter: CLASS Class 0 Class 1 Class 2 Class 3 Rules Implies reconstruction of the BDA Put BSC out of service (i.e. BSC state set to “locked”), takes new parameters into account by resetting active chain and passive chains Declares the object (or its parent) temporarily out-of-service before modification Modification is dynamically taken into account Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 284/629 V17.0 BSS Parameter User Guide (BPUG) 5.2. 2G CELL SELECTION AND RESELECTION PARAMETERS cellReselectHysteresis Description: Class3 V7 Hysteresis to reselect towards a cell: when the MS is in IDLE mode and reselects a cell with a different LA (Location Area) when the MS is in GPRS STANDBY mode and reselects a cell with a different LA (Location Area) or a different RA (Routing Area) when the MS is in GPRS ready state and reselects a different cell [0 to 14, by steps of 2] dB bts 6 dB DP, Optimization 6 dB (rural / low cell overlap), 10 dB (urban / high cell overlap) Criteria for reselection towards a cell of a different Location Area (Sel_2) GSM case: A high value prevents the MS from making frequent location updates and may also prevent an MS from performing adequate location updates, thus risking not receiving calls. The level variation of the signal is more important in an urban context, so a higher value of hysteresis should be set. To avoid frequent location updates, there is also a timer forbidding the reselection of the previous server cell. For a reselection with change of location area, the value is 15 seconds. GPRS case: In order to minimize the impact of the introduction of the GPRS in an existing GSM network, it is recommended not to modify the current value of CellReselectHysteresis used for voice. A high value would keep the link for a long time hence some communications would have a high BLER due to an important load of the cell. The throughput would then decrease because of the retransmission at RLC/MAC layer. On the other hand a low value would ease the cell reselection pingpong in data mode which could severely decrease the overall user throughput due to the gap of transmission during the reselection. In case of cell overlap (i.e. urban environment, site covered in several frequency bands), 10dB should be considered in order to minimize ping-pong reselections. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 285/629 V17.0 BSS Parameter User Guide (BPUG) cellReselectOffset Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: [0 to 126, by steps of 2] dB bts 4 DP, Optimization Between 4 and 10 Additional reselection criterion (for phase 2) (Sel_3) Class 3 Encouragement to reselect a cell (C2 criterion) for phase 2 MS V8 Otherwise, if there is no privileged layer, the recommended value remains the same for both sites, between 4 dB and 10 dB. cellReselInd Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: [true / false] bts true DP, Optimization True Additional reselection criterion (for phase 2) (Sel_3) See chapter Selection, Reselection Algorithms Class 3 Whether cell reselection criterion (C2) use is authorized V8 msTxPwrMaxCCH Description: Class 3 V7 Maximum MS transmission power in a cell CCCH The BSC relays the information to the mobiles in the Abis CELL MODIFY REQUEST message. [5 to 43, by steps of 2] dBm (GSM 900, GSM-R, GSM850, GSM850GSM1900 and GSM 900& 850MHz - GSM 1800 networks) [0 to 36, by steps of 2] dBm (GSM 1800 and GSM 1900 - GSM 900 & 850MHz networks) [0 to 33] dBm (GSM 1900 network and 1900-850 network) [0 to 33] dBm (E-GSM network) bts Typical value of 33 dBm for GSM 900 & 850MHz handhelds, 30 dBm for GSM 1800 and 1900 DP, Optimization 33 dBm for GSM 900 & 850MHz, 30 dBm for GSM 1800 and 1900 Selection or reselection between cells of current Location Area (Sel_1), Criteria for reselection towards a cell of a different Location Area (Sel_2), Additional reselection criterion (for phase 2) (Sel_3) Value range: Object: Default value: Type: Rec. value: Used in: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 286/629 V17.0 BSS Parameter User Guide (BPUG) Eng. Rules: In GSM 900 & 850MHz, msTxPwrMax = msTxPwrMaxCCH. In GSM 1800 or 1900, msTxPwrMaxCCH ≤ msTxPwrMax. Both are verified at OMC-R level. This value is related to typical mobile (handheld or vehicle-mounted) and assumed an environment (urban, rural). If the cell is rural, it is possible to put a higher value because lot of mobiles have car kits (can transmit at a higher power). In urban environment, the density of mobile increases and care should be taken to reduce interferences. Furthermore, the major part of the mobile market are handsets. If the cell is used as a neighbor cell of another serving cell in the network, msTxPwrMaxCCH must be identical to the msTxPwrMaxCell power defined for the corresponding adjacentCellHandOver object (the values must be checked by users). Remark: penaltyTime Description: Class 3 V8 Timer used by an idle mobile before reselecting a cell (C2 criterion) When a mobile places the cell on the list of strongest carriers, it starts a timer that stops after penaltyTime seconds. This timer is reset when the mobile removes the cell from the list. For the entire timer duration, the reselection criterion (C2) is assigned a negative temporaryOffset value. Refer to the cellReselectOffset parameter in the Dictionary. [20 to 640, by steps of 20] seconds. The value “640” is reserved and indicates that the temporary offset is ignored in the reselection criterion (C2) calculation. It also changes the sign in the C2 formula. bts 20 DP, Optimization 20 Additional reselection criterion (for phase 2) (Sel_3) The longer this timer is, the longer a penalty is applied for reselecting that cell. The value should be correlated with the expected mobiles speeds, which are to be managed by that cell. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 287/629 V17.0 BSS Parameter User Guide (BPUG) rxLevAccessMin Description: Class 3 V7 Minimum signal strength level received by the mobiles for being granted access to a cell. The information is sent to MS prior to registering. As an example, a threshold level of -104 dBm corresponds to an acceptable BER of approximately 10-2 (minimum recommended value). [less than -110, -110 to -109, ... , -49 to -48, more than -48] dBm bts less than -110 dBm DP, Optimization GSM 900/GSM 850: -101 to -100 dBm, GSM 1800/1900: -99 to -98 dBm Selection or reselection between cells of current Location Area (Sel_1), Criteria for reselection towards a cell of a different Location Area (Sel_2), Additional reselection criterion (for phase 2) (Sel_3) Main parameter for selection or reselection. Notice that the tuning of this parameter strongly depends on the operator strategy. Decreasing the value eases the access to the network by reducing the quality. This parameter defines the cell access size. The difference between GSM 900/GSM 850 and GSM 1800/1900 is due to MS sensitivity (-104 dBm (GSM 900/GSM 850), -102 dBm (GSM 1800/1900)). Example: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Remark: RxLevAccessMin 1 = -100 dBm RxLevAccessMin 2 = -99 dBm A rough calculation gives the following impact on the cell access surface: Access Zone 1 = Access Zone 2 x 1.2 CAUTION! A very low value of RxlevAccessMin allows mobiles to camp and attempt calls. Most of calls attempts at very low field levels fail, or lead to a call drop a few seconds after the call has been established. This assessment is also true for GPRS/EDGE procedure, a very permissive value of RxlevAccessMin leads to data establishment failure and TBF drop. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 288/629 V17.0 BSS Parameter User Guide (BPUG) temporaryOffset Description: Class 3 V8 Negative offset applied during Penalty Time for reselecting a cell (C2 criterion) This negative offset is applied during the entire penaltyTime duration and allows to prevent speeding mobiles from selecting the cell. Refer to the cellReselectOffset entry in the Dictionary. [0 to 70, by steps of 10] dB bts 70 DP, Optimization 0 (microcell & macrocell in mono-layer), 70 (macrocell in multi-layers) Additional reselection criterion (for phase 2) (Sel_3) The value prevents a mobile from reselecting a cell during PenaltyTime. By giving the highest possible value, which is higher than the field strength range (0 to 63), we ensure that the mobile will not reselect the cell before the timer expires. Then, the value 70 means the applied offset is infinite. It could be dangerous on a microcell or macrocell in a mono-layer environment to have a high value, because it slows down the reselection process. However, on a macrocell in a multi-layers environment, it is recommended to prevent from reselecting a cell (value 70), in keeping a low value for “penaltyTime” (20 seconds). Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 289/629 V17.0 BSS Parameter User Guide (BPUG) 5.3. 2G-3G CELL RESELECTION PARAMETERS gsmToUmtsReselection Description: gsmToUmtsReselection is composed of 4 parameters: uMTSsearchMinLevel uMTSreselectionOffset uMTSAccessMinLevel uMTSReselectionARFCN bts DP Class 3 V14 Object: Type: uMTSAccessMinLevel Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Note: Class 3 V14 A minimum threshold for Ec/No for UTRAN FDD cell re-selection (GSM spec 45.008 name for this parameter is FDD_Qmin) [0: - 20 dB, 1: - 6 dB, 2: - 18 dB, 3: - 8 dB, 4: - 16 dB, 5: - 10 dB, 6: 14 dB, 7: - 12 dB] bts - 12 dB DP - 12 dB 2G - 3G Cell Reselection below the recommended value UE may not be able to reach the 3G network in good conditions. The SI2Quater message broadcasted by the BSS is an index [0 to 7] that is interpreted by the mobile depending on the release date of that mobile: Index Mobiles’ interpretation before October 2003 Mobiles’ interpretation after October 2003 0 1 2 3 4 5 6 7 - 20 dB - 19 dB - 18 dB - 17 dB - 16 dB - 15 dB - 14 dB - 13 dB - 20 dB - 6 dB - 18 dB - 8 dB - 16 dB - 10 dB - 14 dB - 12 dB One should be advised that OMC-R may eventualy display “old” values while the offset is broadcasted. uMTSReselectionARFCN Description: Class 3 V14 Neighbouring UMTS cell ARFCN. Although no control is performed on the value, it shall be indicated on the OMC-R display as a comment that a UTRAN ARFCN FDD is from 10562 to 10838. (GSM spec 45.008 name for this parameter is FDD_ARFCN) Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 290/629 V17.0 BSS Parameter User Guide (BPUG) Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: 0 to 16383 bts 0 DP a non-null value to broadcast the SI2Quater on the BCCH 2G - 3G Cell Reselection uMTSReselectionOffset Description: Class 3 V14 Applies an offset to RLA_C for cell reselection to access technology / mode FDD (GSM spec 45.008 name for this parameter is FDD_Qoffset) [-∞dB, -28 dB, -24 dB, -20 dB, -16 dB, -12 dB, -8 dB, -4 dB, 0 dB, 4 dB, 8 dB, 12 dB, 16 dB, 20 dB, 24 dB,28 dB] bts -∞dB DP see Engineering Rules 2G - 3G Cell Reselection that parameter allows a fine tuning in UMTS re-selection by introducing a favorable/defavorable offset toward a UMTS cell. The recommanded value by default is “0 dB”. This parameter should set according to the operator strategy. Indeed 3G layers can be seen as an 1800 Layer, therefore the reselection 2G 3G layer should be as reselection strategy between 900 and 1800 layer. Value range: Object: Default value: Type: Checks: Rec. value: Used in: Eng. Rules: uMTSSearchLevel Description: Value range: Class 3 Search for 3G cell if signal level is below or above the threshold (GSM spec 45.008 name for this parameter is Qsearch_I) V14 [0: “< -98 dBm”, 1: “< -94 dBm”, 2: “< -90 dBm”, 3: “< -86 dBm”, 4: “< 82 dBm”, 5: “< -78 dBm”, 6: “< -74 dBm”, 7: “Always”, 8: “> -78 dBm”, 9: “> -74 dBm”, 10: “> -70 dBm”,11: “> -66 dBm”, 12: “> -62 dBm”, 13: “> -58 dBm”, 14: “> -54 dBm”, 15: “Never”] bts -98 dBm DP see Engineering Rules 2G - 3G Cell Reselection this parameter set whether UE should search for UMTS cells or not. It can allow UE to search above a certain level, below a certain level, or always. Note that in this last case the UE battery autonomy can be impacted. Object: Default value: Type: Rec. value: Used in: Eng. Rules: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 291/629 V17.0 BSS Parameter User Guide (BPUG) 5.4. LEGACY MEASUREMENT REPORTING PARAMETERS powerControlIndicator Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 3 V7 Whether MS signal strength measurements on the TCH or SDCCH should include measurements on BCCH frequency or not. [include BCCH measurements / do not include BCCH measurements] bts include BCCH measurements DP, Optimization See Eng. Rules Power Control Algorithms Downlink measurements performed by the mobile on TCH or SDCCH should not include measurements done when the channel frequency is the BCCH frequency if the following two conditions are met: The radio channel hops at least on two different frequencies, on of which is the BCCH frequency. Power control on the downlink is used. This parameter is only relevant with BTS using cavity coupling because only cavity coupling allows to use BCCH frequency as part of the hopping frequency list. For BTS using hybrid coupling, the BCCH frequency is never part of the hopping list, so this parameter is irrelevant in that case. See §4.5.9 for details. CAUTION! Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 292/629 V17.0 BSS Parameter User Guide (BPUG) 5.5. ENHANCED MEASUREMENT REPORTING PARAMETERS fDDMultiratReporting Description: Class 3 V17 (applicable both to normal measurement reporting and EMR) Number of UTRAN FDD cells to be reported by the mobile in the list of strongest cells inside the normal or Enhanced Measurement Report message. 0: “no UTRAN cell is favoured” 1: “1 UTRAN strongest cell is favoured” 2: “2 strongest UTRAN cells are favoured” 3: “3 strongest UTRAN cells are favoured” Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: bts 0 DP, Optimization see Eng. Rules Enhanced Measurement Reporting (EMR) UTRAN cell reporting using legacy measurement reports (V17) The value depends on the network operator strategy. However, in case of HO2G-3G enabled with normal measurement reporting (EMR disabled), it is necessary to exercise caution when fDDMultiRatReporting and setting the parameters multiBandReporting. These parameters define the number of UTRAN cells and non-serving band GSM cells, respectively, that must be included by the mobile in the list of strongest cells in the measurement report. Therefore it leaves (6 - fDDMultiRatReporting multiBandReporting) spaces for the serving band GSM cells. Therefore, if EMR is disabled, it is recommended not to exceed fDDMultiRatReporting = 2 and multiBandReporting = 2. fDDreportingThreshold Description: Class 3 V17 CPICH RSCP level measured on UTRAN cells, above which the mobile shall apply a higher priority to UTRAN cells in the enhanced measurement report message -115 dBm, -109 dBm, -103 dBm, -97 dBm, -91 dBm, -85 dBm, -79 dBm, never handoverControl never DP, Optimization -97 dBm Enhanced Measurement Reporting (EMR) An operator willing to unload GSM network to UMTS network but keeping calls in good conditions should set this parameter to at least 97dBm, ensuring a high probability of good Ec/No value after the HO and limiting the high increase of UTRAN incoming HO due to ping pong handover. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 293/629 V17.0 BSS Parameter User Guide (BPUG) This parameter must be in accordance with 3G to 2G HO parameters. In order to limit ping pong effect, a hysteresis of 5 dB is recommended between fDDreportingThreshold and UTRAN hard HO 3G to 2G CPICH RSCP threshold. fDDreportingThreshold2 Description: Class 3 V17 (applicable both to normal measurement reporting and EMR, applicable from MS release 5) CPICH Ec/N0 level measured on UTRAN cells, above which the mobile shall report UTRAN cells in the enhanced measurement report message 0 to 63 (0 means “always reported”) handoverControl 0 (“always reported”) DP, Optimization 28 Enhanced Measurement Reporting (EMR) UTRAN cell reporting using legacy measurement reports (V17) To ensure a good quality after the handover, a simultaneously not too restrictive and good C/I value must be required. Setting this parameter at 28 which corresponds to Ec/No = -10 dB seems to be a good compromise. This parameter must be in accordance with 3G to 2G HO parameters. In order to limit ping pong effect, a hysteresis of 2 dB is recommended between fDDreportingThreshold2 and UTRAN hard HO 3G to 2G Ec/No threshold. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Note: The Ec/No step is in half dB: - “0” means always reported - In range 1 to 49, “1” means “CPICH Ec/No ≥ -24 dB” and “49” means “CPICH Ec/No ≥ 0 dB”. CPICH Ec/N0 level measured = - 24 + fDDreportingThreshold2/2 - Values from 50 to 63 should not be used for Ec/No. qsearchC Description: Class 3 V17 (applicable both to normal measurement reporting and EMR). This parameter is called Qsearch_C in the GSM specification. It gives the serving cell’s BCCH level below which the MS must listen to neighbours. If the serving BCCH frequency is not part of the BA(SACCH) list, the dedicated channel is not on the BCCH carrier, and qsearchC is not equal to 15, the MS shall ignore the qsearchC parameter value and always search for UTRAN cells. If qsearchC is equal to 15, the MS shall never search for UTRAN cells. 0: “< -98 dBm” 1: “< -94 dBm” 2: “< -90 dBm” 3: “< -86 dBm” 4: “< -82 dBm” 5: “< -78 dBm” Nortel confidential Value range: PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 294/629 V17.0 BSS Parameter User Guide (BPUG) 6: “< -74 dBm” 7: “always” 8: “> -78 dBm” 9: “> -74 dBm” 10: “> -70 dBm” 11: “> -66 dBm” 12: “> -62 dBm” 13: “> -58 dBm” 14: “> -54 dBm” 15: “never” QsearchC < -XX dBm: the HO towards the UMTS can be done only if the RxLev from the serving cell is below -XX dBm. QsearchC > -XX dBm: the HO towards the UMTS can be done only if the RxLev from the serving cell is above -XX dBm. Object: Default value: Type: Rec. value: Used in: handoverControl 15 (“never”) DP, Optimization 7 (“always”) Enhanced Measurement Reporting (EMR) UTRAN cell reporting using legacy measurement reports (V17) Eng. Rules: Cases where a different value from “always” could be useful have not been identified. Therefore value “always” is recommended. reportTypeMeasurement Description: Value range: Object: Default value: Type: Rec. value: Used in: Class 3 V17 type of measurement report to be reported on this cell : enhanced measurement report or legacy measurement report 0 : Measurement report 1 : Enhanced Measurement Report bts 0 DP, Optimization 1 Enhanced Measurement Reporting (EMR) UTRAN cell reporting using legacy measurement reports (V17) Eng. Rules: To take advantage of EMR benefits it is recommended to activate EMR. In case of HO 2G -3G activation either EMR or legacy measurement does not have any impact on the Handover 2G to 3G efficiency. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 295/629 V17.0 BSS Parameter User Guide (BPUG) servingBandReporting Description: Class 3 V17 (applicable to EMR only) This parameter sets the value of the SERVING_BAND_REPORTING field in Measurement Information messages. It defines the number of cells from the GSM serving frequency band that shall be included in the list of strongest cells in the enhanced measurement report. Value range: 0 : “no inband cell is favoured” 1: “1 strongest inband cell is favoured” 2: “2 strongest inband cells are favoured” 3: “3 strongest inband cells are favoured” Object: Default value: Type: Rec. value: Used in: Eng. Rules: bts 3 DP, Optimization 3 Enhanced Measurement Reporting (EMR) Depends on the network operator strategy. servingBandReportingOffset Description: Class 3 V17 (applicable to EMR only) This parameter sets the value of the XXX_REPORTING_OFFSET field in Measurement Information messages, for the GSM band (XXX =900 or 1800 or 400 or 850 or 1900). If there is not enough space in the report for all valid cells, the cells shall be reported that have the highest sum of the reported value (RXLEV) and the parameter servingBandReportingOffset (XXX_REPORTING_OFFSET) for the serving GSM band. Note that this parameter shall not affect the value itself of the reported measurement. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: 0, 1, ... 7, 0xFF : 0 dB, 6 dB, …, 42 dB, “not significant” handoverControl empty DP, Optimization See Eng. Rules Enhanced Measurement Reporting (EMR) This parameter should be tuned if EMR is used during an IM campaign. If, during the Interference Matrix campaign in a dual band network, the reporting of serving band neighbours is deliberately favoured by using the servingBandReportingOffset , then, as a sideeffect, the traffic distribution may be modified. This undesirable sideeffect may in turn modify the results of the IM measurements, which therefore may no longer reflect the real situation in the field once the IM has ceased. Therefore it is recommended to ensure that the chosen value of servingBandReportingOffset does not cause unacceptable changes in the traffic distribution. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 296/629 V17.0 BSS Parameter User Guide (BPUG) 5.6. RADIO LINK FAILURE PARAMETERS callReestablishment Description: Class 3 V7 Whether call re-establishment in a cell is allowed when the radio link is broken off for propagation reasons The information is broadcast to the mobiles at regular intervals on the cell BCCH. On receipt of a CHANNEL REQUIRED message with cause “call reestablishment”, the BSC attempts to allocate a TCH in one of the cells where call re-establishment is allowed. Then, if no TCH is available the BSC attempts to allocate a SDCCH. [allowed / not allowed] bts not allowed DP, Optimization allowed Radio link failure process (run by the MS), Call reestablishment procedure Enabling or not this feature is a MSC capability issue Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: radioLinkTimeout Description: Class 2 V7 Maximum value of the counter (S) associated with the downlink SACCH messages, beyond which the radio link is cut off. It is lower than or equal to t3109. Mobiles comply with system operating conditions when the counter (S) is assigned a value lower than or equal to t3109. If the receiver is unable to decode a downlink SACCH message (BTS–to–MS direction), the counter is decreased by 1. If the message is received, the counter is increased by 2. When the counter goes down to zero, the radio link is declared “faulty”. Value range: Object: Default value: Type: Rec. value: [4 to 64, by steps of 4] SACCH frames (1 unit = 480 ms on TCHs, 470 ms on SDCCHs) bts 20 SACCH DP, Optimization 20 32 when AMR is activated Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 297/629 V17.0 BSS Parameter User Guide (BPUG) Used in: Eng. Rules: Radio link failure process (run by the MS), AMR - Adaptative Multi Rate FR/HR radioLinkTimeOut < t3109. If surrounding cells accept re-establishment (from GSM08 for DMS MSC), overall process should not be too long. Small value: call might be dropped before a move to a more favorable environment could occur. High value: in case of permanent bad conditions, user’s anger and taxation increase before actual call’s end or reestablishment. Remark: The rlf1 attribute serves the same goal on the uplink, but the system does not check that the values of the two attributes are consistent. rlf1 Description: Class 2 V8 Value to compute the initial and maximum value of the (CT) counter used in the BTS radio link control algorithm The FP runs the following algorithm to monitor the uplink SACCHs (MS–to–BTS direction): The CT counter is reset to zero when the FP receives a CHANNEL ACTIVATION message. On each occurence of an uplink SACCH, the following occurs: if the channel is decoded and CT = 0, then CT = 4 * rlf1 + 4 if the channel is decoded and CT ≠ 0, then CT = min (4 * rlf1 + 4, CT+rlf2) if the channel is not decoded, then CT = max (0, CT - rlf3) When the CT counter goes down to zero, the radio link is broken and the BTS sends a CONNECTION FAILURE INDICATION message to the BSC. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: [0 to 15] bts 4 DP, Optimization 4 7 when AMR is activated Radio link failure process (run by the BTS), AMR - Adaptative Multi Rate FR/HR The resulting CT value is the same as “radioLinkTimeOut” value. There is no reason to recommend to cut a communication more rapidly in the uplink or downlink direction. In a network with a lot of traffic or with many zones of interference, a lower value (between 2 and 4) of this parameter is recommended. Typically the value, in such a case should be 2. The radioLinkTimeOut attribute serves the same goal on the downlink, but the system does not check that the values of the two attributes are consistent. Notes: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 298/629 V17.0 BSS Parameter User Guide (BPUG) rlf2 Description: Class 2 V8 Step value by which the (CT) counter is increased by the radio link control algorithm when an uplink SACCH is decoded. Refer to the rlf1 entry. [1 to 4] SACCH frames bts 2 DP, Optimization 2 Radio link failure process (run by the BTS) The value should be higher than rlf3 value, in order to encourage the continuity of service. The higher the value, the longer an MS will keep a bad quality communication in a disturbed zone. The choice of this value must be made by the operator, in keeping with its service quality level. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: rlf3 Description: Class 2 V8 Step value by which the (CT) counter is decreased by the radio link control algorithm when an uplink SACCH is not decoded Refer to the rlf1 entry. [1 to 4] SACCH frames bts 1 DP, Optimization 1 Radio link failure process (run by the BTS) It is recommended to fix this value to 1. This allows the use of the rlf1 value to set the maximal duration of consecutive non-reception of SACCH frame. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 299/629 V17.0 BSS Parameter User Guide (BPUG) 5.7. SIGNAL QUALITY AVERAGING PARAMETERS missRxQualWt Description: Class 3 V7 Weight applied to missing Quality measurement The missing measurement is replaced by the latest computed arithmetic average, or by the latest received raw measurement if no average value is available, weighed by this corrective factor when calculating the average bit error rate in the radio link. The range of permitted values makes missing quality measurements not favored. [100 to 200] % handOverControl 110 DP, Optimization 110 Missing Downlink Measurements The higher the value is, the higher the missing measurement will be weighted. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: rxQualHreqave Description: Class 3 V7 Number of bit error rate measurements performed on a serving cell, used to compute arithmetic BER averages in handover and power control algorithms [1 to 10] number of measurement results handOverControl 8 DP, Optimization 4 in urban environment, > 8 in rural environment Measurement Processing In order to minimize calculation of temporary averages it is better if runHandOver and runPwrControl are multiples or sub multiples of rxQualHreqAve. Length of weighed average window should be reduced when the cell is small or environment requires quick reactivity. Studies have shown that a reduction of the window size value (from 8 to 4 for instance) does not increase the number of handovers on a network and does not change handover causes. However, it has a positive impact, because it leads to a greater reactivity.Then, the weighted average window size (rxQualHreqAve * rxQualHreqt) has to be correlated to the hoMargin value to keep a low ping-pong probability. The larger the window size, the lower the hoMargin should be. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 300/629 V17.0 BSS Parameter User Guide (BPUG) rxQualHreqt Description: Class 3 Number of arithmetic averages taken into account to compute the weighted average bit error rate in handover and power control algorithms. Each is calculated from rxQualHreqave bit error rate (BER) measurements on a radio link. [1 to 16] handOverControl 1 DP, Optimization 1 Measurement Processing V7 Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: The quality and signal strength weighted average window should encompass the same period. For the sake of simplicity, the default value disables weighting. The weighed average window size (rxQualHeqAve * rxQualHreqt) must be correlated to the hoMargin value to keep a low ping-pong probability. The larger the window size, the lower the hoMargin should be. rxQualWtsList Description: Class 3 V7 List of up to sixteen weights used to compute the average bit error rate on a radio link The L1M function calculates rxQualHreqave arithmetic averages from raw measurements, and balances rxQualHreqt averages among those with the weights defined in rxQualWtsList. Each arithmetic average is partnered with one weight in the list. Weight/average associations are set in the order in which the weights are recorded. The latest computed arithmetic average is always partnered with the first weight in the list. Super–average = [∑ (averagei x weighti)] / 100, i = 1 to rxQualHreqt [0 to 100] % handOverControl 100 DP, Optimization 100 Measurement Processing Values add up to 100. If there are several values, the biggest weights must be used for more recent reports. In rural environment, rxLev and rxQual weighed average window will not refer to the same time window. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 301/629 V17.0 BSS Parameter User Guide (BPUG) 5.8. SIGNAL STRENGTH AVERAGING PARAMETERS missRxLevWt Description: Class 3 V7 Weight applied in case of missing signal strength measurement report The missing measurement is replaced by the latest computed arithmetic average, or by the latest received raw measurement if no average value is available, weighed by this corrective factor when calculating the average signal strength in the cell. Selecting the greatest value makes missing strength measurements not favored. [0 to 100] % handOverControl 90 DP, Optimization 90 Measurement Processing Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: rxLevHreqave Description: Class 3 V7 Number of signal strength measurements performed on a serving cell, used to compute arithmetic strength averages in handover and power control algorithms [1 to 10] number of measurement results handOverControl 8 DP, Optimization 6 for small cells (Dintersite < 800m) between 8 and 10 for large cells (Dintersite > 1600m) Measurement Processing In order to minimize calculation of temporary averages it is better if runHandOver and runPwrControl are multiples or sub multiples of rxLevHreqAve. In an urban environment, the window size should be minimized and the hoMargin value should be high. However, choosing too small a value leads to averaging meaningless measures in case of DTX activation uplink or downlink. Then, in an urban environment, according to building density, antenna height and global environment, the window size can fluctuate between 6 and 8. The minimum value, 6, may be preferred, because it ensures a good reactivity without bad influence if the parameter hoMargin is well chosen. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 302/629 V17.0 BSS Parameter User Guide (BPUG) rxLevHreqaveBeg Description: Class3 V11 Number of measurement reports used in short averaging algorithm on current cell for signal strength arithmetic average Refer to the rxLevHreqave entry in the Dictionary. [1 to 10] handOverControl 2 DP, Optimization 2 Early HandOver Decision Automatic handover adaptation Fast power control at TCH assignment rxLevHreqaveBeg < rxLevHreqave This parameter has to be coupled rxLevNCellHreqaveBeg. with hoMarginBeg and Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Remark: This parameter is only available for DCU4 or DRX transceiver architecture. rxLevHreqt Description: Class 3 Number of arithmetic averages taken into account to compute the weighted average signal strength in handover and power control algorithms. Each is calculated from rxLevHreqave signal strength measurements on a serving cell. [1 to 16] handOverControl 1 DP, Optimization 1 Measurement Processing V7 Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: In a urban environment, the window size should be minimized and the hoMargin value should be high. For the sake of simplicity, weighted averaging is disabled by default value. The weighted average is not used for the PBGT. The weighed average window size (rxLevHreqAve * rxLevHreqt) has to be correlated to the hoMargin value to keep a low ping-pong probability. The larger the window size, the lower the hoMargin should be. CAUTION! Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 303/629 V17.0 BSS Parameter User Guide (BPUG) rxLevWtsList Description: Class 3 V7 Values of weights to be used for signal strength weighed average The L1M function first calculates rxLevHreqave arithmetic averages from raw measurements, and balances rxLevHreqt averages among those with the weights defined in rxLevWtsList. Each arithmetic average is partnered with one weight in the list. Weight/average associations are set in the order which the weights are recorded. The latest computed arithmetic average is always partnered with the first weight in the list. Super–average = [ ∑ (averagei x weighti)] / 100, i = 1 to rxLevHreqt [0 to 100] % handOverControl 100 DP, Optimization 100 Measurement Processing Arithmetic law to be preferred, biggest weight for most recent reports Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 304/629 V17.0 BSS Parameter User Guide (BPUG) 5.9. NEIGHBOR CELL AVERAGING PARAMETERS cellDeletionCount Description: Class 3 V7 The cellDeletionCount is to be compared to the number of consecutive Measurement Results messages not containing information on one of the neighbour cells that would result in the cell being no longer eligible. Before V12, the neighbour cells information of such a cell would be discarded. From V12 (TF 1089-2), from a number ≥ cellDeletionCount the cell will be non eligible, but the information of that neighbour cell will only be discarded when the number of consecutive Measurement Results with no information on the cell will reach 10 (i.e. 5 sec). [0 to 31] bts 5 in rural environment, 2 in microcell environment DP, Design 5 in rural, 2 in urban environment Measurement Processing Handovers screening As there is no weighting factors on neighboring cells, low values of cellDeletionCount are advised and so the rule cellDelectionCount < rxNcellHrequave. A mobile is required to keep synchronization information at least 10 seconds after a cell was removed from the best cells list. This synchronisation becomes quickly obsolete in the case of fast moving mobiles. This mechanism applies only for Power budget handover. Further informations are provided in chapter Best Neighbor Cells Stability Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: CAUTION! Remark: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 305/629 V17.0 BSS Parameter User Guide (BPUG) rxNCellHreqave Description: Class 3 V7 Number of measurement results used in the PBGT algorithm to compute the average neighboring signal strength No weighed average is computed for this category of measurement [1 to 10] number of measurement results handOverControl 8 DP, Optimization 6 for small cells (Dintersite < 800m) between 8 and 10 for large cells (Dintersite > 1600m) Measurement Processing Early HandOver Decision Automatic handover adaptation In the PBGT formula, the RXLEV_DL is the last arithmetic signal strength on the current cell. In order to use the same time base, we should have rxNcellHreqAve = rxLevHreqAve. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: rxLevNCellHreqaveBeg Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 3 V11 Number of measurement results used in short averaging algorithm to compute the average neighboring signal strength [1 to 10] handOverControl 2 DP, Optimization 2 Early HandOver Decision rxLevNCellHreqaveBeg < rxLevNCellHreqave This parameter has to be coupled with rxLevHreqaveBeg. hoMarginBeg and Remark: This parameter is only available for DCU4 or DRX transceiver architecture. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 306/629 V17.0 BSS Parameter User Guide (BPUG) 5.10. DISTANCE AVERAGING PARAMETERS distHreqt Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 3 V7 Number of distance measurements, used to compute the weighted average MS–to–BTS distance in handover algorithms [1 to 16] handOverControl 4 DP, Optimization 4 Measurement Processing For distance handover and Call Clearing, a weighted average of the MS-BS distance is computed from timing-advance results. distWtsList Description: Class 3 V7 List of no more than sixteen weights, used to compute the average MS–to–BTS distance from distHreqt measurements The L1M function balances distHreqt raw measurements with the weights defined in the distWtsList list. Each measurement is partnered with one weight in the list. Weight/measurement associations are set in the order which the weights are recorded. The latest received measurement is always partnered with the first weight in the list. Super–average = [∑ (measurementi x weighti)] / 100, i = 1 to distHreqt [0 to 100] % handOverControl 40 30 20 10 DP, Optimization 40 30 20 10 Measurement Processing A supply weights to distHreqt values, highest value for latest measurements. Choosing an arithmetic law enables to enhance latest values while not putting too much weight upon the period of time which might not be representative of the current trend. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 307/629 V17.0 BSS Parameter User Guide (BPUG) missDistWt Description: Class 3 V7 Weight applied to missing Distance measurement. The missing measurement is replaced by the latest received raw measurement weighed by this corrective factor when calculating the average MS–BTS distance. The range of permitted values makes missing distance measurements not favored. [100 to 200] % handOverControl 110 DP, Optimization TBD Measurement Processing The higher the value is, the higher the missing measurement will be weighted. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 308/629 V17.0 BSS Parameter User Guide (BPUG) 5.11. HANDOVER (GLOBAL) PARAMETERS bts time between HO configuration Description: Value range: Class 3 V9 Whether the hoPingpongTimeRejection timer can be used at bts level when processing handovers [0 / 1] “0”:The timer is disabled. “1”:The timer is used. bts 0 DP, Optimization 1 Minimum time between Handover General protection against HO ping-pong (from V12) New semantic in V12 in order to restore the minimum time between HO feature (TF218, V9): timeBetweenHOconfiguration = used bts time between HO configuration = 1 ho Pingpong combinaison = (all, allPBGT) ho Pingpong Time Rejection > 0 Object: Default value: Type: Rec. value: Used in: Eng. Rules: forced handover algo Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 3 V9 Minimum signal strength level received by the mobiles to be granted access to a neighbor cell in case of forced handover [less than -110, -110 to -109, ..., -49 to -48, more than -48] dBm adjacentCellHandover less than -110 DP, Optimization = rxLevMinCell -1 Forced Handover The neighbour cell eligibility criterion for forced handover compares the Rxlev received by the mobile from the neighbour cells with the value of "forced handover algo". If the Rxlev is greater than "forced handover algo", then the forced handover is triggered. Therefore : the higher the value of "forced handover algo" parameter, the less efficient the forced handover feature, because fewer mobiles will comply with the eligibility criterion. The mobiles who are located too far away from the strongest neighbour cell will be kept by the network on the current cell. So, it will take longer to empty the cell because the operator has to wait for all mobiles to move around and get closer to a neighbour cell. Note that it does not make sense to set "forced handover algo" to a higher value than "rxLevMinCell", although nothing prevents from doing so. the smaller the value of "forced handover algo" parameter, the faster mobiles will be forced out of the current cell. On the downside, if "forced handover algo" is significantly lower than "rxlevMinCell", quality of service for the mobile on the destination cell will be poorer with a risk, ultimately, of call drop. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 309/629 V17.0 BSS Parameter User Guide (BPUG) Therefore a compromise should be found, and BPUG recommends that forced handover algo = RxlevMinCell - 1dB. This is only a recommendation. A different value may be chosen by the customer. handOver from signalling channel Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 3 V7 Authorization to perform intercell handovers on signalling channels (SDCCH or TCH in signalling mode) [enabled / disabled] handOverControl disabled DP, Design disabled Direct TCH Allocation and Handover Algorithms It is recommended to enable this feature when queuing is activated. hoMargin Description: Value range: Object: Default value: Type: Rec. value: Class 3 V7 Margin to use for PBGT handovers to avoid subsequent handover, in PBGT formula [-63 to 63] dB adjacentCellHandOver 4 DP, Optimization between 4 and 6 for small cells (4 in an 1X1 pattern, 5 or 6 otherwise), 5 for large cells. Used in: Handovers Power budget formula Handover for traffic reasons (from V12) Define eligible neighbor cells for intercell handover (except directed retry) Automatic handover adaptation As a general rule, this parameter enables to harden access to a new cell in order to avoid a subsequent return to the current cell (provided rxLevMinCell is set to its minimal value and does not already take into account ping-pong handover protection). The value of this hoMargin must be correlated to the window size value to keep a low ping-pong probability. In case of ping-pong, handover hoMargin value must be incremented, and the window size value must be decremented. For a dual Band Network where one frequency band is privileged, it is advised to increase this value in neighbouring objects with a frequency belonging to the low priority frequency band. Thus, these neighbours will be underprivileged. Eng. Rules: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 310/629 V17.0 BSS Parameter User Guide (BPUG) hoMarginBeg Description: Class 3 V11 Margin that is added to hoMargin, concentAlgoExtRxLev, amrDirectAllocRxLevUL, amrDirectAllocRxLevDL, amrDirectAllocIntRxLevUL, amrDirectAllocRxLevDL, bizonePowerOffset, until rxLevHreqave for short averaging algorithm in order to compensate the lack of reliable measurements This parameter is coupled with hoMargin, concentAlgoExtRxLev, amrDirectAllocRxLevUL, amrDirectAllocRxLevDL, amrDirectAllocIntRxLevUL, amrDirectAllocRxLevDL, bizonePowerOffset and rxLevHreqaveBeg. Value range: Object: Default value: Type: Rec. value: Used in: [0 to 63] dB bts 4 dB DP, Optimization 4 dB 2 dB with Automatic Handover Adaptation Handovers Early HandOver Decision Automatic handover adaptation Direct TCH Allocation This parameter is only available for DCU4 or DRX transceiver architecture. Eng. Rules: Remark: hoMarginDist Description: Value range: Object: Default value: Type: Rec. value: Margin to be used for Distance Handovers [-63 to 63] dB adjacentCellHandOver - 24 dB DP, Optimization - 2 dB Class 3 V8 Depends on the environment and on the value of the msRangeMax Threshold. Used in: Handover condition for leaving a cell on distance Define eligible neighbor cells for intercell handover (except directed retry) Because the priority of the handover on Distance cause is lower than the Quality and Strength causes, it is performed while the quality and the signal strength on the current cell are still acceptable. Setting a negative value decreases the interference. PBGT hoMargin in the target cell should be set in order to avoid a ping-pong handover. For a dual Band Network where one frequency band is privileged, it is advised to increase this value in neighbouring objects with a frequency belonging to the low priority frequency band. Thus, these neighbours will be underprivileged. Eng. Rules: CAUTION! Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 311/629 V17.0 BSS Parameter User Guide (BPUG) hoMarginRxLev Description: Value range: Object: Default value: Type: Rec. value: Margin to be used for signal strength Handovers [- 63 to 63] dB adjacentCellHandOver - 24 dB DP, Optimization Class 3 V8 From 3 to 6 dB in urban environment, from 1 to 3 in rural environment. Depends on the environment and the value of lRxLevXXH. threshold. Handovers Define eligible neighbor cells for intercell handover (except directed retry) In rural environments, the hoMargin value on signal strength should be between 1 and 3. On the contrary, due to fast radio signal variations in urban environments, this criteria must be selective to allow good reactivity. Furthermore, this criteria can be selective due to site density in urban environments. The value of this hoMargin must be correlated to the window size value to keep a low ping-pong probability. In case of ping-pong handover, hoMargin value must be incremented, and the window size value must be decremented. This parameter, defined per neighbor, is used to select and sort neighbors. The setting of hoMarginRxLev depends of the gap between rxLevMinCell and lRxLevXXH. The higher the difference between these two values is, the higher the hoMarginRxLev. For a dual Band Network where one frequency band is privileged, it is advised to increase this value in neighbouring objects with a frequency belonging to the low priority frequency band. Thus, these neighbours will be underprivileged. Used in: Eng. Rules: hoMarginRxQual Description: Value range: Object: Default value: Type: Rec. value: Used in: Margin to be used for Signal Quality Handovers [-63 to 63] dB adjacentCellHandOver - 24 dB DP, Optimization in [- 2; 0] without SFH, in [1; (hoMargin - 2)] with SFH (#2 or 3) Class 3 V8 Handovers Define eligible neighbor cells for intercell handover (except directed retry) Handover cause on Signal Quality: case where access to another cell should be encouraged, provided target cell field strength is not much lower than the current one. If bad quality remains there is a risk of return handover but there is nothing much to be done. Eng. Rules: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 312/629 V17.0 BSS Parameter User Guide (BPUG) CAUTION! PBGT hoMargin in target cell should be set in order to avoid a pingpong handover. This parameter, defined per neighbor, is used to select and sort neighbors. For a dual Band Network where one frequency band is privileged, it is advised to increase this value in neighbouring objects with a frequency belonging to the low priority frequency band. Thus, these neighbours will be underprivileged. hoMarginTrafficOffset Description: Class 3 V12 Minimum signal strength margin with the serving cell that allows to select the best neighbor cell when a handover is triggered for overload reasons [0 to 63] dB adjacentCellHandOver 0 dB DP, Optimization 6 dB (if overlapping exists) Handovers Handover for traffic reasons (from V12) Since the HO for traffic reasons uses the PBGT HO procedure, the parameter powerBudgetInterCell shall be “enabled”. It is advised to combine the HO for traffic reason with the feature HO decision according to priority and Load. This parameter shall be set at a value which guarantees that cell overlapping exists with (hoMargin -hoMarginTrafficOffset). See Paragraph 2.5k9 for more details. When set to “0”, handovers for traffic reasons are not allowed in the adjacent cell (the PBGT HO is done before because it has a higher priority than the HO for traffic). Only applicable to BTSs equipped with non mixed DCU4, or DRX boards Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: CAUTION hoPingpongCombination Description: Class3 V12 List of couples of causes (HOInitialCause and HONonEssentialCause) indicating the causes of ping-pong handovers in the overlapping areas The following causes are defined with regard to the neighboring cell: HOInitialCause indicates the essential handover cause which leads to enter the neighbor cell (cause of incoming handover). HONonEssentialCause indicates the non-essential handover cause which leads to leave the cell (cause of outgoing handover). This parameter defines the combination for which the HOPingpongTimeRejection attribute is used. Value range: Object: Default value: Type: Rec. value: Used in: [rxQual, rxLev, distance, powerBudget, capture, directedRetry, OaM, traffic, all, allCapture, allPowerBudget, AMRquality] adjacentCellHandOver DP, Optimization (all, PBGT) General protection against HO ping-pong (from V12) Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 313/629 V17.0 BSS Parameter User Guide (BPUG) Eng. Rules: This parameter shall be known by the new BSC (whatever the type of HO is intra or inter BSC) ; so, it must be defined at the “entering cell” (relatively to the first HO of the combination) level, for the neighbouring cell (adjacentCellHandover object) corresponding to the “left cell” (still relatively to the first HO of the combination). Example: if you perform a handover from cell A to cell B for quality reason and you want to protect against pingpong HO for PBGT reason (from B to A), you have to declare (rxQual, PBGT) as one of the forbidden handover combinations at cell B level (for the neighbouring cell A). The hoPingpongCombination list can hold up to 4 couples of causes. No protection against intracell or interzone pingpongHO No protection against pingpong HO between more than 2 cells except for allcapture / all PBGT causes. Directed retry can only be an initial cause. timeBetweenHOConfiguration and bts Time Between HO configuration shall be set accordingly in order for the feature to be activated. Note: CAUTION! hoPingpongTimeRejection Description: Class 3 V12 Time before a new handover attempt can be triggered Refer to bsc object timeBetweenHOConfiguration and bts object bts time between HO configuration attributes in this Dictionary of Parameters for this timer activation. Refer to adjacentCellHandOver object HOPingpongCombination attribute in this Dictionary of Parameters for the combinations for which this timer applies. To avoid ping-pong handovers this new timer is started after a successful handover. Up to the expiration of this timer, the receipt of HANDOVER INDICATION message is ignored. [0 to 60] s adjacentCellHandOver 30 s DP, Optimization between 8 and 30 s General protection against HO ping-pong (from V12) The value of “HOPingpongTimeRejection” may be between 8 and 30 to have a real impact. The following rule can be applied: HOPingpongTimeRejection = 50% TCH effective occupancy average in a cell. If the rescue handovers are disabled in the network a too high value can result in dropped calls. The value depends on the speed of the mobile, the size of the cell and the type of cell (micro-micro etc). For an area where there are ping-pong handovers on “Quality” cause (the first HO occurs on “Quality” reason, the second one on PBGT), the value corresponds to the distance between the interference point and the limit of the cell. Care must be taken for small cells with high speed mobiles. See also chapter Minimum Time Between Handover Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 314/629 V17.0 BSS Parameter User Guide (BPUG) hoSecondBestCellConfiguration Description: Class 3 V9 Number of neighbor cells in which the BSC immediately attempts to perform a new handover when the previous handover attempt failed with return to the old channel Giving the attribute a value greater than 2 allows the BSC to renew the handover request without waiting for a new set of radio measurements (the first attempt is included in this count). The same list of neighbor eligible cells is used to process the request (no new list is provided by the BTS). [1 to 3] bsc 3 DP, Design 3 Handover to 2nd best candidate when return to old channel The value 1 means no new attempt after a handover failure, 2 means one new attempt and 3 corresponds to another new attempt if the first new attempt has failed. The recommended value optimizes the handover completion rate. Comment about the process: when all handover attempts have failed, the mobile returns on the previous channel. The measurement history is then complety lost, and the BTS will wait until the next (HReqAve x HReqt) period to relaunch a handover request. See also chapter Directed Retry Handover Benefit Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: hoTraffic Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: [disabled / enabled] bts enabled DP, Optimization enabled Handover for traffic reasons (from V12) Class 3 Whether handovers for traffic reasons at bts level are allowed. V12 “enabled” will be effective only if it is also “enabled” for the bsc object. In order to activate the feature “handover decision according to adjacent cell priority and load” (TF716), either hoTraffic shall be “enabled” or btsMSAccessClassBarringFunction shall be “enabled” (with also bscMSAccessClassBarringFunction). See parameter hoMarginTrafficOffset hoTraffic Description: Value range: Object: Default value: Type: [disabled / enabled] bsc disabled DP, Optimization Nortel confidential Class 3 Whether handovers for traffic reasons at bsc level are allowed. V12 PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 315/629 V17.0 BSS Parameter User Guide (BPUG) Rec. value: Used in: Eng. Rules: enabled (only if “hot spot”cells linked to the BSC) Handover for traffic reasons (from V12) See parameter hoMarginTrafficOffset incomingHandOver Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Whether incoming handovers are allowed in a cell. [disabled / enabled] handOverControl enabled DP enabled Class 3 V7 msTxPwrMax Description: Value range: Class 3 Maximum MS transmission power in a serving cell. It is equal to msTxPwrMaxCCH in a GSM 900 network. V7 [5 to 43, by steps of 2] dBm (GSM 900, GSM850, GSM-R, GSM850GSM1900 and GSM 900 - GSM 1800 networks) [0 to 36, by steps of 2] dBm (GSM 1800, and GSM 1800 - GSM 900 networks) [0 to 33] dBm (GSM 1900 network) [0 to 33] dBm (E-GSM network and 1900-850 network) [0 to 33] dBm (GSM850 network) bts Typical value of 33 dBm for GSM 900 handhelds and 30 dBm for GSM 1800 and 1900 handhelds DP, Optimization 33 dBm for GSM 900 in urban environment 39 dBm for GSM 900 in rural environment handhelds 30 dBm for GSM 1800 and 1900 handhelds 33 dBm for GSM 850s Object: Default value: Type: Rec. value: Used in: Accuracy related to measurements General formulas Forced Handover One shot power control Power control on mobile side We must have msTxPwrMax = msTxPwrMaxCCH for GSM 900 Networks and msTxPwrMaxCCH ≤ msTxPwrMax for GSM 1800 and 1900 Networks (check done at OMC-R). This parameter is adapted to mobile classes taken into account in Network Design. Eng. Rules: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 316/629 V17.0 BSS Parameter User Guide (BPUG) msTxPwrMaxCell Description: Class 3 V7 Maximum MS transmission power in a neighbor cell. It is equal to msTxPwrMaxCCH when the cell is declared as a serving cell on the network (the value must be checked by users). [5 to 43, by steps of 2] dBm (GSM 900, GSM850, GSM-R and GSM 900 - GSM 1800 networks) [0 to 36, by steps of 2] dBm (GSM 1800 network and GSM 1800 - GSM 900) [0 to 33] dBm (GSM 1900 network) [0 to 33] dBm (E-GSM network) [0 to 33] dBm (GSM 1900-850 network) adjacentCellHandOver Typical value of 33 dBm for GSM 900/850 handhelds and 30 dBm for GSM 1800 and 1900 handhelds DP, Optimization msTxPwrMaxCell = msTxPwrMaxCCCH of the current cell General formulas Handovers screening Directed Retry Handover: BTS (or distant) mode Forced Handover Define eligible neighbor cells for intercell handover (except directed retry) One shot power control Power control on mobile side If this value is higher than the actual MS classmark, then MS will apply its own capability. If the cell is used as a neighbor cell of another serving cell in the network, msTxPwrMaxCell should be identical to the msTxPwrMaxCCH power defined for the corresponding adjacentCellHandOver object (the values must be checked by users). Value range: Object: Default value: Type: Rec. value: Used in: See Paragraph 2.5.1 and Paragraph 2.7. Eng. Rules: Remark: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 317/629 V17.0 BSS Parameter User Guide (BPUG) offsetLoad Description: Value range: Object: Default value: Type: Rec. value: Class 3 Load offset applied by the bsc in the cell selection process of the Handover algorithm. [0 to 63] dB adjacentCellHandOver 0 dB DP, Optimization 3 dB V12 offsetLoad ≥ hoMarginTrafficOffset (Handovers for traffic reason feature activated) Used in: Eng. Rules: Handover decision according to adjacent cell priorities and load (from V12) When set to “0”, no offset is effective. This parameter is set to “0” for the cells that do not belong to the related bsc object. This parameter allows to put a disadvantage to overloaded eligible cells for HO (for cells with the same offsetPriority). In order to take into account this parameter, the overload detection must be activated ; so either hoTraffic shall be “enabled” (bsc and bts objects) or btsMSAccessClassBarringFunction shall be “enabled” (with also bscMSAccessClassBarringFunction). A bad offset load parameter tuning can induce a risk of ping-pong HO or longer handover procedures; so, it is advised to set the “General protection against HO ping-pong” feature with HOPingpongCombination including (traffic, all PBGT). See also chapter Handover for Traffic Reasons Activation Guideline. offsetPriority Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 3 V12 Priority offset applied by the bsc to the cell selection process in the Handover algorithm [1 to 5] adjacentCellHandOver 1 DP, Optimization 1 Handover decision according to adjacent cell priorities and load (from V12) “1” is the highest priority. This parameter allows to classify eligible cells according to its value; so, it is used to optimize the traffic distribution between layers. See also chapter DualBand Networks. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 318/629 V17.0 BSS Parameter User Guide (BPUG) powerBudgetInterCell Description: Value range: Object: Default value: Type: Rec. value: Used in: [enabled / disabled] handOverControl enabled DP, Optimization enabled Handovers screening Power budget formula Handover for traffic reasons (from V12) Class 3 V7 Authorization to perform intercell handovers for power budget Eng. Rules: Handover on PBGT should be enabled, because for an optimized network it ensures the best quality of service. runHandOver Description: Value range: Object: Default value: Type: Rec. value: Used in: Class 3 V7 Number of Measurement Results messages that must be received before the handover algorithm in a cell is triggered [1 to 31] SACCH frames (1 unit = 480 ms on TCHs, 470 ms on SDCCHs) bts 1 DP, System 1 Handovers Microcellular Algo type A Protection against RunHandover=1 Should be run as often as possible, main impact is upon BSS load. The V11 feature protection against runHandover=1 allows some protections in order to avoid that the setting of this parameter to 1 leads some overload problems (SICD overload).. Therefore, runHandOver may be set to 1 in some environments where the reactivity is crucial (microcell, high-speed environment). So from V11, it is recommended to set this parameter to 1. However, this parameter setting must be done in accordance with the value of handover thresholds, margins and timers. See also chapter Impact of the Averaging on the Handovers and chapter Street Corner Environment Eng. Rules: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 319/629 V17.0 BSS Parameter User Guide (BPUG) rxLevMinCell Description: Value range: Object: Default value: Type: Rec. value: Class 3 Minimum signal strength level received by MS for being granted access to a neighbor cell [less than -110, -110 to -109, ... , -49 to -48, more than -48] dBm adjacentCellHandOver V7 - 95 to -94 dBm (GSM 900 & 850), - 93 to - 92 (GSM 1800 & 1900) DP, Optimization - 95 to - 94 dBm (GSM 900 & 850) - 93 to - 92 dBm (GSM 1800& 1900) in urban environment RxLevMinCell = lRxLevDLH if HOmargin ≥ 0 in rural environment Used in: General formulas Handovers screening Define eligible neighbor cells for intercell handover (except directed retry) A method to estimate this value is to use MS sensitivity (-104 dBm in GSM 900 for handheld, and -102 dBm in GSM 1800/1900 for handheld, otherwise -104 dBm) and applying a margin to it. However, if most of communications are handled in an indoor environment, or overlap between cell coverage is not sufficient, these recommended values can be decreased. For a dual Band Network where one frequency band is privileged, it is advised to set this parameter to a lower value in neighbour cells belonging to the priority frequency band. Thus, this band will be preferred. However, it may be greater than the value rxLevAccessMin. Thus the recommended value is -99 to -98 dBm (GSM900) or -97 to 96 dBm (GSM1800) for neighbour cells belonging to the priority frequency band. Studies have shown that the subjective quality depends on the way erroneous bits are spread into each frame. Experiments have shown that with frequency hopping in TU3 (Typical urban at 3 Km/h) up to Rxqual = 5 the subjective quality seems to be good, on the other hand without frequency hopping Rxqual = 4 seems to be the maximum value for which subjective quality is good. The table below gives examples of the margins that could be taken into account for an infinite C/I and for different mobile speeds. t 50 km/h margin with FH margin without FH u 50 km/h - t 80 km/h u 80 km/h Eng. Rules: 2 dB 5 dB 2 dB 4 dB - 2 dB 2 dB 2 dB And that other table below shows the different margins that could be taken into account in a slow mobile area depending of the C/I. C/I = 35 margin with FH margin without FH C/I = 20 C/I = 15 2 dB 5 dB 3 dB 6 dB 4 dB 10 dB See also chapter Directed Retry Handover Benefit and chapter DualBand Networks. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 320/629 V17.0 BSS Parameter User Guide (BPUG) synchronized Description: Value range: Class 3 Whether the neighbor cell and the associated serving cell are synchronous, that is attached to the same BTS [not synchronized cells / synchronized cells / pre sync HO with timing advance / pre sync HO, default timing advance] “not synchronized cells”: the neighbor cell and the serving cell are not attached to the same BTS. “synchronized cells”: the neighbor cell and the serving cell are attached to the same BTS “pre sync HO with timing advance”: the handover procedure between the neighbor cell and the serving cell is pre–synchronized with the real Time Advance. “pre sync HO, default timing advance”: a pre–defined timing advance is used in the pre–synchronized handover procedure between the serving cell and the neighbor cell. Refer to preSynchroTimingAdvance parameter. adjacentCellHandOver not synchronized cells DP, Optimization See Eng. Rules Pre-synchronized HO Handover Algorithms on the Mobile Side It is recommended to use pre-synchronized HO in microcellular environment because in small cells the timing advance when handovers are triggered is generally a low value (less than 3). It is also interesting to use this feature for determined path such as railways, highways, and tunnels where handovers between two cells happen always at the same place. See also chapter Synchronized HO versus Not Synchronized HO V7 Object: Default value: Type: Rec. value: Used in: Eng. Rules: timeBetweenHOConfiguration Description: Class 3 V9 Whether the HOPingpongTimeRejection timer can be used in a BSS when processing handovers. Refer to bts object bts time between HO configuration and adjacentCellHandOver object HOPingpongTimeRejection attributes in this Dictionary of Parameters. [used / not used] bsc used DP, Design used Power Budget Handover General protection against HO ping-pong (from V12) see Engineering Rules for the parameter bts time Between HO Configuration. See also chapter Minimum Time Between Handover and chapter Directed Retry Handover Benefit. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 321/629 V17.0 BSS Parameter User Guide (BPUG) 5.12. INTRACELL HANDOVER PARAMETERS intraCell Description: Value range: Class 3 Whether intra–bts handovers on TCH are allowed in a cell for interference reasons or Cell Tiering reasons [cellTieringHandover / intraCellHandover / handoverNotAllowed] cellTieringHandover: the intraBTS handovers are allowed for CellTiering reason intraCellHandover: the intraBTS handovers are allowed for interference reason handoverNotAllowed: the intra bts handovers are not allowed handOverControl handoverNotAllowed DP, Design cellTieringHandover Intracell Handover decision for signal quality For mono-TRX cell, do not enable intracell handover (handoverNotAllowed). As the MS power is not checked before performing an intracell handover, it is not advised to enable this feature as intraCellHandover. It would lead to a high ratio of intracell handover. In V7, the resource allocator does not classify free TCH resources according to their interference level. From V8, the channel is selected from the best not empty pool. To enable “tiering”, the cell tiering conditions shall be fulfilled and the cell tiering advantages shall be estimated as well (see chapter Automatic cell tiering (from V12) and hoMarginTiering parameter). V7 Object: Default value: Type: Rec. value: Used in: Eng. Rules: intraCellSDCCH Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 3 V8 Whether intraBTS handovers on SDCCH are authorized in a cell for interference reasons [enabled / disabled] handOverControl disabled DP, Optimization disabled Intracell Handover decision for signal quality None except system ability. Note that, some mobiles have been reported to drop the call when that feature is performed. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 322/629 V17.0 BSS Parameter User Guide (BPUG) rxLevDLIH Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: CAUTION! Class 3 V7 Maximum interference level in BTS–to–MS direction, beyond which an intraCell handover may be triggered [less than -110, -110 to -109,..., -49 to -48, more than -48] dBm handOverControl -85 to -84 dBm DP, Optimization -85 to -84 dBm Intracell Handover decision for signal quality Path balance must be looked for this threshold parameter setting. rxLevULIH Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: CAUTION! Class 3 V7 Maximum interference level in MS–to–BTS direction, beyond which an intra cell handover may be triggered [less than -110, -110 to -109, ... , -49 to -48, more than -48] dBm. handOverControl -85 to -84 dBm DP, Optimization -85 to -84 dBm Intracell Handover decision for signal quality Path balance must be looked for this threshold parameter setting. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 323/629 V17.0 BSS Parameter User Guide (BPUG) rxQualDLIH Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 3 V12 Bit error rate threshold in BTS-to-MS direction for intracell handover, above which a handover may be triggered. [less than 0.2, 0.2 to 0.4, 0.4 to 0.8, ... , 6.4 to 12.8, more than 12.8] % handOverControl 1.6 to 3.2 % DP, Optimization rxQualDLIH ≤ lRxQualDLH Intracell Handover decision for signal quality From V12, intracell HO for signal quality uses a different threshold than the intercell one and intracell HO can only use either hopping channels having low interference or non hopping channels having low interference. This should improve the voice quality and the performance. The possible drawback could be to increase queuing at BSC level for networks experiencing interferences. To favor intracell HO for quality (compared to intercell HO for quality), the following rule shall be satisfied: rxQualDLIH < lRxQualDLH. From V12, the intracell HO has a lower priority than the intercell HO for quality. rxQualULIH Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 3 V12 Bit error rate threshold in MS-to-BTS direction for intracell handover, above which a handover may be triggered. [less than 0.2, 0.2 to 0.4, 0.4 to 0.8, ... , 6.4 to 12.8, more than 12.8] % handOverControl 1.6 to 3.2 % DP, Optimization rxQualULIH ≤ lRxQualULH Intracell Handover decision for signal quality From V12, intracell HO for signal quality uses a differentthreshold than the intercell one and intracell HO can only use either hopping channels having low interference or non hopping channels having low interference. This should improve the voice quality and the performance. The possible drawback could be to increase queuing at BSC level for networks experiencing interferences. To favor intracell HO for quality (compared to intercell HO for quality), the following rule shall be satisfied: rxQualULIH < lRxQualULH. From V12, the intracell HO has a lower priority than the intercell HO for quality. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 324/629 V17.0 BSS Parameter User Guide (BPUG) 5.13. INTERCELL HANDOVER THRESHOLD PARAMETERS lRxLevDLH Description: Value range: Object: Default value: Type: Rec. value: Used in: Class 3 Signal strength threshold in BTS–to–MS direction, below which a handover may be triggered [less than -110, -110 to -109, ... , -49 to -48, more than -48] dBm handOverControl -101 to -100 dBm (GSM 900) / -99 to -98 dBm (GSM1800/1900) DP, Optimization -95 to -94 dBm in urban environment (900 MHz or 850 MHz) -101 to -100 dBm in rural environment (900 MHz or 850 MHz) Handover condition for leaving a cell on rxlev Define eligible neighbor cells for intercell handover (except directed retry) This threshold must be set from the MS sensitivity. A margin must be taken to consider shadowing, fast fading and MS measurement accuracy. At least, a 3 dB margin can be taken into account in a rural environment and a 10 dB margin in an urban environment. where the cell is declared as a neighbor, we should have: lRxLevDLH < rxlevMinCell, and path balance must be considered for this threshold parameter setting. See also chapter lRxlevDLH and lRxlevULH Definition. V7 Eng. Rules: CAUTION! lRxLevULH Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 3 Signal strength threshold in MS–to–BTS direction, below which a handover may be triggered [less than -110, -110 to -109, ... , -49 to -48, more than -48] dBm handOverControl -101 to -100 dBm (GSM 900) / -99 to -98 dBm (GSM 1800/1900) DP, Optimization -95 to -94 dBm in urban environment (900 MHz or 850 MHz) -101 to -100 dBm in rural environment (900 MHz or 850 MHz) Handover condition for leaving a cell on rxlev V7 The recommended values given above correspond to the worst case BTS (e-cell). An e-cell has -104 dBm Rx sensitivity in all frequency bands and diversity is not applicable, thus leading to "-95 to -94" for urban environments and "-101 to -100" for rural environments when applying a 3dB margin in a rural environment and a 10 dB margin in an urban environment. In fact, these thresholds depend on BTS sensitivity. Values should be increased if one of the following points is verified: the thresholds on quality are permissive run-handover 3 scarce mobile speed is high initial tuning causes frequent level strength handover failure rate Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 325/629 V17.0 BSS Parameter User Guide (BPUG) At least, a 3 dB margin can be taken into account in a rural environment and a 10 dB margin in an urban environment. CAUTION! where the cell is declared as a neighbor, we should have: lRxLevULH < rxLevMinCell, and path balance must be considered for this threshold parameter setting. See also chapter lRxlevDLH and lRxlevULH Definition. lRxQualDLH Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 3 V7 Bit error rate threshold in BTS–to–MS direction, above which an inter cell handover may be triggered [less than 0.2, 0.2 to 0.4, 0.4 to 0.8, ... , 6.4 to 12.8, more than 12.8] % handOverControl 1.6 to 3.2 % DP, Optimization 1.6 to 3.2 % (4 in rxqual GSM unit) without frequency hopping. See Engineering Rules in case of frequency hopping. Handover condition for leaving a cell on rxqual According to some experiments and studies, 4 in GSM unit is the upper limit for TU3 no hopping, while 5 in GSM unit for TU3 hopping. Suggested values become 4 in GSM unit (no frequency hopping or MS speed > 80km/h) and 5 in GSM unit (frequency hopping and low urban speed). High BER rate for threshold is dangerous (risk of handover failure). On the contrary, if a tight rxqual threshold is linked with a short averaging period, the risk is that a single bad quality report will affect the whole result (ie: if 8 samples without weighting and a threshold of 2 in GSM unit: if 7 of these samples are 2 in GSM unit and 1 of them is 5 in GSM unit, handover decision will be taken on a wrong basis). Experience shows whatever the MS speed, rxQual = 6 does not provide a comfortable voice quality. The average in the above is equal to: (7 * 0.57 + 4.53) B 8 = 1.065 greater than 0.57 (2 in GSM unit). In case of using synthesized frequency hopping, this threshold has to be increased in order to limit the increase of the number of handover on quality criteria. In a 1X1 pattern, it is advised to set this value to 5 or 6 (3.2 to 6.4 % or 6.4 to 12.8 %). In case of a 1X3 pattern, the recommended value is 4 or 5 (1.6 to 3.2 % or 3.2 to 6.4 %). DTX is often used with Frequency Hopping. There are less measurement reports with DTX, and thus the RxQual_average may be less reliable. But no degradation was observed when using both features therefore there is no need to disable handovers on quality criteria in this case. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 326/629 V17.0 BSS Parameter User Guide (BPUG) lRxQualULH Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 3 V7 Bit error rate threshold in MS–to–BTS direction, above which an inter cell handover may be triggered [less than 0.2, 0.2 to 0.4, 0.4 to 0.8, ... , 6.4 to 12.8, more than 12.8] % handOverControl 1.6 to 3.2 % DP, Optimization 1.6 to 3.2 % (4 rxqual GSM unit) without frequency hopping. See Engineering Rules in case of frequency hopping. Handover condition for leaving a cell on rxqual According to some experiments and studies, 4 in GSM unit is the upper limit for TU3 no hopping while 5 in GSM unit for TU3 hopping. Suggested value becomes 4 in GSM unit (no frequency hopping or MS speed > 80km/h) and 5 in GSM unit (frequency hopping and low urban speed). High BER rate for threshold is dangerous (risk of handover failure). On the contrary, if a tight rxqual threshold is linked with a short averaging period, the risk is that a single bad quality report will affect the whole result (ie: if 8 samples without weighting and a threshold of 2: if 7 of these samples are 2 and 1 of them is 5, handover decision will be taken on the wrong basis). In case of using synthesized frequency hopping, this threshold has to be increased in order to limit the increase of the number of handover on quality criteria. In a 1X1 pattern, it is advised to set this value to 5 or 6 (3.2 to 6.4 % or 6.4 to 12.8 %). In case of a 1X3 pattern, the recommended value is 4 or 5 (1.6 to 3.2 % or 3.2 to 6.4 %). DTX is often used with Frequency Hopping. There are less measurement reports with DTX, and thus the RxQual_average may be less reliable. But no degradation was observed when using both features therefore there is no need to disable handovers on quality criteria in this case. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 327/629 V17.0 BSS Parameter User Guide (BPUG) rxLevDLPBGT Description: Class 3 V11 Downlink signal strength threshold above which handovers for power budget are inhibited In certain issues, the operator may want to prevent handover for power budget in case of the received level in the serving cell is good enough so that a handover would not improve the situation. This parameter shall be set such as rxLevDLPBGT > lRxLevDLH. [less than -110, -110 to -109,..., -49 to -48, more than -48] dBm adjacentCellHandOver more than -48 DP, Optimization TBD Handovers screening Maximum RxLev for Power Budget rxLevDLPBGT > lRxLevDLH This parameter has to be managed carefully because it can prevent all the handover for power budget when set to less than -110. Moreover, the setting of this parameter has to be done with the help of some radio measurement campaigns. This parameter shall be disabled by setting the value to more than – 48 (dBm). This parameter is only available for DCU4 or DRX transceiver architecture. It shall be disabled for DCU2 architecture. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Remark: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 328/629 V17.0 BSS Parameter User Guide (BPUG) 5.14. HANDOVER FOR MICROCELLULAR NETWORK PARAMETERS cellType Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Type of the adjacent cell [normalType / umbrellaType / microType] adjacentCellHandOver normalType DP, Design normalType Microcellular Algo type A To run a capture handover (umbrella to micro) on a neighbor, which must be microType, the bts must be declared as umbrellaType. It is possible to manage a three layer network by declaring cell A and cell B as umbrellaType, neighbor B and neighbor C as microType for cell A, neighbor A as umbrellaType and neighbor C as microType for cell B, and finally neighbor B as umbrellaType for cell C. See also chapter Minimum Time Between Handover Class 3 V7 cellType Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Type of the serving cell [normalType / umbrellaType / microType] bts normalType DP, Design normalType Microcellular Algo type A Class 3 V7 To run a capture handover (umbrella to micro) on a neighbor, which must be microType, the bts must be declared as an umbrellaType. It is possible to manage a three layer network by declaring cell A and cell B as umbrellaType, neighbor B and neighbor C as microType for cell A, neighbor A as umbrellaType and neighbor C as microType for cell B, and finally neighbor B as umbrellaType for cell C. The adjacent cell umbrella Ref attribute is defined at the OMC-R if the cell is a microcell (cellType) and directed retry handovers are processed in BSC mode (directed-RetryModeUsed). Remark: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 329/629 V17.0 BSS Parameter User Guide (BPUG) microCellCaptureTimer Description: Value range: Class 3 V8 Time used to confirm a capture (signal strength stability) when using microcell Algorithm type A Time = N multiplied by runHandOver. According to microCellCaptureTimer value, N values are the following: [0 to 249] 250 251 252 253 254 255 N = [0 to 249] N = 512 N = 1024 N = 2048 N = 4096 N = 8192 N = 16384 Object: Default value: Type: Rec. value: Used in: Eng. Rules: adjacentCellHandOver 0 DP, Design 8s, whatever runHandOver value (e.g. if runHandOver = 2 Microcellular Algo type A Experiments done in urban areas show that a timer of 8 seconds to 10 seconds allows a better use of the capture. See also chapter Impact of the Averaging on the Handovers. N = 8, if runHandOver = 1 N = 16) microCellStability Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: [0 to 255] dB adjacentCellHandOver 10 dB DP, Design 63 dB Microcellular Algo type A Class 3 Strength Level Stability Criterion for Capture Algorithm A V8 To allow handovers on capture this parameter has to be set at a value greater than 0. A value of microCellStability equal to 63 dB has to be set first, because with such a value, the stability constraints are always verified. The value of this parameter can then be decreased case by case. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 330/629 V17.0 BSS Parameter User Guide (BPUG) 5.15. DISTANCE MANAGEMENT PARAMETERS callClearing Description: Class 3 Maximum distance between MS and BTS before call is cleared It is greater than msRangeMax. This distance defines the cell maximum coverage area. [2 to 35] km (non-extended mode) [2 to 120] km (extended mode) bts 35 in non-extended mode, 90 in extended mode DP, Product Depends on the environment, typical value = (1.5 * cell diameter) + 2 km or best cell distance coverage server Generaly for non-extended mode: 7 km for urban, 35 km for rural Used in: Eng. Rules: Call Clearing Process (run by BTS) (Cc) The value should be related to the current cell coverage. A margin is taken by using the 1.5 coefficient. A 2km margin is also considered to compensate lack of mobile timing advance accuracy. If the observation counter shows a high number of call clearings, it may mean that handover parameters on that cell are too permissive or badly tuned. At the OMC-R, a control exists: callClearing > msRangeMax Class 2 V9 V7 Value range: Object: Default value: Type: Rec. value: extended cell Description: Whether the cell is extended (up to 120 km large) or not The cell working mode governs the upper limit of the following attribute values (refer to theses entries in the Dictionary): callClearing, msRangeMax, and rndAccTimAdvThreshold attributes of the bts object concentAlgoExtMsRange and concentAlgoIntMsRange attributes of the associated handOverControl object if the bts object describes a concentric cell Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: [true (extended) / false (normal)] bts false DP, Optimization see Engineering Rules Extended cells will be used to reach mobiles that are far from the BTS (in the case of sea shores and pleasure boats, for example). In an extended cell, two consecutive time slots are reserved for each channel. The capacity is then decreased. Up to V10, an extended cell cannot be concentric. Whatever the MSBTS distance is, two consecutive time slots are reserved on Air interface. See also chapter SDCCH Dimensioning an TDMA Models. GPRS/EDGE is not supported when extended cell feature is activated. Nortel confidential CAUTION! CAUTION! PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 331/629 V17.0 BSS Parameter User Guide (BPUG) msRangeMax Description: Class 3 V7 Maximum MS–to–BTS distance beyond, which a handover may be triggered. It can be set to 1 for a microcell and is less than callClearing in all cases. [1 to 34] km (non-extended mode) [1 to 120] km (extended mode) handOverControl 34 in non-extended mode, 89 in extended mode DP, Optimization = callClearing - 1 km Handover condition for leaving a cell on distance If the associated serving cell is a concentric cell, the following inequality, that is not checked by the system, must be true (refer to this entry in the Dictionary): concentAlgoExtMsRange ≤ concentAlgoIntMsRange ≤ msRangeMax Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: CAUTION! callClearing > msRangeMax is controled at the OMC level. It must be adapted to current cell extent in order to be an efficient preventive handover. If value is too small, there is a big risk of ping-pong handover. Due to lack of mobile timing advance accuracy this parameter must not be set at a too low value (not < 2). Generaly for non-extended mode (6 km for urban and 34 km for rural) CAUTION! msBtsDistanceInterCell Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 3 V7 Whether inter–bts handovers are allowed in a cell for distance reasons [enabled / disabled] handOverControl enabled DP, Optimization enabled Handovers screening Handover condition for leaving a cell on distance Due to the imprecision of some MS on Timing Advance (see chapter Distance - timing advance conversion) and due to the delay spread in a very urban environment, it is possible to set this parameter to “disabled” (in an urban environment). However, for all cells with a radius of more than 1 km, handover on distance must be authorized. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 332/629 V17.0 BSS Parameter User Guide (BPUG) preSynchroTimingAdvance Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 3 V10 Pre-defined timing advance used in a pre-synchronized handover procedure between the serving cell and this neighbor cell. [1 to 35] (km) adjacentCellHandOver Refer to parameter synchronized DP, Design see Engineering Rules Pre-synchronized HO This value of timing advance is used when the parameter synchronized is set to “pre sync HO with timing advance”. A predefined timing advance can be defined when phase 2 MSs always handove from the serving cell to this neighbor cell approximately at the same place (railway, highway). If the parameter synchronized is set to “presyncho HO, default timing advance”, the default TA value is “-1” (554 m). If the parameter synchronized is set to “presyncho HO, with timing advance”, the parameter preSynchroTimingAdvance must be tuned to the estimated value of TA. See also chapter Synchronized HO versus Not Synchronized HO. preSynchroTimingAdvance value is not controlled at the OMC-R CAUTION! rndAccTimAdvThreshold Description: Class 3 V8 MS–to–BTS distance beyond which mobile access requests to a cell are refused. It defines the maximum timing advance value accepted. The effective timing advance value is broadcast in the CHANNEL REQUIRED message sent by the BTS to the BSC. If it is above the user defined threshold, the BSC ignores the request. [2 to 35] km (non-extended mode) [2 to 120] km (extended mode) bts 35 (non-extended cell), 90 (extended cell) DP, Optimization msRangeMax (= call clearing - 1km = 1.5* cell diameter + 2 km -1 km) Generally for non-extended mode: 6 km for urban, 35 km for rural Request access command process (RA) The maximum authorized value will inhibit the feature. By adjusting the value to the size of the cell (see recommended value), parasite RACH (noise which is decoded by the system like a RACH) are filtered. This avoids the unnecessary assigment of SDCCH. For example, for small cells, if the value is 35 km, almost 30% of the RACHs are parasite. If the value is modified to 2, almost no parasites RACH are detected. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 333/629 V17.0 BSS Parameter User Guide (BPUG) runCallClear Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 3 V7 Number of “Measurement Results” messages that must be received before the call clearing algorithm in a cell is triggered [1 to 31] SACCH frames (1 unit = 480 ms on TCHs, 470 ms on SDCCHs) bts 16 DP, System 16 Call Clearing Process (run by BTS) (Cc) It is not necessary to run Cc too often, since those calls are going to be ended anyway. Nevertheless, traffic out of a cell’s range interferes on other cells or timeslots. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 334/629 V17.0 BSS Parameter User Guide (BPUG) 5.16. POWER CONTROL PARAMETERS bsMsmtProcessingMode Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 2 V7 Whether radio measurements collected by the mobiles for a cell are processed by the BTS or the BSC [preProcessedMeasurementReporting (BTS) / basicMeasurementReporting (BSC)] bts preProcessedMeasurementReporting DP, Product preProcessedMeasurementReporting Measurement Processing Since radio measurements are always preprocessed by the BTS, changing this attribute has no meaning. bsPowerControl Description: Value range: Object: Default value: Type: Rec. value: Used in: [enabled / disabled] powerControl disabled DP, Optimization enabled Step by step Power control One shot power control Fast power control at TCH assignment Power Control (AMR) Class 3 Whether BTS transmission power control is allowed at cell level V7 Eng. Rules: CAUTION! Not useful for mono-TRX cells, because BTS power control on BCCH frequency is not allowed. During a measurement field campaign, it can be normal to disable this feature in order to have the real signal strength and not the adjusted one. bsTxPwrMax Description: Class 3 V7 Maximum theoretical level of BTS transmission power in a cell The BSC relays the information to the mobiles in the Abis CELL MODIFY REQUEST message. [0 to 47] dBm powerControl 43 dBm DP, Optimization depends on the equipment General formulas Cabinet Output Power Setting Value range: Object: Default value: Type: Rec. value: Used in: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 335/629 V17.0 BSS Parameter User Guide (BPUG) Eng. Rules: This power is used to calculate the cabinet output power. From V9, it depends on the attribute “attenuation” of btsSiteManager objects (see chapter Pr computation), because the value of the parameter “attenuation” is then taken into account as DLU attenuation. For a GSM 1900 network (standardIndicator of bts object set to ‘pcs1900’), the MD-R checks the following: bsTxPwrMax < 32 (dBm) when an edge frequency is defined for the cell (i.e. if the value is included in the cellAllocation attribute values). Some bsTxPwrMax values are not compatible with the effective power output by the BTS (see chapter Pr computation). Remark: lRxLevDLP Description: Value range: Object: Default value: Type: Rec. value: Used in: Class 3 V7 Signal strength threshold in BTS–to–MS direction, below which the power control function increases power. It is lower than uRxLevDLP. [less than -110, -110 to -109, ... , -49 to -48, more than -48] dBm powerControl -95 to -94 dBm DP, Optimization -95 to -94 dBm (step by step) -85 to -84 dBm (one shot) Step by step Power control One shot power control Fast power control at TCH assignment Power Control (AMR) The difference between lower and upper thresholds must be greater or equal to max (powerIncrStrepSize, powerRedStepSize), because it is controled at the OMC level. lRxLevDLP > lRxLevDLH, up to V7, because power Control and handover algorithms are decorrelated. In case the AMR power control algorithm is activated ( refer to the amrReserved2 parameter) that parameter defines the threshold below which the AMR power control is inhibited. In that case the recommended values remain the same if the AMR penetration is low, and the same + 2dB if the AMR penetration is high. Eng. Rules: CAUTION! lRxLevULP Description: Value range: Object: Default value: Type: Rec. value: Used in: Class 3 V7 Signal strength threshold in MS–to–BTS direction, below which the power control function increases power. It is lower than uRxLevULP. [less than -110, -110 to -109, ... , -49 to -48, more than -48] dBm powerControl -95 to -94 dBm DP, Optimization -95 to -94 dBm (step by step) -85 to -84 dBm (one shot) Step by step Power control One shot power control Fast power control at TCH assignment Power Control (AMR) Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 336/629 V17.0 BSS Parameter User Guide (BPUG) Eng. Rules: CAUTION! lRxLevULP > lRxLevULH, up to V7, because power Control and handover algorithms are decorrelated. In case the AMR power control algorithm is activated ( see amrReserved2 parameter) that parameter defines the threshold below which the AMR power control is inhibited. In that case the recommended values remain the same if the AMR penetration is low, and the same + 2dB if the AMR penetration is high. lRxQualDLP Description: Class 3 V7 Bit error rate threshold in BTS–to–MS direction, above which the power control function increases power. It is greater than or equal to uRxQualDLP. [less than 0.2, 0.2 to 0.4, 0.4 to 0.8, ... , 6.4 to 12.8, more than 12.8] % powerControl 0.4 to 0.8 DP, Optimization 0.8 to 1.6 % (RxQual = 3 in GSM unit) without SFH 3.2 to 6.4 % (RxQual = 5 in GSM unit) with SFH Step by step Power control One shot power control Fast power control at TCH assignment Power Control (AMR) This value must be lower than lRxQualDLH in order to maintain priority between power control and handover. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: lRxQualULP Description: Class 3 V7 Bit error rate threshold in MS–to–BTS direction, above which the power control function increases power. It is greater than or equal to uRxQualULP. [less than 0.2, 0.2 to 0.4, 0.4 to 0.8, ... , 6.4 to 12.8, more than 12.8] % powerControl 0.4 to 0.8 DP, Optimization 0.8 to 1.6 % (RxQual = 3 in GSM unit) without SFH 1.6 to 3.2 % (RxQual = 4 in GSM unit) with SFH Step by step Power control One shot power control Fast power control at TCH assignment Power Control (AMR) This value must be lower than lRxQualULH in order to maintain priority between power control and handover. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 337/629 V17.0 BSS Parameter User Guide (BPUG) msTxPwrMax2ndBand Description: Value range: Class 3 V12 Maximum MS transmission power in the band 1 of the dualband cell depending on the network type (BCCH is only defined in band 0) [0 to 36] for GSM 900 – GSM 1800 (gsmdcs), [5 to 43] for GSM 1800 – GSM 900 (dcsgsm) [0 to 33] for GSM 850 – GSM 1900 (gsm850pcs) [5 to 43] for GSM 1900 – GSM 850 (pcsgsm850) for all in the steps of 2 + value = 33 for GSM 850 – GSM 1900 0..43 for other standardIndicator types bts Typical value of 33 dBm for GSM 900 & 850 handhelds, 30 dBm for GSM 1800 and 1900 DP, Optimization 33 dBm for dcsgsm 30 dBm for gsmdcs & 850 Concentric/DualCoupling/DualBand Cell Handover This parameter is only used for power control. The attribute value is within the range [0 to 36] and even when the bts object standardIndicator attribute is “gsmdcs”. The attribute value is within the range [5 to 43] and odd when the bts object standardIndicator attribute is “dcsgsm”. Object: Default value: Type: Rec. value: Used in: Eng. Rules: new power control algorithm Description: Class 3 V9 Algorithm used by the BTS to control power in a cell “step by step” value refers to the standard power control algorithm. “one shot” value refers to the advanced power control algorithm. “enhanced one shot “ value refers to the advanced power algorithm used in connection with the handOverControl object rxLevHreqaveBeg attribute used in the early handover mechanism. [step by step / one shot / enhanced one shot] bts one shot DP, Optimization one shot (if DCU2 boards) enhanced one shot (otherwise) Power Control Algorithms “Enhanced one shot” is not supported with DCU2 boards or with a mix of DCU2/DCU4 boards Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: CAUTION! Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 338/629 V17.0 BSS Parameter User Guide (BPUG) powerIncrStepSizeDL Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Increment step size for downlink power control. [2, 30] dB powerControl 4 dB DP, Optimization 4 dB Step by step Power control Class 3 V14 A high step is required to be reactive in increasing the power when entering an area where propagation is not acceptable. A higher step (6 dB) is recommended for specific networks or environment (high speed trains for example). The attribute powerIncrStepSizeDL must verify: lRxLevDLP + powerIncrStepSizeDL ≤ uRxLevDLP Not used in one shot power control nor in AMR power control. CAUTION! powerIncrStepSizeUL Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Increment step size for uplink power control. [2, 30] dB powerControl 4 dB DP, Optimization 4 dB Step by step Power control Class 3 V14 A high step is required to be reactive in increasing the power when entering an area where propagation is not acceptable. A higher step (6 dB) is recommended for specific networks or environment (high speed trains for example). The attribute powerIncrStepSizeUL must verify:lRxLevULP + powerIncrStepSizeUL ≤ uRxLevULP Not used in one shot power control nor in AMR power control. CAUTION! powerRedStepSizeDL Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Decrement step size for downlink power control. [2, 8] dB powerControl 2 dB DP, Optimization 2 dB Step by step Power control Class 3 V14 Small steps are enough to adapt two subsequent changes in quality and strength. Moreover, calls become sensitive to low MS or BS TxPower. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 339/629 V17.0 BSS Parameter User Guide (BPUG) The attribute powerIncrStepSizeDL must verify: uRxLevDLP – powerRedStepSizeDL ≥ lRxLevDLP CAUTION! Not used in one shot power control. powerRedStepSizeUL Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Decrement step size for uplink power control. [2, 30] dB powerControl 2 dB DP, Optimization 2 dB Step by step Power control Class 3 V14 Small steps are enough to adapt two subsequent changes in quality and strength. Moreover, calls become sensitive to low MS or BS txPower. The attribute powerRedStepSizeUL must verify: uRxLevULP – powerRedStepSizeUL ≥ lRxLevULP Not used in one shot power control. CAUTION! runPwrControl Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 3 V7 Number of Measurement Results messages that must be received before the power control algorithm in a cell is triggered. [1 to 31] frames (1 unit = 480 ms on TCH, 470 ms on SDCCH) bts 4 DP, System 2 Power Control Algorithms Power Control (AMR) The lowest is the parameter value, the best will be the reactivity; nevertheless, it is better to wait for the effect of MS power decrease on the uplink quality. uplinkPowerControl Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Nortel confidential Class 3 V8 Whether power control in the MS–to–BTS direction is authorized at cell level [enabled / disabled] powerControl enabled DP, Optimization enabled Power Control Algorithms Power Control (AMR) PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 340/629 V17.0 BSS Parameter User Guide (BPUG) uRxLevDLP Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: CAUTION! Class 3 Upper strength threshold for BTS txpwr decrease for step by step algorithm (it is greater than IRxLevDLP) [less than -110, -110 to -109, ... , -49 to -48, more than -48] dBm powerControl -85 to -84 dBm DP, Optimization = lRxLevDLP + Max (powerIncrStepSizeDL, powerRedStepSizeDL) typically Power Control Algorithms V7 Difference between the lower and upper thresholds must be greater or equal to the maximum power step size. Not used in one shot power control. uRxLevULP Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: CAUTION! Class 3 Upper strength threshold for MS txpwr decrease for step by step algorithm (it is greater than lRxLevULP). [less than -110, -110 to -109, ... , -49 to -48, more than -48] dBm powerControl -85 to -84 dBm DP, Optimization V7 lRxLevULP + Max (powerIncrStepSizeUL, powerRedStepSizeUL) typically Power Control Algorithms Difference between the lower and upper threshold, must be greater or equal to the maximum power step size. Not used in one shot power control. uRxQualDLP Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: CAUTION! Class 3 V7 Upper quality threshold to reduce BTS txpwr for step by step algorithm (it is lower than or equal to lRxQualDLP). [less than 0.2, 0.2 to 0.4, 0.4 to 0.8, ... , 6.4 to 12.8, more than 12.8] % powerControl 0.2 to 0.4 DP, Optimization 0.8 to 1.6 % (RxQual = 3 in GSM unit) without SFH 3.2 to 6.4 % (RxQual = 5 in GSM unit) with SFH Power Control Algorithms This value must be lower than lRxQualDLH in order to maintain priority between power control and handover. Not used in one shot power control. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 341/629 V17.0 BSS Parameter User Guide (BPUG) uRxQualULP Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 3 V7 Upper quality threshold to reduce MS txpwr for step by step algorithm (it is lower than or equal to lRxQualULP). [less than 0.2, 0.2 to 0.4, 0.4 to 0.8, ... , 6.4 to 12.8, more than 12.8] % powerControl 0.2 to 0.4 DP, Optimization 0.8 to 1.6 % (RxQual = 3 in GSM unit) without SFH 1.6 to 3.2 % (RxQual = 4 in GSM unit) wtih SFH Power Control Algorithms This value must be lower than lRxQualULH in order to maintain priority between power control and handover. There is no reason why this value should differ from uRxQualDLP. Not used in one shot power control. CAUTION! Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 342/629 V17.0 BSS Parameter User Guide (BPUG) 5.17. TCH ALLOCATION MANAGEMENT PARAMETERS accessClassCongestion Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 3 V9 List of access classes that are not authorized in a cell during TCH congestion phase (class 10 not included) [0 to 9] User classes [11 to 15] Operator classes bts [0,1,2,3,4,5,6,7,8,9] DP, Design see Engineering Rules Dynamic barring of access class (All_4) V15.0 Changes of dynamic barring of access class (All_4) Usually, in a low capacity cell (between 1 and 2 TRXs), many classes must be forbidden in case of congestion (few resources available). In a high capacity cell, only a few classes must be forbidden. allocPriorityTable Description: Class 3 V7 Table of eighteen elements that define the internal priorities for processing TCH queued allocation requests for each external priority defined (among them, fourteen are GSM priorities) TCH is always allocated using the internal priority. [0 to 12]. “0” defines the highest priority. bts 000000000000000000 DP, System 02222222222223042 0 8 9 10 11 12 2 2 2 2 2 2 2 2 3 0 4 2 for WPS use Allocation and priority (run by the BSC) (All_1) Queuing driven by the MSC (All_2) Queuing driven by the BSC (All_3) WPS – Queuing management The default set means that all TCH allocation requests have the same priority, which is equal to 0. When queuing is activated, set the following parameters in order not to disadvantage the interCell handover procedures: Priority for interCell handover: 0 Priority for other procedures: ≠ 0 allocPriorityThreshold > 0 Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: CAUTION! When WPS Queuing Management is activated, the WPS priorities (8 to 12) have to be set as recommended, otherwise WPS queues will be managed like internal public queues. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 343/629 V17.0 BSS Parameter User Guide (BPUG) allocPriorityThreshold Description: Class 3 V7 Number of free TCHs needed for processing a TCH allocation request with an internal priority higher than 1 These channels are reserved to allocation requests with a maximum internal priority (priority 0). The TCH allocation is performed according to this algorithm: Nb of free TCH = 0 TCH request of priority 0 TCH request of priority > 0 1 ≤ Nb of free TCH ≤ allocPriorityThreshold Nb of free TCH > allocPriorityThreshold queuing if defined or rejected queuing if defined or rejected TCH allocated queuing if defined or rejected TCH allocated TCH allocated For GPRS with shared PDTCH, the allocation is performed according to this algorithm: free resources are composed of free TCH and shared PDTCH not already used by a GSM call: Nb of free TCH = 0 1 ≤ Nb of free TCH ≤ allocPriorityThreshold Nb of free TCH > allocPriorityThreshold TCH allocated if TCH free > 0 if preemption is authorized and PCU ACK, allocation of a shared PDTCH if preemption is not authorized or PCU NACK, queuing if defined or rejected TCH allocated if TCH free > 0 if preemption is authorized and PCU ACK, allocation of a shared PDTCH if preemption is not authorized or PCU NACK, queuing if defined or rejected TCH allocated if TCH free > 0 if preemption is authorized and PCU ACK, allocation of a shared PDTCH if preemption is not authorized or PCU NACK, queuing if defined or rejected TCH request of priority 0 queuing if defined or rejected TCH request of priority > 0 queuing if defined or rejected queuing if defined or rejected Value range: Object: Default value: Type Rec. value: Used in: [0 to 2147483646] bts 0 DP, Design n, with n TRX Allocation and priority (run by the BSC) (All_1) Queuing driven by the MSC (All_2) Queuing driven by the BSC (All_3) Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 344/629 V17.0 BSS Parameter User Guide (BPUG) Eng. Rules: When TCH channels are reserved and the internal priority for assignRequest is ≠ 0, the capacity for incoming calls decreases: Example: 1 TRX, 7 TCH, 2 % blocking rate, allocPriorityThreshold = 0, capacity for incoming calls = 2,88 Erlang 1 TRX, 7 TCH, 2 % blocking rate, allocPriorityThreshold = 1, capacity for incoming calls = 2,23 Erlang Queuing spreads out the TCH allocation request. As incoming handover requests are not queued, such requests are disadvantaged. A solution is to reserve 1 TCH channel (for 1 or 2 TRXs) or 2 TCH channels (for at least 2 TRX) for calls of internal priority 0, and set the priority 0 for incoming handovers only. Note that when TCH channels are reserved for handovers, the capacity for incoming calls decreases. allocPriorityTimers Description: Value range: Object: Default value: Type: Rec. value: Used in: Class 3 V7 Table of timers defining the maximum waiting time of TCH allocations request (public and WPS request), according to the internal priority. [0 … 65535] for BSC3000 [0 … 2147483646] for BSC12000 bts 0 0 0 0 0 0 0 0 28 28 28 28 28 DP, System 5 0 5 5 0 0 0 0 28 28 28 28 28 Queuing driven by the MSC (All_2) Queuing driven by the BSC (All_3) WPS – Queuing management A high value of timer is not realistic, since a subscriber will not wait unless the last TCH is available quickly. The last five parameters in the table (those set to 28) define the waiting time of WPS calls queued. See also chapter Directed Retry Handover Benefit Eng. Rules: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 345/629 V17.0 BSS Parameter User Guide (BPUG) allocWaitThreshold Description: Class 3 V7 Table of thresholds defining the maximum number of TCH allocation requests queued (public and WPS), according to their internal priority. A TCH request of priority Pi, P0<Pi<P7, is queued if the total number of requests of priority Pj, with j<i, already in the queue does not exceed the waiting threshold of the queue “i” (element “i” of the allocWaitThreshold table). A WPS request priority is queued according to the rules of WPS queuing. [0 to 63] MMI Range bts 0000000055555 DP, System n 0 n n 0 0 0 0 5 5 5 5 5, with n = integer part of (number of SDCCH subchannels / 2) Queuing driven by the MSC (All_2) Queuing driven by the BSC (All_3) WPS – Queuing management The maximum size in each queue must be lower than the number of SDCCH channels in the cell. For an incoming call, when the assignRequest is queued, it remains on the SDCCH subchannel. The last five parameters in the table are determining the maximum number of WPS calls of the same priority that can be queued. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: allOtherCasesPriority Description: Class 3 V7 Index in the allocPriorityTable that defines the processing priority of TCH allocation requests with cause “other cases” This priority is used in primo–allocations or when an SDDCH cannot be allocated for overload reasons. [0 to 17] bts 17 DP, System 16 Allocation and priority (run by the BSC) (All_1) Queuing driven by the MSC (All_2) Queuing driven by the BSC (All_3) The associated internal priority is > 0. A TCH allocation request (in signaling mode) whose cause is “other case” is acknowledged when at least allocPriorityThreshold + 1 channels are free. Refer also to the allocPriorityTable parameter. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 346/629 V17.0 BSS Parameter User Guide (BPUG) answerPagingPriority Description: Class 3 V7 Index in the allocPriorityTable that defines the processing priority of TCH allocation requests with cause “reply to paging” This priority is used in signaling mode on TCH only. [0 to 17] bts 17 DP, System 16 Allocation and priority (run by the BSC) (All_1) Queuing driven by the MSC (All_2) Queuing driven by the BSC (All_3) The associated internal priority is > 0. A TCH allocation request (in signaling mode) whose cause is “other case” is acknowledged when at least allocPriorityThreshold + 1 channels are free. Refer also to the allocPriorityTable parameter. Value range: Object: Default value: Type: Rec. valueb Used in: Eng. Rules: assignRequestPriority Description: Class 3 V7 Index in the allocPriorityTable that defines the processing priority of TCH allocation requests with cause “immediate assignment” This priority is used when radio resource allocation queuing is not requested by the MSC or not authorized in the BSS (refer to the bscQueuingOption parameter). [0 to 17] bts 17 DP, System 17 Allocation and priority (run by the BSC) (All_1) Queuing driven by the MSC (All_2) Queuing driven by the BSC (All_3) When queuing driven by the MSC is used, this parameter is not significant. It is recommended not to associate an internal priority equal to 0. There is no queuing for TCH in “signaling mode”. Refer also to the allocPriorityTable parameter. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 347/629 V17.0 BSS Parameter User Guide (BPUG) bscMSAccessClassBarringFunction Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: [enabled / disabled] bsc disabled DP, Design enabled, see Engineering Rules Class 3 V9 Enable or disable dynamic barring of access class at the bsc level Dynamic barring of access class (All_4) V15.0 Changes of dynamic barring of access class (All_4) Set to disabled, this parameter allows to inhibit the dynamic barring of access class feature for the whole BSC whatever the values of the other parameters related to All_4 are. If queuing or directed retry is activated, the following parameters must be used: numberOfTCHQueuedBeforeCongestion numberOfTCHQueuedToEndCongestion bscQueuingOption Description: Class 1 V7 Whether radio resource allocation requests are queued in the BSC when no resources are available If no resource is available when an allocation request is received and queuing is not allowed, the allocation request is refused immediately. Value range: [allowed (MSC driven) / forced (O&M driven) / not allowed] allowed: resource allocation request queuing depends on the type of operation and indicative items provided with the messages received from the MSC. forced: resource allocation request queuing depends on the type of operation only. not allowed: resource allocation request queuing is forbidden. signallingPoint forced DP, Design forced (O&M driven) allowed (MSC driven) for WPS use Used in: Queuing driven by the MSC (All_2) Queuing driven by the BSC (All_3) WPS – Queuing management When queuing is activated, the queued procedures (assignRequest and intraCellHO if OMC driven) statistically take advantage on the other procedures. If all the TCH channels are already allocated, the queued procedures stay in the queue during a defined time (see allocPriorityTimers), when the others are rejected. Object: Default value: Type: Rec. value: Eng. Rules: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 348/629 V17.0 BSS Parameter User Guide (BPUG) Suppose the operator expects to enable the queuing later. Due to the class of the parameter bscQueuingOption, it is recommended not to set “not allowed”. Otherwise, the BSC will need to be switched off to implement the feature. See also chapter Directed Retry Handover Benefit CAUTION! WPS Queuing Management can be activated only if bscQueuingOption is set to “allowed”, i.e if MSC can handle different priorities of assignement request. btsMSAccessClassBarringFunction Description: Value range: Object Default value: Type: Rec. value: Used in: Eng. Rules: [enabled / disabled] bts disabled DP, Design See Engineering Rules Class 3 V9 Enable or disable dynamic barring of access class at the bts level Dynamic barring of access class (All_4) V15.0 Changes of dynamic barring of access class (All_4) To enable dynamic barring of access class at the bts level, this parameter and the bscMSAccessClassBarringFunction parameter of the corresponding bsc must be set to enabled. This feature globally reduces the cell capacity. The fewer the number of TRXs on the cell, the more the capacity is reduced. callReestablishmentPriority Description: Class 3 V7 Index in the allocPriorityTable that defines the processing priority of TCH allocation requests with cause “call reestablishment” This priority is used in primo–allocations or when an SDDCH cannot be allocated for overload reasons. [0 to 17] bts 17 DP, System 15 Allocation and priority (run by the BSC) (All_1) Queuing driven by the MSC (All_2) Queuing driven by the BSC (All_3) The value that must be given should correspond to a priority 0. Refer to the allocPriorityTable parameter. Value range: Objectb Default value: Type: Rec. value: Used in: Eng. Rules: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 349/629 V17.0 BSS Parameter User Guide (BPUG) cellBarQualify Description: Class 3 V8 Cell selection priority used in the C2 algorithm in Phase II The information is broadcast to the mobiles at regular intervals on the cell BCCH. [true (low priority) / false (normal priority)] bts False DP, Optimization False Selection or reselection between cells of current Location Area (Sel_1) Additional reselection criterion (for phase 2) (Sel_3) New SYS INFO messages refer to Sel_3 algorithm, see also chapter DualBand Networks. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: cellBarred Description: Class 3 V7 Whether direct cell access are barred to mobiles The information is broadcast to the mobiles at regular intervals on the cell BCCH.During a call, it is transmitted on a signaling link. If the attribute value is changed to “barred”, all in–progress calls can continue but the BSC will direct further mobile calls to another cell. [barred / not barred] bts not barred DP, Optimization not barred Selection or reselection between cells of current Location Area (Sel_1) Additional reselection criterion (for phase 2) (Sel_3) refer to Sel_3 algorithm, see also chapter DualBand Networks. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: channelType Description: Value range: Object: Default value: Type: Rec. value: Type of logical channel supported by a radio TS Class 2 [tCHFull / sDCCH / mainBCCH / mainBCCHCombined / bcchsdcch4CBCH / sdcch8CBCH / cCH (V12) / pDTCH (V12)] channel None DP, Optimization None. No recommended value is specified since this parameter depends on the strategy of the operator. V7 Used in: Eng. Rules: In the case of GSM, refer to chapter SDCCH Dimensioning an TDMA Models for the rules with SDCCH. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 350/629 V17.0 BSS Parameter User Guide (BPUG) emergencyCallPriority Description: Class 3 V7 Index in the table allocPriorityTable for a TCH allocation request whose cause is “emergency call” This priority is used in primo–allocations or when an SDDCH cannot be allocated for overload reasons. [0 to 17] bts 17 DP, System 15 Allocation and priority (run by the BSC) (All_1) Queuing driven by the MSC (All_2) Queuing driven by the BSC (All_3) The internal priority associated is 0. A TCH allocation request (in signaling mode) whose cause is “emergency call” is acknowledged when at least 1 channel is free. Refer also to the allocPriorityTable parameter. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: interCellHOExtPriority Description: Class 3 V7 Index in the allocPriorityTable that defines the processing priority of incoming inter–bss handovers in a cell This priority is used when radio resource allocation queuing is not requested by the MSC or not authorized in the BSS (refer to the bscQueuingOption parameter). [0 to 17] bts 17 DP, System 15 Allocation and priority (run by the BSC) (All_1) Queuing driven by the MSC (All_2) Queuing driven by the BSC (All_3) The internal priority associated is 0. A TCH allocation request (in signaling mode) on interBSC handover is aknowledged when at least 1 channel is free. When queuing is used, it is recommended to give the priority 0 and reserve the TCH channels (allocPriorityThreshold) since it disadvantages requests that cannot be queued. Refer also to the allocPriorityTable parameter. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 351/629 V17.0 BSS Parameter User Guide (BPUG) interCellHOIntPriority Description: Class 3 V7 Index in the allocPriorityTable that defines the processing priority of incoming intra–bss handovers in a cell This priority is always used, whether radio resource allocation queuing is authorized in the BSS or not. [0 to 17] bts 17 DP, System 15 Allocation and priority (run by the BSC) (All_1) Queuing driven by the MSC (All_2) Queuing driven by the BSC (All_3) The internal priority associated is 0. A TCH allocation request (in signaling mode) on intraBSC handover is aknowledged when at least 1 TCH is free. When queuing is used, it is recommended to give the priority 0 and reserve the TCH channels (allocPriorityThreshold) since it disadvantages requests that cannot be queued. Refer also to the allocPriorityTable parameter. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: intraCellHOIntPriority Description: Class 3 V7 Index in the allocPriorityTable that defines the processing priority of an intra–bts handover in a cell This priority is always used, whether radio resource allocation queuing is authorized in the BSS or not. [0 to 17] bts 17 DP, System 14 Allocation and priority (run by the BSC) (All_1) Queuing driven by the MSC (All_2) Queuing driven by the BSC (All_3) Refer also to the allocPriorityTable parameter. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 352/629 V17.0 BSS Parameter User Guide (BPUG) directedRetryPrio Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: DP, Optimization 17 TCH Allocation Management V12 Index in the allocPriorityTable that defines the processing priority for directed retry handovers [0 to 17] bts Before V12, the directed retry used the incoming handover priority, which is the highest priority; to avoid this, this new priority is introduced. Refer also to the allocPriorityTable parameter. intraCellQueuing Description: Class 3 V8 Whether intra–bts handover requests are queued for a cell. This parameter is significant only when queuing radio resource allocation requests is allowed in the BSS. Refer to the bscQueuingOption parameter. [enabled / disabled] bts disabled DP, Optimization Enabled Queuing driven by the MSC (All_2) Queuing driven by the BSC (All_3) None. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: minNbOfTDMA Description: Class 2 V7 Minimum number of TDMA frames that must be working in order for the cell itself to be working. The frame carrying the cell BCCH must be among them and is successfully configured. [1 to 16] bts 1 DP, Optimization 1 None. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 353/629 V17.0 BSS Parameter User Guide (BPUG) notAllowedAccessClasses Description: Class 3 V7 List of mobile access classes that are forbidden in the cell, except case of congestion. This attribute, together with the emergencyCallRestricted attribute, allows to control access to a cell according to the service classes authorized. List of mobile access class: [0 to 9]: user classes [11 to 15]: operator classes bts Leave the field empty DP,Operation “null” (empty list) Dynamic barring of access class (All_4) V15.0 Changes of dynamic barring of access class (All_4) This parameter contains the list of forbidden access classes. Usually all users are authorized, in this case, the list must be empty. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: numberOfTCHFreeBeforeCongestion Description: Class 3 V9 Minimum number of free TCHs which triggers the beginning of the TCH congestion phase and the beginning of the traffic overload condition [0 to infinite] bts 0 DP, Design 1 for cells with 1-2 TRXs 2 or 3 for cells with more than 3 TRXs Dynamic barring of access class (All_4) V15.0 Changes of dynamic barring of access class (All_4) Handover for traffic reasons (from V12) Note that the congestion feature does not distinguish between reserved or unreserved TCHs. A reserved TCH is a TCH booked for a priority 0 procedure. Setting this parameter must consider the number of reserved TCHs. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 354/629 V17.0 BSS Parameter User Guide (BPUG) numberOfTCHFreeToEndCongestion Description: Value range: Object: Default value: Type: Rec. value: Used in: Class 3 V9 Threshold that gives the number of free TCHs, which triggers the end of TCH congestion phase and the end of the traffic overload condition. [0 to infinite] bts 0 DP, Design 2 for cells with 1-2 TRXs 3 or 4 cells with more than 3 TRXs Dynamic barring of access class (All_4) V15.0 Changes of dynamic barring of access class (All_4) Handover for traffic reasons (from V12) numberOfTCHFreeToEndCongestion > numberOfTCHFreeBeforeCongestion Note, this inequality is not checked at the OMC. Eng. Rules: numberOfTCHQueuedBeforeCongestion Description: Class 3 V9 Maximum number of TCH allocation requests queued which triggers the beginning of the TCH congestion phase and the beginning of the traffic overload condition [0 to infinite] bts 0 DP, Design TBD Dynamic barring of access class (All_4) V15.0 Changes of dynamic barring of access class (All_4) Handover for traffic reasons (from V12) Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: numberOfTCHQueuedToEndCongestion Description: Class 3 V9 Maximum number of TCH allocation requests queued which triggers the end of TCH congestion phase and the end of the traffic overload condition [0 to infinite] bts 0 DP, Design TBD Dynamic barring of access class (All_4) V15.0 Changes of dynamic barring of access class (All_4) Handover for traffic reasons (from V12) Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 355/629 V17.0 BSS Parameter User Guide (BPUG) otherServicesPriority Description: Class 3 V7 Index in the table allocPriorityTable for a TCH allocation request (in signaling mode) whose cause is “other services” This priority is used in primo–allocations or when an SDDCH cannot be allocated for overload reasons. Value range: Object: Default value: Type: Rec. value: Used in: [0 to 17] bts 17 DP, System 16 Allocation and priority (run by the BSC) (All_1) Queuing driven by the MSC (All_2) Queuing driven by the BSC (All_3) The internal priority associated is > 0. A TCH allocation request (in signaling mode) whose cause is “other services” is acknowledged when at least allocPriorityThreshold + 1 channels are free. Refer also to the allocPriorityTable parameter. Eng. Rules: priority Description: Class 2 V7 Priority level of a TDMA frame for mapping TDMA onto TRXs. At least minNbOfTDMA TDMA frames related to a cell must be successfully configured for the cell to be working. They include the TDMA frame carrying the cell BCCH and those with the other priority(ies). [0 to 255] transceiver DP, Optimization See Engineering Rules Refer to section SDCCH Dimensioning and TDMA priorities. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 356/629 V17.0 BSS Parameter User Guide (BPUG) 5.18. EMLPP RADIO RESOURCE PREEMPTION PARAMETER Note that other parameters related to eMLPP Radio Resource Preemption (emergencyThreshold and eMLPPThreshold) are only meaningful in GSM-R, therefore they are not described in this document. preemptionAuthor Description: Class 3 V15 This parameter activates or deactivates radio resource preemption capability in the BSS (used in the context of eMLPP supplementary service). This parameter and the radio resource preemption capability introduced in V12.4 used to be GSM-R only. They are available in public GSM from v15.1 onwards. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: [forbidden, authorizedWithRelease, authorizedForcedHO] signallingPoint forbidden DP see Eng Rules eMLPP Preemption preemptionAuthor = “forbidden” means that the BSC never performs radio resource preemption, whatever the priority and PCI/PVI flags’ values. preemptionAuthor = “authorizedWithRelease” means that the BSC is allowed to perform radio resource preemption if necessary and if authorised by the MSC.A successful preemption results in the preempted call being released. preemptionAuthor = “authorizedWithForcedHO” means the same thing as preemptionAuthor = “authorizedWithRelease” in the current implementation, despite the different name Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 357/629 V17.0 BSS Parameter User Guide (BPUG) 5.19. DIRECTED RETRY HANDOVER PARAMETERS adjacent cell umbrella ref Description: Class 3 V9 Identifier of the adjacentCelHandOver object that describes the neighbor cell towards which a directed retry will be triggered in BSC mode [0 to 31] bts DP, Design Identifier of the adjacentCellHandOver of the macrocell which totally covers the micro cell. Directed Retry Handover: BSC (or local) mode BSC mode is especially used in a two layer network. For micro cells, directed retry needs to be triggered towards the macro cell. However, if the recovering of each micro cell is good enough, adjacentUmbrellaRef can identify a micro cell. To facilitate the procedure, the BCCH frequency of the target neighbor cell must be in the reselection list. See also chapter Directed Retry Handover Benefit. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: directedRetry Description: Class 3 V9 Minimum signal strength level received by the mobiles to be granted access to the neighbor cell, used in processing directed retry handovers in BTS mode [less than -110, -110 to -109, ... , -49 to -48, more than -48] dBm adjacentCellHandOver more than -48 dBm DP, Optimization = rxLevMinCell + 3 to 25 dB Directed Retry Handover: BTS (or distant) mode The choice of recommended value has to be done regarding the general design of the network. A 3 dB margin must be considered as a minimum on a network to eliminate field strength bumps effect due to multipath. However, this margin must be increased in an urban environment or with the use of reuse pattern (overall for a 1X1 pattern) because of the generated interference when the MS is not on the best server cell. See also chapter Directed Retry Handover Benefit. Directed retry is not allowed between 2 zones of a concentric cell. For a dual Band Network where one frequency band is privileged, it is possible to set this parameter to a higher value in neighbour cells belonging to the low priority frequency band. Thus, this band will be underprivileged. However, it will impact the directed retry for monoband MS on this band (less directed retry). Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: CAUTION! Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 358/629 V17.0 BSS Parameter User Guide (BPUG) directedRetryModeUsed Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 3 V9 Specify how directed retry handovers are processed in a cell either directly by the BSC (microcells only) or by querying the BTS first [bsc / bts] bts bts DP, Design bts Directed Retry Handover: BSC (or local) mode Directed Retry Handover: BTS (or distant) mode The micro cell should be entirely covered by the macro cell in order to use efficiently the bsc mode. The use of the bts mode is recommended in a hot spot when there are several micro cells under the umbrella. The bts mode allows the use of micro cells to rescue the umbrella cell and also avoids a saturation of the umbrella cell. See also chapter Directed Retry Handover Benefit. Class 3 V9 interBscDirectedRetry Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: CAUTION! [allowed / not allowed] bsc allowed DP, Design allowed Directed Retry Handover: BSC (or local) mode Directed Retry Handover: BTS (or distant) mode See also chapter Directed Retry Handover Benefit. Whether inter–bss directed retry handovers are allowed in a BSS Directed retry is not allowed between 2 zones of a concentric cell. interBscDirectedRetryFromCell Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: [allowed / not allowed] bts allowed DP, Optimization allowed Directed Retry Handover: BSC (or local) mode Directed Retry Handover: BTS (or distant) mode Class 3 V9 Whether inter–bss directed retry handovers are allowed in a cell If the value is “not allowed” then, the value of interBscDirectedRetryFromCell must be set to “not allowed” for the concerned cells. See also chapter Directed Retry Handover Benefit. Directed retry is not allowed between 2 zones of a concentric cell. Nortel confidential CAUTION! PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 359/629 V17.0 BSS Parameter User Guide (BPUG) intraBscDirectedRetry Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: CAUTION! [allowed / not allowed] bsc allowed DP, Design allowed Directed Retry Handover: BSC (or local) mode Directed Retry Handover: BTS (or distant) mode See also chapter Directed Retry Handover Benefit. Directed retry is not allowed between 2 zones of a concentric cell. Class 3 V9 Whether intra–bss directed retry handovers are allowed in a BSS intraBscDirectedRetryFromCell Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: [allowed / not allowed] bts allowed DP, Optimization allowed Directed Retry Handover: BSC (or local) mode Directed Retry Handover: BTS (or distant) mode Class 3 V9 Whether intra–bss directed retry handovers are allowed in a cell If the value is “not allowed” then, the value of intraBscDirectedRetryFromCell must be set to “not allowed” for the concerned cells. See also chapter Directed Retry Handover Benefit. Directed retry is not allowed between 2 zones of a concentric cell. CAUTION! modeModifyMandatory Description: Value range: Object: Default value: Type: Rec. value: Used in: Class 3 V9 Whether a CHANNEL MODE MODIFY message should be sent to the mobile after a directed retry handover in the BSS [used (yes) / not used (no)] bsc not used DP, Optimization not used Directed Retry Handover Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 360/629 V17.0 BSS Parameter User Guide (BPUG) Eng. Rules: In the early days of GSM, this parameter was useful for mobiles belonging to specific brands, that used not to be able to switch directly from signaling (SDCCH) to speech (TCH) when executing a Directed retry procedure. For that reason, this parameter used to be set to "used" so that a Channel Mode Modify procedure could be done, forcing an explicit change of channel upon the mobile. However, today, as these mobile bugs have now presumably been corrected, with few or no faulty mobiles remaining in the field today, the systematic invokation of the CMM procedure is no longer required. Setting to "used" may, in addition, have detrimental side-effects for some kinds of inter-cell handovers (problem noted on instances of intercell 3G-2G Handovers) which will systematically invoke a Channel Mode Modify. Therefore it is recommended to set this parameter systematically to value “not used”. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 361/629 V17.0 BSS Parameter User Guide (BPUG) 5.20. CONCENTRIC CELL PARAMETERS biZonePowerOffset Description: Class 3 V12 Offset added in calculation formula to draw up the list of eligible cells for handover towards a dualband, dualcoupling, or concentric cell inner zone to take into account the difference of propagation models between the two bands of the cells and the difference of transmission power between TRXs of the two zones due to either BTS configuration or coupling. [-63 to 63] dB adjacentCellHandOver if main band = 850 MHz biZonePowerOffset = 3 dB if main band = 1900 MHz biZonePowerOffset = -3 dB DP, Optimization See Engineering Rules General formulas Direct TCH allocation Concentric/DualCoupling/DualBand Cell Handover Used for intercell handover to control whether the inner zone is “eligible” or not. to inhibit Direct TCH Allocation on an adjacent cell (when the adjacent cell is declared as monozone / concentric / dualband / dualcoupling) biZonePowerOffset(n) = 63 to allow Direct TCH Allocation on an adjacent cell (when the adjacent cell is declared as concentric / dualband / dualcoupling) biZonePowerOffset(n) =concentAlgoExtRxLev(n) - rxLevMinCell(n) Shall be 63 for a monozone adjacent cell. The higher (in positive) is the value, the more difficult it will be to handover in the inner zone of the adjacent cell. It is advised to set a value higher than the max offset (in rxLevDL band 0) corresponding to the biggest difference of coverages between the 2 bands (for the adjacent cell) otherwise an intercell handover to the inner zone would be wrongly decided. If HO decision is made toward the inner zone of a multizone cell, then related EXP1XX(n) is computed with biZonePowerOffset(n). See also chapters Concentric Cells and DualBand Networks. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Note: CAUTION! Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 362/629 V17.0 BSS Parameter User Guide (BPUG) biZonePowerOffset Description: Value range: Object: Default value: Type: Rec. value: Used in: Class 3 V12 Power offset between inner and outer TRXs of the handOverControl object of a dualband, dualcoupling, or concentric cell. [-63 to 63] dB handOverControl if main band = 850 MHz, biZonePowerOffset = 3 dB if main band = 1900 MHz, biZonePowerOffset = -3 dB DP, Optimization See Engineering Rules General formulas Direct TCH allocation Concentric/DualCoupling/DualBand Cell Handover monozone cell: biZonePowerOffset = 63 concentric cell: biZonePowerOffset = zone Tx powermax reduction concentric cell with HePA only on outer zone: biZonePowerOffset = 3 dualband cell (main band = 850 or 900 MHz): biZonePowerOffset = 6 dualband cell (main band = 1800 or 1900 MHz): biZonePowerOffset = - 6 dualcoupling cell: biZonePowerOffset = zone Tx powermax reduction = coupling losses difference between inner and outer zone dualband + dualcoupling cell combination: biZonePowerOffset = coupling losses + propagation losses Eng. Rules: CAUTION! When using dualcoupling cell DLU attenuation should be NULL and compensated by the zone Tx power max reduction, see concentric cell parameter Shall be 63 for a monozone adjacent cell. If HO decision is made in the small zone of a multizone cell then related EXP2xx(n) = hoMarginxx(n) + biZonePowerOffset. See also chapters Concentric Cells and DualBand Networks. Note: CAUTION! Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 363/629 V17.0 BSS Parameter User Guide (BPUG) concentAlgoExtMsRange Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 3 V9 MS to BTS distance below which a handover is requested from the large zone to the small zone if the level criteria is verified [1 to 34] km (non-extended mode) [1 to 120] km (extended mode) handOverControl 1 DP, Design 34 Direct TCH Allocation Concentric cell / dualcoupling cell intracell handovers The calculated distance between the MS and the BTS is based on timing advance (TA), which has an accuracy of ± 3 bits (corresponding to more than 1,5 km), thus not very useful in urban areas where the cell size is relatively small and multipath affect the MS_BS distance. However this parameter can be useful in rural areas or suburban areas, and concentAlgoExtMsRange should respect following rules: concentAlgoExtMsRange = concentAlgoIntMsRange - 1 km concentAlgoExtMsRange < concentAlgointMsRange concentAlgoExtMsRange < msRangeMax Note: 34 disable the parameter since condition is always fullfilled. See also chapters Concentric Cells and DualBand Networks. concentAlgoIntMsRange Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 3 V9 MS to BTS distance from which a handover from the small zone to the large zone will be requested [1 to 34] km (non-extended mode) [1 to 120] km (extended mode) handOverControl 34 DP, Design 34 Concentric cell / dualcoupling cell intracell handovers The calculated distance between the MS and the BTS is based on timing advance (TA), which has an accuracy of ± 3 bits (corresponding to more than 1,5 km), thus not very useful in urban areas where the cell size is relatively small and multipath affect the MS_BS distance. However this parameter can be useful in rural areas or suburban areas, and concentAlgoIntMsRange should respect following rules: concentAlgoIntMsRange > concentAlgoExtMsRange concentAlgoIntMsRange < msRangeMax Note: 34 disable the parameter since condition is always fullfilled. See also chapters Concentric Cells and DualBand Networks. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 364/629 V17.0 BSS Parameter User Guide (BPUG) concentAlgoExtRxLev Description: Value range: Object: Default value: Type: Rec. value: Used in: Class 3 V9 The level of the MS signal strength above which a handover is requested from the large zone to the small zone [less than -110, -110 to -109, ... , -49 to -48, more than -48] dBm handOverControl - 95 to - 94 DP, Design See Engineering Rules Direct TCH Allocation Concentric/DualCoupling/DualBand Cell Handover Concentric cell / dualcoupling cell intracell handovers The recommended value depends on the network design. Depending on capacity distribution between inner and outer zone, CPT can be used to match the RxLev DL number of samples to concentAlgoExtRxLev, which defines when users interzone handover from outer to inner zone, i.e. inner zone traffic load. The following rules shall be respected: concentAlgoExtRxLev > concentAlgoIntRxLev concentAlgoExtRxLev ≤ rxLevMinCell + biZonePowerOffset See also chapters Concentric Cells and DualBand Networks. Eng. Rules: concentAlgoIntRxLev Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 3 V9 Level of the MS signal strength below which a handover is requested from the small zone to the large zone [less than -110, -110 to -109, ... , -49 to -48, more than -48] dBm handOverControl less than -110 DP, Design See Engineering Rules Concentric/DualCoupling/DualBand Cell Handover Concentric cell / dualcoupling cell intracell handovers In order to avoid unnecessary ping-pong interzone HO a Hysteresis Margin should be added: concentAlgoIntRxLev = concentAlgoExtRxLev - biZonePowerOffset - Hysteresis Margin where recommended Hysteresis Margin = 4 dB See also chapters Concentric Cells and DualBand Networks. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 365/629 V17.0 BSS Parameter User Guide (BPUG) concentric cell Description: Class 2 V9 Whether the cell is monozone, concentric, dualband or dualcoupling A concentric, dualband, or dualcoupling cell describes a combination of two transmission zones, the outer (or large) zone and the inner (or small) zone. The inner zone is entirely included in the outer zone. A dualband cell is a particular type of concentric cell for which GSM 900 and GSM1800 (or GSM 850 and GSM1900) TRXs/DRXs coexist and share the same BCCH. A dualcoupling cell is a particular type of concentric cell for which the TRXs/DRXs are combined with two types of combiners. For concentric configurations (concentric, dualband or dualcoupling), a TDMA frame belongs to one zone or the other, but never to both. [monozone / concentric / dualband / dualcoupling] from V12 monozone: normal cell concentric: two concentric transmission zones dualband: two concentric transmissions zones with GSM 900 TRXs/DRXs for the one and GSM 1800 TRXs/DRXs for the other dualcoupling: two concentric transmission zones with TRXs/DRXs combined with one type of combiner for the one and with another type of combiner for the other bts monozone DP, Optimization See Engineering Rules Concentric/DualCoupling/DualBand Cell Handover concentric cell: From V12, it is possible to allocate directly a TCH in the innerzone for call set-up or HO and to reuse the same frequency in both zones, and hopping concerns the total available number of frequencies. A cell configuration with HePA only on outer zone is concentric cell, not a dualcoupling cell. dualband cell: The dualband combining into one cell allows to save up to one SDCCH in particular configurations, the combining of GSM 900 / GSM 1800 (or GSM 850 / GSM 1900) resources into one pool allows to increase the traffic capacity. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: CAUTION! dualband is not supported on S4000 with DCU2/DCU4, S4000 with DCU2, S4000 with DCU4 dualcoupling cell: The DLU attenuation shall be used: so configure the “attenuation” parameter (btsSiteManager object) to null, configure the max power for the cell to the desired max power (power for the outer zone) and configure zone Tx power max reduction for the inner zone to the delta value. dualcoupling is not supported on mixed DCU4 or DRX transceiver architecture. See also chapters Concentric Cells and DualBand Networks. CAUTION! Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 366/629 V17.0 BSS Parameter User Guide (BPUG) small to large zone HO priority Description: Class 3 V12 External priority of inter-zone handovers from the inner zone to the outer zone in a concentric cell. This attribute is defined if the associated bts object describes a concentric cell. [0 to 17] handOverControl 17 DP 14 Allocation and priority (run by the BSC) (All_1) Queuing driven by the MSC (All_2) Queuing driven by the BSC (All_3) Concentric cell / dualcoupling cell intracell handovers Refer also to the allocPriorityTable parameter. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: transceiver equipment class Description: Class 2 V9 Class of a TRX/DRX. The class of a TRX/DRX sets, among others, its maximum transmission power. The attribute possible values have the following meaning: Class 1 corresponds to GSM 850/900 class 5 or GSM 1800/1900 class 1 (20W to 40W transmitters) Class 2 corresponds to GSM 900 class 6 which is not supported or GSM 1800/1900 class 2 (10W to 20W transmitters) Value range: Object: Type: Rec. value: [0 (reserved) / 1 / 2] transceiverEquipment DP monozone: 1 concentric cell: outer=1, inner=1 dualband cell: outer=1, inner=2 dualbcoupling cell: outer=1, inner=2 Used in: Eng. Rules: Concentric/DualCoupling/DualBand Cell Handover When dual band is used, the class of a TRX/DRX enables to distinguish which DRX and which TDMA are used in the outer zone or inner zone. Class 1 corresponds to to a TDMA in the frequency band carrying BCCH so belonging to transceiverZone = 0 (large/outer zone). Class 2 corresponds to a TDMA in the frequency band not carrying BCCH so belonging to transceiverZone = 1 (small/inner zone). If the TRX/DRX is partnered with a TDMA frame, its class matches the TRX/DRX class allotted to the zone to which the TDMA frame belongs (refer to the next parameter). In case of concentric cell configuration, setting inner and outer class to “1” allows a reconfiguration of TRX/DRX from the inner to the outer if needed. Note: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 367/629 V17.0 BSS Parameter User Guide (BPUG) transceiver equipment class Description: V9 Class of the TRX/DRXs partnered with the TDMA frames of the zone. The class of a TRX/DRX sets, among others, its maximum transmission power. Refer to the previous parameter. [1 / 2] transceiverZone DP monozone: 1 concentric cell: outer=1, inner=1 dualband cell: outer=1, inner=2 dualbcoupling cell: outer=1, inner=2 Value range: Object: Type: Rec. value: Used in: Eng. Rules: Concentric/DualCoupling/DualBand Cell Handover When dual band is used, the class of a TRX/DRX enables to distinguish which DRX and which TDMA are used in the outer zone or inner zone. Class 1 corresponds to to a TDMA in the frequency band carrying BCCH so belonging to transceiverZone = 0 (large/outer zone). Class 2 corresponds to a TDMA in the frequency band not carrying BCCH so belonging to transceiverZone = 1 (small/inner zone). In case of concentric cell configuration, setting inner and outer class to “1” allows a reconfiguration of TRX/DRX from the inner to the outer if needed. Note: transceiverZone Description: Class 2 V12 Identifier of the transceiverZone object that defines the zone to which a TDMA frame belongs in a concentric cell. The transceiverZone objects are only significant for the bts objects that describe concentric cells. Two transceiverZone objects are created for each created concentric bts object; one describes the large or outer transmission zone, and the other describes the smallor inner transmission zone. [0 (large outer zone) / 1 (small or inner zone)] transceiverZone DP 0 for outer zone 1 for inner zone Concentric/DualCoupling/DualBand Cell Handover When a concentric/dualband/dualcoupling cell is created the transceiverZone outer zone must set to “0” and the transceiverZone inner zone must be set to “1”. It is not applicable for monozone cells. Value range: Object: Type: Rec. value: Used in: Eng. Rules: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 368/629 V17.0 BSS Parameter User Guide (BPUG) zone Tx power max reduction Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 2 V9 Attenuation vs bsTxPwrMax that defines the maximum TRX/DRX transmission power in the zone large zone = [0] dB, small zone = [1 to 55] dB transceiverZone 0 dB DP, Design see Engineering Rules Concentric cell / dualcoupling cell intracell handovers concentric cell: zone Tx Power Max Reduction(outer) = 0 zone Tx Power Max Reduction(inner) ≤ zone Tx Power Max Reduction(outer) (zone Tx Power Max Reduction(inner) = 0 is recommanded) dualband cell (homogeneous coupling): zone Tx Power Max Reduction(outer) = 0 zone Tx Power Max Reduction(inner) = 1 dualcoupling cell: zone Tx Power Max Reduction(outer)=0 zone Tx Power Max Reduction(inner)=3 simulates the D/H2D configuration zone Tx Power Max Reduction(inner)=4 simulates the H2D/H4D configuration CAUTION! when using dualcoupling cell DLU attenuation should be NULL and compensated by the zone Tx power max reduction, see concentric cell parameter See also chapters Concentric Cells and DualBand Networks. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 369/629 V17.0 BSS Parameter User Guide (BPUG) 5.21. INTERFERENCE LEVEL PARAMETERS averagingPeriod Description: Class 2 V7 Number of SACCH multiframes over which the interference levels are averaged. This averaging will be performed immediately before the transmission of the RESOURCE INDICATION message. This attribute, together with the “thresholdInterference” attribute, allows users to manage interferences in radio cells. Refer to this entry in the Dictionary. [0 to 255] SACCH frame (1 unit = 480 ms on TCH, 470 ms on SDCCH) handOverControl 20 DP, System 20 Radio channel allocation Interference Management (BTS and BSC) (If) Performing this message broadcast has a great impact on the system load and should not be done too often. Reducing this value speeds-up the channel allocation algorithm, since it checks temporary channel interference non frequently. However, the main purpose of this algorithm is to take into account long term interference and not short term interference which do not have a statistically large impact on call quality. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 370/629 V17.0 BSS Parameter User Guide (BPUG) radChanSelIntThreshold Description: Class 3 V8 Maximum interference level on free radio channels, below which the channels are ranged in the group of allocation priority channels The information is used to first allocate the free channels with the lowest interference level. The levels depend on the thresholdInterference attribute value defined for the cell. Refer to this entry in the Dictionary. The BSC distributes the free radio channels among two groups: The first group contains the list of channels with a measured averaged interference level equal to or lower than the defined level. The second group contains the list of channels with a measured averaged interference level higher than the defined level, and recently released channels for which no measurement is available. Four resource pools are defined for each SDCCH or TCH type of channel: low interference level radio channels that are authorized to hop low interference level radio channels that are not authorized to hop high interference level radio channels that are authorized to hop high interference level radio channels that are not authorized to hop Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: [0 to 4] handOverControl 1 DP, Optimization 3 1 (for 1X1 & 1X3) Interference Management (BTS and BSC) (If) A high value for this parameter means a tolerant interference sorting. It is easier to change the value of this pointer than to tune the thresholds themselves since the thresholds are used in the lower layer of signal processing at the BTS. The radChanSellIntThreshold counter can be set after interference counters monitoring. Ideally, it should depend on the average traffic load expected on the cell and on the interference distribution. With low Traffic per TCH, radChanSellIntThreshold can be set to 1. This means that the selection of the non interefered channels is very selective. The few TCH selected are sufficient for the traffic to be carried. RadChanSellIntThreshold can be decreased to 1 when using 1X1 or 1X3 reuse pattern in order to use as more BCCH resources as possible. With high Traffic per TCH, radChanSellIntThreshold can be set to 4. This means MS will get allocated to a channel regardless of the interference as long as there are resources available. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 371/629 V17.0 BSS Parameter User Guide (BPUG) thresholdInterference Description: Class 2 V7 List of four thresholds defined in ascending order, used to sort idle channels on the basis of measured interference levels This attribute, together with the averagingPeriod attribute, allows managing interferences in a radio cell. The classification is used by the radio resource allocator. For each idle radio channel, the BTS permanently measures the signal strength level RXLEV. When averagingPeriod “Measurement results” messages have been received, the L1M function in the BTS calculates interference level averages, sorts the idle channels according to the five defined interference levels, and sends the information to the BSC. Level 0 corresponds to: RXLEV < threshold 1 Level 1 corresponds to: threshold 1 < RXLEV < threshold 2 Level 2 corresponds to: threshold 2 < RXLEV < threshold 3 Level 3 corresponds to: threshold 3 < RXLEV < threshold 4 Level 4 corresponds to: threshold 4 < RXLEV Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: [-128 to 0] dBm handOverControl -100 -90 -80 -70 DP, Optimization -114, -112, -108, -100 Radio channel allocation Interference Management (BTS and BSC) (If) Those values define 5 interference level ranges, so free channel classification can be displayed at the OMC-R level. The setting of the threshold Interference level should be linked to the interference level distribution in the cell. As a first definition, thresholds can be evenly distributed over the defined range. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 372/629 V17.0 BSS Parameter User Guide (BPUG) 5.22. RADIO RESSOURCES CONTROL AT CELL LEVEL radResSupBusyTimer Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Useful, for example, to see problems of resource deallocation. 10 during busy day for high traffic area 3 for other cases (at night, in rural areas). Class 3 V8 Maximum time that SDCCH or TCH can be continuously occupied without generating an alarm [1 to 18] hours bsc 3 DP, System 10 or 3 (see Engineering Rules) radResSupervision Description: Class 3 V8 Indicates whether radio resources are controlled at the cell level (both busy resources and free resources) When no control is performed, no alarm related to the use or non–use of an SDCCH or TCH is generated. Refer to the radResSupBusyTimer and radResSupFreeTimer parameters. [true / false] bts True DP, System True It is recommended to use this control mainly after a frequency plan update, to regularly supervise the network. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: radResSupFreeTimer Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 3 V8 Maximum time an SDCCH or TCH can be continuously free without generating an alarm [1 to 18] hours bsc 18 DP, System 10 or 3 (see Eng. Rules) Useful, for example, to see problems of design at busy hours or if some channels are jammed. 10 during busy day for high traffic area 3 for other cases (at night, in rural areas). Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 373/629 V17.0 BSS Parameter User Guide (BPUG) 5.23. BSS TIMERS bssMapT1 Description: Class 1 V7 A interface timer triggered by the BSC in the BSSMAP management procedure. It is started on transmission of BLOCK or UNBLOCK by the BSC and cancelled on receipt of BLOCK ACKNOWLEDGE or UNBLOCK ACKNOWLEDGE sent by the MSC. [2 to 300] seconds bsc 5 DP, System 5, 60 (if using DMS switch) Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: bssMapT12 Description: Class 1 V7 A interface timer triggered by the BSC in the BSSMAP management procedure. This timer is used with a Phase I MSC only. It is started on transmission of RESET CIRCUIT by the BSC and cancelled on receipt of RESET CIRCUIT ACKNOWLEDGE sent by the MSC. [2 to 300] seconds bsc 5 DP, System 5, 60 (if using DMS switch) Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: bssMapT13 Description: Class 1 V7 An interface timer triggered by the BSC in the BSSMAP management procedure. It is started on receipt of RESET sent by the MSC. On elapse, the BSC sends RESET ACKNOWLEDGE to the MSC. [2 to 300] seconds bsc 32 DP, System 32 Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 374/629 V17.0 BSS Parameter User Guide (BPUG) bssMapT19 Description: Class 1 V8 A interface timer triggered by the BSC in the BSSMAP management procedure. This timer is used with a Phase II MSC only. It is started on transmission of RESET CIRCUIT by the BSC and cancelled on receipt of RESET CIRCUIT ACKNOWLEDGE sent by the MSC. [2 to 300] seconds bsc 32 DP, System 32 Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: bssMapT20 Description: Class 1 V8 A interface timer triggered by the BSC in the BSSMAP management procedure. It is started on transmission of CIRCUIT GROUP BLOCK or CIRCUIT GROUP UNBLOCK by the BSC and cancelled on receipt of CIRCUIT GROUP BLOCK ACKNOWLEDGE or CIRCUIT GROUP UNBLOCK ACKNOWLEDGE sent by the MSC. [2 to 300] seconds bsc 32 DP, System 32 Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: bssMapT4 Description: Class 1 V7 A interface timer triggered by the BSC in the BSSMAP management procedure. It is started on transmission of RESET and cancelled on receipt of RESET ACKNOWLEDGE sent by the MSC. On elapse, the BSC sends RESET. [5 to 600] seconds bsc 60 DP, System 60 Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 375/629 V17.0 BSS Parameter User Guide (BPUG) bssMapT7 Description: Class 1 V7 A interface timer triggered by the BSC in the BSSMAP management procedure. It is started on transmission of HANDOVER REQUIRED and cancelled on receipt of HANDOVER COMMAND, RESET, RESET CIRCUIT, CLEAR COMMAND or HANDOVER REQUIRED REJECT. [2 to 120] seconds bsc 7 DP, Optimization 7 Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: bssMapT8 Description: Class 1 V7 A interface timer triggered by the BSC in the BSSMAP management procedure. It is greater than t3103 for each cell managed by the BSC. It is started on transmission of HANDOVER COMMAND and cancelled on receipt of CLEAR COMMAND sent by the MSC or HANDOVER FAILURE sent by MS. [0 to 255] seconds bsc 15 DP, Optimization 15 It is greater than t3103 for each cell managed by the BSC. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: bssMapTchoke Description: Class 1 V7 A interface timer triggered by the BSC in the handover management procedure. It is started by the BSC when the last neighbour cell in the list is rejected. On timer elapse, the BSC asks the BTS to provide a new list of eligible cells. [1 to 255] seconds bsc 4 DP, System 4 It is strongly recommended to keep this value. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 376/629 V17.0 BSS Parameter User Guide (BPUG) bssSccpConnEst Description: Class 1 V7 A interface timer triggered by the BSC in the handover management procedure. It is set on transmission of CONNECTION REQUEST and cancelled on receipt of CONNECTION CONFIRM or CONNECTION REFUSED. [5 to 360, by steps of 5] seconds signallingPoint 5 DP, System 5 A high value is dangerous in case of slowing down on A interface. Then, the minimum value (5 s) must be chosen for this parameter; it is strongly recommended not to modify this value. Value rang: Object: Default value: Type: Rec. value: Used in: Eng. Rules: t3101 Description: Class 3 V7 BSC timer triggered during the immediate assignment procedure. Use the suggested system value. It is set on transmission of CHANNEL ACTIVATION by the BSC and cancelled on receipt of ESTABLISH INDICATION sent by the BTS. [1 to 255] seconds bts 3 DP, System 3 Most of the time, the timer expires in the case of double allocation (i.e, when two RACHs are sent by the same mobile to the network). The higher the timer is the longer unnecessary signaling resources are reserved. Up to 30% of signaling resources are allocated for a second RACH for phase 1 MS according to numberOfSlotsSpreadTrans (32). To optimize signaling resources (especially in case of Queuing), it could be useful to decrease the timer value. The minimum time between the two messages is 600 ms and the maximum for a lightly loaded BSS is almost 1.8 seconds when MS is answering. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 377/629 V17.0 BSS Parameter User Guide (BPUG) t3103 Description: Class 3 V7 BSC timer triggered during the handover procedure. Use the suggested system value. It is set on transmission of HANDOVER COMMAND by the BSC and cancelled on receipt of either HANDOVER COMPLETE or HANDOVER FAILURE sent by the MS (intra–bss handover), or CLEAR COMMAND sent by the MSC (inter–bss handover). At expiry of T3103, the channel is released. [2 to 255] seconds (t3103 < bssMapT8) bts 5 seconds DP, Optimization 9 seconds The longest procedure (inter BSS handover) is taken as an example. The timer is set on receipt of the HO command and reset on clear complete. It means that as long as the timer runs, 2 channels are kept: one on the originating BSC and one on the target BSC. If the timer is too long, two resources are used which can be a bad in case of capacity problems. Tests showed that t3103 set to 9 seconds offers the best compromise between the execution of the procedure and the hold of ressources. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: t3107 Description: Class 3 V7 BSC timer triggered during the assignment command procedure. Use the suggested system value. It is set on transmission of ASSIGN COMMAND by the BSC and cancelled on receipt of either ASSIGN COMPLETE or ASSIGN FAILURE sent by MS. [2 to 255] seconds bts 10 seconds DP, Optimization 10 seconds in a network without any capacity problems. If not, the value can be decreased. The minimum theoretical value is 5 seconds. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: At expiry of the timer, the mobile is assumed to be lost and its resource can be used by another mobile. Mobile on SDCCH is a constraining case: the timer T200 leads to a 230 ms wait instead of 180 ms on TCH, before repeating a message. If no message is repeated, this procedure lasts about 1 second. However, if the radio link is bad, it is necessary to repeat some messages. The maximum time before resetting t3107 is approximately 5 seconds: after this time, the timer will expires: no new message will be received to reset t3107. The default value of 10 seconds is then a good value to ensure that the link is not cut too early. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 378/629 V17.0 BSS Parameter User Guide (BPUG) t3109 Description: Class 3 V7 BSC timer triggered during the SACCH deactivation procedure. Use the suggested system value. It is set on receipt of DEACTIVATE SACCH ACKNOWLEDGE sent by the BTS and cancelled on receipt of RELEASE INDICATION sent by the BTS. If the timer expires, a RF CHANNEL RELEASE message is sent to the BTS and a RF CHANNEL RELEASE ACK is expected. Mobiles comply with system operating conditions when the counter (S) associated with SACCH messages is assigned a value below or equal to t3109. [2 to 255] seconds (t3109 ≥ radioLinkTimeout) bts 12 seconds DP, Optimization 12 seconds (related to radioLinkTimeOut value) On receipt of the Deactivate SACCH message, the radio link control algorithm will lead to a decrease on the value of the ‘radioLinkTimeOut’ timer and this on MS side or on BTS side according to the situation. t3109 added to t3111 must be greater than radioLinkTimeOut and greater than the time corresponding to rlf1: t3109 ≥ radioLinkTimeOut If t3109 is too small, the ressources could be allocated even if radiolinkTimeOut did not reach zero yet. When AMR is activated that parameter should be set to 17. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: CAUTION! t3111 Description: Class 3 V7 BSC timer triggered during the radio resource clearing procedure. Use the suggested system value. It is set on receipt of RELEASE INDICATION sent by the BTS. On elapse, the BSC sends RF CHANNEL RELEASE. [1 to 255] seconds bts 2 seconds DP, System 2 seconds This timer is used to delay the channel deactivation after disconnection of the main signalling link. Its purpose is to allow time for the possible repetition of the disconnection by the BTS to the MS. After Release Indication, resources are kept until t3111 expires. In case of capacity problems, t3111 must be as little as possible. The smallest possible value is 2 seconds (range 2-255 seconds).The minimum theoretic value is 5 times the repetition time which is less than 2 seconds No advantage has been found to have a higher value than the smallest possible one. This timer is also used in the formula to compute the preemtion timer : Tpreempt = Tdeactack + 4* T3111 Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 379/629 V17.0 BSS Parameter User Guide (BPUG) t3122 Description: Class 3 V7 Minimum time that mobiles must wait before issuing a channel allocation request when an immediate assignment has failed. In a similar way, in GPRS mode, this value is indicated in the Packet Access Reject (PAREJ) to inform the MS with the waiting time before sending a new Channel Request. The timer is called T3172 in GPRS mode, with T3172 = T3122. [0 to 255] seconds bts 10 seconds DP, Optimization 10 seconds This value is broadcast to the mobile stations. When an immediate assignment reject command is received (when no SDCCH and no TCH in signalling mode is available or when the A-interface is down), mobile stations wait t3122 seconds before sending the request again. In case of BSC Overload, t3122 is automatically increased or decreased between its value set by O&M and 30s according to a specific algorithm. This parameter can be used to solve a problem of a load pick. By increasing the value, the access to the network is regulated. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: timerPeriodicUpdateMS Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Time between two location update requests Class 3 V7 [0 to 255] 1/10th of hour. “0” means that no periodic location update is requested. bts 60 DP, Optimization 10 (not loaded network) 20 (loaded network) Location updatings are performed when initiating a call or when entering a new location area in idle mode. When those events do not occur, timerPeriodicUpdateMS is used to ensure a maximum time between two location update requests. The value of this timer should be set regarding the value of the same timer used in the switch (‘attach mobile audit’ for a DMS) If the value chosen is low, the load of the BSC is severely increased. On the contrary, a too high value would lead to a smaller reactivity of the mobile (e.g. if a mobile is in a hole of coverage and a short message is sent to it, it will be aware of it only at the next location update which could be several hours later). A good trade-off is 2 hours. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 380/629 V17.0 BSS Parameter User Guide (BPUG) 5.24. PAGING PARAMETERS delayBetweenRetrans Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 2 V8 Number of occurences of a paging sub–group that separates two transmissions of the same paging message. [0 to 22] bts 0 DP, Optimization 0 Paging command repetition process (run by BTS) (Pag_rep) The recommended value is 0 because the time between two paging commands broadcast must not be too long, otherwise there is a risk of double allocation. This phenomenon occurs when the suscriber answers and hangs up very quickly. In that case, the mobile is ready to receive a new paging message, for example the previous one if it is resent. The value of this parameter is linked to the values of the nbOfRepeat and retransDuration parameters. Furthermore, the following inequality, that is not checked by the system, must be true: retransDuration ≥ (delayBetweenRetrans + 1) x nbOfRepeat See also chapter GSM Paging Repetition Process Tuning. maxNumberRetransmission Description: Class 3 V8 Maximum number of RACH burst retransmissions allowed in a call in case of non-system response. The information is broadcast to the mobiles at regular intervals on the cell BCCH. It defines the maximum number of times a mobile can renew access requests to the BTS on RACH. [one / two / four / seven] bts two DP, Optimization two in non-interfered areas four in interfered areas Request access command repetition process (RA_rep) In interfered areas, it is necessary to repeat RACHs because of bad conditions. Even if it increases a little overall noise, the gain in decreasing the number of RACHs not received should be significant (under study). In non-interfered areas, the value of ‘two’ is sufficient. ‘one’ is not advised because mobile stations can be in holes of coverage due to multipath fading and, in these cases, at least one retransmission is necessary. See also chapter GSM Paging Repetition Process Tuning. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 381/629 V17.0 BSS Parameter User Guide (BPUG) nbOfRepeat Description: Class 2 V8 Maximum number of times that paging messages are repeated to mobiles that belong to the same paging sub-group It is set to “3” in former BSS versions (static configuration parameter). The following inequality, that is not checked by the system, must be true (refer to these entries in the Dictionary): retransDuration ≥ (delayBetweenRetrans + 1) x nbOfRepeat [0 to 22] bts 3 DP, Optimization See Engineering Rules Paging command repetition process (run by BTS) (Pag_rep) The value of 3 ensures a good quality of service. With less repetition, paging messages can be lost, and, as the repetitions are performed systematically, a signicantly higher value would increase the load of the system and the risk to page a mobile twice. The value of this parameter is linked to the values of the delayBetweenRetrans and retransDuration parameters. That parameter can be tuned regarding the paging parameters and the TDMA configuration, but very cautiously with some metric monitoring (see chapter GSM Paging Repetition Process Tuning) Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: noOfBlocksForAccessGrant Description: Class 2 V7 Number of CCCH blocks not used for paging A BCCH is combined when it shares the same radio time slot with four SDCCHs, which can include a CBCH (refer to the channelType entry in the Dictionary). In that case, the attribute value is no greater than to 2 (the value must be checked by users). [0 to 2] if the cell uses a combined BCCH, [1 to 7] otherwise. “0” means that PCH blocks are used for sending immediate assignment messages as and when needed. bts 0 DP, System 0 if no SMS-CB or SMS-CB with combined BCCH 1 if SMS-CB with non-combined BCCH > 0 if SI2Quater or/and SI13 on ext BCCH are activated Value range: Object: Default value: Type: Rec. value: Used in: Paging command Process (Pag) Effects of SMS-Cell Broadcast Use on “noOfBlocksForAccessGrant” SI2Quater & SI13 on Extended or Normal BCCH See also chapter GSM Paging Repetition Process Tuning. Eng. Rules: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 382/629 V17.0 BSS Parameter User Guide (BPUG) noOfMultiframesBetweenPaging Description: Class 2 V7 Number of occurrences of a paging sub–group The greater this number, the greater the number of paging sub– groups. [2 to 9] multi–frame of fifty-one frames bts 6 DP, Optimization 6 for rural environments 2 or 4 for urban environments Paging command Process (Pag) This parameter has an impact on the use of mobile batteries (determine when an MS needs to listen to paging channels) and on reselection selectivity. For this operation, frequency of measurements performed on idle neighbours thanks to the formula: mesurements done every Max (5 seconds, ((5*nb of idle neighbors + 6) DIV 7) * noOfMultiframesBetweenPaging /4). Regarding mobile batteries, a value of 6 is sufficient to have a tradeoff between the saving of energy and effective paging. In rural environments, the maximum size of reselection list is usually 4/5. 5 seconds is then the maximum in the formula, so it does not slow down the reselection mechanism. The value of 6 is then advised. In urban environments, the size of the list is a bit higher. Furthermore, in this kind of environment, reselection reactivity is a key issue. The way to avoid having more than 5 seconds in the formula is to decrease noOfMultiframesBetweenPaging to 2 or 4 even if it increases battery consumption. Some studies are in progress to determine the value with more accuracy. See also chapter Effects of “noOfMultiFramesBetweenPaging” on Mobile Batteries and Reselection Reactivity. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 383/629 V17.0 BSS Parameter User Guide (BPUG) numberOfSlotsSpreadTrans Description: Class 3 V7 Number of radio time slots over which RACH transmission access are spread in a random way to avoid collisions The information is broadcast to the mobiles at regular intervals on the cell BCCH. In the event of non-system response, the mobile will renew the RACH bursts after a randomly defined period that varies with numberOfSlotsSpreadTrans. MS Phase 1 The time T between two transmissions of the same RACH burst is the following: T= [D + (N+1) x 4.615]ms D is the maximum system response pending time: D= 250 ms for BCCH not combined (i.e. 55 time slots) D= 350 ms for BCCH combined (i.e. 77 time slots) N is the randomly number generated by the mobile in the range [0 to numberOfSlotsSpreadTrans-1] 4.615 ms is the time occupied by a time slot. MS Phase 2 The time T between two transmissions of the same RACH burst is the following (whatever the BCCH is combined or not): T= 4.615 x [S+(N + 1)] ms where S is a parameter depending on the BCCH configuration and on the value of numberOfSlotsSpreadTrans (see table hereafter) N is the randomly number generated by the mobile in the range [0 to numberOfSlotsSpreadTrans-1] 4.615 ms is the time occupied by a time slot. numberOfSlotsSpreadTrans 3, 8, 14, 50 4, 9, 16 5, 10, 20 6, 11, 25 7, 12, 32 S on non-combined BCCH S on combined BCCH 55 76 109 163 217 41 52 58 86 115 Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: [3 to 12, 14, 16, 20, 25, 32, 50] time slots bts 32 DP, Optimization 32 Request access command repetition process (RA_rep) From Rec 04.08, numberOfSlotsSpreadTrans has a different meaning for phase 1 and phase 2 mobiles. For phase 1 mobiles, if the value is too small, two resources may be allocated to the same mobile (double allocation). For phase 2 mobiles, it is different. The best trade-off is to take “32” which is very good for phase 2 mobiles and not too bad for phase 1 mobiles. The choice will depend on the quantities of GSM phase 1 and GSM phase 2 mobiles. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 384/629 V17.0 BSS Parameter User Guide (BPUG) For Mobile phase 1, numberOfSlotsSpreadTrans = 50 leads to the lower double allocation rate. For Mobile phase 2, numberOfSlotsSpreadTrans = 6, 7, 11, 12, 25, 32 (respectively 5, 10, 20) for BCCH combined (respectively BCCH not combined) leads to the lower double allocation rate. Therefore, for a network that handles a combination of both types of mobiles, numberOfSlotsSpreadTrans should be set to 32 (default value). See also chapter GSM Paging Repetition Process Tuning. pagingOnCell Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Enable or disable paging requests in a cell [enabled / disabled] bts enabled DP, Optimization Class 3 V9 enabled but can be disabled on special occasions (see Engineering Rules) PCH and RACH channel control When pagingOnCell is set to disabled, the BSC does not send any PAGING_COMMAND to the cell. This feature is used when operators want to forbid mobile terminated call set-up in specific cells. It can be useful during special events or in places like cinemas, theaters... retransDuration Description: Class 2 V8 Maximum number of occurrences of a same paging sub-group that separates the first and the last transmissions of the same paging message. [0 to 22] bts 10 DP, Optimization 10 Paging command repetition process (run by BTS) (Pag_rep) If many paging commands must be broadcast, repetitions of old paging messages are delayed because fresh paging has a higher priority. Therefore, repetitions could be so delayed that it leads to double paging. By setting this parameter to an accurate value retransDuration , the risk of sending very old paging messages is limited. Anyway, the value of this parameter is linked to the ones of nbOfRepeat and retransDuration. Furthermore, the following inequality, that is not checked by the system, must be true: retransDuration ≥ (delayBetweenRetrans + 1) x nbOfRepeat See also chapter GSM Paging Repetition Process Tuning. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 385/629 V17.0 BSS Parameter User Guide (BPUG) 5.25. FREQUENCY HOPPING PARAMETERS bscHopReconfUse Description: Class 1 V8 Whether frequency hopping reconfiguration is authorized in BTSs that use cavity coupling When frequency reconfiguration is authorized, it allows to automatically reconfigure the hopping sequence whenever a frequency is lost or recovered in the BTS. This parameter is only useful if there is at least one BTS with cavity coupling in the BSS. Otherwise its effect is neutral regardless of the value. [true / false] bsc true DP, Design true for a BSC that manages at least one BTS using cavity coupling The value (true or false) is indifferent for a BSC that manages only BTS with hybrid coupling Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Reconfiguration procedure If the value is ‘True’ then the value of btsHopReconfRestart (bts object) must be true in case of cavity coupling in the BTS. However, when enabling frequency hopping, it is advised to use hybrid coupling and synthesized frequency hopping. In order to facilitate the further use of frequency hopping in the network, the parameter bscHopReconfUse can be set to “True”, even if frequency hopping is not used yet. btsHopReconfRestart Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 2 V8 Whether hopping frequency reconfiguration is authorized on TX restarts in a cell [true / false] bts true DP, Optimization true (for a BTS using cavity coupling) false (for a BTS using hybrid coupling) Reconfiguration procedure If the value is ‘True’ then the value of bscHopReconfUse must be true. However, when enabling frequency hopping, it is advised to use hybrid coupling and synthesized frequency hopping. With cavity coupling, in order to facilitate the further use of frequency hopping in the network, the parameter btsHopReconfRestart can be set to “True”, even if frequency hopping is not used yet. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 386/629 V17.0 BSS Parameter User Guide (BPUG) btsIsHopping Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Whether frequency hopping is allowed in a cell [hopping / noHopping / hoppingWithCarrierFilling / noHoppingWithCarrierFilling] bts Hopping DP, Design Hopping Frequency Hopping Class 2 V7 The two main advantages of using Frequency Hopping are interferer and frequency diversities. Enabling frequency hopping allows to adapt and maximize the frequency reuse efficiency by maximizing the capacity in terms of offered Erlang/MHz/km². Moreover, enabling frequency hopping makes easier the task of frequency planning and TRXs addition. Although when using DTX there is a few number of RxQual measurements, there is no need to disable handovers on quality criteria, as no degradation was observed. When TRX are hopping, it is highly recommended to modify some TDMA configuration. Channel SDCCH must be set on time slot 1 of the concerned TDMA. Moreover this modification can be introduced before enabling frequency hopping. It is also recommended not to use Power Control with Frequency Hopping in case of cavity couplers. Indeed, with cavity couplers, the BCCH frequency can be part of the Mobile Allocation List (that is not possible in case of Hybrid couplers) and then the gap between the emitted power of two adjacent bursts could be at its maximum. Except this particular case (cavity coupler + FH + PWC) there is no restriction in combining Frequency hopping with Power Control. CAUTION! CAUTION! Remark: btsThresholdHopReconf Description: Class 2 V8 Minimum number of frequencies that must be working in a cell to allow frequency hopping reconfiguration. If this attribute defines the nominal number of cell frequencies, the reconfiguration process is deactivated. Refer to the btsHopReconfRestart parameter. [1 to 64] bts 1 DP, Optimization 1 Reconfiguration procedure This parameter is checked before reconfiguration is started, for cavity coupling. If there are less remaining frequencies than the value of this parameter, the cell is deconfigured. The minimum value (1) allows a cell to be reconfigured even if there is only one frequency still available. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 387/629 V17.0 BSS Parameter User Guide (BPUG) cellAllocation Description: Class 2 V7 List of no more than 64 frequencies allocated to a cell in the network frequency band. Normally, the maximum number of frequencies that can be set up with this parameter is 64 per frequency band. However, due to SI13 size constraints, when GPRS or EDGE is activated in the cell and there is at least one hopping data TDMA, the limitation becomes a maximum of 55 frequencies (in V15.0 and V15.0.1) ,52 frequencies (in V15.1 and V15.1.1), 49 frequencies (from V16). By definition, all cells covered by a given radio site use the same frequency band defined by the type of the network (standardIndicator). All cells declared as neighbor cells of a serving cell use the same frequency band as the serving cell. [1 to 124] (GSM 900 network), [975 to 1023] & [0 to 124] (E-GSM network), [955 to 1023] & [0 to 124] (GSM-R network), [512 to 885] (GSM 1800 network), [512 to 810] (GSM 1900 network) [128 to 251] (GSM 850 network) bts DP, Optimization see Engineering Rules This list must include all the frequencies used by TRX of the cell, even the BCCH frequency and shall respect following rules: With cavity couplers, two (2) consecutive frequencies must be spaced of at least 600 kHz in order to avoid interference With hybrid couplers, considering UL power control activated: in case of intra cell and intrasite configuration Nortel recommends 400kHz frequency spacing between TRX with or without frequency hopping. in case of intersite configuration, 200kHz frequency spacing are necessary between TRX with or without frequency hopping. These frequency spacings (400kHz in intrasite and intracell, 200kHz in intersite) guarantee a minimum of 12dB in C/I. This can provide certain quality of service. With particular applications (e.g. EDGE), an upper frequency spacing is needed (600kHz for EDGE). It is recommended to declare only 1 hopping frequency list by band (the use of the frequency band is optimal with all hopping frequencies in the same list and it is much easier for OAM). If at least one of the cell allocation ARFCN is in the range [975; 1023] & [0], the BCCH should be in that range also (this monoband EGSM cell does not support monoband PGSM MS nor dualband PGSM/DCS1800 MS), else BCCH should be a PGSM one. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 388/629 V17.0 BSS Parameter User Guide (BPUG) CAUTION! When setting CellAllocation, a check is performed at OMCR in order to verify the number of frequencies. This number is limited by the spread of frequencies • • • • if 1 =< spread of frequencies =< 112 Then max number of frequencies = 64 if 113 =< spread of frequencies =< 128 Then max number of frequencies = 29 if 129 =< spread of frequencies =< 256 Then max number of frequencies = 22 if 257 =< spread of frequencies =< 512 Then max number of frequencies = 18 The spread of frequencies is the maximal distance between the value of frequence calculed as (Fmax – Fmin +1).This spread of frequencies verification is performed for each band separately. For standard indicators like e-gsm and r-gsm, which have 2 ranged bands, the following must be taken into account: For E-GSM the range is [0..124]U[975..1023] ; so by realigning the frequence the result is [975…1022, 1023, 1,..124]. the distance for example100 and 1000 is 125 (not 901) because: 100 belongs to [0...124] spread of frequencies is 101 1000 belong to [975…1023] spread of frequencies is 24 fhsRef Description: Class 2 V7 Identifier of the frequencyHoppingSystem object that defines the frequency hopping management parameters for the radio time slot Setting this attribute and the maio attribute allows the time slot to obey frequency hopping laws. [0 to 63] channel DP, Optimization see Engineering Rules It is advised to use only one (1) fhsRef per cell (when the Mobile Allocation is the same for all its TRX), because it is time saving for creation at the OMC. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 389/629 V17.0 BSS Parameter User Guide (BPUG) hoppingSequenceNumber Description: Class 2 V7 Hopping sequence number used by a radio time slot which obeys frequency hopping laws. Select different HSNs for nearby cells that use the same set of frequencies. [0 to 63] frequencyHoppingSystem DP, Optimization see Engineering Rules Synthesised frequency hopping In case of synthesized frequency hopping, whatever the fractional reuse pattern for TCH, using a unique HSN per site allows to avoid frequency collisions. However, it leads to a specific MAIO plan, more restricting than with the use of different HSN in cells (needs more frequencies). Indeed, the frequency load would be higher with different HSN. But it is possible to reach the maximum fractional load (value limited by RF constraints to 16,6 % for 1X1 pattern and 50 % for 1X3 pattern in case of no intra-site collision). When intra-site collision is allowed, field experience has shown that with an appropriate tuning of the parameters, 1X1 can go up to 20% fractional load and 1X3 up to 58% while keeping a very good quality for the offered capacity.) with a unique HSN per site and then systematically avoiding frequency adjacencies. See also chapter General Rules For Synthesised Frequency Hopping Class 2 V7 Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: maio Description: Index in the list of frequencies allotted to a radio time slot, which obeys frequency hopping laws. Setting this attribute, together with the fhsRef attribute, allows the time slot to obey frequency hopping laws. [0 to N-1] N is the number of frequencies allotted to the time slot. channel DP, Optimization see Engineering Rules Synthesised frequency hopping The MAIO must be different for each TRX within a cell in order to avoid frequency collision. If the Mobile Allocation contains adjacent frequencies, the difference between two TRX MAIO within a cell must be greater or equal than two (2). However, for a 1X3 pattern, it is possible to use the same MAIO sequence in all cells of a same site. Moreover, for such a pattern, if each list of MA frequencies does not contain adjacent frequencies, adjacent MAIO can be used. For a 1X1 pattern, different MAIO for each TRX must be used and no adjacent MAIO if there are adjacent frequencies in the MA list. See also chapter General Rules For Synthesised Frequency Hopping Nortel confidential Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 390/629 V17.0 BSS Parameter User Guide (BPUG) mobileAllocation Description: Class 2 V7 List of frequencies allocated in the network frequency band to a radio time slot which obeys frequency hopping laws. Normally, the maximum number of frequencies that can be set up with this parameter is 63 i.e. 64 – BCCH frequency. However, due to SI13 size constraints, when GPRS or EDGE is activated in the cell and there is at least one hopping data TDMA (carrying at least one PDTCH), the limitation becomes a maximum of 55 – n frequencies (for V15.0 and V15.0.1) or 52 – n frequencies (for V15.1 and V15.1.1),or 49 – n frequencies (from V16) where n is the number of non-hopping frequencies in the cell. [1 to 124] (GSM 900 network), [975 to 1023] & [0 to 124] (E-GSM network), [955 to 1023] & [0 to 124] (GSM-R), [512 to 885] (GSM 1800 network), [512 to 810] (GSM 1900 network) [128 to 251] (GSM 850 network). frequencyHoppingSystem DP, Optimization Synthesised frequency hopping Baseband Frequency Hopping see Engineering Rules This list must include all the hopping frequencies used by a TRX. As the first TRX of a cell does not hop, it is not related to a MA (TRX channels frequency is BCCH). The following TRXs may have a common MA containing all the hopping frequencies (not including the BCCH frequency). With cavity couplers, two (2) consecutive frequencies must be spaced of at least 600 kHz in order to avoid interference, because of material constraints. With hybrid couplers, considering UL power control activated: in case of intra cell and intrasite configuration Nortel recommends 400kHz frequency spacing between TRX with or without frequency hopping. in case of intersite configuration, 200 kHz frequency spacing are necessary between TRX with or without frequency hopping. These frequency spacings (400kHz in intrasite and intracell, 200kHz in intersite) guarantee a minimum of 12dB in C/I. This can provide certain quality of service. With particular applications (e.g. EDGE), an upper frequency spacing is needed (600kHz for EDGE). It is recommended to declare only 1 hopping frequency list by band (the use of the frequency band is optimal with all hopping frequencies in the same list and it is much easier for OAM). Value range: Object: Type: Used in: Rec. value: Eng. Rules: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 391/629 V17.0 BSS Parameter User Guide (BPUG) trafficPCMAllocationPriority Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: DP, Optimization 255 for the TDMA supporting the BCCH 0 for the others Class 2 V9 Allocation priority of a TDMA frame on the covering site PCMs This attribute is used in case of Abis PCM reconfiguration. [0 to 255] transceiver see chapter SDCCH Dimensioning and TDMA priorities. zoneFrequencyHopping Description: Class 2 V9 Whether frequency hopping is authorised in the zone. If frequency hopping is not allowed in a zone, a channel objects that describe the radio time slots of the TDMA frames used in the zone cannot be allowed to hop. [hopping / not hopping] transceiverZone not hopping DP see Engineering Rules In case of a dualband cell and if PDTCHs are configured on the inner zone, that parameter must be set to “not hopping” on the transceiverZone corresponding to the inner zone. In any other case that parameter must be set to “hopping”. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: zoneFrequencyThreshold Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 2 V9 Minimum number of frequencies needed to allow frequency reconfiguration in the zone. [1 to 64] transceiverZone 1 DP TBD Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 392/629 V17.0 BSS Parameter User Guide (BPUG) 5.26. BSC LOAD MANAGEMENT PARAMETERS processorLoadSupConf Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: CAUTION! [0] The only accepted value is 0 (outOfRangeError). bsc 0 DP, Optimization 0 Mechanism up to V11 Mechanism defined from V12 This parameter was used before V12 release only to control the load on the BSC CPU boards. This parameter is valid for BSC12000 only. Class 3 V8 Threshold used in the load control algorithm by the BSC estimatedSiteLoad Description: Class 3 V15 This parameter is used: at site creation, in order to preset the erlang consumption of the new Cell Group ortherwise, in order to set the erlang consumption [0 to 1100] erlangs. 1100 is the internal erlang capacity of a TMU2. btsSiteManager 0 DP see Engineering Rules V15.1 Evolution of Load Balancing It is usually recommended to try to set the estimatedSiteLoad of a site at the creation of this site (with the maximum configuration wanted for this site) to be sure that at this time the global dimensioning of the BSC is correct. It may also help in handling exceptional events on some parts of the network. This parameter is available only from V15.1 Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: CAUTION! Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 393/629 V17.0 BSS Parameter User Guide (BPUG) 5.27. DUALBAND CELL PARAMETERS early classmark sending Description: Class 3 V10 Whether Early classmark sending procedure initiated by a multiband mobile and/or a 2G-3G mobile is allowed. The information is broadcast to the mobiles at regular intervals on the cell BCCH (SYSTEM INFORMATION n°3). [Not Allowed, Allowed] bts Not Allowed DP, Design Allowed Modified SYS INFO 3 Location Services GSM to UMTS handover (v17) When this parameter is set to “allowed”, the mobile sends the Classmark_Change message just after the SABM and UA frames exchanged during the Immediate_Assignment procedure. This message enables interband handover procedures (handovers on TCH and SDCCH, Directed Retry); Morever this parameter allows the mobile to send its capacity downlink Advanced Receiver performance. In GSM cells where handover to UTRAN is possible, or UTRAN measurement reporting is expected from the mobile, the "early classmark sending" must also be requested from the mobile. Therefore, if the operator is interested to have the SAIC mobile penetration, it is recommended to set this parameter to “Allowed” In single band networks where no handover to 3G is required, “early classmark sending” will be set to “not allowed”. In dual-band networks and in networks where handover to 3G may be requested, then early classmark sending will be set to “allowed”. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: multi band reporting Description: Class 3 V10 Indication of the number of cells to be reported for each GSM frequency band in multiband operation. This parameter is used both for normal and enhanced measurement reporting. [0 : “no outband cell is favoured” / 1 : “1 strongest outband cell is favoured” / 2 : “2 strongest outband cells are favoured” / 3 : “3 strongest outband cells are favoured” bts 0 : “no outband cell is favoured” DP, Optimization “two strongest outband cells are favoured” (case of privileged band) ”no outband cell is favoured” (case of no privileged band) Multiband reporting Enhanced Measurement Reporting (EMR) UTRAN cell reporting using legacy measurement reports (V17) Value range: Object: Default value: Type: Rec. value: Used in: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 394/629 V17.0 BSS Parameter User Guide (BPUG) Eng. Rules: For values indicating the one (1), two (2) or three (3) strongest cells out band, the multiband MS respectively reports the one, two or three strongest allowed cells outside the current frequency band. The remaining space in the report (at least 5, 4 or 3 cells) is used to give information about cells in the current frequency band. If there are still some remaining positions, they are used to report cells outside the current frequency band. When the operator wants to privilege one of the frequency band, it is advised to report two (2) cells outside the current frequency band, for cells in the privileged frequency band. Then, neighbour cells in the priority frequency band will be privileged. Actually, if multibandReporting is set to “1”, the risk is to report five (5) priority frequency band neighbour cells with a bad quality or signal strength (near priority frequency band boundaries for example) and one (1) good neighbour cell in the low priority frequency band, but under congestion. Thus the MS will not make a handover toward a good neighbour cell and the quality of service may be impacted. For cells outside the privileged frequency band, it is advised to report three (3) cells outside the current frequency band. Thus, it ensures the report of all (if less than 3) or at least three (3) neighours in the priority frequency band. In case no frequency band is preferred, the report of the “the six strongest cells” allows to make a handover toward the best neighbour cell, whatever the current cell is. In case of 2G-3G handover being enabled, and EMR disabled (use of normal measurement reporting), it is necessary to exercise caution fDDMultiRatReporting and when setting the parameters multiBandReporting . These parameters define the number of UTRAN cells and non-serving band GSM cells, respectively, that must be included by the mobile in the list of strongest cells in the measurement report. Therefore it leaves (6 - fDDMultiRatReporting multiBandReporting ) spaces for the serving band GSM cells. Therefore, if EMR is disabled, it is recommended not to exceed fDDMultiRatReporting = 2 and multiBandReporting = 2. standard indicator AdjC Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Type of network in which this neighbour cell is working Class 3 V10 [gsm / extended gsm / dcs1800 / pcs1900 / R gsm / gsmdcs (V12) / dcsgsm (V12) / gsm850 / gsm850pcs / pcsgsm850] adjacentCellHandover gsm DP, Optimization extended gsm if available in the network. See Engineering Rules Oher procedures (Dual Band Handling) The indicates standard indicator must have the same value in adjacentCellHandover or adjacentCellReselection objects and in the associated neighbour bts object. Refer to the standardIndicator parameter engineering rules to get more information about neighbours management. “gsmdcs” and “dcsgsm” are only available for S8000 DRX transceiver architecture. “eGSM” is only available for S8000 CBCF transceiver architecture. Nortel confidential CAUTION! PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 395/629 V17.0 BSS Parameter User Guide (BPUG) standard indicator AdjC Description: Value range: Object: Default value: Type: Rec. value: Used in: Type of network in which this neighbor cell is working [gsm / extended gsm / dcs1800 / pcs1900 / R gsm / gsmdcs (V12) / dcsgsm (V12) / gsm850 / gsm850pcs / pcsgsm850] adjacentCellReselection gsm DP, Optimization extended gsm if available in the network. See Engineering Rules Oher procedures (Dual Band Handling) Class 3 V10 Eng. Rules: The standard indicator must have the same value in adjacentCellHandover or adjacentCellReselection objects and in the associated neighbour bts object Refer to the standardIndicator parameter engineering rules to get more information about neighbours management. “gsmdcs” and “dcsgsm” are only available for S8000 DRX transceiver architecture. “eGSM” is only available for S8000 CBCF transceiver architecture. CAUTION! bCCHFrequency Description: Class 3 V7 Radio frequency allocated to a neighbour cell BCCH in the network frequency band. The information is broadcast on the serving cell SACCH. [1 to 124] (GSM 900 network), [512 to 885] (DCS 1800 network), [512 to 810] (PCS 1900 network), [955 to 1023] & [0 to 124] (R–GSM network), [975 to 1023] & [0 to 124] (E–GSM network), [128 to 251] (GSM 850 network). adjacentCellHandOver DP Value range: Object: Type: Rec. value: Used in: Eng. Rules: bCCHFrequency Description: Value range: Class 3 V7 Radio frequency used for selection and reselection management. The information is broadcast on the serving cell BCCH. [1 to 124] (GSM 900 network ), [512 to 885] (DCS 1800 network), [512 to 810] (PCS 1900 network), [955 to 1023] & [0 to 124] (R–GSM network), [975 to 1023] & [0 to 124] (E–GSM network). [128 to 251] (GSM 850 network) adjacentCellReselection DP Nortel confidential Object: Type: PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 396/629 V17.0 BSS Parameter User Guide (BPUG) Rec. value: Used in: Eng. Rules: Note: An adjacentCellReselection object can use the same BCCH as the serving cell to which it is associated. This allows a mobile to immediately recover the cell on which it was “camping” after being switched off, then switched back on, and is especially useful in the selection process. Directed Retry Handover: BSC (or local) mode bCCHFrequency Description: Class 2 V7 Radio frequency allocated to a cell BCCH (Broadcast Control CHannel) in the network frequency band. The information is broadcast on the cell SACCH. The BCCH frequency is automatically assigned to the radio time slot carrying the cell BCCH when the cell is brought into service (absoluteRFChannelNo attribute of the channel object describing the carrier TDMA frame TS0). It is broadcast to the radio time slot whenever modified. The BCCH is used by the BTS for broadcasting cell related system information to MS, such as frequency band and list of frequency channels used, authorized services and access conditions, list of neighbour cells, and radio parameters (maximum transmission strength, minimum reception strength, etc). [1 to 124] (GSM 900 network ), [512 to 885] (DCS 1800 network), [512 to 810] (PCS 1900 network), [955 to 1023] & [0 to 124] (R–GSM network), [975 to 1023] & [0 to 124] (E–GSM network). [128 to 251] (GSM 850 network) bts DP Value range: Object: Type: Rec. value: Used in: Eng. Rules: If at least one of the cell allocation ARFCN is in the range [975; 1023] & [0], the BCCH should be in that range also (this monoband EGSM cell does not support monoband PGSM MS nor dualband PGSM/DCS1800 MS), else BCCH should be a PGSM one. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 397/629 V17.0 BSS Parameter User Guide (BPUG) standardIndicator Description: Class 2 V10 Type of network in which the cell is working From the value given to this attribute, the OMC–R determines the network frequency band and the frequencies that can be used by all radio entities (cells and radio time slots) in the related site. [gsm / extended gsm / dcs1800 / pcs1900 / R gsm / gsmdcs (V12) / dcsgsm (V12) / gsm 850 / gsm850pcs / pcsgsm850] bts DP Value range: Object: Type: Rec. value: Checks: GSM 900 network (gsm) The GSM 900 frequency band is 2*25 MHz wide and includes 124 pairs of carrier frequencies, numbered [1 to 124], which are 200 kHz apart: Uplink direction (MS–to–BTS) = 890 to 915 MHz f1 = 890 + 0.2xN MHz where N = [1 to 124] Downlink direction (BTS–to–MS) = 935 to 960 MHz f2 = f1 + 45 MHz GSM 850 network The GSM 850 frequency band is 2*25 MHz wide and includes 124 pairs of carrier frequencies, numbered [1 to 124], which are 200 kHz apart: Uplink direction (MS–to–BTS) = 824 to 849 MHz f1 = 824.2 + 0.2x N MHz where N = [1 to 124] Downlink direction (BTS–to–MS) = 869 to 894 MHz f2 = f1 + 45 MHz EXTENDED GSM network (extended gsm) The extended GSM frequency band is 2*35 MHz wide and includes 174 pairs of carrier frequencies, numbered [0 to 124] and [975 to 1023], which are 200 kHz apart: Uplink direction (MS–to–BTS) = 880 to 915 MHz f1 = 880.2 + 0.2x(N – 975) MHz where N = [975 to 1023] f1 = 890 + 0.2xN MHz where N = [0 to 124] Downlink direction (BTS–to–MS) = 925 to 960 MHz f2 = f1 + 45 MHz GSM–R network (R gsm) The GSM–R frequency band is 2*39 MHz wide and includes 194 pairs of carrier frequencies, numbered [0 to 124] and [955 to 1023], which are 200 kHz apart: Uplink direction (MS–to–BTS) = 876 to 915 MHz f1 = 876.2 + 0.2x(N – 955) MHz where N = [955 to 1023] f1 = 890 + 0.2xN MHz where N = [0 to 124 Downlink direction (BTS–to–MS) = 921 to 960 MHz f2 = f1 + 45 MHz GSM 1800 network (dcs1800) Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 398/629 V17.0 BSS Parameter User Guide (BPUG) The GSM 1800 frequency band is 2*75 MHz wide and includes 374 pairs of carrier frequencies, numbered [512 to 885], which are 200 kHz apart: Uplink direction (MS–to–BTS) = 1710 to 1785 MHz f1 = 1710k2 + 0.2x(N – 512) MHz where N = [512 to 885] Downlink direction (BTS–to–MS) = 1805 to 1880 MHz f2 = f1 + 95 MHz GSM 1900 network (pcs1900) The GSM 1900 frequency band is 2*60 MHz wide and includes 299 pairs of carrier frequencies, numbered [512 to 810], which are 200 kHz apart: Uplink direction (MS–to–BTS) = 1850 to 1910 MHz f1 = 1850.2 + 0.2x(N – 512) MHz where N = [512 to 810] Downlink direction (BTS–to–MS) = 1930 to 1990 MHz f2 = f1 + 80 MHz GSM 900 – GSM 1800 network (gsmdcs) The primary band is GSM 900 The secondary band is GSM 1800 GSM 1800 – GSM 900 network (dcsgsm) The primary band is GSM 1800 The secondary band is GSM 900 GSM 850 – GSM 1900 network (gsmdcs) The primary band is GSM 850 The secondary band is GSM 1900 GSM 1900 – GSM 850 network (dcsgsm) The primary band is GSM 1900 The secondary band is GSM 850 Remark: Used in: Eng. Rules: As P-GSM range is included in E-GSM one, the following table gives for each current cell standard indicator, the type (main or other) of neighbouring cells according to their standard indicator: standard indicator Adjc (neighbouring cell) PGSM standardIndicator (current cell) GSM 900 E GSM GSM 1800 E GSM GSM 1800 The frequency bands defined hereabove are the definition of the ETSI. Concentric/DualCoupling/DualBand Cell Handover main main other other main other other other main If one of a cell ARFCN is in [975;1023] & [0] range, this monoband EGSM (RGSM or EGSM) cell does not support monoband PGSM MS nor dualband PGSM/DCS1800 MS. If a EGSM cell has a BCCH in PGSM band, a PGSM mobile will listen to it and may be handed over in that cell on a TCH in the E band. In that case, the mobile will send a handover failure. Sys-infos management: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 399/629 V17.0 BSS Parameter User Guide (BPUG) According to recommendations, only « main » frequencies can be present in the SI2 and SI2bis (resp. 5 and 5bis). Following table gives the standard indicator of the neighbouring cells that can be included in the different sys_info messages. (extended gsm is noted EGSM in the table). SYS_INFO SI2 / SI5 GSM 900 standardIndicator (current cell) E GSM GSM 1800 SI2 bis / SI5 bis SI2 ter / SI5 ter GSM GSM + E GSM GSM 1800 GSM if needed GSM + E GSM if needed GSM 1800 if needed E GSM + GSM 1800 (1) GSM 1800 GSM + E GSM Note (1): In that case, the number of frequencies in the frequency list is limited due to their large range. => Thus, due to the range of frequencies in EGSM + GSM 1800 bands, and the fact that only 1 message (ter) can contain such neighbours info (if StandardIndicator = GSM), it is strongly recommended to set the standard indicator of PGSM cells containing EGSM neighbours to extended gsm (2 messages to encode EGSM neighbours). Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 400/629 V17.0 BSS Parameter User Guide (BPUG) 5.28. DTX PARAMETERS cellDtxDownLink Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 3 Whether the use of discontinuous transmission in BTS–to–MS direction is allowed in a cell [enabled / disabled] bts enabled DP, Optimization see Engineering Rules Downlink DTX DTXDownLink is particularly interesting in case of low interfered networks with fractional reuse patterns for frequency plan. In this case, it is recommended to uses a reactive configuration with a short delay between HO decision (runHandover=1) and with short average windows (Hreqt = 1, HreqAve = 4). Ho margins can also be lowered. Using this feature may create a more sensitivity to bad values (fading, frequencies collision). Activation of DTXDownlink when DTX is already used leads to a diminution in the precision of the measurement on the cell, on quality and on level. V7 CAUTION! dtxMode Description: Class 3 V7 MS control of the discontinuous transmission mechanism in a cell Discontinuous transmission is designed to lessen MS battery consumption and diminish interference by breaking off the transmission when no data or speech are being transmitted. [FRmsmayuseDTX / HRmsshallnotuseDTX, FRmsshalluseDTX / HRmsshallnotuseDTX, FRmsmayuseDTX / HrmsmayuseDTX, FRmsshallnotuseDTX / HRmsshallnotuseDTX, FRmsshalluseDTX / HrmsshalluseDTX, FRmsshallnotuseDTX / HRmsshalluseDTX] bts msMayUseDtx DP, Optimization msShallUseDtx Uplink DTX When AMR is activated that parameter should be set to FRmsshalluseDTX / HRmsshalluseDTX See also chapter Impact of DTX on Averaging Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: CAUTION! Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 401/629 V17.0 BSS Parameter User Guide (BPUG) 5.29. MISCELLANEOUS Data14_4OnNoHoppingTs Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 3 V12 Whether data 14.4 kbit/s transmission rate is allowed at bts level on the non hopping TSs [disabled / enabled] bts disabled DP, Optimization TBD data mode 14.4 kbit/s Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Whether data 14.4 kbit/s transmission rate is allowed [disabled / enabled] transcoderBoard disabled DP TBD Class 2 V12 data non transparent mode Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: data non transparent mode Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Nortel confidential Class 3 V12 Set of transmission rates used for data non transparent mode transmission of the Radio interface and Abis interface. [9.6 / 14.4] (kbit/s) bts 9.6 kbit/s DP TBD Class 3 V12 Set of transmission rates used for data non transparent mode transmission of the Radio interface and Abis interface. [9.6 / 14.4] (kbit/s) signallingPoint 9.6 kbit/s DP TBD PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 402/629 V17.0 BSS Parameter User Guide (BPUG) data transparent mode Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: DP TBD Class 3 V12 Set of transmission rates used for data transparent mode transmission of the Radio interface and Abis interface. [“1.2/0.075” / 0.6 / 1.2 / 2.4 / 4.8 / 9.6 / 14.4] (kbit/s) bts data transparent mode Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: DP TBD Class 3 V12 Set of transmission rates used for data transparent mode transmission of the Radio interface and Abis interface. [“1.2/0.075” / 0.6 / 1.2 / 2.4 / 4.8 / 9.6 / 14.4] (kbit/s) signallingPoint measurementProcAlgorithm Description: Value range: Whether the new L1M interface is used [L1MV1, L1MV2] L1MV1: the older L1M is used L1MV2: the newer L1M is used bts DP, Optimization L1MV2 Measurement Processing Direct TCH Allocation and Handover Algorithms Class 2 V12 Object: Type: Rec. value: Used in: Eng. Rules: L1MV2 is not supported on DCU2. It is not recommended to set L1MV2 on a DCU2/DCU4 BTS mixed configuration since the enhancements offered will be available only on part of the site so with a call processing not homogeneous on the whole communications. Major benefits are: ability to support advanced capacity and coverage features such as “Automated cell tiering” capture process more reactive less handover failure (better updating of eligible cells) Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 403/629 V17.0 BSS Parameter User Guide (BPUG) early decisions more accurate (0.5 s saved on the processing delay of first measurements) Refer also to chapter Layer 1 Management: Changes Between V1 and V2 siteGsmFctList Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 2 V7 List of up to 14 elements that identify the GSM functions configured in a site BCF [entityMgt / download / siteMgt / abisSig / abisTraf / rfTrans / rfRecep / cellMgt / fhMgt / tdmaMgt / tsMgt / gsmTime / car0Fil / freqMgt] btsSiteManager site Mgt/abisSig DP, Optimization [entityMgt / download / siteMgt / abisSig / abisTraf / rfTrans / cellMgt / fhMgt / tdmaMgt / tsMgt] It is always useless to put the elements “rfRecep”, “gsmTime” and “car0Fill” in the list because these functions are not yet implemented. The function “freqMgt” must be included in the list only when using cavity coupling. It is advised to put the function “fhMgt” even if frequency hopping is not used in the network, in order to avoid a class 2 parameter change when introducing this feature. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 404/629 V17.0 BSS Parameter User Guide (BPUG) 5.30. INTERFERENCE CANCELLATION PARAMETERS interferer cancel algo usage Description: Class 2 V10 Correlation ratio of the input signals received from the normal and diversity antennas. This ratio enables to adapt the SPU software (the interferer cancellation algorithm) to the propagation conditions. Correlation ratio = 0 means that the interferer cancellation algorithm is inactive. [0 to 100] % bts 0 DP, Design see Engineering Rules Interference Cancellation Three values are necessary and sufficient to cover the client’s needs according to the sold options (it is quite unlikely that a more refined fine-tuning will bring anything more): - 0%: Maximum Ratio Combining (best pure thermal noise sensitivity): no interference cancellation, minimum speed correction. - 50%: MRC when no interferers (same pure thermal noise sensitivity as 0%): interference cancellation, medium speed correction. - 100%: Approximate MRC when no interferers: interference cancellation, best speed correction. See also chapter Interference Cancellation Usage. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: diversity Description: Class 2 V7 Activation parameter of Receive diversity in a cell. This parameter is used to control the activation of receive diversity and the choice of the diversity uplink signal processing algorithm. before v17.0 : “enabled”/”disabled” In v17.0 and after : “enabled”/”disabled”/”enhancedDiversity” bts enabled DP see Eng. rules Joint Diversity (v17) and Interference Cancellation. Note that Joint Diversity is useful specifically for EDGE, not for speech services. Please refer to aPUG document ([A1]) To activate the interference cancellation feature, diversity must be activated. 1/ Before v17.0 : Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 405/629 V17.0 BSS Parameter User Guide (BPUG) diversity = “enabled”, provided diversity antenna(s) have been fitted to the BTS. diversity = “disabled” otherwise 2/ In and after v17.0 : diversity = “enhancedDiversity”, for eDRX and Radio Module family, provided diversity antenna(s) have been fitted to the BTS. diversity = “disabled” in other cases. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 406/629 V17.0 BSS Parameter User Guide (BPUG) 5.31. PCM ERROR CORRECTION PARAMETERS Note : this feature is no longer supported as of V17. enhancedTRAUFrameIndication Description: before V17 : Whether the BTS uses the Enhanced TRAU Frame (ETF) for TCU After V17 : This parameter is no longer useful in V17 as the feature PCM Error Correction is no longer supported Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: [notAvailable / available / active] bsc n/a DI, Optimization n/a PCM Error Correction The PCM Error Correction is no longer supported as of BSS V17 release. This parameter is no longer useful and the OMC-R V17 automatically forces its value to “notAvailable”. V12 pcmErrorCorrection Description: Class 2 V12 Before V17 : whether the bts uses the new ETF (Enhanced TRAU Frame) frame (set to “1”) or the ETSI “Rec 08.60” frame (set to “0”). After V17 : This parameter is no longer useful in V17 as the feature PCM Error Correction is no longer supported. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: [0 / 1] bts n/a DP, Optimization n/a PCM Error Correction The PCM Error Correction is no longer supported as of BSS V17 release. This parameter is no longer useful and the OMC-R V17 automatically forces its value to 0. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 407/629 V17.0 BSS Parameter User Guide (BPUG) 5.32. CELL TIERING PARAMETERS enhCellTieringConfiguration Description: Class 3 V14 This attribute allows to configure the cell tiering algorithm at BTS level instead of the cellTieringConfiguration attribute from V14 release BSC. This parameter is composed of the following five parameters: hoMarginTiering nbLargeReuseDataChannels numberOfPcwiSamples pwciHreqave selfTuningObs Object: Type: handOverControl DP, Optimization hoMarginTiering Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 3 V14 Hysteresis between the uCirDLH and lCirDLH tiering thresholds. Used to avoid ping-pong handovers (expressed in dB) [0 to 63] dB handOverControl 4 dB DP, Optimization 4dB (to be optimized with the HO cell tiering monitoring) Automatic cell tiering (from V12) interferenceType Description: Class 3 V14 It is used for identifying the type of interference created by a neighbor cell. The possible values are not applicable (no interference), adjacent interference or cochannel interference. [notApplicable / adjacent / coChannel] adjacentCellHandOver notApplicable DP, Optimization This parameter should be set according to frequency plan strategy. Automatic cell tiering (from V12) Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 408/629 V17.0 BSS Parameter User Guide (BPUG) nbLargeReuseDataChannels Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 3 V14 Mean number of logical channels belonging to the large frequency reuse pattern and used at the same time for data communications [-16 to +16] handOverControl 0 DP, Optimization To be determined according to configuration (see below) Automatic cell tiering (from V12) This parameter gives the mean number of radio TS in the large reuse pattern (BCCH) used for data communications (and consequently not available for tiering). nbLargeReuseDataChannels = number of timeslots dedicated GPRS + average number of timslots for 14.4 if the parameter data 14.4 OnNoHoppingTs is set to 1. This last value can be obtained through the counters 1705/2 and 1707/2. numberOfPwciSamples Description: Class 3 V14 Minimum number of PwCI samples required to reach a reliable distribution (representative of the real distribution in the whole cell) * 1000 [0 to 60] handOverControl 20 DP, Optimization 20. However, it is a deal between PWCI distribution refresh time and accurancy (see below). Automatic cell tiering (from V12) It gives the minimum number of PWCI samples required to reach a reliable distribution of PWCI that will be representative of the real distribution in the whole cell x 1000. The number of samples before a PWCI distribution is undertaken is : 1000 x numberOfPwciSamples. For example, in a cell bearing 29 TCHs and loaded at 75%, at each moment, 0.75x29=21.75 TCHs are occupied. Then, every 480 ms we’ll have 21.75 samples available and every second (1000*21.75)/480=45.3 samples. If we set numberOfPwciSamples at 20, a PWCI distribution will be computed when 20000 samples will be available, wich means that a PWCI distribution will be computed every 20000/45.3 = 441.5 seconds ( almost every 7 minutes and a half). Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 409/629 V17.0 BSS Parameter User Guide (BPUG) pwciHreqave Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 3 Averaging window size for PwCI. It defines the number of measurement reports for a PWCI arithmetic averaging. [0 to 16] handOverControl 8 DP, Optimization 8 Automatic cell tiering (from V12) V12 In a given cell, each communication in the cell reports its measurements every 480 ms which allows computing the PWCI. When 20000 samples are gathered in the cell, a distribution of all the PWCI is computed and, lCirDLH and uCirDLH are determined for the cell. In order to take a tiering decision, a PWCI is averaged over a pwciHreqAve window, for each communication and compared to lCirDLH and uCirDLH obtained from the previous distribution, to lead (or not) to a handover decision. selfTuningObs Description: Class 3 V12 BTS mode of the sending the PwCI distribution on the Abis interface. This allows a closer monitoring of the cell tiering feature behavior once activated. [pwCi distribution not sent, pwCi distribution sent after gathering, one pwCi distribution sent per hour] handOverControl pwCi distribution not sent DP, Optimization Other than “pwCi distribution not sent” when fine tuning the feature, with close monitoring needed. Automatic cell tiering (from V12) The possible values are pwCi distribution not sent (PWCI distribution is gathered but not sent onto the Abis interface), pwCi distribution sent after gathering (the distribution is sent each time a new tiering threshold is computed for a maximum of 10 cells) or one pwCi distribution sent per hour (the distribution is sent when a new tiering threshold is computed but no more than one message every hour for a maximum of 40 cells). PWCI distribution may be gathered and sent onto the Abis interface independantly of tiering activation. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Remark: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 410/629 V17.0 BSS Parameter User Guide (BPUG) 5.33. ENCODING PARAMETERS speechMode Description: Class 3 V12 List of the speech algorithms associated with channel use modes in the cell The “full rate” value refers to the standard algorithm. The “enhanced full rate” value only applies when all the TCUs linked to the BSC are equipped with TCB2 boards. list of [algoid] where algoid id: full rate, enhanced, full rate, AMR full rate, AMR half rate bts [full rate, enhanced full rate] DP [full rate, enhanced full rate] AMR - Adaptative Multi Rate FR/HR When AMR is activated, SpeechMode must be set to full rate, enhanced full rate, AMR full rate, AMR half rate Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: CAUTION! speechMode Description: Class 3 V12 List of the speech algorithms associated with channel use modes on the A interface. The “full rate” value refers to the standard algorithm. The “enhanced full rate” value only applies when all the TCUs linked to the BSC are equipped with TCB2 boards. list of [algoid] where algoid id: full rate, enhanced, full rate, AMR full rate, AMR half rate signallingPoint [full rate, enhanced full rate] DP [full rate, enhanced full rate] AMR - Adaptative Multi Rate FR/HR When AMR is activated, SpeechMode must be set to full rate, enhanced full rate, AMR full rate, AMR half rate Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: CAUTION! Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 411/629 V17.0 BSS Parameter User Guide (BPUG) 5.34. SMS-CELL BROADCAST PARAMETERS smsCB Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: SMS-Cell Broadcast Configuration of logical channels and broadcast of short messages are managed by two separate OMC-R functions. When a short message broadcast is started, the presence of a CBCH in the channelType of a channel object is dependent on a concerned bts object. However, the SMS-CB function are not aware of changes made to that attribute. Consequently, withdrawing a CBCH from the configuration will stop any short message broadcast in the concerned cell without th SMSCB function knowing. Class 3 V12 Whether broadcasting of short messages in unacknowledged mode is authorized in a cell. [used / unused] bts used DP Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 412/629 V17.0 BSS Parameter User Guide (BPUG) 5.35. PROTECTION AGAINST INTRACELL HO PING-PONG PARAMETERS capacityTimeRejection Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Remark: CAUTION! Applies to a BSC 3000 architecture only. When AMR is activated that parameter should be set to 40 s Class 3 V14 Rejection time of a capacity intracell handover after an intracell handover [0 to 120 s.] handOverControl 0 s. DP [15 to 30 s.] Protection against Intracell HO Ping-Pong Handover mechanisms (AMR) minTimeQualityIntraCellHO Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Remark: Note: CAUTION! Applies to a BSC 3000 architecture only. Class 3 V14 Rejection time of a quality intracell handover after an intracell handover [0 to 120 s.] handOverControl 0 s. DP [0 to 10 s.] Protection against Intracell HO Ping-Pong AMR - Adaptative Multi Rate FR/HR That parameter can be named qualityTimeRejection in the literature. When AMR is activated that parameter should be set to 5 s Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 413/629 V17.0 BSS Parameter User Guide (BPUG) 5.36. AUTOMATIC HANDOVER ADAPTATION PARAMETERS selfAdaptActivation Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Use for activate the Automatic Handover adaptation [enabled / disabled] bts disabled DP enabled Automatic handover adaptation Class 3 V12 servingfactorOffset Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 3 This attribute defines the offset linked to the serving cell, used to decrease the HO margin, in some specific cases [-63 to 63] handoverControl -2 DP 0 Automatic handover adaptation V12 Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 414/629 V17.0 BSS Parameter User Guide (BPUG) neighDisfavorOffset Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Note: Class 3 V12 This attribute modifies the offset linked to the neighbouring cell, used to increase the HO marging, in some specific cases [-63 to 63] handoverControl 2 DP 2 Automatic handover adaptation That parameter can be named offsetNeighbouringCell at the MMI. rxQualAveBeg Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 3 V12 This attribute defines the number of quality measurement results used by the power control mechanism, in short averaging algorithm [1 to 10] handoverControl 2 DP same as RxlevHreqAveBeg Automatic handover adaptation Fast Power Control at TCH assignment (Pc_3) Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 415/629 V17.0 BSS Parameter User Guide (BPUG) 5.37. GSM TO UMTS HANDOVER PARAMETERS cId Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: 0..65535 adjacentCellUTRAN 0 DP n/a GSM to UMTS handover (v17) N/A Class 3 Cell identity of the UMTS neighbouring cell for handover V17 compressedModeUTRAN Description: Class 3 V17 flag to indicate whether compressed mode UTRAN is supported or not. This flag is used by the network to indicate to mobiles whether to use a compressed version of the INTER RAT HANDOVER INFO message (UE to UTRAN message). enabled/disabled bts disabled DP disabled GSM to UMTS handover (v17) The UTRAN_CLASSMARK_CHANGE message sent by UE to the BSS takes about 2 or 3 radio frames. However, when supported by the UTRAN network, it is possible to reduce the size of this message thanks to the compression of UE radio access capabilities and predefined configuration IE. This option is indicated in IMMEDIATE_ASSIGNMENT message sent to the UE (IA rest octets fields). For that purpose, the parameter compressedModeUTRAN indicates whether compression of UE information elements is supported. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: diversityUTRAN Description: Value range: Object: Default value: Type: Rec. value: Class 3 V17 flag indicating whether there is diversity in the neighbouring UTRAN cell no diversity/diversity adjacentCellUTRAN no diversity DP see Eng. rules Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 416/629 V17.0 BSS Parameter User Guide (BPUG) Used in: Eng. Rules: GSM to UMTS handover (v17) Please refer to diversity earlyClassmarkSendingUTRAN Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 3 V17 flag indicating whether UTRAN classmark change message shall be sent with Early Classmark Sending disabled/enabled bts disabled DP enabled GSM to UMTS handover (v17) earlyClassmarkSendingUTRAN shall be set to “enabled” before handover 2G to 3G feature is activated. fDDARFCN Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: fDD channel number of the UTRAN neighbouring cell 0..16383 adjacentCellUTRAN N/A DP N/A GSM to UMTS handover (v17) N/A Class 3 V17 gsmToUMTSServiceHo Description: Class 3 V17 This parameter serves to disable 2G-3G handover at BSC level or to indicate the preference (2G versus 3G cells) to be applied for handovers “should”/”should not”/”shall not”/”gsm to UMTS HO disabled” bsc “gsm to UMTS HO disabled” DP “should” GSM to UMTS handover (v17) See GSM to UMTS handover (v17) section. This parameter is useful in only 2 cases : Case n°1 : the “service handover” field in HANDOVER REQUEST and ASSIGNMENT REQUEST is missing. Nortel confidential Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 417/629 V17.0 BSS Parameter User Guide (BPUG) Case n°2 : the network operator wants to disable the 2G to 3G handover on the BSC, regardless of the presence, and/or the value, of the “service handover” field. hoMarginUTRAN Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Handover margin for PBGT handover to a UMTS cell -63 dB to 63 dB, in 1dB steps adjacentCellUTRAN 63 dB DP -6 GSM to UMTS handover (v17) If the operator wants to unload GSM traffic: Class 3 V17 UMTS RSCP is lower than GSM Rxlev where a quite a high value is required for a good quality. This margin controls the probability to perform a handover. Note that a the quality of UTRAN neighboring is ensured by the fDDreportingThreshold and fDDreportingThreshold2 parameter hoMarginAMRUTRAN Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 3 V17 Handover margin for intercell quality handovers to UMTS, for AMR calls -63 dB to 63 dB, in 1dB steps adjacentCellUTRAN 63 dB DP see Eng. Rules GSM to UMTS handover (v17) TBD hoMarginRxLevUTRAN Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: -63 dB to 63 dB, in 1dB steps adjacentCellUTRAN 63 dB DP see Eng. Rules GSM to UMTS handover (v17) TBD Class 3 V17 handover margin for signal strength handover to UMTS Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 418/629 V17.0 BSS Parameter User Guide (BPUG) hoMarginRxQualUTRAN Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: -63 dB to 63 dB, in 1dB steps adjacentCellUTRAN 63 dB DP see Eng. Rules GSM to UMTS handover (v17) TBD Class 3 V17 handover margin to be used for signal quality handover to UMTS hoMarginDistUTRAN Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: -63 dB to 63 dB, in 1dB steps adjacentCellUTRAN 63 dB DP see Eng. Rules GSM to UMTS handover (v17) TBD Class 3 handover margin for handover to UMTS on distance criterion V17 hoMarginTrafficOffsetUTRAN Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 3 V17 offset to be subtracted to the homarginUTRAN to allow handover for traffic reason when the current cell is congested 0 dB to 63 dB, in 1dB steps adjacentCellUTRAN 63 dB DP see Eng. Rules GSM to UMTS handover (v17) TBD Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 419/629 V17.0 BSS Parameter User Guide (BPUG) hoPingpongCombinationUTRAN Description: Class 3 V17 list of pair of causes indicating the causes of ping-pong handovers in the overlapping areas. Each pair is structured as follows : (incoming HO cause, outgoing HO cause). Incoming HO cause indicates the essential handover cause which leads to enter the neighbour cell. outgoing HO cause indicates the non-essential handover cause which leads to leave the neigbour cell. list of pairs of causes (GSM to UMTS HO, UMTS to GSM HO): traffic, powerbudget, directed retry, Rxlev, Rxqual, distance, O&M (forced HO), all, allpowerbudget. adjacentCellUTRAN (rxqual, pbgt) DP (all, pbgt) GSM to UMTS handover (v17) Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: hoPingpongTimeRejectionUTRAN Description: Class 3 V17 time that must elapse before attempting another handover towards an UTRAN cell. Refer to HOPingpongCombinationUTRAN attribute for the combinations of HO causes for which this timer applies. To avoid ping-pong handovers this new timer is started after a successful handover. Up to the expiry of this timer, any HANDOVER INDICATION message received from the BTS is ignored by the BSC. list of pairs of causes (GSM to UMTS HO, UMTS to GSM HO): traffic, powerbudget, directed retry, Rxlev, Rxqual, distance, O&M (forced HO), all, allpowerbudget. adjacentCellUTRAN (Rxqual, pbgt) DP (all, pbgt) GSM to UMTS handover (v17) Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: hoRejectionTimeOverloadUTRAN Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 3 V17 time that must elapse before attempting another handover towards a congested UTRAN cell 0..60 (60 means “immediately”) bsc 30 seconds DP 30 seconds GSM to UMTS handover (v17) Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 420/629 V17.0 BSS Parameter User Guide (BPUG) locationAreaCodeUTRAN Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Location area code of the UMTS neighbouring cell 0..65535 adjacentCellUTRAN N/A DP N/A GSM to UMTS handover (v17) N/A Class 3 V17 mobileCountryCodeUTRAN Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: 000…999 (string) adjacentCellUTRAN N/A DP N/A GSM to UMTS handover (v17) N/A Class 3 V17 Mobile Country Code (MCC) of the UTRAN neighbouring cell mobileNetworkCodeUTRAN Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: 000…999 (string) adjacentCellUTRAN N/A DP N/A GSM to UMTS handover (v17) N/A Class 3 V17 Mobile Network Code (MNC) of the UTRAN neighbouring cell offsetPriorityUTRAN Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 3 V17 priority offset applied by the BSC when selecting the candidate cell for the handover process 1..5 adjacentCellUTRAN 1 DP 1 GSM to UMTS handover (v17) Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 421/629 V17.0 BSS Parameter User Guide (BPUG) rNCId Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: identity of the UTRAN neighbouring cell’s RNC 0..4095 adjacentCellUTRAN N/A DP N/A GSM to UMTS handover (v17) N/A Class 3 V17 rxLevDLPbgtUTRAN Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 3 V17 downlink signal strength threshold above which handovers to UTRAN for cause power budget are inhibited <-110 dBm, -110<x<-109, … to >-48 dBm adjacentCellUTRAN >-48 DP see Eng. Rule GSM to UMTS handover (v17) This parameter has to be managed carefully because it can prevent all the UTRAN handover for power budget when set to less than -110. Moreover, the setting of this parameter has to be done with the help of some radio measurement campaigns. This parameter shall be disabled by setting the value to more than –48 (dBm). rxLevMinCellUTRAN Description: Class 3 V17 minimum signal strength level that the MS must measure on an UMTS neighbour cell to be able to be granted a handover to this UMTS neighbour cell <-110 dBm, -110<x<-109, … to >-48 dBm adjacentCellUTRAN >-48 DP see Eng. Rule GSM to UMTS handover (v17) The value of rxLevMinCellUTRAN must be greater than the value of minimumCpichRscpValueForHO UTRAN parameter. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 422/629 V17.0 BSS Parameter User Guide (BPUG) scramblingCode Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: scrambling code of the UTRAN neighbouring cell 0..511 adjacentCellUTRAN N/A DP N/A GSM to UMTS handover (v17) N/A Class 3 V17 t3121 Description: Class 3 V17 t3121 has the same use as t3103 in the GSM inter-BSC handover procedure. It sets the value before countdown of T3121 timer defined in the GSM specification . T3121 starts when the BSC sends an INTER SYSTEM TO UTRAN HANDOVER message to the mobile. T3121 stops when the mobile has correctly seized the UTRAN channel. The purpose of this timer is for the BSC to keep the old channels long enough for the mobile to be able to return to the old channels if necessary. On expiry of T3121 (indicating the mobile is lost), the BSC may release the channels. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: 2..255 seconds bts 12 seconds DP 12 seconds GSM to UMTS handover (v17) T3121 purpose is very similar to T3103 one. However, INTERSYSTEM TO UTRAN HANDOVER COMMAND message from BSS to Mobile is much larger than the HANDOVER COMMAND message so it takes about one second more to send the inter system message to the MS. An additional safety margin should therefore be considered for LAPDm repetitions. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 423/629 V17.0 BSS Parameter User Guide (BPUG) 5.38. AMR - ADAPTATIVE MULTI RATE FR/HR PARAMETERS BTS OBJECT amrUlFrAdaptationSet Description: Class 3 V15 Define the lines of parameter used for the adaptation mechanism. It sets the C/I thresholds when AMR speech codecs are used on a FR channel in UL.when AMR speech codecs are used. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: [0 to3] bts 0 DP 3 Codec mode adaptation 0: typical radio condition 1: optimistic radio condition 2: pessimistic radio condition 3: personalize with the BSC data configuration table The recommanded value of 0 offers a good compromise between HR penetration and radio environment. For optimization of the table amrUlFrAdaptationSet should be turn to 3 (refer to AMR Activation Guideline PE/BSS/APP/11438 in Reference Documents) See also chapter AMR Engineering Studies. amrUlHrAdaptationSet Description: Class 3 V15 Define the lines of parameter used for the adaptation mechanism. It sets the C/I thresholds when AMR speech codecs are used on a FR channel in UL.when AMR speech codecs are used. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: [0 to3] bts 0 DP 3 Codec mode adaptation 0: typical radio condition 1: optimistic radio condition 2: pessimistic radio condition 3: personalize with the BSC data configuration table The recommanded value of 0 offers a good compromise between HR penetration and radio environment. For optimization of the table amrUlHrAdaptationSetshould be turn to 3 (refer to AMR Activation Guideline PE/BSS/APP/11438 in Reference Documents) See also chapter AMR Engineering Studies. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 424/629 V17.0 BSS Parameter User Guide (BPUG) amrDlFrAdaptationSet Description: Class 3 V15 Define the lines of parameter used for the adaptation mechanism. It sets the C/I thresholds when AMR speech codecs are used on a FR channel in UL.when AMR speech codecs are used. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: [0 to3] bts 0 DP 3 Codec mode adaptation 0: typical radio condition 1: optimistic radio condition 2: pessimistic radio condition 3: personalize with the BSC data configuration table The recommanded value of 0 offers a good compromise between HR penetration and radio environment. For optimization of the table amrDlFrAdaptationSetshould be turn to 3 (refer to AMR Activation Guideline PE/BSS/APP/11438 in Reference Documents) See also chapter AMR Engineering Studies. amrDlHrAdaptationSet Description: Class 3 V15 Define the lines of parameter used for the adaptation mechanism. It sets the C/I thresholds when AMR speech codecs are used on a FR channel in UL.when AMR speech codecs are used. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: [0 to3] bts 0 DP 3 Codec mode adaptation 0: typical radio condition 1: optimistic radio condition 2: pessimistic radio condition 3: personalize with the BSC data configuration table The recommanded value of 0 offers a good compromise between HR penetration and radio environment. For optimization of the table amrDlHrAdaptationSetshould be turn to 3 (refer to AMR Activation Guideline PE/BSS/APP/11438 in Reference Documents) See also chapter AMR Engineering Studies. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 425/629 V17.0 BSS Parameter User Guide (BPUG) filteredTrafficCoefficient Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: hrCellLoadEnd Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: [0..1] step 0.001 bts 0 DP 0.5 AMR based on traffic The parameter shoud be set to 1 to reach V15.1 behaviour (HR calls allocated on RxLev criterion only) Class 3 V14 This attribute is used to trigger the end of AMR HR allocation in the cell. [0 to 100] bts 0 DP 60 Channel allocation The parameter should be set to 0 to reach V15.1 behaviour (HR calls allocated on RxLev criterion only). This value should be tuned according to the operator strategy and the number of TCH (preemptable PDTCH are not taken into account). 60 is a good compromise but it can be increased for cells with more than 12 TCH. Class 3 V15 Filter coefficient taken into account in the cell load evaluation. hrCellLoadStart Description: Value range: Object: Default value: Type: Rec. value: Class 3 V14 This attribute is used to trigger the beginning of AMR HR allocation in the cell. [0 to 100] bts 100 DP 0 for AMR FR only, different from 0 to trigger the HR allocation in the cell. 80 for AMR based on Traffic Channel allocation This parameter shall be different from “0” to use Half Rate allocation. The parameter should be set to 1 to reach V15.1 behaviour (HR calls allocated on RxLev criterion only) This value should be tuned according to the operator strategy and the number of TCH (preemptable PDTCH are not taken into account). 80 is a good compromise but it can be increased for cells with more than 12 TCH. Used in: Eng. Rules: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 426/629 V17.0 BSS Parameter User Guide (BPUG) radioAllocator Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Radio allocator type used in the cell [voice + dataCircuit, voice + dataCircuit + packetData] bts voice + dataCircuit DP voice + dataCircuit + packetData Class 2 V12 Lab tests have shown that the recommended value has to be set to voice + dataCircuit + packetData when AMR is activated TRANSCODER OBJECT coderPoolConfiguration Description: Class 2 V12 This attribute indicates enumerated speech coding algorithms supported by the TCU. List of algoid [minimumCalls, powerUplink, powerDownlink] Algoid: fullRateCoder, enhancedFullRateCoder, amrFullHalfRateCoder, ctmEnhancedFullRateCoder MinimumCall: 0 to 65535 PowerUL: -15 to +15 PowerDL: -15 to +15 Transcoder fullRateCoder, minimumCall = 1, pwrUL = 0, pwrDL = 0 enhancedFullRateCoder, minimumCalls = 1, pwrUL = 0, pwrDL = 0 amrFullHalfRateCoder, minimumCalls = 1, pwrUL = 0, pwrDL = 0 ctmEnhancedFullRateCoder, minimumCalls = 1, pwrUL = 0, pwrDL = 0 DP see Engineering Rules Channel allocation (AMR) Cellular Telephone Text Modem (TTY) Used for the AMR, TTY activation at the TCU level (downlink and uplink amplification level and use to define the minimum of AMR communications on the TCU level). Each coded has to be present only if is is activated by the operator, FR is mandatory. During normal operation, it dynamically reallocates the resources between the TRMs to meet traffic demand. For the EFR and FR codecs, the archipelago capacity is 72, i.e. 216 circuits per TRM. For the AMR codec, the archipelago capacity is 60, i.e.180 circuits per TRM. For the EFR+TTY codec, the archipelago capacity is 48, i.e. 144 circuits per TRM. The customer can set for each enabled vocoder type (FR, EFR, AMR) a warrantied minimum number of communications. This field is called minimumCalls and is used for the initial distribution. Nortel confidential Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 427/629 V17.0 BSS Parameter User Guide (BPUG) The TCU assigns CODEC to each available archipelago in an roundrobin manner until the TCU satisfies the minimumCalls condition for each enabled CODEC. Remaining archipelagoes are configured in order to achieve as close as possible the CODEC ratios given by minimumCalls parameters. Let nbMinimumCalls = sum of minimumCalls of each enable CODEC. The ratio to achieve for a given CODEC is computed as follows: CODEC_rate = (minimumCalls (for this CODEC) / nbMinimumCalls). Examples: For E1 network with 20% FR, 40% EFR and 40% AMR setting could be: FullRateCoder, minimumCalls = 4, powerUL = 0, powerDL = 0 EnhancedFullRateCoder, minimumCalls = 8, powerUL = 0, powerDL = 0 amrFullHalfRateCoder, minimumCalls = 8, powerUL = 0, powerDL = 0 Remark: Whatever is the repartition between the codecs, the two parameters powerUL and powerDL should always be set to “0“. For T1 network, no TTY CODEC is available at the MMI. So when theTCU receives TRM related config messages indicating for each CODEC(FR, EFR and AMR) their minimumCalls, the equivalent EFR+TTYCODEC is enabled with a minimumCalls set to 1 by default. CAUTION! All TCUe3 releases below V16.0, if the transmission network uses the T1 PCM, TTY is activated by default. For any TCUe3 upgrade from V14/V15 to release V16.0, TTY must be explicitly set at MMI on G3Trans object via the coderPoolConfiguration field. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 428/629 V17.0 BSS Parameter User Guide (BPUG) TRANSCEIVER OBJECT frAMRPriority Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: defines TDMA allocation priority for AMR FR calls. [0 to 2] Transceiver 0 DP 1 for BCCH TDMA 0 for hopping TDMA Channel allocation (AMR) BCCH and non-hopping TDMA should be set to low priority, i.e. 1, while hopping TDMA should be set to high priority, i.e. 0. Priority 0 is given to a high priority TDMA, Priority 1 is given to a low priority TDMA, Priority 2 disables this service on the TDMA. See also chapter Isolated Areas in AMR Monitoring. Priority 2 is not recommended as it could introduce an AMR congestion on the cell due to a barring of access to some TDMAs for AMR calls. However, that setting could be interesting in some specific cases. Class 2 V14 CAUTION! hrAMRPriority Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: defines TDMA allocation priority for AMR HR calls. [0 to 2] Transceiver 0 DP 1 for BCCH TDMA 0 for hopping TDMA Channel allocation Class 2 V14 BCCH and non-hopping TDMA should be set to low priority, i.e. 1, while hopping TDMA should be set to high priority, i.e. 0 Priority 0 is given to a high priority TDMA, Priority 1 is given to a low priority TDMA, Priority 2 disables this service on the TDMA. See also chapter Isolated Areas in AMR Monitoring. Priority 2 is not recommended as it could introduce an AMR congestion on the cell due to a barring of access to some TDMAs for AMR calls. However, that setting could be interesting in some specific cases. CAUTION! Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 429/629 V17.0 BSS Parameter User Guide (BPUG) POWER CONTROL OBJECT Since the introduction of the ML0, there is a treshold preventing from doing Power Control below a defined level when using AMR power control (refer to the amrReserved2 parameter). The two parameters lRxLevDLP and lRxlevULP setting that threshold are defined in chapter Power Control Parameters. hrPowerControlTargetMode Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 3 V14 AMR codec target to define the Uplink power control threshold for HR AMR calls [4k75, 5k9, 6k7, 7k4] power control 7k4 DP 7k4 Power Control (AMR) Power has to be decreased when call quality is very good and increased when the quality could be better. Even if 7k4 AMR HR is set, which corresponds to the most constraining Power control value, AMR Power control has shown to be more aggressive than EFR Legacy L1m. If cell radio conditions are very good, optimization to 6k7 HR target could be justified. Power control has to be triggered before handover for quality reason. AMRHRIntercellCodecModeThreshold<hrPowerControlTargetMode frPowerControlTargetMode Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 3 V14 AMR codec target to define the Uplink power control threshold for FR AMR calls [4k75, 5k9, 6k7, 10k2, 12k2] power control 12k2 DP 12k2 Power Control (AMR) Power has to be decreased when call quality is very good and increased when the quality could be better. Even if 12k2 AMR HR is set, which corresponds to the most constraining Power control value, AMR Power control has shown to be more aggressive than EFR Legacy L1m. If cell radio conditions are very good, optimization to 10k2 FR target could be justified. Power control has to be triggered before handover for quality reason. AMRFRIntercellCodecModeThreshold<frPowerControlTargetMode Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 430/629 V17.0 BSS Parameter User Guide (BPUG) hrPowerControlTargetModeDl Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 3 V16 AMR codec target to define the downlink power control threshold for HR AMR calls [4k75, 5k9, 6k7, 7k4] power control 7k4 DP 7k4 Power Control (AMR) Power has to be decreased when call quality is very good and increased when the quality could be better. Even if 7k4 AMR HR is set, which corresponds to the most constraining Power control value, AMR Power control has shown to be more aggressive than EFR Legacy L1m. If cell radio conditions are very good, optimization to 6k7 HR target could be justified. Power control has to be triggered before handover for quality reason. AMRHRIntercellCodecModeThreshold<hrPowerControlTargetModeDl frPowerControlTargetModeDl Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 3 V16 AMR codec target to define the downlink power control threshold for FR AMR calls [4k75, 5k9, 6k7, 10k2, 12k2] power control 12k2 DP 12k2 Power Control (AMR) Power has to be decreased when call quality is very good and increased when the quality could be better. Even if 12k2 AMR HR is set, which corresponds to the most constraining Power control value, AMR Power control has shown to be more aggressive than EFR Legacy L1m. If cell radio conditions are very good, optimization to 10k2 FR target could be justified. Power control has to be triggered before handover for quality reason. AMRFRIntercellCodecModeThreshold<frPowerControlTargetModeDl Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 431/629 V17.0 BSS Parameter User Guide (BPUG) HANDOVER OBJECT amrDirectAllocRxLevUL Description: Class 3 V14 Uplink RxLev threshold for direct AMR TCH allocation in a normal cell or in the large zone of a bizone cell (in conjunction with amrDirectAllocRxlevDL). [less than -110, -110 to -109, ... , -49 to -48, more than -48] dBm handoverControl - 80 dBm DP, Optimization -80 to -79 dBm Handover mechanisms (AMR) Direct TCH Allocation Direct HR allocation enables to avoid some unnecessary handovers from FR to HR channels. To define the value of those parameters it is necessary to study the distribution of RxLev for the codec mode defined as the target for the HR to FR intra cell HO to avoid a immediate come back on a FR channel after a direct HR allocation. The uplink parameter may be set considering a threshold corresponding to 90% of C/I values higher than 16 dB (proposed value, depends on the network quality). Furthermore, it has to be checked that the RxLev value is more restrictive than the threshold to go back to the large zone to avoid an immediate comeback on the large zone. See also chapter Half Rate Penetration Analysis. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: amrDirectAllocRxLevDL Description: Class 3 V14 Downlink RxLev threshold for direct AMR TCH allocation in a normal cell or in the large zone of a bizone cell (in conjunction with amrDirectAllocRxlevUL). [less than -110, -110 to -109, ... , -49 to -48, more than -48] dBm handoverControl - 80 dBm DP, Optimization -75 to -74 dBm Handover mechanisms (AMR) Direct TCH Allocation Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Direct HR allocation enables to avoid some unnecessary handovers from FR to HR channels. To define the value of those parameters it is necessary to study the distribution of RxLev for the codec mode defined as the target for the HR to FR intra cell HO to avoid a immediate come back on a FR channel after a direct HR allocation. The uplink parameter may be set considering a threshold corresponding to 90% of C/I values higher than 16 dB (proposed value, depends on the network quality). Furthermore, it has to be checked that the RxLev value is more restrictive than the threshold to go back to the large zone to avoid an immediate comeback on the large zone. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 432/629 V17.0 BSS Parameter User Guide (BPUG) See also chapter Half Rate Penetration Analysis. amrDirectAllocIntRxLevUL Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 3 V14 UplinkRxLev threshold for directAMR TCH allocation in the inner zone of a bizone cell (in conjunction with amrDirectAllocIntRxlevDL). [less than -110, -110 to -109, ... , -49 to -48, more than -48] dBm handoverControl - 80 dBm DP, Optimization -80 to -79 dBm Handover mechanisms (AMR) Direct TCH Allocation see Engineering Rules of amrDirectAllocRxLevUL. amrDirectAllocIntRxLevDL Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 3 V14 Downlink RxLev threshold for directAMR TCH allocation in the inner zone of a bizone cell (in conjunction with amrDirectAllocIntRxlevUL). [less than -110, -110 to -109, ... , -49 to -48, more than -48] dBm handoverControl - 80 dBm DP, Optimization -75 to -74 dBm Handover mechanisms (AMR) Direct TCH Allocation see Engineering Rules of amrDirectAllocRxLevUL. Furthermore, it has to be checked that the RxLev value is more restrictive than the threshold to go back to the large zone to avoid an immediate comeback on the large zone. amrDirecAllocIntRxLevDL ≥ concentAlgoIntRxLev amrFRIntercellCodecMThresh Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: [4k75, 5k9, 6k7, 10k2, 12k2] handoverControl 6k7 DP, Optimization 10k2 Handover mechanisms (AMR) Class 3 V14 Target codec mode to trigger an intercell AMR quality handover. The target codec mode has to be more restrictive than the one for intracell handover otherwise intracell handover will not be possible most of the time. amrFRIntercellCodecMThresh<amrFRIntracellCodecMThresh. On the other hand, the codec mode threshold for intercell handover has to be smaller than the target codec for power control. amrFRIntercellCodecMThresh<frPowerControlTargetMode Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 433/629 V17.0 BSS Parameter User Guide (BPUG) This parameter is directly linked to AMR adaptation set and the C/I threshold. Intercell codec target, which directly applies on a C/I target, has to be aligned to C/I relation with RxQual. CPT could be used. C/I associated to HO intercell codec target should be between 7dB and 14 dB depending on radio environment amrFRIntracellCodecMThresh Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: [4k75, 5k9, 6k7, 10k2, 12k2] handoverControl 4k75 DP, Optimization 4k75 (AMR intracell deactivation value) Handover mechanisms (AMR) Class 3 V14 Target codec mode to trigger an intracell quality handover FR to FR The target codec mode has to be less restrictive than the one for intercell handover otherwise intracell handover will not be possible most of the time. amrFRIntercellCodecMThresh<amrFRIntracellCodecMThresh amrHRIntercellCodecMThresh Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 3 V14 Target codec mode to trigger an intercell quality handover from a HR channel. [4k75, 5k9, 6k7, 7k4] handoverControl 5k9 DP, Optimization 5k9 Handover mechanisms (AMR) The target codec mode has to be more restrictive than the one for intracell handover otherwise intracell handover will not be possible most of the time. amrHRIntercellCodecMThresh<amrHRtoFRIntracellCodecMThresh. On the other hand, the codec mode threshold for intercell handover has to be smaller than the target codecs for power control. amrHRIntercellCodecMThresh<hrPowerControlTargetMode. amrHRtoFRIntracellCodecMThresh Description: Value range: Object: Default value: Type: Rec. value: Used in: Class 3 V14 Target codec mode to trigger an AMR intracell quality handover from AMR HR to FR [4k75, 5k9, 6k7, 7k4] handoverControl 6k7 DP, Optimization 6k7 Handover mechanisms (AMR) Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 434/629 V17.0 BSS Parameter User Guide (BPUG) Eng. Rules: The target codec mode has to be less restrictive than the one for intercell handover otherwise intracell handover will not be possible most of the time. In case same intercell and intracell codec target is chosen, intercell has the priority. amrHRIntercellCodecMThresh<AMRHRtoFRIntracellCodecMThresh If the operator’s strategy is to increase capacity versus quality, low values for AMRHRtoFRIntracellCodecModeThreshold can be chosen to delay a come back on a FR channel. Change of AMR adaptation set could also be used for HR penetration increase (see chapter Half Rate Maximization Analysis) amriRxLevDLH Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 3 V14 Minimum downlink level to receive to trigger an intracell handover FR to FR [less than -110, -110 to -109, ..., -49 to -48, more than -48] dBm handoverControl - 75 dBm DP, Optimization -75 to -74 dBm Handover mechanisms (AMR) Since AMR coding is better than standard coding, the threshold for intracell AMR handover must be more restrictive than the one for standard calls: amriRxLevDLH>rxLevDLIH. amriRxLevULH Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 3 V14 Minimum uplink level to receive to trigger an intracell handover FR to FR [less than -110, -110 to -109, ... , -49 to -48, more than -48] dBm handoverControl - 75 dBm DP, Optimization -75 to -74 dBm Handover mechanisms (AMR) Since AMR coding is better than standard coding, the threshold for intracell AMR handover must be more restrictive than the one for standard calls: amriRxLevULH>rxLevULIH. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 435/629 V17.0 BSS Parameter User Guide (BPUG) amrReserved1 Description: Value range: [0 to 2] 0: RATSCCH procedure enabled (default value) Class 3 Allows the activation of RATSCCH procedure for AMR FR calls V16 1: RATSCCH procedure disabled - initial Full Rate ACS if optimistic therefore; ACS is [12.2k, 10.2k, 6.7k, and 5.9k] 2: RATSCCH procedure disabled - initial Full Rate ACS if pessimistic therefore; ACS is [10.2k, 6.7k, 5.9k and 4.75] Object: Default value: Type: Rec. value: Used in: Eng. Rules: handoverControl 0 DP 0 AMR Legacy L1M Before v15.1.1, in case of poor uplink radio conditions, the BTS is sometimes unable to detect RATSCCH acknowledgements from mobiles. This triggers a mismatch between the AMR Codec Set used by the mobile and the one used by the BTS. Then the BTS (or MS) cannot correctly decode the codec used by the MS (or BTS). This sequence leads to a mute call until the next RATSCCH procedure is correctly executed. A workaround for this problem of mute call consists in setting amrReserved1 to value “1” which means “RATSCCH disabled and initial ACS optimistic” : only codec 5k9, 6k7, 10k2 and 12k2 will be used. The only drawback of the workaround is that this parameter setting prevents the usage of 4,75 AMR FR codec, useful in case of very degraded radio conditions. In v16, an improvement of the L1M has been implemented which consists in the BTS repeating the RATSCCH command until it receives an acknowledgment from the mobile. In v17, a further improvement has been implemented. It consists in improving the robustness of the detection of the acknowledgement message received from the mobile : this increases the probability of correctly decoding this message when it is first received. Thanks to these 2 improvements, amrReserved1 should be set to "0" in V16 and V17. Warning: pessimistic Codec Set 10,2 / 6,7 / 5,9 /4,75 (amRreserved1 = 2) must not be chosen because it would inhibit capacity HO i.e. handover from AMR FR to AMR HR (as 12.2 cannot be used). . amrReserved2 Description: Class 3 V12 Legacy L1m procedures (Power control and Handover) or AMR L1m mechanisms (based on (n,p) voting algorithm and codec target) can be chosen [0 to 3] Nortel confidential Value range: PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 436/629 V17.0 BSS Parameter User Guide (BPUG) Object: Default value: Type: Rec. value: Used in: Eng. Rules: amrReserved2 0 1 2 3 AMR alarm handovers based on AMR PowerControl algorithm based on handoverControl 0 DP see Engineering Rules AMR Legacy L1M CMR/CMC [(n,p) voting] RxQual CMR/CMC [(n,p) voting] RxQual CMR/CMC CMR/CMC RxQual RxQual CAUTION! A mix between AMR L1m for Power Control and Legacy L1m for AMR alarm HO is recommended at this stage (amrReserved2 = 1); however AMR activation with full AMR algorithms on HO management and Power Control has shown good performances. Class 3 V14 nCapacityFRRequestedCodec Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Number of 12k2 codec mode requested to trigger a capacity handover (FR to HR) [0 to 196] handoverControl 44 DP, Optimization set to 100% of pRequestedCodec, i.e. 48 Handover mechanisms (AMR) The recommended value was chosen in order to increase capacity in real good conditions: 100% of the requested codecs should be 12k2 meaning the radio conditions are really good. If the operator’s strategy is to increase capacity vs. quality, low value for nCapacityFRRequestedCodec can be chosen. Higher nCapacityFRRequestedCodec assures a better HR radio conditions and reduce probability intraHO ping pong. See also chapter Half Rate Settings. nFRRequestedCodec Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 3 V14 Minimum number of codecModeRequest out of pRequestedCodec in the (n,p) voting mechanism to trigger an AMR HO while in FR mode. [0 to 196] handoverControl 24 DP, Optimization set to 50% of pRequestedCodec, i.e. 24 Handover mechanisms (AMR) Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 437/629 V17.0 BSS Parameter User Guide (BPUG) nHRRequestedCodec Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 3 V14 Minimum number of codecModeRequest out of pRequestedCodec in the (n,p) voting mechanism to trigger an AMR HO while in HR mode. [0 to 196] handoverControl 34 DP, Optimization set to 50% of pRequestedCodec, i.e. 24 Handover mechanisms (AMR) pRequestedCodec Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 3 Number of codec mode requests to consider in the (n,p) voting decisions. [12 to 192] (step of 12) handoverControl 48 DP, Optimization 48 Handover mechanisms (AMR) V14 A similar reactivity between AMR and non-AMR calls should be reached. The recommended value corresponds to the same quality averaging window as for standard calls in urban environment. Field experimentation should give further information as for the value of pRequestedCodec. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 438/629 V17.0 BSS Parameter User Guide (BPUG) ADJACENTCELLHANDOVER hoMarginAMR Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 3 V14 HO margin taken into account in an intercell quality handover for AMR calls in order to manage the eligible cell list. [-63 to 63] dB AdjacentCellHandover -2 DP, Optimization same as hoMarginRxQual Handover mechanisms (AMR) Handovers screening In case of AMR L1mis activated (cf. amrReserved2) Handover cause AMR quality: case where access to another cell should be encouraged, provided target cell field strength is not much lower than the current one. If bad quality remains, there is a risk of return handover but there is nothing much to be done. Depending on radio environment: Interfered environment: It is better to have a low C/I threshold for Quality HO (chosen via AMR adaptation set or intercell HO codec target) and have homarginAMR = hoMarginRxQual Coverage limited environment: It is better to have a high C/I threshold for Quality HO (chosen via AMR adaptation set or intercell HO codec target) and have hoMargin = hoMarginRxQual + 2 Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 439/629 V17.0 BSS Parameter User Guide (BPUG) REPEATED DOWNLINK FACCH enableRepeatedFacchF Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 2 V16 Enable/ disable the Repeated FACCH feature on AMR FR calls Disable / FR 4.75 / FR 5.9 and lower / FR 6.7 and lower bts Disable DP, Optimization FR 6.7 and lower Handover mechanisms (AMR) TX POWER OFFSET FOR SIGNALLING CHANNELS facchPowerOffset Description: Value range: Object: Default value: Type: Rec. value: Used in: Power offset to be applied on FACCH signalling [0 to 10] dB (with 2 dB step) bts 0 DP, Optimization 6 This parameter is used to tune the power offset to be applied on FACCH re-transmission, specific FACCH messages (for first transmission) as well as RR and REJect frames on FACCH corresponding to an uplink re-transmission (F bit set to 1) and UA frames corresponding to an uplink re-transmission of SABM or DISC frames (F bit set to 1). Class 2 V16 Eng. Rules: sacchPowerOffset Description: Value range: Object: Default value: Type: Rec. value: Used in: Power offset to be applied on SACCH signalling [0 to 6] dB (with 2 dB step) bts 2 DP, Optimization 6 This parameter is used to tune the power offset to be applied on selected SACCH frames transmission Class 2 V16 Eng. Rules: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 440/629 V17.0 BSS Parameter User Guide (BPUG) sacchPowerOffsetSelection Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 2 V16 CODEC selection for applying a power offset on SACCH NULL / FR 4.75 kbps / FR 5.9 and lower / FR 6.7 and lower bts NULL DP, Optimization FR 6.7 and lower AMR-HR CHANNEL ON PREEMPTED PDTCH gprsPreemptionForHR Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Activation of PDTCH pre-emption for HR channel enabled/disabled bsc disabled DP, Optimization enabled pDTCH Preemption by AMR FR or HR calls (V17) “AMR based on traffic” thresholds may need to be retuned if the PDTCH preemption for HR channels is enabled. Class 3 V17 Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 441/629 V17.0 BSS Parameter User Guide (BPUG) 5.39. WPS - WIRELESS PRIORITY SERVICES PARAMETERS wPSManagement Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: CAUTION! WPS feature is enabled or disabled [disabled ; enabled ] bsc disabled DP, System enabled for WPS use WPS - Wireless Priority Service In order to enabled the new queuing management of WPS requests the wPSManagement flag has to be set to the value “enabled” Queuing management of WPS requests can only be activated if the bscQueuingOption parameter is set to “allowed” (MSC driven) and the WPS priorities have been set properly Class 3 V15 wPSQueueStepRotation Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 3 V15 One out of the wPSQueueStepRotation value to first have an evaluation of the WPS queues in the radio resource allocator. [1 to 10] bts 4 DP, System 4 WPS - Wireless Priority Service If the operator choose to activate WPS queuing management on its network this parameter can ensure a minimum amount of non-WPS calls (with low priorities) that can access the network even if it is very congested With that parameter fixed to “4”, when a radio resource become free and there are WPS or public call requests queued, the priority is given 1 out of 4 times to a WPS call request and 3 out of 4 times to a public call. In that case WPS calls are favored in 25% of the time. The operator can choose to enable queuing uniquely on WPS calls, hence public calls are never queued and this parameter becomes obsolete. The Algorithm for the traffic channel allocation applies at a cell level in the BSC, and hence wPSQueueStepRotation is a cell parameter. CAUTION! Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 442/629 V17.0 BSS Parameter User Guide (BPUG) 5.40. NETWORK SYNCHRONIZATION PARAMETERS btsSMSynchroMode Description: Type of site synchronization. Activation of the Synchronisation feature (either site synchro either network synchro features). Its value defines also the synchronization mode (burst or time) Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: tnOffset Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 2 V15 Its value allows to specify and control TN difference between BTS in case of network synchronisation by GPS [0..7] btsSiteManager 0 DP, Optimization 0 Network Synchronization [normal, master, slave, gprBurstSync, gpsTimeSync, masterGpsBurstSync, masterGpsTimeSync] btsSiteManager normal DP, Optimization normal Network Synchronization Class 2 V15 fnOffset Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: dARPPh1Priority Description: Value range: Object: Default value: [high priority, low priority] transceiver high priority Class 2 V15 Its value allows to specify and control FN difference between BTS in case of network synchronisation by GPS [0..84863] btsSiteManager 0 DP, Optimization N/A Network Synchronization Class 2 V15 Its value allows specifying the priority of SAIC mobiles on the TDMA. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 443/629 V17.0 BSS Parameter User Guide (BPUG) Type: Rec. value: Used in: Eng. Rules: DP, Optimization high priority Network Synchronization Actually, for radio resource allocation only SDCCH requests are not differentiated depending if the mobile requesting is SAIC capable or not. masterBtsSmId Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 2 V15 Gives the identity of the master BTS if the BTSSMSynchroMode is slave and remains empty if the BTS is master or normal Master BTS id or empty btsSiteManager Empty DP, Optimization Depends on context Network Synchronization baseColourCode Description: Class 2 V7 Base station Color Code assigned to a serving cell. It is broadcast on the cell SCH and is used to distinguish cells that share the same BCCH frequency. The (BCC, NCC) pair forms the cell BSIC. The information is broadcast on the cell SCH. Several BCCs may be assigned to a same BTS. Hence, different codes can be allotted to cells that may have overlapping areas (adjacent cells). The Base Station Identity Code (BSIC) is a 6–bit code: bits 6-5-4 = NCC (PLMN color code), bits 3-2-1 = BCC (Base station color code). At cell level, the NCC bits can be used to increase BCC color possibilities when the NCC is not needed. The BCC value is determining the TSC (training sequence code) of the cell. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: [0 to 7] bts N/A DP, Optimization N/A Network Synchronization Several BCCs may be assigned to cells of a same site. Hence, different codes can be allotted to cells that may have overlapping areas (adjacent cells). See also chapter Set Up Principles of a Neighboring List and a BCC Plan Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 444/629 V17.0 BSS Parameter User Guide (BPUG) 5.41. NETWORK MODE OF OPERATION PARAMETERS gprsNetworkModeOperation Description: Value Range: Object: Default value: Rec. value: Used in: Eng. rules: Flag to choose the network mode of operation. Class 3 V15 [0 - 2] ; 0 = NMO II , 1 = NMO I , 2 = NMO 3 (value forbidden) . bts. 0. 1. Network Mode of Operation I support in BSS NMO 1 must be activated or deactivated at RA level: the setting must be consistent in all cells of a RA. NMO1 activation is recommended when GPRS is activated on all cells of the network: NMO1 should not be activated on a LA where some cells do not affer GPRS service. As combined procedures are performed on PDTCH with NMO1 (combined attach/detach and combined LA/RA update), it is strongly recommended to guaranty the continuity of GPRS service by setting minNbrGprsTs > 0. The feature must be activated first at Core Network level and then at BSS level. The bscDataConfig must be modified to take the value of gprsNetworkModeOperation into account. (see [R36] for details) 5.42. BSS CS PAGING COORDINATION PARAMETER bssPagingCoordination Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 3 V17 Activation parameter of BSS CS Paging Coordination feature 0: disable BSS CS paging coordination/ 1: enable BSS CS paging coordination bts disable BSS CS paging coordination DP, Optimization see Eng. Rules BSS CS Paging Coordination On (legacy) PCUSP board, the processing load is expected to consume a significant proportion of the available processing capability. In that case, the impact of the feature activation should be monitored. See section Performance of BSS CS Paging coordination Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 445/629 V17.0 BSS Parameter User Guide (BPUG) 5.43. NOVEL ADAPTIVE RECEIVER PARAMETER adaptiveReceiver Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Activation parameter of the novel adaptive receiver enabled/disabled transceiver disabled DP, Optimization enabled Novel Adaptive Receiver Class 2 V17 1/ For cells operating under very specific radio conditions, namely hard Hilly Terrain profiles, the Novel Adaptive Receiver structure may possibly cause a slight performance loss compared with the initial processing. Therefore, it is recommended to disable the adaptive receiver for these cells. 2/ If Rx diversity is used, best receiver performance is achieved by activating both the Joint diversity and the Novel Adaptive Receiver features 3/ Novel Adaptive Receiver does not interwork with the Extended Cell feature. Therefore, for extended cells, the Novel Adaptive Receiver must be deactivated. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 446/629 V17.0 BSS Parameter User Guide (BPUG) 5.44. A5/3 ENCRYPTION ALGORITHM PARAMETERS cypherModeReject Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 1 V8 Whether the CIPHER MODE REJECT messages are used (Phase II compliance). true/false signallingPoint false DP true A5/3 Encryption algorithm (V17) This parameter must be set to true for the ciphering procedures to operate correctly between the BSS and the NSS Class 1 V8 encrypAlgoAssComp Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Whether the "Chosen encryption algorithm" element is used in the ASSIGN COMPLETE messages (Phase II compliance). true/false signallingPoint false DP true A5/3 Encryption algorithm (V17) This parameter must be set to true for the ciphering procedures to operate correctly between the BSS and the NSS Class 1 V8 encrypAlgoCiphModComp Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Whether the "Chosen encryption algorithm" element is used in the CIPHER MODE COMPLETE messages (Phase II compliance). true/false signallingPoint false DP true A5/3 Encryption algorithm (V17) This parameter must be set to true for the ciphering procedures to operate correctly between the BSS and the NSS Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 447/629 V17.0 BSS Parameter User Guide (BPUG) encrypAlgoHoPerf Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 1 V8 Whether the "Chosen encryption algorithm" element is used in the HANDOVER PERFORMED messages (Phase II compliance). true/false signallingPoint false DP true A5/3 Encryption algorithm (V17) This parameter must be set to true for the ciphering procedures to operate correctly between the BSS and the NSS Class 1 V8 encrypAlgoHoReq Description: Whether the "Chosen encryption algorithm" element is used in the HANDOVER REQUEST ACKNOWLEDGE messages (Phase II compliance). true/false signallingPoint false DP true A5/3 Encryption algorithm (V17) This parameter must be set to true for the ciphering procedures to operate correctly between the BSS and the NSS Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: encryptionAlgorSupported Description: Class 3 V8 Type of ciphering capability supported by the BTSs of a BSS. When no ciphering capability is supported, users’ calls are not encrypted by the BSS over the air interface. [none, gsmEncryptionV1, gsmEncryptionV3FallbackNoEncryption, gsmEncryptionV3FallbackV1] bsc none DP see Eng. Rules A5/3 Encryption algorithm (V17) The setting of this parameter depends on the level of data integrity and security required by the network operator. A5/3 is more powerful than A5/1 but may slightly impact Call setup time and handover duration. Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 448/629 V17.0 BSS Parameter User Guide (BPUG) Notes: 1/This parameter’s class has been modified from class 0 to class 3 in v17.0. 2/This parameter’s range has been modified from [none / gsmEncryptionV1 / gsmEncryptionV2] to [none, gsmEncryptionV1, gsmEncryptionV3FallbackNoEncryption, gsmEncryptionV3FallbackV1] in v17.0. 3/A5/2 must no longer be used in any network, as of December 2006. layer3MsgCyphModeComp Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 1 V8 Whether the "Layer 3 message" element is used in the CIPHER MODE COMPLETE messages (Phase II compliance). true/false signallingPoint false DP true A5/3 Encryption algorithm (V17) This parameter must be set to true for the ciphering procedures to operate correctly between the BSS and the NSS Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 449/629 V17.0 BSS Parameter User Guide (BPUG) 5.45. BTS SMART POWER MANAGEMENT PARAMETERS smartPowerManagementConfig Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Enable/disable the smart power management feature. enabled/disabled powerControl disabled DP enabled see Eng. Rules BTS Smart Power Management (V17) Class 3 V17 1/ It is recommended to put combined BCCH and SDCCH/8 TS on the same TDMA as BCCH. 2/ As a TRX supporting a PDTCH never switches its PA off, it is recommended not to configure more PDTCH TS than necessary. smartPowerSwitchOffTimer Description: Value range: Object: Default value: Type: Rec. value: Used in: Eng. Rules: Class 3 V17 Sets the initial countdown value of the timer that must expire before the PA may be switched OFF. 5 to 255 minutes in 1-minute steps powerControl 5 minutes DP 5 minutes see Eng. Rules BTS Smart Power Management (V17) The smaller the switch-off timer : • the more reactive the power management will be to the minute-by-minute changes to the call profile as the day progresses towards quieter moments the more power is likely to be saved as a result. but the more frequently the PA is likely to go through off/on cycles, especially at the transition from busy hour to quieter hours, thus possibly impacting its lifespan. • • Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 450/629 V17.0 BSS Parameter User Guide (BPUG) 6. 6.1. ENGINEERING ISSUES GSM/GPRS TS SHARING: PRIORITY HANDLING AND QUEUING With GSM/GPRS TS sharing, the operator’s strategy can be of three main different kinds: • • • Minimize the impact of GPRS introduction on GSM. Guarantee GPRS quality of service thus impacting on GSM if no resources are added Find a trade-off impacting GSM as little as possible and guaranteeing GPRS as much as possible. The tuning of priority handling, queuing and also the use of the preemption mechanism depends on the adopted strategy. 6.1.1 RESOURCES RESERVED FOR PRIORITY 0 AND PREEMPTION allocPriorityThreshold is a parameter used to reserve resources for priority 0 TCH allocation requests. This reservation of resources decreases the capacity for incoming calls when resources are reserved for handovers. Depending on the difference between allocPriorityThreshold and the number of shared PDTCH, several phenomenon can happen. IF allocPriorityThreshold ≥ shared PDTCH THEN GPRS preemption mechanism is reserved for priority 0 TCH allocation requests This behaviour is normal and comes from the definition of allocPriorityThreshold and the allocation strategy that allocates in priority free TCH. On the contrary: IF allocPriorityThreshold ≤ Number of shared PDTCH THEN the only free resources left for priority 0 TCH allocation request are shared PDTCH. • • Reestablishment will not be enabled at those periods of time (no reestablishment on shared PDTCH is allowed). A more frequent issue will come from GprsPreemption set to yes enabling the PCU to NACK a preemption requested by the BSC. This phenomenon decreases the efficiency of allocPriorityThreshold: reserved resources considered free by the BSC might not be used to serve a TCH allocation request when the PCU NACKs the preemption. This phenomenon will only happen in case of heavy GPRS traffic at the same time as heavy GSM traffic. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 451/629 V17.0 BSS Parameter User Guide (BPUG) The table below proposes a setting of GSM/GPRS TS dynamic sharing with priority handling with or without reestablishment (MinNbOfGprsTs is only indicative). With reestablishment, two sets of values are sometimes proposed, one of them for less GPRS capacity. Number of TRX 1 TRX with or without reestablishment 2 TRX with or without reestablishment 3 TRX without reestablishment 3 TRX with reestablishment 4 TRX without reestablishemnt 4TRX with reestablishment allocPriorityThreshold minNbOfGprsTs Number of shared PDTCH 1 2 2 2 3 2 2 3 1 1 2 2 2 2 2 2 0 1 2 1 2 2 1 2 6.1.2 GSM/GPRS TS SHARING AND QUEUING: No queued allocation request can use the preemption mechanism to leave the queue. The allocation request must wait until a TCH is free. Hence, a too high number of shared PDTCH (without adding a TDMA) increases the time a queued request will stay in the queue. A solution to decrease the length of the queue is to forbid intracell queuing (intraCellQueuing set to disabled). The intracell handover request will be repeated later (increases the BSC signaling load) if no resource is free but thanks to the repetition of the handover request if the radio conditions are still bad, the shared PDTCH preemption will be allowed (not the case if put in queue). For example on a 2 TDMA cell queuing can be done on 14 TCH TS, but in the case of a 2 TDMA cell with 3 shared PDTCH and minNbOfGprsTs = 0 the queuing can only be done on 11 TCH TS, so queued requests will leave the queue less quickly and one could see an increase in the number of discarded requests. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 452/629 V17.0 BSS Parameter User Guide (BPUG) 6.1.3 RESOURCES STRATEGY MINIMIZE IMPACT OF GPRS INTRODUCTION ON GSM • • Gprspreemption is set to no MinNbGprsTS is set to 0 It means that all PDTCH configurated are shared by GSM and GPRS and thePCU is not allowed to NACK the preemption requested by the BSC.Impact on queuing, impact on preemption depending on allocPriorityThreshold value. GUARANTEE GPRS QUALITY OF SERVICE • • GprsPreemption set to yes MinNumberGprsTs > 0 It means that some resources are always dedicated to GPRS and that the PCU can NACK a pre-emption requested by the BSC. Impact on queuing and preemption efficiency since the PCU can NACK the preemption It might be interesting to activate HO traffic so as to enable a spatial repartition of traffic on overlapping cells (with protection against HO ping pong): this spatial repartition of traffic will save PDTCH channels for GPRS traffic and guarantee a constant availability of preemptable PDTCH. TRADE-OFF ON GSM AND GPRS • • GprsPreemption set to no minNumberGprsTs> 0 IMPACT ON QUEUING. Minimum resources are guaranteed to GPRS and all the other resources can be used by GSM calls if needed since the PCU can never NACK a preemption. It might be interesting to activate HO traffic so as to enable a spatial repartition of traffic on overlapping cells (with protection against HO ping pong): this spatial repartition of traffic will save PDTCH channels for GPRS traffic and guarantee a constant availability of preemptable PDTCH. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 453/629 V17.0 BSS Parameter User Guide (BPUG) 6.2. LAYER 1 MANAGEMENT: CHANGES BETWEEN V1 AND V2 L1M corresponds to the BTS software; it manages radio measurements and their processing. Within the context of Automated Cell Tiering introduction, a new version of the L1m application software (L1mV2) has been developed to support advanced features. This new version is mandatory since V14. This chapter is intended to highlight the major improvements of L1mV2 compared to L1mV1. 6.2.1 MAIN DIFFERENCES In addition to the ability to support advanced features, L1mV2 brings enhancement on the following points: • • • • • Measurement processing Rescaling Capture process Neighbouring cell management Power Control Algorithm MEASUREMENT PROCESSING The measurement processing ensures that the network and mobiles communicate with each other with the minimum interference, at the lowest possible transmission power and the best transmission quality. With the L1mV2: • The measurement processing is optimized in order to provide valid measurements as early as possible: the MS and BTS measurements are available as soon as MS measurements are received by the BTS, i.e. 1 SACCH period (480ms) delay instead of 2 SACCH (960 ms) periods with L1mV1. The process of averaging/superaveraging is based on fully sliding windows in order to take into account the most updated samples. In case of missing measurement, the last sliding average will be used instead of the last synchronous average. That gives a better missing measurement update. • • These major improvements will allow earlier decisions on SDCCH/TCH to be more accurate since 0.5 seconds (over 1second) are saved on the processing delay of first measurements. This will decrease the number of assignment failure. Moreover, the new measurement processing will provide more reactive handover and power control decisions, enhancing the global quality of the network. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 454/629 V17.0 BSS Parameter User Guide (BPUG) RESCALING RxLevel (UL & DL) measurement are rescaled in order to take into account the difference between the reference Power and the real transmitted Power • • Example: Rescaling with msTxPwrMax = 30, rxLevHreqave = 4 lRxLevULP = -97 to -96 uRxLevULP = -93 to -92 L1mV1 msTxPower RxLev Delta Rescaled RxLev Reference: last msTxPower = mr4 = 26 L1mV1: Reference power = Last value of power control command L1mV2: Reference power = maximum transmission power (Pmax) mr1 20 - 93 6 - 87 mr2 24 - 93 2 - 91 mr3 26 - 95 0 - 95 mr4 26 - 97 0 - 97 Average - 92,5 L1mV2 Reference: msTxPwrMax = 30 mr1 msTxPower RxLev Delta Rescaled RxLev mr2 24 - 93 6 - 87 mr3 26 - 95 4 - 91 mr4 26 - 97 4 - 93 Average 20 - 93 10 - 83 - 88,5 • • computed Delta for rescaling = msTxPower - Ref_msTxPower computed Rescaled RxLev = OldRxLev - Delta The rescaling performed by L1mV2 ( taking as the reference power = Pmax ) gives a RxLev that is closer to real conditions. So L1mV2 will anticipate the decision of Power control and Handover earlier than L1mV1. CAPTURE PROCESS Before L1mV2, the capture was launched only on the best microcell reported by the mobile, and then the algorithm waited for the failure of the confirmation process before starting another capture on the second best cell. With L1mV2, this sub-feature launches in parallel the confirmation process for all the microcells which verify the capture threshold providing a better reactivity of the system. If a confirmation fails for a cell, the capture can be performed rapidly towards another cell satisfying the criterion, increasing the probability to capture a microcell in a dense area. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 455/629 V17.0 BSS Parameter User Guide (BPUG) NEIGHBOURING CELL MANAGEMENT For the neighbouring cells monitoring and measurements, the mobile Measurement Report contains received level from the 6 best neighbouring cells RXLEV_NCELL(n) and associated BSICs + frequencies. The new L1m the Neighbouring cell management feature brings two enhancements on the cellDeletionCount parameter and on the update of the neighbouring informations. CELLDELETIONCOUNT The parameter cellDeletionCount is considered as a pure eligibility criterion. With L1mV1, the neighbour cell information was discarded if the number of consecutive measurement reports which does not contain measurements for this neighbouring cell was equal to cellDeletionCount. With L1mV2, the CellDeletionCount corresponds to the number of missing measurements reports after which the neighbour cell is not eligible for a PBGT handover. But the measurements related to this neighbour cell are not deleted as far as less than 10 consecutive measurements (i.e. 5 seconds) are missing. That always allows a rescue handover after the CellDeletionCount Example: CellDeletionCount = 5 Rn measurement report n of a neighboring cell C by the MS Rn+1 Rn+2 Rn+3 Rn+4 Rn+5 cell_Deletion_Counter = 4, Nb_of_Missing = 1 cell_Deletion_Counter = 3, Nb_of_Missing = 2 cell_Deletion_Counter = 2, Nb_of_Missing = 3 cell_Deletion_Counter = 1, Nb_of_Missing = 4 cell_Deletion_Counter = 0, Nb_of_Missing = 5 No more PBGT HO possible on this neighbouring cell Rn+6 Rn+7 Rn+8 Rn+9 Rn+10 Nb_of_Missing = 6 Nb_of_Missing = 7 Nb_of_Missing = 8 Nb_of_Missing = 9 Nb_of_Missing = 10 this cell is no more candidate whatever the HO type, measurement reports for this cell are deleted from the L1M. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 456/629 V17.0 BSS Parameter User Guide (BPUG) Update on neighbouring informations The other benefit concerns the updating of information for a neighbour cell not reported for less than 5 seconds: when the number of neighbour cell reported by the MS is 6 (the maximum), the RxlevNcell of non reported neighbour cells are update, for this period, by taking the minimum value between: • • The RxLevNcell reported at the previous period And the lower RxLevNcell reported by the MS for this period and for a neighbour cell in the same frequency band, degraded by 3 dB. This process degrades gradually the level of a missing neighbouring cell, only when it is not any more among the 6 best cells. POWER CONTROL IMPROVEMENT RF power control is used to minimize the transmit power required by the MS or BTS while maintaining the quality of the radio links. With the new version of L1m, the “step by step” power control algorithm is defined as “path loss compensation” algorithm, with the introduction of a limitation based on the one shot computation when there is a need to re-compute the attenuation (high level and good quality) ALGORITHM STEP BY STEP When Signal strength is bad (high path loss) or the quality is poor: SAveRxLev < lRxLevXXP OR SAveRxQual > lRxQualXXP with SAveRxLev is the weighted averages, there is no difference between L1mV2 and L1mV1. Both compute a new attenuation request: NewAttRequestdB = Max (CurrentAttRequestdB - IncrStepSize, 0) When reception level and quality are good: SAveRxLev > uRxLevXXP AND SAveRxQual < uRxQualXXP L1mV1 always decrease the Tx power with the reduce step size set at the OMCR while L1mV2 compute a new transmission power with total path loss compensation (increase or decrease). The new increase (or reduce) step size is not necessarily the same as the one set at the OMCR but it can not be higher than IncrStepSizeXX (or RedStepSizeXX) Main Step for the new Tx power computed by L1mV2: NewAttRequestdB = K* (SAveRxLev - lRxLevXXP) with K=1 for the algorithm step by step Limitation of attenuation Request Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 457/629 V17.0 BSS Parameter User Guide (BPUG) Case1: IF NewAttRequestdB < CurrentAttRequest - IncrStepSize THEN ordered attenuation = CurrentAttRequest - IncrStepSize Case2: IF NewAttRequestdB > CurrentAttRequest + RedStepSize THEN ordered attenuation = CurrentAttRequest + RedStepSize Case3: IF CurrentAttRequest - IncrStepSize ≤ NewAttRequestdB ≤ CurrentAttRequest + RedStepSize THEN ordered attenuation = NewAttRequestdB Note: The ordered attenuation request is always in the range [0, AttMaxdB], and with L1mV1 the SAveRxLev is the rescaled RxLev at last power command. EXAMPLE 1: MS UPLINK POWER CONTROL WITH L1MV2 lRxLevULP = -97 to -96, RedStepSizeUL = 4 URxLevULP = -93 to -92, IncrStepSizeUL = 4 RxQual = 0.2 to 0.4 CurrentAttRequest + RedStepSizeUL CurrentAttRequest - IncrStepSizeUL CurrentAttRequest NewMsAttRequest CurrentMsPower ordered attenuation Step 1 2 3 4 5 6 7 8 Stable Rxlev at Pmax = -87 30 30 30 30 30 30 30 30 26 22 20 20 23 23 23 19 4 8 10 10 7 7 7 11 -91 -87 10 0 -95 -87 10 4 -97 -87 10 6 Path loss of 3 dB Rxlev at Pmax =-90 -100 -90 7 6 -97 -90 7 3 -97 -90 7 3 Path gain of 4 dB Rxlev at Pmax =-86 -93 -86 11 3 -97 -86 11 7 8 12 14 14 11 11 11 15 8 10 10 7 7 7 11 11 22 20 20 23 23 23 19 19 Rxlev Rough = RxlevPmax - currentAttRequest Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 NewMsTx Power MsTxPowerMax Rxlev rough RxLevUL Page 458/629 V17.0 BSS Parameter User Guide (BPUG) RxLev Rough is the RxLev before the rescaling. Here, the RxLevrough tends to reach lRxLevP when signal strength at Pmax is good, furthermore the reduce step size and increase step size set at the OMCR are not necessarily used. Note: we have on the step 1 a decrease of 4 dB then on step 2 a decrease of 2 dB (even if the reduce step size set at the OMC is 4 dB), this makes the Power Control distribution with algorithm step-by-step different in L1mV1 from L1mV2. EXAMPLE 2: MS UPLINK POWER CONTROL WITH L1M V1 CurrentAttRequest CurrentMsPower NewMsTx Power 22 22 22 26 26 26 22 22 Target R xLev V1 Medium Target RxLev V1 Target R xLev V2 MsTxPowerMax Step 1 2 3 4 5 6 7 8 30 30 30 30 30 30 30 30 26 22 22 22 26 26 26 22 4 NOP NOP Path loss of 3 dB 4 NOP NOP Path gain of 4 dB 4 NOP -91 -95 -95 -98 -94 -94 -90 -94 Here the NewMsTxPower computed by L1mV1 is often higher than the MsTxPower computed with the new version. So L1mV2 gains in efficiency. Initial Power control "Step by step" decrease -1 1 -1 0 08 -1 0 -1 6 04 -1 02 -1 00 -9 8 -9 6 -9 4 -9 2 -9 0 -8 8 -8 6 -8 4 -8 2 -8 0 -7 8 -7 6 -7 4 -7 2 -92 -94 -96 RxLev resul -98 -100 -102 -104 -106 -108 -110 Note: the RxLev result in this graph corresponds to the RxLevrough Nortel confidential PE/DCL/DD/000036 17.03 / EN No new com mand between -97 and -92dBm -90 Standard Rxlev rough Path loss (RxLevPmax in dBm) 03/03/2008 Page 459/629 V17.0 BSS Parameter User Guide (BPUG) The figures below summarize the command for (UL or DL) transmission power according to Rxlev and RxQual. L1MV1 RxQual Increase Tx Power lRxQual No new command for MS (or BS) transmission power uRxQual Decrease Tx Power lRxLev uRxLev RxLev L1MV2 RxQual Increase Tx Power lRxQual No new command for MS (or BS) transmission power uRxQual New Tx Power computation lRxLev uRxLev RxLev Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 460/629 V17.0 BSS Parameter User Guide (BPUG) STEP BY STEP POWER CONTROL EFFICIENCY With the aim of minimizing the transmit power required by the MS or BTS, the new algorithm “step by step” uses a realistic Rxlev (Rxlev rescaled at Pmax), this leads to a better anticipation of the power control decisions. Histograms below show an example of a RxLev downlink power control distribution for L1M V1 and L1M V2 DL RxLev Distribution (L1MV1) 600 110% 90% 70% 50% 30% 10% 04 07 01 8 5 2 9 6 3 0 7 -7 4 -9 -8 -8 -1 -1 -1 -7 -9 -9 -8 -8 -7 1 # of Samples 500 400 300 200 100 0 -1 10 Rx Lev DL RxLev Distribution (L1MV2) 700 110% 90% 70% 50% 30% 10% -8 0 -7 7 -7 4 -1 01 -7 1 -8 9 -9 2 -8 6 -9 8 -9 5 -8 3 # of Samples 600 500 400 300 200 100 0 -1 10 -1 07 -1 04 Rx Lev One can see 50% time RxLev is better than -87 dB for L1mV1 and better than -89 dB for L1MV2, so for the same percentage of time with L1mV2 lower power levels are used. This explains the gain in the power control efficiency. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 461/629 V17.0 BSS Parameter User Guide (BPUG) 6.2.2 BENEFIT The major benefit of L1mV2 is the ability to support advanced capacity and coverage features such as Automated Cell Tiering (fromV12) which enhances quality and/or capacity of fractional reuse in loaded networks. In addition, as shown in the next chapter other benefits will be perceived on the network thanks to introduction of some modifications • In microcellular dense areas, the capture process will be more reactive thanks to the parallel launch of confirmation process for all the micro cells reported by the mobile. In dense urban areas where the neighbouring cells reported by the mobile are numerous and fluctuant, with a better updating of eligible cells, the operator will experience less handover failure. The uplink and downlink RxLev handover and intracell handover processes will be triggered considering the RxLev which could correspond to a transmission at maximum power, by comparing RxLev + attenuation (instead of RxLev) to the handover threshold. This will result in less call drop, better quality. Handover which could be avoided by powering up transmission will not be performed. Moreover the interference level on the network will be decreased as mobiles will remain as much as possible on the best server cell. Early Handover decisions on SDCCH/TCH will be more accurate since 0.5 seconds (over 1second) are saved on the processing delay of first measurements. This will decrease the number of assignment failure. Moreover, the new averaging of measurements based on sliding window will provide more reactive handover and power control decisions, enhancing the global quality of the network. The power control is more efficient thanks to the rescaling performed by L1M V2; it gives a better approach to real conditions. • • • • 6.2.3 CHANGE IN HANDOVER PERFORMANCE AFTER L1MV2 IMPLEMENTATION When L1mV1 is activated, with mobiles in bad radio conditions (limit of cell coverage for example), it can lead to a Radio Link Failure drop call. In same conditions, when L1mV2 is activated, as missing measurements are better managed more handovers will be requested by the BTS, that can save the call if the HO succeeds. As the mobile is in bad radio conditions, some of these HO can fail but some of them succeed. That’s why with L1mV2 (compare to L1mV1) one can see more HO failures (the system tries to perform more HO in bad radio conditions) and less Radio Link Failures. Some of these HO succeed instead of leading to a Radio Link Failure, thus the total number of dropped calls decreases, leading to an improvement of the call drop ratio. Then, globally we can say that the QoS is improved. Many trials were performed on different networks to try to quantify this improvement. We can assess that the repartition between Radio Link Failure drops and handover drops is modified: less Radio_Link samples and more T3103 samples are observed after L1mV2 activation; nevertheless the global call drop ratio is slightly improved. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 462/629 V17.0 BSS Parameter User Guide (BPUG) 6.3. ONE-SHOT POWER CONTROL The one-shot power control algorithm allows high path loss compensation. However, some mobiles are perturbed by high received signal strength variations and hence, several of their measurements are wrong. If the mobile is near the base station antenna, with a few types of mobiles the BTS will first decrease in a one-shot its transmit power, and then, because of wrong measurements performed by the mobile, will increase its power to its maximum, this is an oscillating effect. Due to this effect, a maximum variation step of 8 dB has been introduced. During each SACCH period, the power can be modified by 8 dB. From V12, the 8dB limitation applies only for decrease. One of the V8 step-by-step power control improvements consists of correlating both handover and power control algorithms. However, this is not the case for the one-shot power control algorithm (V9), hence it is possible to handoff even if the MS (or BTS) does not transmit at its maximum power. This difference is due to the fact that the one-shot power control algorithm should be reactive enough to be decorrelated from the handover algorithm. With the step-by-step power control algorithm, an order to transmit at maximum power is sent as soon as a handover is triggered. With the one-shot power control algorithm, the same order is sent as soon as the power control is triggered. The non correlation between both algorithms will not lead to avoid the increase of the power before a handover. So the L_RXQUAL_XX_P shall be lower than L_RXQUAL_XX_H. A difference of one step between both values provides an effective power control and keeps a good reactivity for handovers. Example: L_RXQUAL_XX_P = 3 and L_RXQUAL_XX_H = 4 A rapid variation of the quality (from 2 to 5) will trigger the handover algorithm and not the power control algorithm. In the above example, a value equal to 4 for the power control threshold (L_RXQUAL_XX_P) would be insufficient to keep a good reactivity for handovers. During the algorithm validation period, a comparison was made between “one shot” power control algorithm and “step-by-step” one. The conclusions were expressed as follows: The “one shot” power control is correctly implemented according to functional specifications. Without any deterioration of uplink and downlink quality, “one shot” power control activation contribues to the following advantages: • • • more power attenuation globally in the cell, quicker decrease to low power, quicker increase to maximum power. Furthermore, the reactivity of the algorithm allows to set the one shot power control thresholds to the step-by-step low ones without any impact on uplink and downlink quality. One shot QoS metrics are also better than step-by-step ones. However, these results come from a study over few days and in a specific configuration. It is difficult to say that the “one shot” power control algorithm is simply better than the “step-bystep” one. The quality is not degraded and it seems to lead to more power attenuation but nothing allows to conclude surely that this algorithm is the one to use in all cases. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 463/629 V17.0 BSS Parameter User Guide (BPUG) 6.4. MINIMUM TIME BETWEEN HANDOVER Different cases of handovers are given, and for each, the parameter setting influence is described. 6.4.1 MICRO-CELLULAR NETWORK HANDOVER MICROCELL TO MICROCELL Avoiding handover ping-pong is important but a mobile could cross a cell in 2 or 3 seconds. A delay (bts Time Between HO configuration) should not be used in this case. The parameter setting should be: • • timeBetweenHOConfiguration = true, because the feature may be important for other cells in the BSS. bts Time Between HO configuration = minimal value, e.g. = rxLevHreqave * rxLevHreqt * 0.48 sec Actually, even in such configuration, the value of the delay depends on the speed of the mobiles. If the speed is low and the mobile speed in the cell is homogeneous then the delay can be significant and have an action on ping-pong handover. If the speed is non homogeneous then the most “rapid-moving mobiles” must be considered for the value of the delay, though ping-pong handovers could occur. The lower the most rapid moving mobiles’ speed, the more important the delay is”. Then bts Time Between HO configuration is a function of the cell size and the mobile speed. In such situation, the problem of field variation is solved: • • If the mobile speed is low then the delay will help to avoid a ping-pong handover If the mobile speed is high, the averaging will not show all these variations. HANDOVER MICROCELL TO MACROCELL microCell means: its bts object cellType is set to microcell. macroCell means: in the microcell adjacentCellHandOver object, the cellType field corresponding to this macrocell is set to “umbrella” whatever the value of its cellType field in its bts object (normal cell, umbrella or microCell). In this way a microCell can be seen as an umbrella for another microCell. This kind of handover is only triggered on alarm cause. So, in this case the delay is not very useful. Let’s consider the following case: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 464/629 V17.0 BSS Parameter User Guide (BPUG) macroCell B microCell A microCell C With a macroCell, the delay can be used for the microCell. A mobile that goes from microCell A to macroCell B will perform a handover (on alarm cause). Then, it is worth setting a delay on cell A to avoid a ping-pong handover (between A and C). Therefore, this delay is beneficial for a mobile in cell C that turns into the street of cell A. The same is true in opposite direction. The only restriction is for a mobile coming from macro B and going to micro C. The delay has a negative influence for the handover microA-microB. It is the same case as before. In V12, the feature General Protection against HO ping-pong can solve this kind of problem. For instance, in this particular case, the parameter hoPingPongCombination should be set to (alarm, capture) and hoPingPongTimeRejection should be set to the previous V9 value of bts Time Between HO configuration. HANDOVER MACROCELL TO MACROCELL The timer is usefull for a cell intersection where there is much interference. Let’s take as an example a handover with cause “quality” triggered from macroCell A towards macroCell B. But just after this change of cell, a handover with cause “power budget” is attempted. Using an appropriate delay, depending on the speed of the mobile, many pingpong handovers may be avoided. In V12, this is also achieved through the General Protection against HO PingPong feature (see chapter General protection against HO ping-pong). In this particular case, the parameter hoPingPongCombination should be set to (quality, PBGT) and hoPingPongTimeRejection should be set to the previous V9 value of bts Time Between HO configuration. In order to inhibit completely the ping-pong hoPingPongCombination should be set to (all, all). Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 465/629 V17.0 BSS Parameter User Guide (BPUG) 6.4.2 NON MICRO-CELLULAR NETWORK. The solution is the use of the minimum time between handover. The value of the delay depends on the distance between the interference point and the point where macroA and MacroB have the same level. With the hypothesis that the following neighbor cell is far away, the value of the delay depends on the minimun speed of the mobile. It is not really obvious to recommend a value because it is a question of interference point position. So, before test and measurement results, the recommended value is the default value: 16, that corresponds to 8 seconds. There are two ways to determine the best value: • system test: the counters show that ping-pong handovers exist. With a little variation of the delay (bts Time Between HO configuration), it is possible to see the influence (always with counters). So with only some steps of delay variation the best value to avoid ping-pong handover and radio link failure can be found. measurements: with mobile measurements, the point of interference and the equivalence point can be found. Then the delay value can be deduced from the distance between both points. • However the following “light constraints” are applied to the value of the delay: • • average time of a mobile in the cell (weighted if nedeed for each speed) bts Time Between HO configuration. Those constraints could also be a way to find the best value of minimum time between handover. In V12, same remark as before. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 466/629 V17.0 BSS Parameter User Guide (BPUG) 6.5. DIRECTED RETRY HANDOVER BENEFIT This paragraph provides theorical studies results of the benefit that Directed Retry can provide in mono and multi-layers Networks.The Directed Retry is mainly a benefit in the case of small congestion zone in the network. In others cases the network is either under-dimensioned or the queuing gives better results. Moreover, the HOTraffic feature must be favoured instead of using Directed Retry. Long duration Directed Retry Duration of congestion Normal situation Network under dimensioned Call Large surface 6.5.1 BENEFIT OF FEATURE ON MONO-LAYER STRUCTURE HYPOTHESIS • • • • • 12 macroCells with 3 TRX/cell Non-combined BCCH 22 TCH available for the 12 cells 9 cells with 41% use rate (i.e. 9 TCH/22) and 3 overloaded cells with 26 channels requested for 22 available (i.e. 24% of blocking rate) 25% of cell overlapping WITHOUT DIRECTED RETRY The carried capacity is: • • 9 cells * 9 TCH + 3 * 76% * 26= 140 Erlang the highest blocking rate is over 24% Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 467/629 V17.0 BSS Parameter User Guide (BPUG) WITH DIRECTED RETRY The added carried capacity is: • • 25% cell overlapping => 25% * (24% * 26 requests * 3) = 4,7 Erlang the highest blocking rate is over 18% With Directed Retry and 25% overlapping: gain on traffic 3,3% on the whole set of 12 cells of this example and gain on blocking rate. 6.5.2 BENEFIT OF FEATURE ON MULTI-LAYERS STRUCTURE HYPOTHESIS • • • • blocking rate of 2% max on the macroCell 3 TRX (22 TCH) with 9 TCH used / 22 (41% use rate) 1 TRX per μ -cell with not combined BCCH 10 requests for 6 TCH on the μ -cell (48% of blocking rate) WITHOUT DIRECTED RETRY Carried capacity of “n” μ-cell under 1 macroCell: = n μ-cell * 52% + 1 macro * 9 * 100% For “n” μ-cell under 1 umbrella cell: number of carried Erlangs = 5,2n + 9 If n = 1, we have carried 14,2 Erlangs. WITH DIRECTED RETRY When the Macrocell begins to be full (the blocking rate will become low (from 2% to 3%)) then no more calls are redirected from the µ-cell to the macro. Capacity of microCell + macroCell: we aim to satisfy the 10 + 9 requests (i.e. 19 Erl needed): n micro * X% * 10 + 1 macro * 9 The macro cell is able to carry: 14.9 Erlang • • 9 requests from the macroCell 5.9 requests from the μ-cells Then, the macroCells keep: X% * ((n macroCell * 10) – 5.9) WITH N = 1: The Erlang law gives X = 87.6% (a blocking rate of 12.4%), the carried traffic is: 14.9 + 87.6% * (10-5.9) = 18.5 Erl Gain 30% on ONE μ-cell and the highest blocking rate is over 12.4% (instead of 48%). Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 468/629 V17.0 BSS Parameter User Guide (BPUG) WITH SEVERAL N: microCells transfer their calls into one umbrella-cell, and with the hypothesis of our example, the gain should be (en = enabled, dis = disabled): Gain%= Erl carried DR(en) Erl carried DR(dis) -1 Gain%= X(n) * (10n – 5,9) – (5,2n + 9) 5,2n + 9 As a consequence Gain(%) = f (number of µ-cells under one umbrella). The best cells to implement directed retry are the cells that have potential problems due to a lack of TCH resources. Directed Retry may solve the problem of load if the cell is the only one to have this kind of problem in the close area. If the entire area is congested, almost no improvement will be observed. If queuing is enabled on the cell, the parameter setting of the queuing should lead to queues of size 3 and a waiting timer of 6 seconds in the candidate cell. From V15.0, Directed Retry can be also activated without queuing. See chapter Directed retry without queuing activation for further informations. The last value to set is the rxLev threshold used in the feature to choose a “good” neighbor cell (distant mode). As the decision is taken on the basis of one measurement, a margin of a few dBs needs to be taken to deal with multipath fading. Then, the advised value should be at least rxLevMinCell + 3 dB. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 469/629 V17.0 BSS Parameter User Guide (BPUG) EXAMPLE OF POSSIBLE CONFIGURATIONS: At BSC level: • • • • • • interBscDirectedRetry = allowed intraBscDirectedRetry = allowed modeModifyMandatory = used bscQueuingOption = forced timeBetweenHOConfiguration = true HOSecondBestCellConfiguration = 3 At Cell level (where directed retry is implemented): • • • • • allocPriorityTimers = 0 0 6 0 0 0 0 0 allocWaitThreshold = 0 0 3 0 0 0 0 0 directedRetryModeUsed = bts interBscDirectedRetryFromCell = allowed intraBscDirectedRetryFromCell = allowed At neighbor cell level: • • • directedRetry = rxLevMinCell + 3 dB hoPingPongTimeRejection = 30 (= the previous V9 value of bts Time Between HO configuration hoPingPongCombination = (DirectedRetry , all) or for instance (DirectedRetry, PBGT) At cell level for neighbor cells: • • bts Time Between HO configuration = 1 (V12 update, the parameter changes its possible vallues) allocPriorityThreshold = 3 Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 470/629 V17.0 BSS Parameter User Guide (BPUG) 6.6. CONCENTRIC CELLS The concentric cell feature has been introduced from the BSS version V9.1. The main principle is to define two zones in a cell: inner (or small) and outer (or large) zone. BCCH and signaling channels use TMDAs of outer zone. Innerzone (small zone) traffic channels Outerzone (large zone) BCCH and signalling channels This feature enables the system to have two separate zones within the same cell using different TDMAs and giving the operator flexibility to have separate frequency hopping systems. Therefore, concentric cell zones give better spectral efficiency through mobility management between zones and being able to increase inner zone frequency reuse. For a good understanding of this feature, please refer to the chapter Concentric/DualCoupling/DualBand Cell Handover, and the associated Functional Notes [R10] Concentric cell improvements (CM888/TF889) and [R11] FN for stepped coupling. Expected Network Impacts: • • Radio Quality Improvement: C/I and RxQual improvement and an overall RF and HO drops improvement Slight increase in intracell HO drops, inherent to concentric cell interzone traffic management. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 471/629 V17.0 BSS Parameter User Guide (BPUG) 6.6.1 CONCENTRIC CELL PARAMETER DEFINITION concentAlgoExtRxLev (outer to inter threshold) concentAlgoIntRxLev (inner to outer threshold) biZonePowerOffset + hysteresis Margin As shown on the figure above, the definition of inner zone coverage depends mainly on concentAlgoExtRxLev; concentAlgoIntRxLev and biZonePowerOffset+hysteresis parameters. Main related parameters to the concentric cell feature are listed below: Parameter Description concentric cell concentAlgoExtRxLev concentAlgoIntRxLev biZonePowerOffset zone Tx power max reduction concentAlgoExtMsRange concentAlgoIntMsRange biZonePowerOffset(n) rxLevMinCell(n) enable the concentric cell feature on the cell (also used for dualband / dualcoupling) level threshold used for TCH Direct Allocation in the inner zone or to trigger an interzone HO from the outer to the inner zone level threshold used to trigger an interzone HO from th inner to the outer zone offset used to simulate the power difference between TDMAs of the inner and the outer zone (power difference either due to power emission, coupling losses or propagation losses) set the power difference between the two zones of a concentric/dualaband/dualcoupling cell distance threshold used for TCH Direct Allocation in the inner zone or to trigger an interzone HO from the outer to the inner zone (not used for dualband functionality) distance threshold used to trigger an interzone HO from th inner to the outer zone offset used to reflect the difference of propagation between the two zones of an adjacent cell in case of handover toward the inner zone minimum signal strength level received by MS for being granted access to a neighbor cell CONCENTALGOEXTRXLEV The concentAlgoExtRxLev value can be set depending on how TRXs capacity in the cell is shared between the inner and outer zone. The following figure shows CPT cumulative distribution of RxLev uplink and downlink of a cell before concentric cell activation. concentAlgoExtRxLev may be deduced from the downlink RxLev distribution which represents samples of communications in function of the strength level. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 472/629 V17.0 BSS Parameter User Guide (BPUG) On the figure above we can see that only 10% of the traffic is handled with a level under -86 dBm. So if the traffic size of inner zone (% of TS in the inner zone with regard to total number of TS in the cell) is 90% of the outer zone, it means that 90% of downlink Rxlev sample may be inside of inner zone, and 10% is outside. A downlink RxLev value L90, L75 or L50 should then correpsond to 90%, 75% or 50% of traffic on the inner zone. concentAlgoExtRxLev = LXX (use of the CPT tool) BIZONEPOWEROFFSET (HANDOVERCONTROL OBJECT) biZonePowerOffset is used to simulate the power offset between TDMAs of the inner and the outer zone. CONCENTRIC CELL CASE In this case biZonePowerOffset simulates the power difference between the two zones introduced by zone Tx power max reduction of the inner zone. • • zoneTxPowerMaxReduction(outer) = 0 zoneTxPowerMaxReduction(inner) = 0, best value tested (see chapter zone Tx power max reduction) biZonePowerOffset = zone Tx power max reduction(inner) DUALCOUPLING CELL CASE In this case biZonePowerOffset simulates the power difference between the two zones introduced by coupling losses. • • • zone Tx power max reduction(outer)=0 zone Tx power max reduction(inner)=3 simulates the D/H2D configuration zone Tx power max reduction(inner)=4 simulates the H2D/H4D configuration biZonePowerOffset = zone Tx power max reduction(inner) Note: DLU Attenuation should be NULL and replaced by zone Tx power max reduction as explained in the parameter description: zone Tx power max reduction and concentric cell. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 473/629 V17.0 BSS Parameter User Guide (BPUG) DUALBAND CELL CASE In this case biZonePowerOffset simulates the power difference between the two zones introduced by propagation losses. It should then be set according to the band used on the cell. biZonePowerOffset = +3 dB (dualband: main band= 850 or 900 MHz) biZonePowerOffset = -3 dB (dualband: main band= 1800 or 1900 MHz) CONCENTALGOINTRXLEV To avoid ping-pong interzone HO, a hysterisis margin is recommended. The level threshold to trigger an interzone HO from the inner to the outer zone could be calculated as follow: concentAlgoIntRxLev = concentAlgoExtRxLev - Hysteresis Margin biZonePowerOffset where Hysteresis Margin = 4 dB is recommended. BIZONEPOWEROFFSET(N) (ADJACENTCELLHANDOVER OBJECT) biZonePowerOffset(n) in adjacentCellHandover object reflects the difference of propagation between the two zones of an adjacent cell in case of handover toward the inner zone. When attempting an HO directly to the inner zone of an adjacent cell EXP2xx(n) = hoMarginxx(n) + biZonePowerOffset (n) > 0 shall be respected. So in order to avoid HO in sequence after incoming HO into inner zone, it’s necessary to respect the following relation: biZonePowerOffset (n) = concentAlgoExtRxLev(n) - rxLevMinCell(n) rxLevMinCell(n) concentAlgo ExtRxLev(n) cellA cellB Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 474/629 V17.0 BSS Parameter User Guide (BPUG) 6.6.2 CONCENTRIC CELL FIELD EXPERIENCE RADIO QUALITY IMPROVEMENT Inner zone isolation-capacity trade-off is found in concentric cell. The smaller the inner zone coverage, the better inner zone isolation is found but less traffic, which takes profit of higher inner zone fractional reuse pattern, is carried. Concentric cell success on improving KPI performances is based on this balance. On one hand reducing inner zone coverage: • • provides better isolation of inner zone interferences by keeping only the calls with very good RxLev to enter the inner zone allows deploying a more constraining inner zone frequency plan (or a consequent inner zone radio quality improvement) and reducing 3107 drops since inter HO are done in better radio conditions. On the other hand, one of the inherent risks of using this approach is to block on the outer zone while resource availability remains on the inner zone. Even though inner zone blocking is not customer perceived (calls can overflow onto the outer zone radios if available TCH resources), a compromise exists between the traffic distribution between the zones, and the improvement in KPI. Therefore, additional tuning of the concentAlgoExt/IntRxLev thresholds may be necessary on certain sites to set an appropriate threshold for transitioning from and to the inner zone. INNER-OUTER ZONE CAPACITY TRADE-OFF It is recommended having more than 1 TDMA on outer zone since it allows redundancy in case BCCH TDMA is lost, and also because TDMAs carrying SDCCH channels must also be on the outer zone. Furthemore, it is advised to have higher capacity in the outer than in the inner zone, because it minimizes the probability that outer zone is blocked, which would cause a capacity cell reduction even if inner zone TS are available. 60%-40% outer-inner capacity is recommended. CONGESTION TARGET FOR HO TRAFFIC Capacity is shared between inner and outer zone depending on TDMAs allocated in each zone. Outer zone congestion targets should be updated to take into account reduction in terms of TDMAs in outer zone. Inner zone is not considered for congestion since no congestion for the user is found when all TS are occupied. SDCCH DIMENSIONING It should be noted that with Concentric Cell SDCCH channels cannot be configured in the inner zone and all the SDCCH channels will have to be re-mapped to the outer zone radios. All the sectors prior to implementation of Concentric Cell in the concerned BSCs must follow Nortel’s recommended rule of spreading the SDCCH channels amongst different radios and therefore had to be re-mapped carefully such that SDCCH congestion is not encountered. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 475/629 V17.0 BSS Parameter User Guide (BPUG) CONCENTRIC CELL PARAMETER TUNING ZONE TX POWER MAX REDUCTION This parameter is used to reduce the output power of the BTS on the inner zone TDMAs to improve inner zone isolation. Simulations show it is preferred to keep the inner zone reduction at 0 dB and rely on power control efficiency to reduce power level. Like this, power control is always capable to power up to maximum power to save worst call who received punctual interferences. Inner zone power reduction has not brought any significant KPI improvement when it has been tested on field trials. Simplified power control simulation results are shown on graph below. 250 meters of cell radius in 1900MHz (150 meters for inner zone coverage which corresponds to 40% inner zone capacity for a uniform traffic distribution) and perfect power control to attempt DL RxLev target of -86 dBm are considered. BTS Power and RxLev evolution depending on BTSoffset parameter 50 45 40 -84,0 -86,0 -88,0 BTS Power [dBm] 30 25 20 15 10 5 0 0,00 BTSPower(Offsetpower0) BTSPower(Offsetpower8dB) InnerZone Coverage (40%) RxLev(Offsetpower0) RxLev(Offsetpower8dB) -92,0 -94,0 -96,0 -98,0 -100,0 -102,0 0,15 0,20 -104,0 0,25 0,05 0,10 Cell Range [km] If BTS inner zone TDMA are not attenuated at all (0dB), 14,8 dBm mean BTS TX DL power would be found while if 8 dB output power would be attenuated, mean BTS TX DL Power would become 13,4 dBm. Therefore the impact on interference and isolation on innerzone is very limited and it is preferred to leave power control the possibility to power up rather than induce an external attenuation CONCENTALGOEXT/INTRXLEV It is recommended to set concentAlgoExtRxLev using CPT tool. DL RxLev number of samples repartition found in CPT is a good indicator on how traffic load is spread around the cell. concentAlgoExtRxLev threshold can be defined to match inner/outer zone capacity repartition. It is recommended to define concentAlgoExtRxLev instead of concentAlgoIntRxLev through CPT methodology. Like this, inner zone RxLev samples are slightly underestimated (signal Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 476/629 RxLev[dBm] 35 -90,0 V17.0 BSS Parameter User Guide (BPUG) level from concentAlgoExtRxLev and concentAlgoIntRxLev could also be allocated in inner zone) and a margin to pack the inner zone TDMAs is left. concentAlgoExt/IntRxLev impact on inner/outer traffic load has not shown to be very sensible to their value. Same mean values have been spread all over clusters in field trials and they have required little tuning to avoid outer zone blocking and KPI improvements. CONCENTALGOEXT/INTMSRANGE concentAlgoExtMsRange and concentAlgoIntMsRange could be used to reinforce or to complement inner and outer inter zone handovers using concentAlgoExt/IntRxLev. The calculated distance between the MS and the BTS is based on timing advance (TA), which has an accuracy of ± 3 bits (corresponding to more than 1,5 km), due to the shift of synchronization of some MSs. Thus, this parameter is not very useful in urban areas where the cell size is relatively small and due to the multipath effect, the MS to BS distance is not very accurate. However this parameter could be used in rural areas or suburban areas. BIZONEPOWEROFFSET IN DUALBAND CELLS 6 dB Rxlev DL level difference has been found between 900 MHz and 1800 MHz calls due to propagation losses in field trials. When a call who is allocated in the outer zone (900MHz) is inter handover to inner zone (1800MHz), 6 dB level loss is expected to be found due to propagation loss. Since biZonePowerOffset is taken into account in power budget handovers, there is a trade-off between biZonePowerOffset value and number of power budgets of inner zone calls. Having a biZonePowerOffset too big can reduce significantly power budget of inner cell provoking calls to be dragged to inner zone cell edge because of overestimating own BCCH level of the outerzone. 6 dB presents a good trade-off and it is the value recommended. INTRACELL HANDOVER DROP SLIGHT INCREASE On activation of concentric cell feature, interzone handovers get triggered based on signal level within the same cell, increasing the probability of dropped calls. The key to successful implementation of Concentric Cell is to reduce the other drop call components such as T3103 and RLT Drops. HYSTERISIS MARGIN DEFINITION The inner to outer Hysteresis Margin corresponds to the delta between concentAlgoIntRxLev and concAlgoExtRxLev minus zone TX power maximum reduction. The delta should be adequate so that the captured traffic in the inner zone (which is the key to spectral efficiency) is not immediately allocated back to outer zone via a ping-pong handover. A big hysterisis zone helps to contain the users in the inner zone and keeps this zone packed in order to avoid losing capacity and interzone HO, therefore it reduces T3107 drops. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 477/629 V17.0 BSS Parameter User Guide (BPUG) L1M REACTIVITY It is not recommended to increase L1m reactivity when concentric cell is used for HO decisions since it can increase significantly interzone HO with the consequent increase on T3107 drops. An average of 8 frames is recommended. CONCENTRIC CELL IMPACT ON AMR HR PENETRATION Interzone handover from inner to outer zone is considered as a quality handover. Therefore, even though an AMR HR call was on going in the inner zone, after a quality inner to outer interzone handover AMR FR is allocated in outer zone. Depending on AMR FR to HR and HR to FR thresholds, this interzone handovers can cause an increase of intracell HO from HR to FR (inner to outer zone) and immediately from FR to HR (in the outer zone), reducing AMR HR penetration on the cell. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 478/629 V17.0 BSS Parameter User Guide (BPUG) 6.7. IMPACT OF DTX ON AVERAGING The RxLev_Full measured on a dedicated channel is the arithmetic mean of 104 received time slots power, excepted in the case of DTX: then it is the arithmetic mean of only 12 received time slots power. A study was done to compare the difference (RxLev_Full - RxLev_Sub). It was based on 10800 measurements from a single network, characterized by a great proportion of microcells and a high RxLev mean value. The following array presents the results of this study. We considered the difference (RxLev_Full - RxLev_Sub), without averaging (1 measurement), and then with averaging on 2, 3, 4 and 8 measurements. number of values for averaging mean value of RxLev_Full - RxLev_Sub (dB) standard deviation (dB) 1 2 3 4 8 - 0,15 2,12 - 0,15 1,48 - 0,15 1,19 - 0,15 1,03 - 0,15 0,72 The results show that, for an averaging on 4 measurements, the standard deviation is only 1 dB. This is insignificant enough to consider that we can run simulations, and analyze the measurements with one of the two levels, if we don’t know which one is used. Moreover, the measurement processing used for the neighbor cells is close to the process used in the case of DTX: it is the arithmetic mean of about (104/N) received time slots power, where N is the number of neighbor cells declared, between 1 and 32. If 6 < N < 12, which is often the case, the two processes are quite comparable. 8 to 10 for neighbor; standard deviation on RxLev_Sub can be extended to RxLev(i). This means that the RxLev_NCell(i) measured on a neighbor cell, is close to the RxLev that would be measured if it was the current cell. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 479/629 V17.0 BSS Parameter User Guide (BPUG) 6.8. BEST NEIGHBOUR CELLS STABILITY The parameter CellDeletionCount is used to keep a neighbor cell eligible, even if a few measurements are lost. A study was done with a measurement file of 2 hours, without handover. Each time one of the 6 best neighbor cells disappeared, the time before it re-appeared, called absent_time, was calculated. 420 absent_times were found; that follow this distribution: absent_time (s) 0,66 1,32 1,98 2,64 3,3 3,96 4,62 5,28 5,94 6 to 11 > 11 % % cumulate 1,18 1,89 4,01 5,42 1,89 4,01 4,48 1,65 1,42 8,02 66,04 1,18 3,07 7,08 12,5 14,39 18,4 22,88 24,53 25,94 33,96 100 Note: absent_time values are multiples of 0,66 seconds. For instance, for the recommended value 5 and according to these measurements, in 12,5 percent of the cases the neighbor cell concerned is accessible after 2,64 seconds, in 87,5 percent, it is still missing. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 480/629 V17.0 BSS Parameter User Guide (BPUG) 6.9. TCH ALLOCATION GENERAL RULES When no queuing is allowed, as no request can be treated by the BSC at the same time, there are two kinds of TCH allocation requests: • • priority 0: the request is acknowledged if there is at least one free TCH priority > 0: the request is acknowledged if there is at least allocPriorityThreshold + 1 free TCHs If allocPriorityThreshold equals 0, all the requests are treated in the same manner. If queuing is in OMC driven mode (run by the BSC), incoming handovers cannot be queued. The highest priority must be given to incoming handovers. The queuing plays a part when, there is not enough TCH resources. When traffic increases to a blocking state, the queuing has no impact on the total ratio of TCH allocation success: the more call attempts that are acknowledged, the more incoming handovers are refused. The queuing is prefered when all TCH resources are busy during a short time; it cannot replace a resource. Please refer to chapter TCH Allocation Management. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 481/629 V17.0 BSS Parameter User Guide (BPUG) 6.10. GENERAL RADIO FREQUENCY RULES 1) In dB, the path loss slope with distance, decreases as 1/D. This means that the received signal variation, in dB/m, is greater at the close vicinity of the base station and decreases with the distance. It depends directly on the propagation exponent. 2) We can assume stationnarity (during some seconds) of the median path loss in dB, assumption is more and more valid since the MS is far from its antenna cell, close to the handover area. 3) Shadowing is due to obstruction of the signal paths, created by obstacles. It is known that these obstacles create log_normal variations of the received signal, ie the received power at a distance, expressed in dBm, fluctuates as a gaussian random variables. 4) The shadowing “depth” is strongly linked to the position of the mobile as compared with the dominant building, and as a consequence, that shadowing decorrelates when different buildings are involved. With a building mean width d = 30m, shadowing can be considered completely decorrelated. 5) The higher the mobile speed, the smaller the impact of the shadowing on the average signal. 6) The higher the average window size is, the smaller the impact of the shadowing on the average signal is. 7) The variance of the signal due to the Rayleigh fading, depends on the speed of the mobile and of the frequency in use. About 30 to 50 wavelengths must be spanned to ”filter out” the fading variations with a residual error less than 1 dB. If the number of samples is equal to N = 10 the mean matches the true local mean to within 2 dB at 90%. 8) Whatever the mobile speed, from a certain window size the increase of the size does not modify the average Rayleigh standard deviation. From 8 to 16 samples, even at a very low speed the gain is inferior than 0.5 dB. 9) The dispersion of two MRC combined Rayleigh is decreased by more than 1.5 dB for an MRC order 2, compared to a single channel. It means that diversity reception can help average out the fading faster than a single channel, i.e the local mean is tracked faster. If d > 20 l, an efficient 2 order space diversity has the same effect as multiplying the speed by 3 to 4. 10) .With Rayleigh fading, it is known that the mean in dB of samples in Watts is greater than the mean in dB of samples in dBm. The limit is 2.5 dB, that means that the RXLEV tends to be artificially 2.5 dB higher for the uplink than for the downlink. 11) The RxLev_Full as measured on a dedicated channel is the arithmetic mean of 104 received time slots power, in the case of DTX, only 12 times. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 482/629 V17.0 BSS Parameter User Guide (BPUG) 6.11. DIFFERENCE BETWEEN UPLINK AND DOWNLINK LEVELS At the BTS, averages are performed from measurements made in Watts before . On the contrary, some MS make measurements in dBm and then, perform their averages. In Rayleigh environment, the first method of calculating can be up to 2.51 dB higher than the second method. This comes from the fact that in Rayleigh fading environment, the information goes through several paths (at least two) between the BTS and the MS. At the antenna, according to the phase of the signal, the different path can add up or not. This varies with time and it can vary from complete cancellation (hole) or, on the contrary, perfect adding. This effect is called multipath fading. This effect implies that received levels follow a Gaussian law and its mean has an exponential density. The evaluation of the bias between the mean of the decibels and the mean in decibels is then: 10 .Log (e) ξ = 2.51 dB This comes from the following expression that relates the mean of the natural logarithm of an exponential random variable of mean one to the Euler constant (ξ): ∑ Ln (x) exp (- x) dx = ξ = 0,57721 The 10.Log (e) factor just accounts for the base 10 log. In this normalised example: • • averaged mean of Watt samples converted in dB = 0 = BTS calculation averaged mean of dB samples = 2.51 dB = MS calculation So, the maximum difference between the two ways of calculating the average power is 2.51 dB. The uplink value will be the higher. However, here, the hypothesis of the Rayleigh fading lead to deal with two paths, if there are many paths, the value of the correction needs to be decreased. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 483/629 V17.0 BSS Parameter User Guide (BPUG) 6.12. EFFECTS OF “NOOFMULTIFRAMESBETWEENPAGING” ON MOBILE BATTERIES AND RESELECTION REACTIVITY The parameter noOfMultiframesBetweenPaging determines how often the mobile must listen to its paging group. It has a great influence on the mobile batteries. Therefore, this value should be raised as far as possible, so the mobile will consume less energy by listening to the paging messages channel less often. Changing noOfMultiframesBetweenPaging from 2 to 6 leads to a gain of at least 18% of the batteries duration. On the other hand, this parameter is involved in the computation of the measurements number that a mobile averages in idle mode over reselection list. The exact formula is: Max(5, ((5xN+6)DIV7)x NoOfMultiframesBetweenPaging /4) seconds with N = number of BCCHs to monitor. This formula, confirmed by field tests, shows that increasing the noOfMultiframesBetweenPaging slows down the cell reselection mechanism. Two different cases must be studied in order to find a trade-off: • In a rural environment the reselection list usually contains a maximum of 5 reselection neighbours. Up to 5 reselection BCCHs, a noOfMultiframesBetweenPaging equal to 6 does not slow down the reselection mechanism too much. So it is possible to advise an increase of the default value. • In a urban environment cells size and mobiles speed generate an important constraint in terms of reactivity. Moreover, an urban cell has much more BCCH frequencies in its reselection list. Therefore, noOfMultiframesBetweenPaging should not be too high to keep a good reselection reactivity. The following curves have been drawn using the formula Max(5, ((5xN+6)DIV7)x NoOfMultiframesBetweenPaging /4) seconds with N = number of BCCH to monitor, to compute the periodicity of reselection measurements average. parameter Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 484/629 V17.0 BSS Parameter User Guide (BPUG) Periodicity of reselection (in seconds) 25 20 15 10 5 0 0 noOfMultiframesBetweenPaging = 2 noOfMultiframesBetweenPaging = 4 noOfMultiframesBetweenPaging = 6 3 6 9 12 15 Number of BCCH to monitor From those curves, one can define a value of noOfMultiframesBetweenPaging that doesn’t slow down the reselection mechanism depending on the number of BCCH to monitor in the reselection list: numbers of BCCH in the reselection list noOfMultiframesBetweenPaging ≤4 ≤6 ≤ 13 from 13 to 32 6 4 2 none With more than 13 neighbours in the reselection list, any NoOfMultiframesBetweenPaging will slow down the reselection mechanism. value for Therefore, with a cell that has up to 4 BCCHs in its reselection list, it is advised to set noOfMultiframesBetweenPaging = 6. In that case, the lost of reselection reactivity will correspond to 10% (5,57 seconds instead of 5), and the gain for batteries is very important. CAUTION! noOfMultiframesBetweenPaging is also used in the paging algorithm. A higher value will decrease the paging reactivity and might lead to double paging response (in case of paging repetitions) if the call is set up and released quickly . A trade-off between the saving of batteries and effective paging has to be found. Please also refer to chapter GSM Paging Repetition Process Tuning. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 485/629 V17.0 BSS Parameter User Guide (BPUG) 6.13. EFFECTS OF SMS-CELL BROADCAST USE ON “NOOFBLOCKSFORACCESSGRANT” If the SMS-CB feature is activated, SMS-CB messages are carried on the CBCH, a sub channel of the SDCCH. The TDMA model mapping of the SDCCH becomes SDCCH-CBCH/8, and the CBCH occurs from frame number 8 to frame number 11 of the SDCCH multiframe. If noOfBlocksForAccessGrant = 0, then a paging message can be transmitted on frames number 8 and 9. Then, if the SDCCH is transmitted on the Time Slot 0 of another TDMA than the one carrying the BCCH, a collision will occur. In that case, the mobile must choose between an incoming call and a SMS-CB, by selecting one kind of data to listen. Setting noOfBlocksForAccessGrant to a value superior or equal to 1 avoids this problem: only AGCH can be transmitted on that block. This rule NoOfBlocksForAccessGrant > 1 is a recommendation requirement on not combined CBCH. In that case, on the frame number 8 and 9, the MS can just receive an Immediate Assignment. If an Immediate Assigment message is transmitted, it means that the mobile has sent a channel request, and is not in idle mode any more. Therefore, the MS won’t listen to the CBCH channel. Please also refer to chapter Consequences of NoOfBlocksForAccessGrant. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 486/629 V17.0 BSS Parameter User Guide (BPUG) 6.14. IMPACT OF THE AVERAGING ON THE HANDOVERS The following study applies only to L1M V1. Simulations have been performed with NMC Engineering tools to determine the impact of some BSS parameters values in terms of handover reactivity. The simulations were performed from real RF measurements and network field configuration. Four Simulations have been performed with the following sets of parameters: runHandOver 1 2 3 4 Hreqt 2 2 1 1 2 1 2 1 The results are spread on three items: • • • Global statistics: number of HO in each configuration. Study of reactivity: impact of parameters on reactivity. Reactivity vs ping-pong. 6.14.1 GLOBAL STATISTICS HO CAUSE PBGT AND QUALITY DL For each of the four sets of parameters presented, the amount of HO on quality DL and PBGT is the same. HO CAUSE LEVEL DL The modification of the parameters has a low impact on the total amount of HO detected on Level DL cause. HO CAUSE CAPTURE For each of the four sets of parameters used, the total amount of handovers is the same. The difference is not significant because microCellCaptureTimer * runHandover is kept constant. CONCLUSION The simulations show that: • • Setting Hreqt=1 instead of 2 has a very low impact on the total amount of handovers (less than 4%) Same conclusion for runHandover=1 instead of 2 Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 487/629 V17.0 BSS Parameter User Guide (BPUG) 6.14.2 STUDY OF REACTIVITY The second item of the study is to show the impact of runHandover and Hreqt on the reactivity: how much sooner do the handovers occur ? RUNHANDOVER=1 Field simulations have shown that such a value of runHandOver has low impact on reactivity compared to runHandOver=2. The increase of reactivity due to runHandOver=1 is less than or equal to 0,5 second. HREQT=1 The influence of Hreqt on reactivity is much more decisive, 15% are being advanced by setting Hreqt=1 (hoMargin unchanged). Two reasons can explain this: • After the beginning of communication on a new TCH, L1M waits for a fixed delay before a new HO: HreqAve*Hreqt*0,48 sec. Among the HO performed within 8 seconds1 after a callsetup or another HO, 45% are advanced thanks to Hreqt=1.This can be very helpful if, for example, the callsetup was initiated on a bad cell, because of Reselection failure. Reducing the length of the weighted averaging window can make the variations of the weighted average less smooth. This effect is observed for only 2% of the HO. For this particular case, it is still possible to tune hoMargin. The low impact of this measure can be explained as follows. • HREQT=2 That configuration does not always double the size of the averaging window. Example: runHandover=1, HreqAve=4, Hreqt=2. Every runHandover, the L1M calculates a weighted average based on the last average stored and the sliding average of the moment. These two averages can have up to 3 measures in common. CONCLUSION • • • Hreqt=1 is an efficient way to increase reactivity for 15% of the HO. Among the HO performed within 8 seconds (after call setup or another HO), 45% are performed sooner with Hreqt=1 (in average 1,6 sec sooner). Among the HO performed long after the beginning of the communication, only 2% are performed sooner because Hreqt=1 makes the weighted average less smooth.It is still possible to tune hoMargin. runHandOver=1 can not advance HO of more than 0,5 sec. • 6.14.3 PING PONG VS REACTIVITY Among the 15% of HOs that were advanced for more than 1 second by Hreqt=1, simulations show that without changing hoMargin, no supplementary ping pong handover was observed. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 488/629 V17.0 BSS Parameter User Guide (BPUG) 6.15. IMPACT OF CALL RE-ESTABLISHMENT ON THE NETWORK 6.15.1 IMPACT ON CAPACITY The Call-Reestablishment feature has a big impact on the MSC resources occupation. Without Call Re-establishment, T3109 (BSC timer) is usually set to a small value (> Min(radioLinkTimeOut, 4*rlf1+4) which is given in SACCH block) in order to free resources as soon as possible after a radio link failure (see t3109 recommanded value). Setting a large value to T3109 for Call Re-establishment leads the MSC to freeze the resource for the call waiting for a Channel Request from the MS. Therefore, if the MS is unable to select a destination cell, or if the radio link failure is due to coverage limits (border cells), the resource is frozen for nothing. Call Re-establishment should not be activated on border cells, or the impact could be reduced by decreasing the value of T3109 on these specific locations. On the other hand, on Sunday network, tests have been performed showing that, after the Call Re-establishment activation, nearly no trunk erlangs have been noticed by Mandarin Radio Engineers. Please also refer to chapter Call reestablishment procedure (Cr). 6.15.2 IMPACT ON CALL DROPS The Call Re-establishment doesn’t decrease the amount of call drops from a counter point of view, even if it improves the quality of service. The subscriber is satisfied to get back his communication after few seconds instead of totally loosing it, but this procedure is launched after a call drop detection, counted by the system. Moreover, the Call Re-establishment can increase in some cases the overall number of call drops. For instance, when a temporary destination cell is selected by the MS without providing a long term solution: The operator can deduce that Call Re-establishment has a bad influence on call drops amount. Actually, the communication lasts longer, maybe allowing the subscriber to end his call properly. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 489/629 V17.0 BSS Parameter User Guide (BPUG) 6.16. FREQUENCY SPACING BETWEEN TWO TRXS OF THE SAME AREA At present, Nortel BTSs use only the hybrid coupling technology. The following recommendations take into account the minimum C/I requirements presented in GSM 05.05: • • • C/I>=-9dB for first adjacent channels (200kHz) C/I>=-41dB for second adjacent channels (400KHz) C/I>=-49dB for third adjacent channels (600KHz) 6.16.1 INTRA_CELL Considering the UL power control activated, Nortel recommends a minimum of 400khz frequency spacing between TRX on a same cell with or without frequency hopping, to guarantee voice quality. 6.16.2 INTRA_SITE No hopping case: Considering the UL power control activated, Nortel recommends a minimum of 400 kHz frequency spacing between TRX on a same cell without frequency hopping, to ensure a satisfactory service quality. Hopping: Generally, when hopping and considering the UL power control activated, the minimum recommended frequency spacing between TRX on a same site is 400 KHz. However, the frequency spacing between TRX on a same site could go down to 200 KHz in the following cases when some intra-site adjacencies allows a satisfactory service quality: - 1x1 or 1x3 hopping plan when the site fractional load <= 60 %; - adhoc hopping plan when different HSN s are used by the co-site cells; 6.16.3 INTER_SITE Nortel recommends a minimum of 200 kHz frequency spacing between inter-site TRX with or without frequency hopping, to ensure a satisfactory service quality. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 490/629 V17.0 BSS Parameter User Guide (BPUG) 6.17. LINK BUDGET (LB) The Link Budget is composed of the Uplink & Downlink gains and losses, and of system and propagation parameters, to determine the path loss. UPLINK BUDGET: MS_pwr + MS_ant_gain - (BTS_sen - BTS_ant_gain - Others_UL_gains + Others_UL_losses) • • Others_UL_gains = BTS_div_gain, OR LNA_gain (for external LNA only) Others_UL_losses = BTS_feeder_loss + Body_loss DOWNLINK BUDGET: BTS_pwr + BTS_ant_gain - Others_DL_gains + Others_DL_losses - (MS_sen MS_ant_gain) • • Others_DL_losses = BTS_feeder_loss + XP_loss + Body_loss XP_loss is for slant polarization loss when using cross-polarized antennas Others_XX_gains and Others_XX_losses (XX stands for UL or DL) represents all the margins that can be taken into account in the LB. Those margins can be grouped into 3 major groups which are: • • • Gains and losses on the BTS side margins, Design margins, Environmental factors margins. 6.17.1 GAINS AND LOSSES Gains and losses on the BTS side margins are composed of DIVERSITY It can be seen as a quality improvement. There are three kinds of diversity: space diversity (mostly used), angle diversity, and polarization diversity. The space diversity uses two antennas far apart enough. The two received signals suffer uncorrelated degradation, allowing to extract a diversity gain from their simultaneous process. This technique is used to decrease the Raleigh fading for slow moving mobiles, fast moving mobiles being less disturbed by this fading. Therefore, this technique is mostly used in suburban and urban areas. More generally, it is applicable in all contexts where the gain brought by diversity can be useful to balance the link budget. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 491/629 V17.0 BSS Parameter User Guide (BPUG) MAST HEAD EQUIPMENT In order to reduce the feeder loss, the PA can be deported to the mast equipment. For the reception part, LNAs are not deported anymore for cost-reduction reasons (they are placed in the RF combiner for S8000 only). This is not a problem given the good sensitivity of the BTS. If the LNA is external, there is an UL gain. COMBINING STRATEGIES A combiner allows several frequencies to be handled by the same antenna. Those losses are taken into account in the BTS_sen, NORTEL giving its BTS sensitivity at the antenna connector 6.17.2 DESIGNS MARGINS Design margins are composed of OVERLAPPING MARGIN Designed to prevent the field of the current cell from dropping under a critical value before the MS locks on the next cell. The value given for this margin depends mainly on two factors: the speed of the mobile and the speed of decreasing signal experienced by the mobile. PENETRATION FACTORS They can be defined with average value based on measurements. • • Incar: designed to take into account a MS used in a car in standard conditions. Indoor: designed to take into account a MS used in a building, using an outdoor network. Note: in the calculation of the link budget, only consider the maximum of (overlapping margin + incar penetration factor) and (indoor penetration factor). 6.17.3 ENVIRONMENTAL FACTORS MARGINS Those factors are due to the fact that a radio signal won’t propagate the same way in a rural environment or in an urban one. SHADOW MARGIN Shadowing effects due to obstacles have been studied in many articles and its probability is described as a Log-normal law. The mean square value depends on the environment (terrain variation and vegetation) and frequency. This margin allows the determination of an x% coverage over the cell surface (typically 90%) by the integration of the Log-normal law over this surface. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 492/629 V17.0 BSS Parameter User Guide (BPUG) For a cell without a surrounding cell, coverage is provided by one server only. Thus, there can have many uncovered areas (behind buildings in an urban environment for example), requiring a high shadow margin. In a multiple servers configuration, the probability of coverage is increased, and a better coverage continuity is achieved at cell edges. The delay introduced in the handover process reduces this gain. ENVIRONMENT CORRECTION FACTOR This factor exists because for the same output power, the signal will propagate much farther in a rural environment than in an urban one, creating more interference. This parameter is defined upon field measurements and a high level of experience is needed to evaluate this value when no measurement is available. If it’s badly defined, it can have a dramatic effect on the coverage range. Note: it is always possible to add more margin to increase the quality of coverage but: • • it will increase the interference level a system limit exists on the quality of service (around 98%) due to high number of handovers, neighboring cells to declare... 6.17.4 LINK BUDGET BALANCE OR DISBALANCE (∆) ∆ = DL_budget - UL_budget The worst link budget between uplink and downlink will be taken as path loss in order to do the cell planning. • • • If ∆ = 0: the link budget is balanced, so either DL or UL_budget is good for path loss If ∆ > 0: the link budget is uplink limited, take the UL_budget as path loss If ∆ < 0: the link budget is downlink limited, take the DL_budget as path loss Example: a link budget calculation with Nortel values for the S8000 Outdoor BTS using duplexor, in GSM1800: Downlink Uplink BTS_Pwr BTS 43,3 dBm 17 dBi - 2 dB 58 dB EIRP MS MS_Pwr MS_Ant_Gain Body_Loss 30 dBm - 2 dBi 3 dB 28 dB BTS_Ant_Gain BTS_Feeder_Loss EIRP MS_Sen MS - 102 dBm -2 dBi 3 dB BTS BTS_Sen BTS_Ant_Gain BTS_Div_Gain BTS_Feeder_Loss - 110 dBm 17 dBi 5 dB 2 dB 155 MS_Ant_Gain Body_Loss DL budget 155,3 UL budget Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 493/629 V17.0 BSS Parameter User Guide (BPUG) IMPORTANCE OF A GOOD LINK BUDGET In the following table, it appears that a path loss increase of 1 dB can improve the coverage range by 7% and reduces the number of sites by 12%, but 5 dB less in the path loss corresponds to a coverage range cut by 28% and a number of sites increased by 90% (figures are slightly higher for linear coverage, typically road coverage). Worst Link Budget 125 dBm 129 dBm 130 dBm 131 dBm 135 dBm Coverage range Coverage area Number of sites 72 % 93 % 100 % 107 % 132 % 52 % 88 % 100 % 114 % 190 % 190 % 114 % 100 % 88 % 52 % Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 494/629 V17.0 BSS Parameter User Guide (BPUG) 6.18. MINIMUM COUPLING LOSS (MCL) The Minimum Coupling Loss is the minimal value recommended in the link budget to avoid problems in the transmission. The MCL is calculated to avoid the two major problems which may occur, broadband noise and blocking. It is mainly used in a micro-cellular and pico-cellular environment where MSs are likely to operate in the vicinity of the BTS antennas. 6.18.1 BROADBAND NOISE The Broadband noise takes into account all kinds of noise which disturb the BTS and the MSs. According to GSM Recommendation 05.05, the MS must keep its output noise level 60 dB below its power level (for a frequency spacing of 600 kHz). On the BTS part, the received noise level must be at least 9 dB below its sensitivity. The decoupling value is the difference between the maximum output noise level and the maximum received noise level. Considering a S2000L BTS and a GSM 1800 MS, values are the following in both uplink and downlink: UPLINK Transmitter Max Power Output Noise Level Margin Max Output Noise Level Receiver Sensitivity Input Noise Level Margin Max Input Noise Level Noise Decoupling Value DOWNLINK A (dBm) B (dB) C (dBm) = A - B D (dBm) E (dB) F (dBm) G (dB) = C - F 30 60 -30 -104 9 -113 83 33 60 -27 -101 9 -110 83 As we can notice in the results of the upper table, the values are the same for uplink and downlink. 6.18.2 BLOCKING The Blocking takes into account the interferences generated by the others MSs. The BTS can handle, for the 600 kHz adjacent frequency, a received signal strength 35 dB below the maximum received power of the current frequency. Over this value, a phenomenon of flashing occurs. The flashing phenomenon consists in a BTS or a MS which would emit at a very high value, and would by this way interfere the communication of the others MSs. The effect of this phenomenon is the deterioration of the wanted signal. The decoupling value is the difference between the maximum output power and the maximum received signal level. Considering an S2000L BTS and a GSM 1800 MS, values are the following in both uplink and downlink: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 495/629 V17.0 BSS Parameter User Guide (BPUG) UPLINK Transmitter Max Power Max Received Signal Strength Decoupling Value DOWNLINK A (dBm) B (dB) C (dB) = A - B 30 -35 65 33 -44 77 Moreover, in the blocking case, the probability of collision of the burst between MS and BTS must be taken into account. In the blocking case, the downlink is more affected than the uplink. However, this difference is not very important (except if the study is done at the frequency of the interferer) since the decoupling value for the Broadband noise is more restricting than the decoupling values for blocking. 6.18.3 HOW TO IMPROVE THE MCL If the MCL is not respected, the communications will be deteriorated and will have a poor quality. To improve that quality (or decrease the probability of such problems to occur), its to say respect the MCL, solutions consist in increasing the frequency spacing between the cell and the neighboring cells and/or ensure a better decoupling between BTS antenna and MS. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 496/629 V17.0 BSS Parameter User Guide (BPUG) 6.19. GENERAL RULES FOR SYNTHESISED FREQUENCY HOPPING 6.19.1 NORTEL CHOICE BETWEEN BASEBAND AND SYNTHESISED FREQUENCY HOPPING In case of cavity (or filter) coupling system, the only way to perform frequency hopping is to use baseband frequency hopping. The wideband coupling system (duplexer or hybrid-2ways and duplexer) allows the use of both types of frequency hopping; however, it is more appropriate with synthesised frequency hopping. Here below are listed the main comparison points between baseband and synthesised frequency hopping. It allows to decide the most appropriate frequency hopping mechanism. USE OF DOWNLINK DTX AND DOWNLINK POWER CONTROL Tests have shown that if DTX downlink and Power Control downlink are activated simultaneously when using baseband frequency hopping, it could lead to quality degradation and eventually to call drops for some mobile brands. With synthesised frequency hopping, this behaviour has never been encountered whatever the mobile brand is. So with simultaneous activation of these two features, interference are significantly reduced. Beside, PowerControl DownLink associated with Baseband frequency hopping may lead to interference, because the BCCH frequency included in the hopping sequence does not perform power control. PARAMETER SETTINGS The parameter setting for the synthesised frequency hopping with a fractional re-use pattern is easily performed due to the fact that the set of frequencies is the same for each cell (1*1 pattern) or a group of cells (for example 1*3 pattern). Implementation of new sites implies a new frequency planning for the BCCH layer, but is not needed for the TCH layer. On the contrary, two different MA per cell are needed when using baseband frequency hopping: • • one for the TS0 of all the TRXs except the one carrying the BCCH, without the BCCH frequency one for the TS1 to TS7 for all the TRXs, including the BCCH frequency TS 0 TDMA 0 TDMA 1 TDMA 2 TDMA 3 TS 1 TS 2 TS 3 TS 4 TS 5 TS 6 TS 7 F1 MA0 MA0 MA0 MA1 MA1 MA1 MA1 MA1 MA1 MA1 MA1 MA1 MA1 MA1 MA1 MA1 MA1 MA1 MA1 MA1 MA1 MA1 MA1 MA1 MA1 MA1 MA1 MA1 MA1 MA1 MA1 MAIO = 0 MAIO = 1 MAIO = 2 MAIO = 3 Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 497/629 V17.0 BSS Parameter User Guide (BPUG) CAPACITY AND QUALITY IMPACT IN CASE OF TRX LOSS In case of baseband frequency hopping, the number of used frequencies is equal to the number of TRX. As a result, in case of TRX loss, the capacity of the site will be reduced, and the number of frequencies in the hopping sequence is also reduced by one. Therefore, the overall benefit of the frequency hopping (i.e. voice quality) is reduced. In case of synthesised frequency hopping, the capacity of the site is also reduced, but the overall load of the fractional pattern is reduced (the number of frequency in the hopping sequence is still the same, but the number of in-service TRX is reduced by one) ; the frequency hopping gain will be maintained. MTBF IMPACT OF THE COUPLING SYSTEM Cavity combiners, which are mechanical equipment, have smaller MTBF than hybrid coupler combiners which are passive equipment. Therefore, the synthesised solution with wideband coupling system shall be more reliable than the baseband solution with cavity coupling system. COUPLING LOSS IMPACT On one hand, cavity coupling systems have an insertion loss around 4,5 dB ; on the other hand, duplexer and hybrid 2-ways coupling systems have a respective insertion loss of 1,3 dB and 4,8 dB. Therefore, when using duplexers, a lower loss in the downlink budget allows to have a lower downlink budget (3.2 dB) to balance the path loss. Otherwise, the use of hybrid 2-ways coupling systems does not badly impact the link budget, in comparison with cavity coupling systems. FREQUENCY HOPPING EFFICIENCY For limited frequency spectrum networks, the maximum configuration of BTS is limited to few TRX in case of baseband frequency hopping. This means that every timeslot is hopping on a few frequencies (often less than 4). When using synthesised frequency hopping, every timeslot (except those of the BCCH TRX) is hopping on more frequencies (not limited by the number of TRX). FADING DIVERSITY From Nortel experience, to get the full benefit of frequency hopping, a minimum of six (6) different frequencies shall be used in each cell. This benefit is increased up to 8 frequencies available within the hopping sequence concerning fading effects. INTERFERER DIVERSITY Beyond 8 frequencies, the additional interferer benefits are still increasing. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 498/629 V17.0 BSS Parameter User Guide (BPUG) TRX ADDITION IN A GIVEN CELL In case of synthesised frequency hopping, it is not always mandatory to stop a sector when adding a TRX in this sector (it only requires that this additional TRX was previously declared within the OMC database). On the contrary, in case of baseband frequency hopping, this is not possible due to the fact that every time a TRX is added, the quantities of frequencies used in the cell have to be increased. Then it is easier to add a TRX in a cell using Synthesised Frequency Hopping as long as the fractional load is under the upper limit. 6.19.2 FRACTIONAL LOAD The fractional reuse pattern which can be implemented on a network depends on the fractional load. FractLoadCell = NbHopTRXCell Nhfcell • • NbHopTRXCell: number of hopping TRX in a cell Nhfcell: number of hopping frequencies in a cell (= number of freq in the MA) It is obvious that the defined fractional load is not comparable in a 1X1 pattern and a 1X3 pattern. In both cases there are three times more TRX in a trisectorial site than in each of its cell. However, though there are also three times more TCH frequencies in a trisectorial site than in each if its cell for a 1X3 pattern, there is the same number of hopping frequencies in a trisectorial site than in each of if its cell for a 1X1 pattern. For that matter, we also need to define a fractional load at the site level that allows us to compare both reuse patterns. We need to mention that when dealing with non homogeneous sites of configuration Sxyz (with x<y<z) this fractional load per site is important. Note: By homogeneous sites (Sxxx) we mean cells that have the same number of TRXs and hopping TRXs. FractLoadSite = NbHopTRXSite Nhfsite • • NbHopTRXSite: number of hopping TRX in a cell Nhfsite: number of hopping frequencies in a site The table below shows the fractional re-use pattern that can be implemented according to the maximum fractional load. The results in this table come from simulations and field experience. Then they have to be understood as maximum values for a “good RF quality” in the network. They are available only in case of using power control and DTX, both uplink and downlink. Otherwise, the maximum fractional load would be smaller. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 499/629 V17.0 BSS Parameter User Guide (BPUG) Cell tiering allows to raise the fractional load limit because of its gains in quality. Simulations have proved that the fractional load can go up to 33% in 1*1 and 100% in 1*3. In those cases, all the frequencies are used at the same time which also means that all the MAIOs are used at the same time. Fractional re-use pattern Hommogenous configuration (Sxxx) 1X1 1X3 FractLoadCell max without intraSite collisions Frational Load max with intraSite collisions Fractional Load max with Automatic Cell Tiering 16,6 % 50 % 20 % 58 % 33 % 100 % CAUTION! 20% and 58% can be reached with an appropriate tuning of the parameters and in this case offer a very good quality for the given capacity (field experience). The maximum fractional load is the basis of the following study for engineering rules concerning HSN and MAIO. Indeed, as the fractional load is a limitation, the aim of HSN and MAIO plans is to be as close as possible to this limitation, and to have as less interference as possible (no adjacent frequency). 6.19.3 MAXIMUM TRX CONFIGURATION (HOMOGENEOUS SITES OF CONFIGURATION SXXX) We suppose here that the frequency reuse pattern for the BCCH is 4*12. With the previous results, it is possible to determine the maximum site configuration according to the number of frequencies and the re-use pattern (1*1, 1*3 or 4*12), and taking into account the results of maximum fractional load. The following tables show the maximum site configuration according to the number of frequencies and the re-use pattern (considering a 4X12 re-use pattern for the BCCH), and taking into account the results of maximum frequency load. number of frequencies 1X3 fractional re-use pattern 1X1 fractional re-use pattern 4X12 re-use pattern 96 84 72 60 48 45 47 S888 S888 S777 S666 S555 S444 S777 S888 number of frequencies 1X3 fractional re-use pattern 1X1 fractional re-use pattern 4X12 re-use pattern 42 39 37 36 33 32 30 S666 S777 S666 S333 S555 S555 S444 number of frequencies 1X3 fractional re-use pattern 1X1 fractional re-use pattern 4X12 re-use pattern 27 24 22 18 17 12 S333 S444 S222 S333 S222 S222 S111 S111 S111 Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 500/629 V17.0 BSS Parameter User Guide (BPUG) 6.19.4 SFH PARAMETER SETTING FOR 1X1 PATTERN: STRATEGY 1 This strategy means the use of the same frequency group of TCH (Mobile Allocation) for all cells in the network. The values of maximum fractional load in a cell show that for a given fractional band, this strategy (1X1 pattern) leads to a capacity increase (more TRX per cell). However, this maximum fractional load must be obtained without an increase of interference. Then, the aim of the following study is to show what are the best HSN and MAIO plans to reach the maximum frequency load without increasing the interference. HSN AND MAIO GENERAL RULES • In case of 1X1 fractional re-use pattern it is obviously forbidden to re-use the same value of HSN and MAIO on two different cells of a same site. As they are synchronised, it would systematically lead to frequency collision. For a 1X1 re-use pattern, it is forbidden to use different HSN in cells of a same site. It would lead to a frequency collision ratio of 1 / n for all the TSs of the communication. Moreover, if some frequencies inside the group are adjacent (general case), the use of two adjacent MAIO in a same site is also extremely inadvisable because it would lead to interference (minimum frequency spacing of 400 kHz). Spread the MAIOs as much as possible Distribute equally the MAIOs in order to have the same distance (e.g. 600 kHz) between used frequencies. • • • • STRATEGY 1A: ADJACENT FREQUENCIES Frequency band for hopping TRX: F1, F1+200, F1+400, F1+600,... CASE 1: NO INTRA-SITE COLLISION RULE: same HSN for all cells within the same site MAIO given according to a step 2 rule and by considering all the TRXs by order (TRX1 of cell 1, TRX1 of cell 2, TRX1 of cell 3, TRX2 of cell 1, TRX2 of cell 2, ...). The maximum number of used MAIOs in the site (which correspond to the maximum number of hopping TRXs in the site) is given by the following rule: NbMaxOfusedMAIOsite = ROUNDDOWN(Nhfcell/2) with ROUNDDOWN[x] the function that returns the round part of x down-wise (for instance ROUNDDOWN(7.9) = 7) Note: this rule can obviously not be exactly applied in the case of non-homogeneous sites. Refer to the following examples. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 501/629 V17.0 BSS Parameter User Guide (BPUG) Let us consider a tri-sectorial site. As defined previously we have for each cell with 1 < i < 3 FractLoadCelli = NbHopTRXCell i / Nhfcelli Since we are in 1X1, we have Nhfcell1 = Nhfcell2 = Nhfcell3 = Nhfsite In order to avoid intra-site channel collision, we use a step 2 MAIO which enables us to put a 400kHz distance between the frequencies at each moment. To have hopping TRXs in 3 cells according to step 2 MAIO is like putting all the hopping TRXs in one cell with still the step 2 MAIO and none in the 2 other cells. In this case, we will be using every other frequency which means that the fractional load of the site must be below 50%. In this case the rule is FractLoadSite ≤ 50% Since FractLoadSite = NbHopTRXSite / Nhfsite = (NbHopTRXcell1 + NbHopTRXcell2+ NbHopTRXcell3) / Nhfsite = FractLoadCell1 + FractLoadCell2 + FractLoadCell3, we can deduce that the condition for no intra-site collision is then (Sxxx or Sxyz): FractLoadCell1 + FractLoadCell2 + FractLoadCell3 ≤ 50% In the particular case of a homogeneous site (Sxxx) and since NbHopTRXCell1 = NbHopTRXCell2 = NbHopTRXCell3 and thus FractLoadCell1 = FractLoadCell2 = FractLoadCell3, this condition becomes: FractLoadCell ≤ 16.6% These results can be summarized in the following table: Homogeneous: Sxxx NO intraSite collision Non homogeneous: Sxyz FractLoadSite ≤ 50% FractLoadCell ≤ 16.6% FractLoadSite ≤ 50% SUM(FractLoadCelli) ≤ 50% CAUTION! The MAIO tuning depends on the case. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 502/629 V17.0 BSS Parameter User Guide (BPUG) Example: Let us call the frequencies according to the following rule: f1=F1, f2=F1+200, f3=F1+400, f4=F1+600, ... Homogeneous site: S333 Let us consider 12 hopping frequencies {f1,f2,f3,f4,f5,f6,f7,f8,f9,f10,f11,f12}. Then, NbMaxOfusedMAIO = 6 which means that of the 12 available MAIOs we can attribute 6 of them at the most in order to respect the non intra-site collision. Since the site is homogeneous we can use 2 hopping TRXs per cell at the most. Then, FractLoadCell is 2/12=16.6%. MAIO cell 1 cell 2 cell 3 0 1 2 3 4 5 6 7 8 9 10 11 f1 f1 f1 f2 f2 f2 f3 f3 f3 f4 f4 f4 f5 f5 f5 f6 f6 f6 f7 f7 f7 f8 f8 f8 f9 f9 f9 f10 f10 f10 f11 f11 f11 f12 f12 f12 As we can see, at each moment (using NORTEL’s BTS which are synchronized), the frequencies used by all TRXs will be spaced by at least 400kHz. This is guaranteed by the step 2 MAIO and the choice of frequencies spaced by 200 kHz. HSN = 1 MAIO 0,6 HSN = 1 MAIO 4,10 HSN = 1 MAIO 2,8 Non homogeneous site: S432 MAIO cell 1 cell 2 cell 3 0 1 2 3 4 5 6 7 8 9 10 11 f1 f1 f1 f2 f2 f2 f3 f3 f3 f4 f4 f4 f5 f5 f5 f6 f6 f6 f7 f7 f7 f8 f8 f8 f9 f9 f9 f10 f10 f10 f11 f11 f11 f12 f12 f12 FractLoadCell1=3/12=25% and FractLoadCell2=2/12=16.6% & FractLoadCell3=1/12=8.3% FractLoadSite = (3+2+1)/12 = 50%. We can see here that the rule of MAIO setting has been adapted because of the non homogeneity of the site: the TRXs were not completely considered by order. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 503/629 V17.0 BSS Parameter User Guide (BPUG) If we want to add a TRX on the third sector for instance, the site becoming now S433, we need to add 2 more frequencies in order to respect the non intra-site collision and the fractional load limitations: MAIO cell 1 cell 2 cell 3 0 1 2 3 4 5 6 7 8 9 10 11 12 13 f1 f1 f1 f2 f2 f2 f3 f3 f3 f4 f4 f4 f5 f5 f5 f6 f6 f6 f7 f7 f7 f8 f8 f8 f9 f9 f9 f10 f10 f10 f11 f11 f11 f12 f12 f12 f13 f13 f13 f14 f14 f14 FractLoadCell1 = 3/14 = 21.4% and FractLoadCell2 = FractLoadCell3 = 2/14 = 14.3% FractLoadSite = (3+2+2)/14 = 50% CASE 2: INTRA-SITE COLLISION ALLOWED RULE: same HSN for all cells within the same site MAIO given according to a step 2 rule as long as possible and by considering all the TRXs by order (TRX1 of cell 1, TRX1 of cell 2, TRX1 of cell 3, TRX2 of cell 1, TRX2 of cell 2, ...). When it is not possible anymore, down to step 1 MAIO. The step 1 MAIO will create the adjacent intra-site interferences as frequencies spaced by only 200 kHz (step 1 MAIO) will be used at the same time in the site. It is up to us to decide where to create the interferences by choosing where to put the step 1 MAIOs. The recommendations are to put them in the cell which has the smallest overlap with its neighbors. If the overlap is similar in all cells of the same site then choose the cell with the smallest traffic as this will have less impact. Field experience with homogeneous sites has shown that with a proper tuning of the parameters it was possible to go up to FractLoadCell=20% while keeping a very good quality in the cell for the capacity offered. Then, we can say that in general FractLoadSite must be ≤ 60% in order keep a very good quality with intra-site collision. In other words: Homogeneous: Sxxx IntraSite collision Non homogeneous: Sxyz 50% ≤ FractLoadSite ≤ 60% 16.6% ≤ FractLoadCell ≤ 20% 50% ≤ FractLoadSite ≤ 60% 50% ≤ SUM(FractLoadCelli) ≤ 60% Example: Let us consider a S333 with 10 hopping frequencies {f1,f2,f3,f4,f5,f6,f7,f8,f9,f10}. With 2 hopping TRXs per cell FractLoadCell is 2/10=20%. Let us assume that at one moment the HSN starts by f3, the frequencies that will be used at each moment are: MAIO cell 1 cell 2 cell 3 0 1 2 3 4 5 6 7 8 9 f3 f3 f3 f4 f4 f4 f5 f5 f5 f6 f6 f6 f7 f7 f7 f8 f8 f8 f9 f9 f9 f10 f10 f10 f1 f1 f1 f2 f2 f2 Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 504/629 V17.0 BSS Parameter User Guide (BPUG) We can see here that we attribute the MAIO according to the step 2 rule as long as we can in order to avoid the intra-site collision (up to MAIO 8 here) and then we have to use the step 1 rule (MAIO 9). In this particular case, we have decided to create most of the collisions on sector 3 as the interferences are created by the simultaneous use of f1, f2 and f3. In order to add a TRX in cell 1 for instance, the site becoming now non homogeneous (S433), we need to add 2 frequencies in order to respect the fractional load limitations: MAIO cell 1 cell 2 cell 3 0 1 2 3 4 5 6 7 8 9 f3 f3 f3 f4 f4 f4 f5 f5 f5 f6 f6 f6 f7 f7 f7 f8 f8 f8 f9 f9 f9 f10 f10 f10 f11 f11 f11 f12 f12 f12 f1 f1 f1 f2 f2 f2 FractLoadCell1 = 3/12 = 25% and FractLoadCell2 = FractLoadCell3 = 2/12 = 16.6% FractLoadSite = (3+2+2)/12 = 58.3% Note: it is important to keep a certain coherence between the fractional loads of each cell within a site. Indeed, if the fractional load of one cell is very high compared to the one of the other cells, it could lead to much more intercell interferences and this should be avoided. STRATEGY 1B: NO ADJACENT FREQUENCY Frequency band for hopping TRX: F1, F1+400, F1+800, F1+1200, ... Frequency band for no hopping TRX: F1+200, F1+600, F1+1000, ... for instance This strategy leads to permanent collisions between the BCCH and the TCH time slots. Moreover, this strategy is not applicable at all when using PowerControl on the TCH time slots. This strategy is not recommended at all. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 505/629 V17.0 BSS Parameter User Guide (BPUG) 6.19.5 SFH PARAMETER SETTING FOR 1X3 PATTERN: STRATEGY 2 This strategy is studied here below in the case of a trisectorial site with an homogeneous repartition of TRX in the cells. This strategy also means the use of the same frequency group (T1) for all sectors 1 (cell 1) in the network, another group (T2) for sectors 2 (cell 2) and a third (T3) for sectors 3 (cell 3). Those 3 groups are completely disjoint and have the same number of frequencies. If this is not respected, it is not 1X3, rather an hybrid version of 1X3 and the following do not apply anymore. HSN AND MAIO GENERAL RULES • • • • If both HSN and MAIO are the same for each cell of a same site, there will be systematical frequency adjacencies. Then, this configuration is not recommended. In order to systematically ensure a non-adjacency, the only way is to use a unique HSN but different MAIO for consecutive cells within a site. The MAIO can be adjacent within a cell, because two (2) consecutive frequencies in a cell are not adjacent (non-continuous frequency bands). The use of different HSN and MAIO in each cell of a site is not recommended because it would lead to frequency adjacencies, then to an increase of interference. Spread the MAIOs as much as possible Distribute equally the MAIOs in order to have the same distance (e.g. 600 kHz) between used frequencies. • • STRATEGY 2A: 3 NON-CONTINUOUS FREQUENCY BANDS group T1 (for cell 1): F1, F1+600, F1+1200,... group T1 (for cell 2): F1+200, F1+800, F1+1400,... group T1 (for cell 3): F1+400, F1+1000, F1+1600,... CASE 1: NO INTRA-SITE COLLISION RULE: same HSN for all cells within the same site MAIO given according to a step 2 rule within a cell knowing that , the setting for cell 2 will be the one for cell 1up-shifted by 1 step and the one for cell 3 will be the same one than for cell 1. Note: This rule can obviously not exactly be applied in the case of non-homogeneous sites. Refer to the following examples. Let us consider a tri-sectorial site. As defined previously we have for each cell with 1 < i < 3 FractLoadCelli = NbHopTRXCell i / Nhfcelli Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 506/629 V17.0 BSS Parameter User Guide (BPUG) Since we are in 1X3 (not hybrid), the spectrum of the site is 3 times bigger than the spectrum of each cell and thus Nhfsite=Nhfcell1+Nhfcell2+Nhfcell3 = 3*Nhfcelli. Thus FractLoadCelli = 3*(NbHopTRXCell i / Nhfsite) The previous rule can be seen differently: indeed the frequencies used at a given moment are: MAIO cell 1 cell 2 cell 3 0 1 2 3 4 f1 f2 f3 f4 f5 f6 f7 f8 f9 f10 f11 f12 ... ... ... If we look at it by a site point of view, we can consider the site as one big cell with one spectrum (equal to the 3 groups: {T1, T2, T3}). Then it becomes: Site f1 f2 f3 f4 f5 f6 f7 f8 f9 f10 f11 f12 In this case, we are brought back to 1X1 (refer to the strategy 1A). Since the frequencies are spaced by 200 kHz, we can avoid intra-site channel collision by using a step 2 MAIO which enables us to put a 400kHz distance between the frequencies at each moment. In this case, we will be using every other frequency which means that the fractional load of the site must be below 50%. In this case the rule is FractLoadSite ≤ 50% Since FractLoadSite = NbHopTRXSite / Nhfsite = 3 * [(NbHopTRXcell1 + NbHopTRXcell2 + NbHopTRXcell3)] / Nhfsite = 3 * (FractLoadCell1 + FractLoadCell2 + FractLoadCell3), we can deduce that the condition for no intra-site collision is then (Sxxx or Sxyz): 3*(FractLoadCell1+FractLoadCell2+FractLoadCell3) ≤ 50% In the particular case of a homogeneous site (Sxxx) and since NbHopTRXCell1 = NbHopTRXCell2 = NbHopTRXCell3 and thus FractLoadCell1 = FractLoadCell2 = FractLoadCell3, this condition becomes: FractLoadCell ≤ 50% Then we can deduce the following rule on the maximum number of possible used MAIOs in a site at a given moment. This number will correspond to the maximum number of hopping TRXs in the site. It is given by the following rule following the previous limitation FractLoadCell ≤ 50%: NbMaxOfusedMAIOsite=ROUNDDOWN(Nhfsite/2)=ROUNDDOWN((3*Nhfell)/2) With ROUNDDOWN[x] the function that returns the round part of x down-wise (for instance ROUNDDOWN(7.9) = 7). Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 507/629 V17.0 BSS Parameter User Guide (BPUG) These results can be summarized in the following table: Homogeneous: Sxxx NO IntraSite collision Non homogeneous: Sxyz FractLoadSite ≤ 50% FractLoadCell ≤ 50% FractLoadSite ≤ 60% SUM(FractLoadCelli) ≤ 150% Example: Let us call the frequencies according to the following rule: f1=F1 , f2=F1+200 , f3=F1+400 , f4=F1+600, ... Let us consider 3 groups of hopping frequencies: T1={f1, f4, f7, f10, f13, f16}; T2={f2, f5, f8, f11, f14, f17} & T3={f3, f6, f9, f12, f15, f18}. Homogeneous site: Then, NbMaxOfusedMAIOsite=9 which means that we can attribute 3 TRXs per cell at the most in order to respect the non intra-site collision. FractLoadCell is 3/6=50% and we have a S444. MAIO cell 1 cell 2 cell 3 0 1 2 3 4 5 f1 f2 f3 f4 f5 f6 f7 f8 f9 f10 f11 f12 f13 f14 f15 f16 f17 f18 As we can see, at each moment (using NORTEL’s BTS which are synchronized), the frequencies used by all TRXs will be spaced by at least 400kHz. This is guaranteed by the step 2 MAIO and the choice of frequencies spaced by 200 kHz. HSN = 1 MAIO 0,2,4 HSN = 1 MAIO 0,2,4 HSN = 1 MAIO 1,3,5 Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 508/629 V17.0 BSS Parameter User Guide (BPUG) Non homogeneous site: We have NbMaxOfusedMAIOsite=ROUNDDOWN(Nhfsite/2)=10: 10 TRXs at the most that we can distribute between the 3 cells. The MAIO setting rule needs to be adapted according to the wanted configuration: S454 MAIO cell 1 cell 2 cell 3 0 1 2 3 4 5 6 f1 f2 f3 f4 f5 f6 f7 f8 f9 f10 f11 f12 f13 f14 f15 f16 f17 f18 f19 f20 f21 FractLoadCell1=FractLoadCell3=42.8% & FractLoadCell2=57.1% FractLoadSite=47.6% S544 MAIO cell 1 cell 2 cell 3 0 1 2 3 4 5 6 f1 f2 f3 f4 f5 f6 f7 f8 f9 f10 f11 f12 f13 f14 f15 f16 f17 f18 f19 f20 f21 FractLoadCell1=57.1% & FractLoadCell2=FractLoadCell3=42.8% FractLoadSite=47.6% Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 509/629 V17.0 BSS Parameter User Guide (BPUG) CASE 2: INTRA-SITE COLLISION ALLOWED RULE: same HSN for all cells within the same site MAIO given according to a step 2 rule within a cell knowing that, the setting for cell 2 will be the one for cell 1 up-shifted by 1 step and the one for cell 3 will be the same one than for cell 1. When it is not possible anymore to do a step 2, down to step 1 MAIO within the cell. The step 1 MAIO will create the adjacent intra-site interferences between the 3 cells as the frequencies are spaced by only 200 kHz between cells (step 1 MAIO. It is up to us to decide where to create the interferences by choosing where to put the step 1 MAIOs. The recommendations are to put them in the cell which has the smallest overlap with its neighbors. If the overlap is similar in all cells of the same site then choose the cell with the smallest traffic as this will have less impact. Field experience with homogeneous sites has shown that with a proper tuning of the parameters it was possible to go up to FractLoadCell=58% while keeping a very good quality in the cell for the capacity offered. Then, we can say that in general FractLoadSite must be ≤ 58% in order keep a very good quality with intra-site collision. In other words: Homogeneous: Sxxx NO IntraSite collision Non homogeneous: Sxyz 50% ≤ FractLoadSite ≤ 58% 50% ≤ FractLoadCell ≤ 58% 50% ≤ FractLoadSite ≤ 58% 150% ≤ SUM(FractLoadCelli) ≤ 174% Example: Let us call the frequencies according to the following rule: f1=F1, f2=F1+200, f3=F1+400, f4=F1+600, ... Let us consider 3 groups of hopping frequencies: T1={f1, f4, f7, f10, f13, f16, f19}; T2={f2, f5, f8, f11, f14, f17, f20} & T3={f3, f6, f9, f12, f15, f18, f21}. FractLoadCell is 4/7=57.1% and we have a S555. MAIO cell 1 cell 2 cell 3 0 1 2 3 4 5 6 f1 f2 f3 f4 f5 f6 f7 f8 f9 f10 f11 f12 f13 f14 f15 f16 f17 f18 f19 f20 f21 In order to see better the interferences, let us assume that at one moment the HSN starts by the third frequency of each group (same HSN), the frequencies that will be used at each moment are: MAIO cell 1 cell 2 cell 3 0 1 2 3 4 5 6 f7 f8 f9 f10 f11 f12 f13 f14 f15 f16 f17 f18 f19 f20 f21 f1 f2 f3 f4 f5 f6 Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 510/629 V17.0 BSS Parameter User Guide (BPUG) In this particular case, the interferences are equally created between the cells. Indeed, the simultaneous use of f13, f14 and f15 creates collisions between (cell1, cell2) and (cell2, cell3). We also have the simultaneous use of f6 & f7 f15 creating collisions between (cell1, cell3). For a non homogeneous S544 for instance: MAIO cell 1 cell 2 cell 3 0 1 2 3 4 5 f1 f2 f3 f4 f5 f6 f7 f8 f9 f10 f11 f12 f13 f14 f15 f16 f17 f18 FractLoadCell1=57.1% and FractLoadCell2=FractLoadCell3=42.8% FractLoadSite=10/18=55.5% The interferences are localized mostly in cell 1. Note: it is important to keep a certain coherence between the fractional loads of each cell within a site. Indeed, if the fractional load of one cell is very high compared to the one of the other cells, it could lead to much more intercell interferences and this should be avoided. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 511/629 V17.0 BSS Parameter User Guide (BPUG) 6.20. DUALBAND NETWORKS This chapter does not consider the new dualband cell feature (introduced in V12). For this new feature, nevertheless, each of these new cells can be considered as monoband at a selection / reselection point of view, the monoband type being defined by the BCCH frequency. Some information must be taken into account to define coverage and parameter setting for Dual Band networks. To optimize network capacity, it is necessary to evaluate balance load between the two bands and to avoid expensive procedures like LAC optimization (leads to frequent location updates) or network topology (for interBSS handovers). Furthermore, the percentage of dualband handsets and the percentage of coverage of each band are also important to know. Two different strategies can be used: adjacent coverage (one layer) or super-imposed coverage (at least, two layers). Parameter setting for a multi-layer network will be similar to microcell case. In both cases, inter-sites distance is also a key parameter to design the network. 6.20.1 FREQUENCY BAND FAVOURING SELECTION To give a lower priority to band 1 cells, it is only necessary to set the parameter cellBarQualify to “true” for these cells, and to “false” for band 2 (with cellBarred set to “not barred” in both cases). A multiband MS (phase 2 MS) will choose a band 1 cell only if no band 2 cells are found with a positive C1. cellBarred barred barred not barred not barred cellBarQualify Priority false true false true no selection possible low normal low RESELECTION Multiband mobile stations are phase 2 mobile stations. Cell reselection will involve C2 computation (if cellReselInd= true). Here is the used formula: C2 = C1 + cellReselectOffset - temporaryOffset *H(x) where: x=penaltyTime - t when: penaltyTime <> 640 C2 = C1 - cellReselectOffset when: penaltyTime = 640 Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 512/629 V17.0 BSS Parameter User Guide (BPUG) Furthermore, as C1 is the criterion used to choose one cell, one band is favoured when using advised parameter setting. Here is the formula used to compute C1: C1 = RXLEV - rxLevAccessMin - Max (B,0) • • B = msTxPwrMaxCCH - P P = maximum RF output power of the MS In both bands, usually Max(B,0) will be equal to 0. As the recommended value for rxLevAccessMin is “-101 to -100 dBm” for GSM 900 and “-99 to -98 dBm” for GSM 1800. It means that for an identical value of RxLev, GSM 900 selection is favoured (2dB) if recommended values are used for both types of cells. However, cell reselect offset can be used in the computing of C2 criteria to advantage one frequency band. Two different cellReselectOffset values can be used according to the cell frequency band. With penaltyTime <> 640, the higher the cellReselectOffset value, the higher the value of C2. Other parameters can be set as follow if no special care needs to be taken for fast mobile stations: penaltyTime <> 640, temporaryOffset = 0. Then, cellReselectOffset can be set to 30 in the favoured frequency band between 4 and 10 in the other-one (some tests using 20 and 0 respectively provided good results). The 2 dB difference for the C1 criteria between GSM900 and GSM1800 can be ignored in this case because the recommended parameter setting for cellReselectOffset leads to a difference of more than 20 dB for the C2 criteria. Another way of favouring one frequency band is to only declare reselection neighbours belonging to the priority frequency band. DIRECTED RETRY For distant mode, the eligible cell list is obtained from a level criteria directedRetry in the adjacentCellHO object. A way to have an underprivileged frequency band is to choose two sets of value for directedRetry, one for each band and to take the higher value for neighbour cells belonging to the low priority frequency band. However, it will impact the directed retry for monoband MS on this band (less directed retry). HANDOVERS If an offset was used to select (rather re-select) the cell, one must be aware that the cell may not be the best one. To avoid going back to another band because it is the best cell, this offset must be taken into account as well during handovers (hoMargin). Another way is also to inhibit power budget handovers from the priority band towards the non-priority one. To penalize handovers towards band 1 cells, it is only necessary to modify the different hoMargin for band 1 neighbouring cells, here-in called hoMargin_nei_cell_band1. hoMargin_nei_cell_band1 > hoMargin_nei_cell_band2. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 513/629 V17.0 BSS Parameter User Guide (BPUG) During interband handovers, care must be taken when GSM900 sites and GSM1800 sites are on different BSCs. This will awfully increase signaling because of interBSS procedures. To avoid this case, interband HO on alarms must also be limited (by modifying thresholds). Interband handovers can also be reduced by limiting the number of outband neighbours for each cell. This will depend on operator priorities. In V12, the feature HO decision according to priority and load allows to favour one band (or just a group of cells) through the parameter offsetPriority, 1 being the highest priority. MICROCELL ALGORITHM Microcell capture A algorithm can also be used to make mobile stations “stay” in the same frequency band. SUM-UP OF THE RECOMMENDED PARAMETER SETTING TO FAVOUR ONE FREQUENCY BAND High Priority band Multiband reporting cellBarQualify cellReselectOffset hoMarginRxQual, hoMarginRxLev... directedRetryAlgo offsetPriority Low priority band Note 3 false 30 hoMargin_nei_cell_band1 for adjacentCellHO object rxLevMinCell + 3 dB 1 2 true between 4 and 10 hoMargin_nei_cell_band2 for adjacentCellHO object rxLevMinCell + 3 dB 2 to 5 hoMargin_nei_cell_band1 > hoMargin_nei_cell_band2 6.20.2 FREQUENCY BAND DEFAVOURING SELECTION To give the same priority to both band cells, it is only necessary to set the parameters cellBarQualify to “false” and cellBarred to “not barred” for all cells. However, as GSM900 selection is favoured of 2 dB with the recommended values for rxLevAccessMin for both bands, a balance can be found in setting rxLevAccessMin to “-100 to -99 dBm” for all cells. RESELECTION No change may be done to the recommended parameter setting, then all cells may have the same values for the parameters cellReselectOffset, temporaryOffset and penaltyTime. As in cell selection, the parameter rxLevAccessMin may be set to “-100 to -99 dBm” for all cells. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 514/629 V17.0 BSS Parameter User Guide (BPUG) OTHER FEATURES For all other features (Directed Retry or handover), the same parameter setting may be kept for both band cells. The remark about interband handovers (see above) is particularly crucial to take into account in the case of no band is favoured. Indeed, a interband handover must be reduced to the minimum (by modifying thresholds) and a particular neighbour plan may be elaborated in order to avoid frequent interBSC handovers when GSM900 sites and GSM1800 sites are not on the same BSC. In V12, the feature HO decision according to priority and load allows not to favour one by setting the parameter offsetPriority to the default value for all cells. SUM-UP OF THE RECOMMENDED PARAMETER SETTING FOR TWO EQUAL FREQUENCY BANDS GSM 900 band Multiband reporting cellBarQualify cellReselectOffset rxLevAccessMin hoMarginRxQual, hoMarginRxLev... GSM 1800 band Note the six strongest cells false between 4 and 10 - 100 to - 99 dBm Value 900 for adjacentCellHO object the six strongest cells false between 4 and 10 - 100 to - 99 dBm Value 1800 for adjacentCellHO object Value 900 = Value 1800 directedRetry 900 = directedRetry 1800 directedRetryAlgo offsetPriority directedRetry 900 1 directedRetry 1800 1 6.20.3 POSSIBLE DUALBAND NETWORK Here is a list of the possible dualband networks: • • • • • gsm900 - dcs1800, gsm850 - pcs1900, E-gsm - dcs1800, gsm900 - pcs1900, (warning : mono-BCCH dualband cells 900-are not supported) gsm850 - dcs1800, (warning : mono-BCCH dualband cells 850-1800 are not supported) Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 515/629 V17.0 BSS Parameter User Guide (BPUG) 6.21. MICROCELL BENEFITS Microcell is a spectral efficiency feature. This algorithm enables us to shift traffic irrespective of the traffic condition based on downlink signal strength and mobile speed. This gives flexibility in filling the micro layer first before loading the macro/umbrella layer. Different gain can be obtained depending on microcell deployment strategy, e.g. capacity gain, indoor coverage gain, voice quality improvement… Several microcell strategies should be considered: 6.21.1 FREQUENCY SUPER REUSE In a good isolated micro layer network, a separated frequency plan can be allocated for microcells with a few frequencies for BCCH and high fractional reuse pattern increasing spectral efficiency increasing capacity keeping same QoS. 6.21.2 TRAFFIC HOMOGENIZATION One of the most critical frequency plan challenge is high configuration sites. Indeed they are difficult to control since they create interferences with no way to minimize the collisions. Declaring cells as microcell allows shifting traffic and homogenizes site configurations having a cleaner frequency plan. Benefits of this feature could be realized by rearranging the DRX counts and carrying more traffic in the micro layer traffic channels and simultaneously carrying lesser traffic and DRXs in the umbrella layer thus giving room to reduce spectrum from the Macro layer which is more interfered. This allows a cleaner and more manageable frequency plan avoiding high configurations 6.21.3 RADIO CONDITIONS IMPROVEMENT Cells with low antenna height are normally better isolated by environment protection. If these cells are declared as micro, shifted traffic generates less interference creating a cleaner frequency plan. Less interferences are traduced in a better voice quality or feasibility to increase fractional reuse pattern keeping same voice quality. On one hand microcell deployment is a good strategy to improve radio conditions., thus the operator can whether increase fractional reuse and therefore increase network capacity or increase voice quality, keeping same fractional reuse pattern. On the other hand, microcell deployment is a good strategy to improve indoor coverage in a specific area, such as business or travelling hot spots. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 516/629 V17.0 BSS Parameter User Guide (BPUG) 6.21.4 MICROCELL FIELD EXPERIENCE MICROCELL IMPACT ON AMR HR PENETRATION Microcell deployment reduces AMR HR penetration. Indeed, in microcell PBGT HO are disabled, and yet when PBGT HO are activated we assume to be on the best serving cell, so in the best C/I conditions. This effect has an impact on AMR HR penetration as good C/I conditions are required for Half Rate, which slightly reduces its penetration. LRXLEVDLH AND LRXLEVULH DEFINITION When a micro to umbrella relationship is declared between two different cells, it is important to have a close look on Call Trace / Call Path Trace in order to determine lRxlevDLH and lRxlevULH. Depending on micro and macro cell layer design, it has been found some cases where a call, which is allocated in the micro cell and getting close to the micro cell limits, receives an RxLev signal from the macro cell which is even lower than micro cell RxLev signal. Since Power Budget is deactivated when micro-umbrella relationship is declared, this phenomenon makes that rescue RxLev handover rarely executed and calls are dragged until quality handover is triggered, which could happen too late to save the call, increasing the call drop rate. In this case, it is recommended to analyze with CT/CPT the level of microcell and the neighboring macrocell level received to declare the suitable value where level handover can safely occur. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 517/629 V17.0 BSS Parameter User Guide (BPUG) 6.22. INTERFERENCE CANCELLATION USAGE All the field results so far lead to the following conclusion: • 50% for interferer cancel algo usage is a very good compromise between interference cancellation and pure thermal noise sensitivity: it does not degrade the sensitivity and gives almost the same interference cancellation performance as 100% with 5dB cancellation loss in the range I/N=0 to 20dB. For instance, it will be very useful in a medium traffic area, where the isolated interferers will be very well removed with no coverage degradation. When pure thermal noise sensitivity is not an issue (not coverage but interference limited situation), 100% achieves the best interference cancellation. In an actual network, some particular synchronization patterns may exhibit a performance loss when interference cancellation is applied although there are many interferers. However, on the overall network a typical net gain of about 1dB will be obtained with 50% (remember that 1dB is 26% increased capacity if the network capacity is limited by the uplink interferers). • • The following guidelines should be applied: when the interference cancellation is available, 50% is an excellent compromise between coverage and interference cancellation. When speed is the main problem (high speed train coverage) 100% is the best value. Improvement appears when there is an update from a previous v15.1.1 BSS to a later one. Indeed, before V15.1.1, gain of interferer cancellation was not optimal in case of low Rxlev. Since V15.1.1 interferer cancellation algorithm has been improved to take into account all range value for parameter “interferer cancel algo usage” for all RxLev range. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 518/629 V17.0 BSS Parameter User Guide (BPUG) 6.23. SET UP PRINCIPLES OF A NEIGHBORING LIST AND A BCC PLAN 6.23.1 INTRODUCTION An optimum neighboring plan consists in having the best compromise between the quality of service and the network load. Indeed, the higher the number of neighboring cells in the neighboring list, the more loaded the traffic due to HO procedures. Moreover, an efficient neighboring plan ensures a better network reliability by avoiding an excessive call drop rate resulting from HO failures. Neighboring plan optimization is a trade off between: • many neighbors which can lead to excessive HO, and thus signaling overload. Moreover, as measurements are performed on all neighbors in the list, measurements on the more used neighbors are less often performed than with a shorter list. Then the system is less reactive to perform handover. few neighbors which would lead to call drop and poor quality of service due to HO failures. • Hereafter are the engineering rules to follow when initializing a neighboring plan, depending on the type of pattern used for the frequency plan. 6.23.2 4/12 REUSES PATTERN INITIALIZATION OF THE NEIGHBOR LIST The first step when initializing a neighbor list consists in choosing a cell as a neighbor of the serving cell if they share a common border in the best server map. The neighboring list will then define a geographical ring (first ring) around the serving cell. Each cell belonging to this first ring of the given cell will be automatically included in the neighboring list without selection on geometrical or mean field level criteria. However, using only the list of first ring neighbor cells can lead to dropped calls or ping-pong handover, because the coverage of some first ring neighbor cells can be thick between the serving cell and a second ring neighbor cell. ESTABLISHING A LIST OF CELLS ON GEOMETRICAL CRITERIA Some neighbors must be added to the previous list, in order to avoid the mentioned troubles. One solution could be to define another geographical ring (second ring) but this solution would often lead to a very high number of neighbors in the neighbor list, and consequently to an excessive number of handover. Thus, the risk is to have signaling overload. Then, a good solution consists in defining a distance criteria, that must be fulfilled by a cell for being considered as a neighbor. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 519/629 V17.0 BSS Parameter User Guide (BPUG) This distance is the one separating the server cell site location, and the other cells contours. This method corresponds to the definition of a circle with a specified diameter. Any cell coverage being totally included within this circle, or having a part of the surface within the circle is added in the neighbor list. This distance can be the same for all the cells of the network. But this method is more efficient if the distance criteria is a multiple of the cell radius. The cell radius should correspond to the maximum length separating the cell site location and any point belonging to its coverage. Note: height and roads are important aspects to keep in mind for neighboring plan: • Indeed, two sites neighbor from a geometrical point of view but separated by a high hill should not be declared as neighbor if no signal is expected to cross the mountain. Also as the channel effect is very important, especially in town, neighborhood should take into account the main roads. Two cells not neighbor with statistical prediction models, have high probability of being really neighbor if they are located just on a large avenue not too far apart. • RESURGENCE PROBLEMS If the resurgence area is large and not too far from the serving cell, it can be considered as a real cell. Consequently, this situation is equivalent to a normal cell’s neighborhood assignment and all the cells surrounding the resurgence must be added to the serving cell neighborhood. This situation is well handled by the automatic tools. However, there are several other situations where the resurgence should not be taken into account: • The resurgence is reduced to a small area. Then the resurgence coverage is not enough significant to be considered as a suitable cell for the handover or selection issue. Any HO operation performs on the cell’s resurgence will lead to a “ pingpong ” handover from the cell resurgence to the surrounding cells. The resurgence is located far from the serving cell (with several cells between the resurgence and the serving cell). This situation leads to a poor stability of the received signal. As the serving cell is far away from the MS, the MS could easily lose the signal and thus almost immediatly perform a handover to another cell (signaling load). • That is why, all the cells assigned as neighbor of a serving cell because of this kind of resurgence should then be removed from the neighbor list. Then, such cells with resurgence which were first assigned as neighbor of a serving cell (after distance criteria application) must be removed from the neighbor list. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 520/629 V17.0 BSS Parameter User Guide (BPUG) CONCLUSION Initialization with the first ring Current cell: antenna, Azimuth, emission power, frequency Candidate cell: antenna, azimuth, geographical position From the current cell Eligibility criteria (distance criteria) List of candidate cells Taking into account resurgency List of neighbours cells 6.23.3 1X3 AND 1X1 FRACTIONAL REUSE PATTERN SPECIFIC CASE When enabling frequency hopping on a network, a 1X3 or 1X1 pattern is generally used for the TCH frequency plan (see chapter Frequency Hopping). Then, if the quality thresholds for handover are not changed, the number of handover on quality criteria will increase because the RxQual distribution is narrower (less bad RxQual samples but also less good RxQual samples). Thus using a distance criteria to create the neighbor list can lead to handover on TCH from a serving cell using the same TCH frequency group than the destination (neighbor) cell. Now if the handover is on quality criteria, the risk is high to arrive on this cell with also a bad quality (and perhaps worst than before). Then a new handover will be triggered. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 521/629 V17.0 BSS Parameter User Guide (BPUG) FIRST RING NEIGHBOR LIST (1X3 REUSE PATTERN) In the case of a 1X3 reuse pattern, a way to avoid this kind of handover is to declare only the first crown of neighbors. In the following schema, the cells in orange are not declared neighbors to the serving cell S. N1, T2 N6, T3 N7, T1 N2, T3 S, T1 N5, T2 N3, T2 N4, T3 N8, T1 In case of hot traffic spot, as this solution leads to a few number of cells in the neighbor list, there is a risk of handover failure due to channel unavailability. In order to avoid this, 2 channels in every cell must be reserved for handover (allocPriorityThreshold = 2). The only exceptions for this rule are the following: • • Coverage hole Limited coverage due to shadowing effect However, this solution means a few number of neighbors in the list and then can lead to call drop and handover failures (see scheme with first ring neighbor list before). DISTANCE CRITERIA NEIGHBOR LIST (1X3 AND 1X1 PATTERNS) A good solution would be to put at a disadvantage handover on quality criteria toward neighbor cells using the same TCH group than the serving cell. It would be done in setting the parameter hoMarginRxQual to 24 for these neighbors. However, this solution could be a good solution for optimization but not for basic neighbor plan, because it needs a study for each cell. A compromise is to increase the handover quality thresholds (lRxQualDLH and lRxQualULH) as it is recommended when enabling frequency hopping. Thus, the global number of handover will not increase and the risk of handover on quality criteria toward a cell using the same TCH group will be low. Then the recommended solution in the case of fractional reuse pattern (1X3 or 1X1) is the same than for a 4X12 pattern. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 522/629 V17.0 BSS Parameter User Guide (BPUG) HANDOVER LIST VERSUS RESELECTION LIST. For all reuse patterns, the same cells should be declared in both handover and reselection list. Moreover, the serving cell should be declared in the reselection list. In case of hole of coverage, this will allow the MS to reselect the best cell and not a distant cell. However, for 1X3 and 1X1 reuse pattern, if only the first ring is used for the neighbor list, a higher number of reselection cells (first ring + second ring or distance criteria) than handover cells (only the first ring) must be declared. 6.23.4 SET-UP PRINCIPLES OF A BSIC PLAN Three main procedures can be used to set easily the BCC parameter of each cell. For all these methods, one should take into account a distance criteria in order to minimize the probability of BSIC / BCCH conflict between nearby cells. • The first method is based on geographical BCC values gathering. It is done by selecting the BCC value of a cell among the values already taken by its neighbor cells. The chosen BCC is the-one not leading to a BSIC / BCCH conflict. The advantage of this solution is an homogeneous distribution of the BCC among the network. However, it is long and difficult to apply by hand and is generally used when allocating BCC with automatic tools. The second method consists in using as less BCC values as possible. Then, for each cell, first BCC equal to 0 is tried. The tried value is increased by one if it leads to a BSIC / BCCH conflict. This operation is repeated until no conflict is detected. This method has the advantage to minimize the number of used BCC. Then when adding new cells, generally a BCC for this cell can be found without creating BSIC / BCCH conflict and without modifying the BCC of existing cells. However, it is long and difficult to apply by hand and is generally used when allocating BCC with automatic tools. The third method consists in allocating a specific BCC to each occurrence of the BCCH reuse pattern. The occurrences having the same BCC must be as far as possible from each other. It is the most currently used method when BSIC plans are done by hand, because it is easy and quick to apply. However it means that a neighbor cell can not have the same BCCH than its serving cell, what is restrictive. • • Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 523/629 V17.0 BSS Parameter User Guide (BPUG) 6.24. STREET CORNER ENVIRONMENT 6.24.1 DESCRIPTION Especially in micro-cellular network, where the antennas are under the roof, the level received by the mobile can dramatically fluctuate. Ping pong handovers and call drop were experienced in this type of environment, and led to bad quality of service as well as a significant increase in signalling traffic. One of the toughest issues to solve in a micro cellular network is street corner environment. cell A cell B Two cases must be distinguished: • • The first one deals with mobile moving straight the cross road. In the case, the handover toward the cell A must be avoided. Mobiles turning at the cross road is the second case. The handover from cell B to A must be performed quickly before the field of the current cell dropped under a critical value, leading a call drop. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 524/629 V17.0 BSS Parameter User Guide (BPUG) 6.24.2 CASE A: MOBILE MOVING STRAIGHT In the case of a mobile moving straight the cross road, a handover for PBGT may be processed from cell B to cell A. Once the cross is passed, the mobile is handed again over the cell B. This ping pong handover shall be avoided as useless handover leads to voice quality degradation. The parameter rxLevDLPBGT allows to cope with that case. Actually, if the signal received by the mobile from the serving cell exceeds this threshold, then the handovers with power-budget criteria are prevented. cell A cell B RxLev rxLevDLPBGT cell B cell A Time Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 525/629 V17.0 BSS Parameter User Guide (BPUG) 6.24.3 CASE B: MOBILE TURNING AT THE CROSS ROAD In a microcell environment, the size of cells is very small (40 to 400 meters). The overlapping margin between cells is not very important. Moreover, a fast moving mobile may cover a few hundred meters during the handover process (in the worst configuration, the duration time of a handover can be more than 1.5 s). The overlapping margin can be insufficient to prevent the field of the current cell from dropping under a critical value before mobile locks on the next cell (with standard parameters values). In such environment, reactivity is essential, handovers have to be performed as quickly as possible. cell A cell B RxLev cell A cell B Time The problem is solved by the combination of the following features: • • • Early Handover decision (see chapter Early HandOver Decision) Protection against runHandOver = 1: in a microcell environment reactivity is essential (see chapter Protection against RunHandover=1). Max rxLev for PBGT: the problem of handover toward cell A when mobile goes straight forward is solved by a negative hoMargin for PBGT that can be set in order to help handover when mobile turns (see chapter Maximum RxLev for Power Budget) Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 526/629 V17.0 BSS Parameter User Guide (BPUG) 6.25. SYNCHRONIZED HO VERSUS NOT SYNCHRONIZED HO 6.25.1 INTRODUCTION Some tests have been carried in order to compare the timing HO of the three kinds of handovers. No interBSC handovers were performed as synchronized handovers are only available for intraBSC HO. The test plan was the following: Intra BSC / Intra BTS HO • • • Not synchronized HO from Cell A to Cell B (UL & DL) Synchronized HO from Cell A to Cell B (UL & DL) Pre–synchronized HO from Cell A to Cell B (UL & DL) with different values of the PresynchTimingAdvance parameter. Intra BSC / Inter BTS HO • • • Not synchronized HO from Cell A to Cell B (UL & DL) Pre–synchronized HO from Cell A to Cell B (UL & DL) with different values of the PresynchTimingAdvance parameter. 6.25.2 OMC-R PARAMETER SETTINGS It has to be noted that ECU was enabled on both Cell A and Cell B. ECU may have an influence on UL measurements. SYNCHRONIZED HO Parameters CellId Synchronized hoMargin Cell A Cell B adjacentCellHO object Cell B Id Synchronized -24 Cell A Id Synchronized -24 NOT SYNCHRONIZED HO Parameters adjacentCellHO object CellId Synchronized hoMargin Cell A Cell B Cell B Id Not Synchronized -24 Cell A Id Not Synchronized -24 Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 527/629 V17.0 BSS Parameter User Guide (BPUG) PRE-SYNCHRONIZED HO Parameters AdjacentCellHO object CellId Synchronized Cell A Cell B Cell B Id Pre sync HO with timing advance 0 1 2 3 4 5 6 30 Cell A Id Pre sync HO with timing advance 0 1 2 3 4 5 6 30 -24 PreSynchroTA hoMargin -24 Note: the value - 1 for the PreSynchroTA parameter stands for a TA value equal to 1 (554 m). 6.25.3 TIMING HO PROCEDURE The test procedure was based on tone recordings. A specific tone is sent for UL (resp. DL) from the MS (resp. the land line). The tone is a pattern of a 3 second 500 Hz signal and a 3 second 700 Hz signal. The use of 2 contiguous signal is needed because problems of no signal emission occurred when a one frequency tone signal is used. The tone was sent for a minute. An HO occurred approximately every 5,7 seconds. Each record has a serial of about 10 HOs. All the averages shown in that study are calculated from these 10 values. SYNCHRONIZED HO RESULTS COLLECTED DATA HO # 1 2 3 4 5 6 7 8 9 10 11 Muting (ms) Silence (ms) Demuting (ms) Total (ms) 26 14 21 31 14 26 70 66 43 49 29 55 60 57 61 52 50 26 28 25 10 18 28 21 15 14 15 19 19 26 46 38 36 Nortel confidential 109 95 93 106 81 95 115 120 114 97 83 PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 528/629 V17.0 BSS Parameter User Guide (BPUG) The (1,2,3,4,5,6) HO # are HOs which occurred in the 500 Hz frequency part of the tone. The (7,8,9,10,11) HO # are HOs which occurred in the 700 Hz frequency part of the tone. STATISTICS & COMMENTS • HOs in 500 Hz frequency tone part Muting (ms) 22 14 31 7 Silence (ms) Demuting (ms) Total (ms) 56 50 61 4 19 14 28 5 97 78 120 16 • HOs in 700 Hz frequency tone part Muting (ms) 51 29 70 17 Silence (ms) Demuting (ms) Total (ms) 21 10 28 7 33 19 46 11 106 58 144 35 For both frequencies, the average timing HO of a synchronized HO is the same, around 100 ms. The interesting part is that the time repartition between the muting, silence and demuting phases are not the same. The muting and demuting phases appear to be dependent on the frequency. However, the muting and demuting algorithms at the TCB are not dependent on the frequency. Actually, the ECU activation on both cells may be responsible of this dependence. It seems that the ECU algorithm at the BTS makes the muting and demuting dependent on frequency. When ECU is enabled, it seems that the muting and demuting slopes are correlated to the frequency. NOT SYNCHRONIZED HO RESULTS COLLECTED DATA HO # 1 2 3 4 5 6 7 8 9 Muting (ms) Silence (ms) Demuting (ms) Total (ms) 25 47 40 20 24 48 18 38 25 133 113 114 137 131 93 123 143 109 4 84 43 47 43 33 46 38 44 162 244 197 204 198 174 187 219 178 Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 529/629 V17.0 BSS Parameter User Guide (BPUG) The (1,2,3,4,5,6,7,8,9) HO # are HOs which occurred in the 500 Hz tone part of the signal. STATISTICS & COMMENTS Muting (ms) 32 18 48 12 Silence (ms) Demuting (ms) Total (ms) 122 93 143 16 42 4 84 20 196 162 244 25 The Not Synchronized Timing HO is around 200 ms. Unfortunately, the high standard deviation value does not allow any conclusion on this specific duration. Note: Not synchronized HO procedure Here is a brief example of the L3 radio protocol of such a HO: • • • • • • DL: HANDOVER COMMAND UL: HANDOVER ACCESS DL: PHYSICAL INFO DL: PHYSICAL INFO DL: PHYSICAL INFO UL: HANDOVER COMPLETE The TA is indicated from the target BTS to the MS in the PHYSICAL INFO. We can make the statement that the not synchronized HO is twice slower than the synchronous one. It is mainly due to the PHYSICAL INFO expectation of the MS. PRE-SYNCHRONIZED HO RESULTS PRINCIPLE The pre-synchronized handover procedure is exactly the same than the synchronized handover procedure. After the Handover Access bursts which shall be sent with a TA value of 0 the MS shall use a TA as specified in the HO Command by the old BTS, or a default value of 1, if the old BTS did not provide a TA value. The BSC indicates in the HO Command message that the handover will be pre-synchronized and, if needed, the predefined Timing Advance to be used by the MS in the new cell (preSynchroTimingAdvance parameter). COLLECTED DATA The real TA of both cells is 0 (but fluctuant sometimes to a TA value of 1). The aim of these tests is to evaluate the voice quality loss and/or gain of a pre-synchronized HO versus the preSynchroTimingAdvance value set at the OMC-R. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 530/629 V17.0 BSS Parameter User Guide (BPUG) STATISTICS PreSynchroTA (kms) Average (ms) Minimum Maximum Standard Deviation 0 -1 1 2 3 4 5 6 30 120 108 129 8 122 94 144 18 89 65 126 17 105 89 105 13 436 79 958 334 739 524 971 172 756 606 970 133 684 532 947 132 705 533 945 133 COMMENTS It has to be understood that the pre-synchronized handover has been implemented in order to fasten the handover procedure in a dense (size <2kms) environment or in a railway / highway optimization. As the setting of the preSynchroTimingAdvance parameter is not that easy (onfield measurements and TA distributions after HO per pair of cells), the behavior of the MS for a wrong (2 or 3 steps of TA) and a very wrong (greater than 3 steps of TA) TA value is very interesting for the network optimization. Actually, regarding the timing HO results versus different preSynchroTimingAdvance values, it seems that the MS is able to re-synchronize with the BTS. The drawback is that the speech cut duration and the handover procedure are highly increased (up to 1 second). CONCLUSION Regarding the results of that study, it clearly appears that the synchronized handover is the faster type of handover. It is available for intraBTS or intracell handovers, or if the Network Synchronisation is activated. In this case, if the two cells are synchronized by GPS, and they have the same TNOffset, handover can be synchronized, even if the two cells are not in the same BSC. However, the pre-synchronized handover has shown very good results (almost the same performance than the synchronized one) if the TA after HO is previously known. Therefore, pre-synchronized HO is a good solution to fasten handover and to decrease (up to 80 ms) the speech cut duration. The fields of appliance should be dense (cell size < 2kms), railway or highway environment to ensure that the distance after handover is known. Not synchronized handover still remains the only setting for InterBSC handovers. Anyway, the UL results of that memo show that the speech cut duration is less than 250 ms. This value allows to keep a pretty good voice quality during handovers. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 531/629 V17.0 BSS Parameter User Guide (BPUG) 6.26. BTS SENSITIVITY 6.26.1 DEFINITION OF SENSITIVITY In this chapter, sensitivity figures are clarified, knowing that such notions as static, dynamic, guaranteed and typical may often lead to confusion. The sensitivity is completely defined in the GSM recommendation 05.05. §6.2., as the input level for which all performances in terms of frame erasure, bit error or residual error rates are met. A reference table specifies rates varying according to the type of GSM channel (traffic, signaling) and the type of propagation channel (static, urban, rural, hilly terrain). Sensitivity is measured at antenna connector, and by definition this figure takes into account all RF elements losses included in BTS cabinet, as shown on the following figure: Antenna Common Cable losses Rx sensivity Antenna connector Duplexor Combiner Power Amplifier Rx diversity gain Base Station Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 532/629 V17.0 BSS Parameter User Guide (BPUG) 6.26.2 STATIC AND DYNAMIC SENSITIVITY Static sensitivity could be viewed as the level at which sensitivity performance is met in the static channel mode. Yet, the static mode is only one of the propagation models among others specified in the GSM Recs. reference table. The static mode is the most favorable case (excepted a few cases of fully not correlated antennas and 2-branchs diversity). In terms of radio, it can be understood that for a given signal input, less communication errors are expected within a configuration where there are no multi-path effects at all. 6.26.3 TYPICAL / GUARANTEED SENSITIVITY Typical sensitivity is 1dB better than the worst-case used, mainly due to the variation in performance of the RF front end and not the variation in the DRX module. The variation in performance of DRXs on a per cell basis is therefore very tightly controlled. For more details, please refer to the BTS Engineering Rules ([R47] to [R56]). 6.26.4 SPACE DIVERSITY GAINS FADING CORRELATION One major parameter to assess space diversity gain is the fading correlation, which depends on many factors, such as radio environment (angular distribution of reflectors), antenna configuration (spacing between antennas) and position of the mobile respective to the BTS. The sensitivity for fully correlated antennas and not correlated antennas (correlation 0.2) can be viewed respectively as the worst case and quasi-best case situations. In reality, the correlation figure lies ‘somewhere between’ both figures, depending on the factors mentioned previously. To assess correlation values applicable to engineering is not an easy task. Yet, it can be observed that by taking 10 wavelengths of antenna separation (recommended distance is 20), the correlation factor is as low as 0.2 for an angular spread of only 1 degree .These results give us enough confidence to interpolate the sensitivity at values near the not correlated case, in such environments as built-up areas (urban, suburban), as well as hilly terrain, which offer a multiplicity of reflectors. However, this appears less obvious for open area environments, typically flat rural, for which we will assume a more conservative correlation factor. BRANCH SENSITIVITY Diversity gains are calculated by doing the difference between “with” and “without” 2 antennas figures. Then diversity gains vary a lot with correlation and propagation channels. Yet, it can be observed that after rounding figures, the overall sensitivity + diversity figure stays relatively constant, independently of the configuration. The trend is a cumulated figure of -113 dBm for the S8000 without enhanced coverage option, and -115 dBm for the S8000 with enhanced coverage option. This observation partly justifies the uniformity of the diversity gain of 5 dB for the S8000. It must be stressed that this artifice is only meant to provide separate figures for sensitivity and diversity gain, which are still distinguished when discussing link budgets Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 533/629 V17.0 BSS Parameter User Guide (BPUG) 6.26.5 CROSS-POLARIZATION ANTENNA USE The use of cross-polarization antenna has followed a growing trend, due to the flexibility offered in terms of site installation (two antenna packaged into one, offering diversity gain and coupling 2 TRXs on a single antenna without hybrid coupling). Cross polar antenna is characterized by: • • 2RF ports for one antenna slant polarized transmission. Hence use of cross polar antennas implies: • • • simplification of the coupling stage. radio link performances modification. diversity of polarization. SIMPLIFICATION OF COUPLING STAGES It should be understood that with the same number of antennas as for spatial diversity crosspolar antennas provide 2 times more RF ports. This means that on one feeder, the number of supported DRX is divided by two, and the size of the coupling stage too. RADIO LINK PERFORMANCES Radio link performances are affected by the transmission over slanted polarization: measurement reports indicate performances of crosspolar antennas compared to vertical antenna are lower: • • in urban area of 1dB in 900 MHz and 2dB in 1800 MHz. in flat rural area of 3dB in 900 MHz and 1800 MHz. Note: performances of crosspolar antennas are strongly dependent on environment, and mainly on reflectors and scatterers: the more they are, the better the performances. For link budget purposes, crosspolar antennas recommended typical losses are: • • in all environment, 1.5dB in 900 MHz and 1800 MHz. in flat open area, 3dB in 900 MHz and 1800 MHz. POLARIZATION DIVERSITY Polarization diversity is obtained by processing the two signals coming from the two branches of one crosspolar antenna. Polarization diversity is estimated after measurements of signal decorrelation between the two diversity receiving branches of one crosspolar. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 534/629 V17.0 BSS Parameter User Guide (BPUG) LINK BUDGET FIGURES Proposed link budget figures for crosspolar antenna use are summarized in the table below: all environments 900 MHz & 1800 MHz radio link performances (DL & UL) diversity gain flat rural, flat open 900 MHz & 1800 MHz -1.5dB +4dB (5dB)* -3dB +4dB (5dB)* (*) Crosspolar antennas offer as diversity solution: • • polarization diversity (4dB gain) when 1 crosspolar antenna is used. spatial diversity(5dB gain) with 2 crosspolar antennas. 6.26.6 CIRCULAR POLARIZATION AND CROSSPOLAR ANTENNAS This system, Nortel patented, combines two types of advantages: • • the crosspolar antenna benefit of the 2 antennas connectors within one antenna chassis. the robustness of circular polarization against depolarization effect and mobile positioning. This system relies on a single 3dB-90° dephaser-hybrid coupler located at the bottom of the crosspolar antenna feeding the two ports of the crosspolar antenna with exactly the same feeder length. The system scheme is shown below: BTS with polarization diversity BTS with space diversity Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 535/629 V17.0 BSS Parameter User Guide (BPUG) In term of radio figures, the benefits of the crosspolar antenna use combined with the 3dBcoupler are: • the radio transmission is no more affected by the slanted polarization due to the transmission of the whole signal over a circular polarized wave. Whatever the position, the mobile receives all the power the combining stages are divided by 2 the diversity gain is: 4dB with 1 crosspolar antenna the polarization diversity gain 5dB with 2 crosspolar antenna the space diversity gain • • Recommended figures for this system are all environments 900 MHz & 1800 MHz diversity gain polarization diversity space diversity radio link performances (UL and DL) +4dB +5dB 0dB Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 536/629 V17.0 BSS Parameter User Guide (BPUG) 6.27. SDCCH DIMENSIONING AND TDMA PRIORITIES The aim of this chapter is to define engineering rules associated to SDCCH dimensioning and TDMA priorities . 6.27.1 SDCCH DIMENSIONING An SDCCH assignment is provided when one of the following Layer 3 message is received: • • • • CM Service Request (includes IMSI attach) Paging Response IMSI Detach Location Update So the number of these messages has to be taken into account in the dimensioning of the SDCCH channels. Some rules are defined here below. PARASITE SDCCH ALLOCATION The level of noise can provide a parasite SDCCH allocation, the BTS seems to receive an RACH and allocates an SDCCH channel. In this case the SDCCH is assigned for a short duration (free after T3101 (3 sec by default)). The parasite SDCCH assignment depends of the BCCH TDMA model. Note that from V8B7 the number of parasite SDCCH becomes negligible with new DRX. BTS GEOGRAPHICAL POSITION IN THE LAC The location update frequency must also be considered for the evaluation of the blocking rate ratio for SDCCH. For BTS located at the border of a Location Area, a lot of location updates are performed. Then, the signaling traffic is very high. In this case (as for area with a high SMS traffic), the number of SDCCH channels must be quite high. Therefore, the blocking rate ratio to consider for SDCCH must be lower than the-one for TCH. Thus, a table can be established for the blocking rates to consider, depending on the load of the network and the kind of signaling. TCH Blocking rate Normal load Very loaded SDCCH Blocking rate Middle LAC LAC border 2% 5% 0.1 % 0.1 % 0.1 % 0.1 % DOUBLE SDCCH ALLOCATION The double SDCCH allocation occurs when a second RACH is sent by the mobile before the Immediate Assignment message of the first RACH is received. The double allocation issue depends on the numberOfSlotsSpreadTrans value. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 537/629 V17.0 BSS Parameter User Guide (BPUG) ACTIVATION OF SMS-CB The SMS-CB is multiplexed with the SDCCH. So the activation of the SMS-CB reduces the number of SDCCH sub-channels and so the signaling capacity of the BTS. For example: • • SDCCH/4 + SMS-CB => 3 SDCCH available (combined case) SDCCH/8 + SMS-CB => 7 SDCCH available (not combined case) TDMA Model SDCCH/4 SDCCH/3 SDCCH/7 SDCCH/8 Capacity (erlang) 0.439 0.194 1.579 2.057 So the activation of the SMS-CB has a great impact on the signaling capacity of cell (see also chapter SMS-Cell Broadcast) Note: in case of SMS-CB, the SDCCH TS number has to be lower than 4 (< 4) SUBSCRIBERS MOBILITIES In a high mobility area (rural, highway) a none negligible number of the RACH are requested for Location Updates. The total number of RACH is then higher than in a low mobility area, it is then better to increase the number of SDCCH channels. In a very high mobility area (high speed train) the number of Location Area are generally reduced in order to avoid a BSS signaling overload due to the LA update. Moreover the TCH allocation has to be as fast as possible in order to avoid dropped calls set-up. So for the cells which are dedicated to the coverage of very high mobility area only, (e.g. cells which cover only the high speed train railways and not surrounding roads or villages) it is better to reduce the SDCCH channels number. If the cell is at the boundary of a location area the SDCCH channels have to be set according to the Location Area update load. NUMBER OF NETWORKS The SIM card can contain the Id of only 4 forbidden networks, i.e if there are more than four networks in a country a mobile can attempted a Location Update on other networks (-> Location Reject). So wherever there are more than four competitors in the same frequency band it is recommended to increase the number of SDCCH channels. 6.27.2 TDMA PRIORITIES It is possible to allocate “priorities” to TDMA frames. Each TDMA has two priorities, each serving a different purpose : the “TRX/TDMA mapping priority”, represented by the parameter priority (transceiver object) the “PCM allocation priority”, represented by the parameter trafficPCMallocationPriority (transceiver object) Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 538/629 V17.0 BSS Parameter User Guide (BPUG) TRX/TDMA MAPPING PRIORITY (PARAMETER : PRIORITY) This priority defines the order with which the BTS allocates the available hardware resources (the transceivers) to the TDMA frames. In practice, if due to a hardware failure, there are fewer TRX than TDMA, then only the TDMAs of higher priority will be mapped onto a TRX. The parameter is called priority (transceiver object). Among the set of TDMA frames attached to a cell, it is mandatory for the one carrying the BCCH to have the highest priority allocated and to be the only one to have that priority. For the TDMA carrying SDCCH channels, that priority should be the second highest priority, i.e. not as high as the BCCH priority. For the TDMA carrying only TCH channels that priority should be the lowest. The generic rule to set the TRX/TDMA mapping priorities is the following : BCCH TDMA : priority = 0 SDCCH TDMA : priority = 1 TCH TDMA : priority = 2 The typical values for priority of each TDMA model is defined in detail in the Radio Interface Engineering Rules ([R58]). PCM ALLOCATION PRIORITY (PARAMETER : TRAFFICPCMALLOCATIONPRIORITY) The parameter trafficPCMAllocationPriority (transceiver object) defines the priority level of a TDMA frame for mapping onto a PCM on the A-bis interface. In case of failure of one or more Abis PCMs, TDMAs of highest such priorities are allocated DS0 on the remaining Abis PCM links before TDMAs of lower priority. The engineering rule associated to this parameter will depend on the strategy the operator wants to use for the corresponding site. The default engineering rule is to give the lowest priority (255) to the TDMA supporting the BCCH, because the BCCH is conveyed on a LAPD TS, which is always present. So the BCCH signalling and the SDCCH signalling is never lost. As the TDMA supporting the BCCH has fewer traffic channels than other TDMA, it makes sense to save these other TDMA before saving the BCCH TDMA. However, one can privilege: • the traffic in one of the sectors: for example on a site linked by two PCMs if a cell is considered as more important by the operator (strategic coverage), one can give to the TDMAs of that cell a higher priority than those of the other cell. Thus, during a PCM failure, those TDMA will be re-configured in priority on the left PCM. circuit traffic instead of packet data traffic, by setting a higher priority for TDMAs having only TCH compared to TDMA that have also pDTCH • Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 539/629 V17.0 BSS Parameter User Guide (BPUG) 6.28. ENGINEERING GUIDELINES FOR EXCEPTIONAL EVENTS This chapter is intended to provide guidelines on how to prepare Nortel GSM networks for “exceptional events” from an engineering perspective. An exceptional event, as described in this document, is a temporary event which is known in advance and which will generate an exceptional high traffic load on the network. Nortel’s estimation is that it is economically not justifiable to dimension a GSM network for these special events. Commonly, a GSM network is dimensioned to carry the traffic of the busy hour. The actions proposed in this document are intended to optimize the behaviour of the network during an exceptional event. The document covers recommended actions on the NSS and on the BSS. On the NSS, the document describes a set of recommended verifications that Nortel encourages the operator to do in order to optimize the DMS behaviour. In addition a set of recommended office parameter settings on the MSC is given with the aim of optimizing the behaviour of the BSC. On the BSS side, this document presents the list of strongly recommended verifications and a set of parameters values to be applied for any wide area special event. Nortel recommends that the normal parameter setting should be reconfigured after the exceptional event. On the NSS side, the document is applicable to GSM09, GSM10, GSM11 and GSM12. It is assumed that all required patches on NSS and BSS are applied. Apart from the paragraphs on CM, LPP and NSS recommendations in Chapter 4.31.3.1, most of the NSS recommendations can also easily be applied on non-Nortel NSS equipment. As signalling is the bottleneck during a high load situation on the BSS, the guiding idea here is to reduce as much as possible unnecessary signalling during the exceptional event. Nortel’s estimation is that this should improve the behaviour of the BSC. The control of this situation is done by various verifications and parameter modifications. The proposal is organised in 4 main levels: • • • • Prerequisite Basic tuning of parameters Overload configuration change Other parameter modification 6.28.1 BSS PREREQUISITE CHECKS SANITY CHECKS Should be done at least one month before the foreseen event : • • • Verification of the state of the different BSC: no BSC boards should be in a faulty state Recommended values are applied Dimensioning rules are respected Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 540/629 V17.0 BSS Parameter User Guide (BPUG) NETWORK: Each BSC is fully operational and a switchover should be done, LapD load balancing over TMU, LapD loadsharing, Location Area (LA) sizing,, TCH congestion (this is particularly important in case of concentric cell use), Call Drop rate, HandOver failure rate (and neighbouring reciprocity). CHECKS CORRELATED WITH THE SPECIAL EVENT The Nortel Recommendation is that these checks be done a few hours before the special event. LIMITATION OF THE OAM ACTIVITIES The Operation, Administration and Maintenance shall be minimum. So: • • • all Call Traces and Call Path Traces shall be stopped/discarded Observations should be limited; temporization for permanent observation should be set to at least 30 minutes Freeze of the network operation: No reparenting activity or NRP should be performed during the critical period Moreover, no modification of the network during the special event (such as command files, OMC commands, …) shall be done. LIMITATION OF THE SIGNALIZATION TOWARDS THE BSC • • • Periodic location updates should be limited on the BSS side (recommended value for timerPeriodicUpdateMS = 60) Operator advertising using SMS should be avoided If a degradation of the QoS is acceptable during the corresponding critical period: Paging repetition at NSS side should be reduced / suppressed, Notification of voice mail through SMS should be limited / deactivated Authentication procedures should be limited / deactivated at NSS level Ciphering should be limited at NSS level 6.28.2 BSS: SUGGESTIONS FOR PARAMETERS TO BE MODIFIED FOR THE SPECIAL EVENT It is suggested that the following parameters be modified before the special event and set back to the previous value afterwards (when the amount of traffic is back to a ”normal” level): These parameters are split into 3 categories. • The modification of parameters of the 1st category does not lead to any service interruption. These modifications may be done very quickly and a few hours before the event. Parameters of the 2 nd category are only applied if it can be done without service interruption (refer to chapter ALGORITHM PARAMETERS). Modification of parameters of the 3 rd category is optional and only applicable on networks in which queuing is already activated. It requires a quite long preparation Nortel confidential • • PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 541/629 V17.0 BSS Parameter User Guide (BPUG) and should be decided at least three months before the special event. It does not lead to service interruption. Parameters to modify: • • • • • • • abisSpy = “not in progress” unknownCellWarning = “disabled” interBscDirectedRetry = “not allowed” intraBscDirectedRetry = “not allowed” Multipaging timer on Abis interface = 200 ms maxNumberRetransmission = 1 bscCapacityLoadReduction feature is not available for BSC3000, but dedicated overload mechanism for BSC3000 exist (see chapterBSC3000 Overload Management) 6.28.3 NSS LEVEL DMS PREPARATION Note: the recommendations in this Chapter should also be followed after the exceptional event. COMPUTING MODULE (CM) The Computing Module (CM) of the DMS is protected by a highly efficient overload mechanism. This mechanism allows the DMS to stand a significant overload. In order to maintain the craftsperson’s capability to access the DMS in the expected overload situation, it is suggested that verification is made to ensure that at least the 2 MAP terminals as well as the ETAS modems are declared as guaranteed background task for the CPU. This is done by setting for these devices in table TERMDEV the GUAR field to Y. A maximum of 5 devices can be declared in this way. Refer to NTP 411-3001-451 Customer Service Data Schema Vol 3. LINK PERIPHERAL PROCESSOR (LPP) The behaviour of the LPP under heavy traffic conditions can be improved by optimizing the allocation of BSSAP instances to LIU7s. It should be checked that the following recommendations are followed. Context Table GSMSSI defines the subsystem instances of the BSSAP local subsystem. These instances reside on an LIU7 and serve SCCP Class 2 connections between the BSS and the DMS-MSC. Table GSMSSI allows the customer to associate BSSAP instances with LIU7s. BSSAP instances are used only for A-interface messaging. They can be datafilled on any LIU7 in the MSC. Also, there is no restriction that an A-interface LIU7 must have a BSSAP datafilled against it. However, datafilling the BSSAPs in a non-optimal manner can negatively impact the DMS-MSC’s performance under heavy messaging conditions. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 542/629 V17.0 BSS Parameter User Guide (BPUG) Further information about table GSMSSI and the BSSAP instances can be obtained in The CCS7 Application Guide, NTP #411-2231-310. This document includes a datafill example for GSMSSI. Recommendations The recommendation is that all customers apply the following guidelines: • • BSSAP instances in table GSMSSI should only be defined against LIU7s which have an inservice link to a BSC. Each A-interface linkset should at least have one BSSAP instance assigned to it. The remaining instances (total of 32) should be spread out among the remaining A-interface LIU7s. Priority should be given to the highest traffic linksets. SS7 LINK Underprovisioned SS7 links can result in link congestion, which potentially inhibit mobile call processing. It is therefore recommended to audit the link provisioning in the network before the special event. During the busy hour the mean link occupancy should not exceed 40%. The expected subscriber growth in the network has to be taken into account. This check should be done about 4 months before the special event in order to allow potential HW extensions. LAC DATAFILL The Location Area Code (LAC) is a configurable parameter on the BSS and on the NSS (table LAC). If the values are not the same, Mobile location updates on the MSC will fail. This will result in all mobiles to repeat the locationupdate attempt. The resulting high signaling load can decrease stability of the LPP due to the increased signaling traffic. It is therefore highly recommended to verify that the LAC values on BSS and NSS match up before the special event. BSC PROTECTION Reduction of the signaling load on the BSC optimizes its behavior in a high traffic situation. This chapter proposes actions in the NSS, which will help to decrease the signaling load on the BSC. SMS VOICEMAIL NOTIFICATION Most of the GSM networks use voicemail notification via SMS. SMS traffic is real-time cost intensive on the BSC processors. Furthermore, in a high traffic situation with degraded QoS, the Voicemail traffic is expected to significantly increase. The operator should consider to deactivate the notification of voicemails via SMS. Under very high load the notified subscribers will not be able to consult their voicemails anyway, due to the high blocking rate at the Air interface. The deactivation should be done either on the VMS or on the SMSC. AUTHENTICATION Authentication in GSM aims at ensuring that only mobiles with an official SIM card can access the network. Reducing authentication reduces the signaling on the BSS. The operator should consider to disable the optional authentication activities in the network. This can be done by Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 543/629 V17.0 BSS Parameter User Guide (BPUG) modifying parameter AUTH_CONTROL_PARM in table OFCVAR. To configure to a minimum activity the parameter has to be set as follows GSM09: AUTH_CONTROL_PARM = NORM_0 PER_0 ATT_0 MO_0 MT_0 IMPACT It should be noted that even with this minimum setting the authentication procedure will be executed at the first Attach or Inter-VLR-location update of a mobile at the MSC. This implies that a reasonable degree of security is reached. The default value of NORM_20 PER_20 ATT_20 MO_20 MT_20 configures that every 20th call, location update and attach will trigger the authentication procedure. The above described minimum value results in only the first location update (inter-VLR or attach) to trigger authentication. The parameter allows to individually set authentication rates for normal (NORM), periodic (PER) location updates location, Attachs (ATT), mobile originated (MO) and mobile terminated (MT) calls. PAGE RETRY The Paging message sent to the BSC is highly costly in terms of BSC CPU processing. After a timer expires without a response from a mobile, the DMS sends a second Paging message. Monitoring of live networks has shown that only an insignificant portion of the second paging message is successfully responded by a mobile. Due to this it is recommended to deactivate the paging retry. This is done by setting the parameter GSM_PAGE_RETRY in table GSMVAR to 0. CIPHERING Ciphering guarantees confidentiality of GSM communications on the radio interface. Deactivating Ciphering reduces the signaling on the BSC. The operator should consider whether the deactivation of ciphering is acceptable during the special event. To deactivate, the officeparameter GMSC_CIPHERING in table OFCENG of the MSC has to be set to OFF. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 544/629 V17.0 BSS Parameter User Guide (BPUG) 6.29. ENGINEERING LIMITS WITH BSC OVERLOAD CONTROL MECHANISM The main objective of the BSC overload control mechanism (introduced in V12) is to maintain BSC robustness during a traffic overload period. The BSC controls achieve this by filtering of Mobile Originated calls, Mobile Terminated calls, Location Updates, Handover or Random Access Channel messages. This results in a Quality of Service degradation when the overload is reached (through an increasing “Call Attempts reject rate”), as illustrated below: Mean CPU occupancy 100 % CPU call processing limit (ex: 70%) CPU engineering limit (ex: 55%) Offered traffic OAM & internal process Carried traffic QoS decrease BSC’s maximum throughput with the highest QoS BSC overload control mechanism is triggered Mean Call Attempts 6.29.1 “CPU ENGINEERING LIMIT” MEANING The “CPU Engineering limit” is defined as the limit of mean CPU occupancy (used for Call Processing only) not to be exceeded in order to maintain the highest Quality Of Service. When exceeding this engineering limit, the probability that the Quality of Service is degraded due to the triggering of the overload control mechanism cannot be neglected. The following set of “CPU Engineering limits” is based on lab performance reports and validated in the field. Below these limits, no QoS degradation has been observed. BSC2G Board MPU & BFIP SICD BSCB OMU - SUP- SWC CPU engineering limits 55 % 60 % 60 % 90 % Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 545/629 V17.0 BSS Parameter User Guide (BPUG) 6.29.2 “CPU CALL PROCESSING LIMIT” MEANING The “CPU Call Processing limit” is defined as the limit of mean CPU occupancy (used for Call Processing only) not to be exceeded by the different boards, regardless of Quality of Service. The overload control mechanism acts to keep the mean Call Processing CPU occupancy due to the traffic below this limit. The remaining x% is reserved for other processes required for OAM signaling and internal processes. The following set of “CPU Call Processing limit” is based on field experience and lab performance reports. BSC2G Board MPU & BFIP SICD BSCB OMU - SUP- SWC CPU call processing limits 70 % 70 % 70 % 100 % The monitored average TMU1-SBC processor load should keep below 70%. The monitored average TMU1-PMC processor load should keep below 85%. The monitored average TMU2-SBC processor load should keep below 80%. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 546/629 V17.0 BSS Parameter User Guide (BPUG) 6.30. POWER CONTROL COMPENSATION IN INTERZONE HANDOVER 6.30.1 IMPORTANT NOTE This chapter deals with the theoretical pre-v17.0 behaviour of the power control during interzone handovers for the 3 concerned cell types (concentric cell, dualcoupling cell, dualband cell) and for each Power Control algorithm (step by step, one shot). Note that in v17.0, a new feature enables the BSS to compensate for the power gap that used to exist between old and new channel, each in a different zone, when performing an interzone handover. The v17.0 behaviour is explained in the Power adaptation after an interzone ho (V17) section of this document and in even more detail in the functional note [R42]. For the study that follows, only the pre v17.0 behaviour is described. 3 phases are defined: • • • Phase 1: the MS is handled by a TDMA belonging to the band0/outerzone and the TX power is stable Phase 2: the MS is handed over toward a TDMA belonging to the band1/innerzone; the power control is not running Phase 3: the power control is started and the power becomes stable 6.30.2 DUALBAND CELL STEP BY STEP ALGORITHM In this example, we suppose that BS transceivers have the same maximum power in each band. The studied case is the RxLev_DL but the RxLev_UL is similar. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 547/629 V17.0 BSS Parameter User Guide (BPUG) interZone handover RxLev DL biZonePowerOffset 2 SACCH BS Pwr Att 2 SACCH Band 0 Band 1 There is no power compensation during the handover: the initial power after a handover doesn’t take into account the difference of radio propagation between the two bands. So, there is a signal drop (approximately biZonePowerOffset). However the condition on level for the Interzone handover ensures that the signal drop has no effect. The Step by step algorithm keeps the RxLev_DL in the interval L_RXLEV_DL_P, U_RXLEV_DL_P. Thus the attenuation on BS power decreases in order to compensate the signal drop. CONCLUSION The Step by step algorithm compensates the signal drop. Note: If the initial attenuation (in level) after the handover is less than biZonePowerOffset, the definitive power compensation is reduced. ONE SHOT ALGORITHM ONE SHOT APPLIED TO THE BS POWER The BS transceivers have the same maximum power in each band. DL_TxPwr_BandX dB are attenuations resulting from the one shot algorithm. Interzone handover toward Band1: there is no power compensation on the HO, e.g. the initial power after a handover doesn’t take into account the difference of radio propagation between the two bands. So, there is a signal drop (approximately biZonePowerOffset). Band1 after the Power control: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 548/629 V17.0 BSS Parameter User Guide (BPUG) RxLev DL_Band1 = RxLev DL _Band0 - biZonePowerOffset + K_DL * Bizone_power_offset / VAL_PWRLEV_TO_DB (with VAL_PWRLEV_TO_DB = 2) Note: if the DL_TxPwr_Band0 (dB) is lower than K_DL * biZonePowerOffset, the power compensation is reduced. Example: Bizone_power_offset = 3 level (6 dB) • • Bad quality without frequency hopping: K_DL = 0.5, RxLev DL_Band1 - RxLev DL_Band0 = -3 + 0.5*3/2 = -3 level (-6 dB) Good quality with frequency hopping: K_DL = 0.9, RxLev DL_Band1 - RxLev DL_Band0 = -3 + 0.9*3/2 = -1 level (-2 dB) ONE SHOT APPLIED TO THE MS POWER There is an MS transceiver maximum output power for each band: • • Pm0 (max transmitting MS power in band0) depends on the MS_classmark in Band0 and on the network parameter MS_TXPWR_MAX. Pm1 (max transmitting MS power in band1) depends on the MS_classmark in Band1 and on the network parameter MS_TXPWR_MAX_BAND1. DPMS = Pm0 - Pm1. UL_TxPwr_BandX dBm are absolute powers resulting from one shot algorithm. There is no power compensation on the HO: the initial power after a handover doesn’t take into account the difference of radio propagation between the two bands. So, there is a signal drop (approximately biZonePowerOffset). Band1 after the Power control: RxLev UL_Band1 = RxLev UL _Band0 - biZonePowerOffset + (K_UL * biZonePowerOffset - (1-K_UL) * DPMS ) / VAL_PWRLEV_TO_DB (with VAL_PWRLEV_TO_DB = 2) Example: Bizone_power_offset = 3 level (6 dB) DPMS = 3 dB • • Bad quality without frequency hopping: K_UL = 0.5, RxLev UL_Band1 RxLevUL_Band0 = -3 + (0.5*3 - 0.5*3) / 2 = -3 level (-6 dB) Good quality with frequency hopping: K_UL = 0.9, RxLev UL_Band1 RxLevUL_Band0 = -3 + (0.9*3 - 0.1*3) / 2 = -2 level (-4 dB) Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 549/629 V17.0 BSS Parameter User Guide (BPUG) CONCLUSION The definitive power compensation with the One shot algorithm is reduced especially when the frequency hopping is not used. However the condition on level for the Interzone handover ensures that the compensation is not indispensable. In comparable conditions, the difference of level (resulting from the Power control) between the two bands of a Dual Band cell always exist. It is not tied to the handover example. 6.30.3 CONCENTRIC CELL ONE SHOT ALGORITHM The BSC knows the BS maximum output TX power in each zone, so the attenuation is compensated during an Interzone handover. RxLev DL_Zone1 = RxLev DL _Zone0 - (1-K_DL )*DP BS ) /VAL_PWRLEV_TO_DB RxLev UL_Zone1 = RxLev UL _Zone0 (with VAL_PWRLEV_TO_DB = 2) Example: DPBS = 15dB • • Bad quality without frequency hopping: K_DL = 0.5, RxLev DL_Zone1 - RxLev DL_Zone0 = - 0.5*15/2 = -3.7 level (-6 dB) Good quality with frequency hopping: K_DL = 0.9, RxLev DL_Zone1 - RxLev DL_Zone0 = - 0.1*15/2 = -0.7 level (-0 dB) 6.30.4 DUALCOUPLING CELL ONE SHOT ALGORITHM The BS maximum output TX power is the same in each zone (DP BS ), but the difference comes from different coupling losses (downlink) which have the same effect than a difference of radio propagation. The power is not compensated during an Interzone handover. The Power control result is nearly the same in the two zones. RxLev DL_Zone1 = RxLev DL _Zone0 - Bizone_power_offset + K DL * Bizone_power_offset / VAL_PWRLEV_TO_DB RxLev UL_Zone1 = RxLev UL _Zone0 (with VAL_PWRLEV_TO_DB = 2) Example: Coupling D (loss about1dB) and H2D (loss about 4dB) Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 550/629 V17.0 BSS Parameter User Guide (BPUG) Bizone_power_offset = 3dB = “1.5 level” • • Bad quality without frequency hopping: K_DL = 0.5, RxLev DL_Zone1 - RxLev DL_Zone0 = - 1.5 + 0.5*1.5/2 = -1.1 level (-2 dB) Good quality with frequency hopping: K_DL = 0.9, RxLev DL_Zone1 - RxLev DL_Zone0 = - 1.5 + 0.9*1.5/2 = -0.8 level (-0 dB) The One shot associated with Dual coupling cells has a good behavior. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 551/629 V17.0 BSS Parameter User Guide (BPUG) 6.31. GSM PAGING REPETITION PROCESS TUNING The paging repetition process is designed to improve the paging answering performances of a network (repetition normally take place at a LAC level). Paging messages broadcasted to locate a mobile are systematically repeated in order to maximize the probability of answering, and the repetition is performed eventhough the mobile answers from the first paging message. This repetition depends on some parameters but also the configuration of the cells broadcasting the paging messages. The paging repetition process can be tuned to avoid in specific cases repeating too much paging messages and thus decrease the number of paging messages queued or discarded. 6.31.1 PAGING PARAMETERS BSS PARAMETERS On the BSS side many parameters have an influence on the paging and the paging repetition process: • noOfBlocksForAccessGrant: it defines the number of blocks reserved to transmit Immediate Assignment messages among the PCH-AGCH blocks of a multiframe. It should be set to 0 if no SMS-CB is activated or in case of SMS-CB with combined BCCH, and set to 1 if SMS-CB is activated without combined BCCH. noOfMultiframesBetweenPaging: it defines the periodicity of a paging group occurrence (paging group A for instance). The unit is the multiframe, and it should be set to 6 in rural environments and to 2 or 4 in urban environments. nbOfRepeat: defines the number of times a paging message will be repeated by the BTS. By setting this parameter to 3 one ensure to maximize the probability of paging answering even in bad radio conditions. delayBetweenRetrans: defines the number of occurrences between 2 repetitions of the same paging group. It should be set to 0 in order to avoid double allocation. retransDuration: defines the maximum time allocated to broadcast a paging message. It should be set according to the following inequality retransDuration ≥ (delayBetweenRetrans + 1) X nbOfRepeat. • • • • The combination of these parameters allow to delay or speed up the broadcasting for a group of mobile and maximize the probability of reception of a paging message, but also to decrease the number of re-emission of paging messages if the radio conditions allow it. NSS PARAMETERS On the NSS side, only one parameter may be taken into account, GSM_PAGING_RETRY which allows to repeat the Paging Command message on the A interface. It is possible to choose between paging repetition at a BSS or a NSS level: one can prefer NSS paging repetition or be dependent on an other vendor NSS paging repetition. In this case BSS paging repetition parameters should be set accordingly. NSS repetition can bring some improvements, as described in chapter Field examples: NSS paging repetition tuning. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 552/629 V17.0 BSS Parameter User Guide (BPUG) TDMA CONFIGURATION Depending on if the CCCH is combined or not on the cell, the number of frames dedicated to the paging are different: it goes from 3 CCCH occurrences in the combined case to 9 occurences. The TDMA configuration can drastically reduce the number of free channels available for paging messages and thus should be taken into account for the number of repetition. See also chapter Consequences of the TDMA Model. 6.31.2 FIELD EXAMPLES: BSS PAGING REPETITION TUNING The optimal way to optimize the number of repetition on a network (BSS side) is to proceed to a step by step analysis of the number of paging messages successfully sent at the first attempt, successfully sent at the following attempts, and all the paging messages discarded. LAC 10000 17500 18000 18100 18500 Traffic (Erl) Page now Page 1w Page 2w Page more Paging discarded 305 401 500 441 422 8011 12550 17625 16397 16118 132 91 437 358 174 2 2 8 8 3 0 0 1 1 0 422 1 7205 1182 1364 With this example we can see that 3 LACs show a large number of discarded paging messages. At this step we can not determine if those discarded messages have been successfully sent previously or not (the repetition take place eventhough the mobile already answer). The first step will be to audit the type of the BTS and the TDMA configuration. In case the CCCH is combined to the BCCH, a reconfiguration should be plan. Then the number of repetition on the NSS side should be taken into account, and set to 0 if it is not the case (in this particular case the GSM_PAGING_RETRY was already set to 0) Finally the BSS parameters could be checked and compared to the recommended values (and especially the noOfMultiframeBetweenPaging that depends on the environment), before trying to tune the nbOfRepeat, and the retransDuration. If good radio conditions are met on the cell, one could try to decrease the nbOfRepeat very cautiously, and subsequently the retransDuration which is correlated. Parameter September’s value January’s value noOfBlocksForAccessGrant noOfMultiframesBetweenPaging nbOfRepeat retransDuration delayBetweenRetrans 1 5 3 10 0 1&5 5 0 3 0 The number of repetition has been set to 0, and the restransmission duration down to 3. Other parameters were still at recommended value. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 553/629 V17.0 BSS Parameter User Guide (BPUG) In that particular case, the decrease was done because good radio conditions were met. We can observe a very good improvement on the number of paging messages discarded, without affecting the QoS (traffic and paging success). LAC 10000 10200 17500 18000 18100 18200 18500 Traffic (Erl) Sum of Page now Page 1w Page 2w Page more Paging discarded 337 246 469 396 392 634 399 1808577 990583 2378638 1265792 3605562 3270930 1711766 1671 1693 3463 6449 37715 25417 1837 3 14 14 87 278 384 7 0 1 0 0 8 17 0 0 0 0 0 0 0 0 From a BSS tuning point of view, the nbOfRepeat has a major influence on the paging queue. Modifying this parameter is a good way to optimize the number of paging messages, as long as good radio conditions are met. 6.31.3 FIELD EXAMPLES: NSS PAGING REPETITION TUNING 1800 1600 1400 1200 1000 800 600 400 200 0 26 27 28 8 3/ 9 3/ 10 6 1 2 3 4 5 3/ 3/ 3/ 3/ 3/ 3/ 3/ 7 2/ 2/ 2/ 3/ 1.60% Action 1 Action 2 1.40% 1.20% 1.00% 0.80% 0.60% 0.40% 0.20% 0.00% Call Drop(Include C1164/17) System Call Drop Rate(Include C1164/17) That field example shows the good impact of NSS Timers tuning on the Call Drop ratio. Action 1 corresponds to a reduction of timers T305 and T308 from 30 to 1second and Action 2 corresponds to a reduction of timer T102 from 5 to 30 seconds. (T305: started when a DISCONNECT message without progress indication is sent and stopped when the network has received a RELEASE or DISCONNECT message; T308: started when a RELEASE message is sent and stopped when the network has received a RELEASE_COMPLETE or a RELEASE message; T102: used by MSC−A when a HANDOVER_COMMAND message is sent and stopped when a HANDOVER_COMPLETE message is received) Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 554/629 V17.0 BSS Parameter User Guide (BPUG) 6.32. AMR FIELD FEEDBACK AMR is the new feature introduced in release v14.3 in order to: • • Increase voice quality in degraded radio conditions, Increase radio capacity due to robustness of Full Rate AMR and introduction of Half Rate channels. The principle of this feature is described in chapter AMR - ADAPTATIVE MULTI RATE FR/HR, and this chapter try to quantify the gain of AMR regarding the two objectives listed above. Note: most of the findings in terms of monitoring and feature optimization are based on the experience gained during the VO activity and the rollout phase that followed. As the Legacy L1m was activated for most of these testings, we recommend and support today the AMR feature with this L1m algorithm enabled. 6.32.1 NSS INTERACTION MULTIPLE VOCODER AT MSC SIDE Field tests have raised in some cases an issue on handovers from one channel type to another channel type. This issue was due to a MSC parameter belonging to OFCVAR table : multiple_vocoder_support. This parameter was positioned on “on_no_changes” and that prevented the MSC to be able to change the channel type if the target cell of another BSC did not support the channel mode of the originating cell. This behavior was fixed by setting multiple_vocoder_support to "on_with_changes" thus handovers from AMR HR channels could go to EFR. CHOSEN CHANNEL BETWEEN MSC AND BSS Another issue was raised concerning the following parameters located on the signallingPoint object of the BSS that have to be set to “TRUE”: • • • chosenChannelAsscomp chosenChannelHoReq chosenChannelHoPerf Indeed, the GSM specifications (3GPP TS 48.008) precise that the chosen channel shall be included in the message between the BSS and the MSC (ASSIGNEMENT COMPLETE, HANDOVER REQUEST ACKNOLEDGE, HANDOVER PERFORMED) at least when the channel rate/type choice was done by the BSS. Issues have been noticed on the field with other vendor Core network when those parameters are not properly set, in this case in particular it was impossible to establish half rate calls. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 555/629 V17.0 BSS Parameter User Guide (BPUG) 6.32.2 AMR THEORETICAL PERFORMANCES The following figures show theoretical AMR FR and HR performances vs. EFR. They are usually expressed in terms of MOS or DMOS vs. C/I. A new voice quality indicator has been defined, the TEPMOS, which is recommended for AMR calls. VOICE QUALITY INDICATORS MOS and DMOS MOS or DMOS are subjective notes given by people who compare the quality of the original (ACR tests) or a reference signal (DCR tests) and the signal at the output of the coder. MOS and DMOS are always a value between 1 and 5: a value equal to 1 means that the listening is unintelligible and a value equal to 5 means that the two signals are the same (which is never the case). One estimate that a value higher than 4 corresponds to an excellent voice quality. A good quality corresponds to a MOS higher than 3.5 and a fair quality is higher than 3-3.2. TEPMOS TEPMOS stands for theoretical extrapolated PMOS. It is theoretical because it is based on simulations in order to translate FER to PMOS values. It is extrapolated, because TEPMOS weight usage of each one of different AMR codecs PMOS in order to establish AMR TEPMOS. AMR FULL RATE The figure below shows the performances recorded for the best AMR Full Rate codec mode for each C/I, with the corresponding performance of EFR (and also FR in car noise conditions) and the related AMR performance requirement (curve Sel. Requir.) Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 556/629 V17.0 BSS Parameter User Guide (BPUG) The figure shows that the combination of all 8 AMR FR codec modes allows to: • • provide a robust quality down to 4 dB C/I in Clean Speech, which means up to 6 dB improvement compared to EFR, provide a robust quality down to 4 dB C/I in Background Noise, which means also significant improvement compared to EFR and GSM FR. In other terms also, capacity can be increased by operating a tighter frequency reuse pattern or by operating a higher fractional load, which is equivalent in the two cases to a higher number of Erl/km2/frequency. AMR HALF RATE Here one compares the performances recorded for the best AMR Half Rate codec mode for each C/I, with the corresponding performance of EFR, GSM FR and HR speech codecs and the related AMR performance requirement (curve Sel.Requir.) This figure shows that the combination of all 6 AMR HR codec modes allows to: • • provide a good quality down to 16 dB C/I in Clean Speech, always significantly better than the GSM FR and GSM HR, provide good performances in Background Noise down to 16-13 dB C/I, equivalent to GSM FR otherwise. It means that AMR HR offers the possibility to have in good radio conditions a capacity increase in term of Erlang (two users can be mapped on the same TS instead of one) keeping comparable quality of a FR speech. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 557/629 V17.0 BSS Parameter User Guide (BPUG) QUALITY PERCEPTION SYNTHESIS The above graph shows the different AMR FR codec performances taken individually in terms of PMOS for a given propagation profile (TU3iFH). The AMR Link Adaptation principle will consist in choosing according to the radio conditions (C/I measured) the appropriate codec in order to provide the best PMOS quality. The below graph provides a simplified view of the voice quality perception (Excellent to Bad quality) between the EFR (12k2 fixed codec) with the AMR FR and AMR HR Link adaptation. C/I RxQual EFR Quality 16 dB 13 dB 10 dB 7 dB 4 dB 1 dB 3 (0.8%<BER<1.6%) Excellent 4 (1.6%<BER<3.2%) 5 (3.2%<BER<6.4%) Good 6 (6.4%<BER<12.8%) Fair Good 7 (BER>12.8%) Poor to Bad Fair Poor to Bad Poor to Bad FR-AMR (LA) Quality HR-AMR (LA) Quality Excellent Excellent Good Fair SACCH FER FACCH FER 1% 1% 3% 3% 20% 20% 50% 50% It is interesting to see that: • down to the limit of acceptable SACCH/FACCH BLER (20%), HR and EFR provide the same level of voice quality (Poor to Bad), slightly better though for EFR. This has driven us in our recommendation of maximizing HR penetration in areas where RLT is not the limiting factor above the 20% of SACCH/FACCH BLER, voice quality for AMR-FR is still fair which may lead to potential drop calls while the speech is still fair from a user perspective. This has driven in our recommendation to extend the radio link timeout timer in order to compensate somehow the user behavior in places where the coverage or low C/I are the limiting factors • Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 558/629 V17.0 BSS Parameter User Guide (BPUG) 6.32.3 AMR ENGINEERING STUDIES DEFINITIONS ENGINEERING TESTS CHARACTERISTICS • • • • • • • • • • DL results are only presented DL collected traces are given by two TEMS T62u mobiles which are ran in parallel, one set to AMR mode and the other to EFR mode connected to same PC Both mobile were connected to same and external antenna All engineering tests presented in this document were done at night during maintenance window 2 hours tests were done in order to collect maximum samples as possible in a wide range of radio conditions Cells were bared to avoid having other users than test mobiles in victim cell Both incoming and outgoing HO for EFR and AMR calls were disabled DTX was de-activated A VQ server was called and used as a “speech player” with a continuous sequence of speech for DL measurements Different adaptation codec tables were used to compare adaptation thresholds on performances ADAPTATION CODEC SET TABLE The link adaptation consists in adapting the “best” codec to speech frames according to the link quality estimated by both entities. Each codec mode, whether used in Uplink or Downlink, and whether used for FR or for HR channel, corresponds to one couple of threshold and hysteresis. The value for these couples depends also on a set of factors: MS speed, FH or no FH, propagation profile. Finally, all these parameters associated to the choice of the codecs are compiled into a table called amrAdaptationSet table. It is composed of 4 subtables each dedicated to a combination of channel type and link direction. In order to optimize the adaptation, NORTEL has implemented 3 sets of pre-defined tables (optimistic, pessimistic and typical settings) plus one set of tables which is user-defined. The parametersamrDlFrAdaptationSet, amrDlHrAdaptationSet, amrUlFrAdaptationSet, amrUlHrAdaptationSet allow the operator to define an amrAdaptationSet table independently for FR and HR mode and for DL and UL. Moreover, this allows more flexibility in the amrAdaptationSet table management since updating the optimized tables requires a change in the Bsc Data Config. CAUTION! Please note that all values expressed in the tables hereunder are in dB. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 559/629 V17.0 BSS Parameter User Guide (BPUG) TYPICAL TABLE (not modifiable) 5k9 to 4k75 6k7 to 5k9 FR thresholds 10k2 to 6k7 12k2 to 10k2 FR hysteresis 5k9 to 4k75 HR thresholds 6k7 to 5k9 7k4 to 6k7 HR hysteresis slow MS no FH 8 10 12,5 17,5 2,5 12,5 14 19 3,5 downlink uplink fast MS ideal FH SFH 900 < 4 FH no FH (>= 4 freq) TU3 2,5 3,5 2,5 4 4 5 4 5,5 6,5 7,5 6,5 7,5 12,5 12,5 12,5 13,5 1,5 2 1,5 2 10 10,5 10 11 12 12,5 12 12,5 17 17,5 17 16,5 2 2 2 3 OPTIMISTIC TABLE (not modifiable) uplink downlink fast MS ideal FH SFH 900 < 4 FH no FH (>= 4 freq) TU3 2 2,5 2 4 3,5 4 3,5 4,5 5,5 6,5 5,5 7 12 11,5 12 12 1,5 2 1,5 2 8,5 9 8,5 10,5 10,5 10,5 10,5 12 15,5 15,5 15,5 17 3 3 3 2 5k9 to 4k75 6k7 to 5k9 FR thresholds 10k2 to 6k7 12k2 to 10k2 FR hysteresis 5k9 to 4k75 HR thresholds 6k7 to 5k9 7k4 to 6k7 HR hysteresis slow MS no FH 5,5 6,5 10 15 3,5 9,5 10,5 15,5 3,5 PESSIMISTIC TABLE (not modifiable) uplink downlink fast MS ideal FH SFH 900 < 4 FH no FH (>= 4 freq) TU3 6 7 6 5 6,5 8 6,5 6 9,5 11 9,5 8,5 14 16 14 13,5 2 2 2 3 13 13,5 13 12,5 13,5 14 13,5 13 18,5 19 18,5 18 2,5 2,5 2,5 3 5k9 to 4k75 6k7 to 5k9 FR thresholds 10k2 to 6k7 12k2 to 10k2 FR hysteresis 5k9 to 4k75 HR thresholds 6k7 to 5k9 7k4 to 6k7 HR hysteresis slow MS no FH 11 12,5 16 20,5 3 14,5 15 19 4,5 Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 560/629 V17.0 BSS Parameter User Guide (BPUG) AMR OPTIMIZED TABLE (customized) slow MS no FH 5,5 6,5 10 19,5 1,5 12,5 14 18 2 downlink uplink fast MS ideal FH SFH 900 < 4 FH no FH (>= 4 freq) TU3 2 2,5 2 4 3,5 4 3,5 4,5 5,5 6,5 5,5 7 14 16 14 17,5 1,5 2 1,5 2 10 10,5 10 12,5 13,5 14 13,5 17 18,5 19 18,5 19 2,5 2,5 3 3 5k9 to 4k75 6k7 to 5k9 FR thresholds 10k2 to 6k7 12k2 to 10k2 FR hysteresis 5k9 to 4k75 HR thresholds 6k7 to 5k9 7k4 to 6k7 HR hysteresis AMR 10k2 ONLY TABLE (customized) slow MS no FH 0 0 0 19,5 0 12,5 14 18 2 downlink uplink fast MS ideal FH SFH 900 < 4 FH no FH (>= 4 freq) TU3 0 0 0 0 0 0 0 0 0 0 0 0 14 16 14 17,5 0 0 0 0 10 10,5 10 12,5 13,5 14 13,5 17 18,5 19 18,5 19 2,5 2,5 2,5 3 5k9 to 4k75 6k7 to 5k9 FR thresholds 10k2 to 6k7 12k2 to 10k2 FR hysteresis 5k9 to 4k75 HR thresholds 6k7 to 5k9 7k4 to 6k7 HR hysteresis CAUTION! In the case of the customized tables defined via the BSC Data config, values are to be entered in ½ dB. For example the threshold to switch from a 12k2 codec to a 10k2 codec in the case of a slow MS non hopping in the table above should be 39 in the BSC Data config to express a C/I of 19,5 dB. Note: The AMR threshold set in the bscdataconfigeditor -- labels 81--125 should to be set with a value small than 63. RATSCCH CODING SPECIFICITY When an Assignment Command or a Handover Command message is sent from the BSC to the BTS in order to provide all AMR L1m and codec mode adaptation informations the hysteresis described in the adaptation codec table is coded on 4 bits, hence can take values from [0 to 7.5] dB with steps of 0.5 dB. Now when the Active Codec Set has to be modified via a RATSCCH message, the coding of that hysteresis becomes: Bit Value 34 … 32 31 30 29 … 28 27 … 20 19 … 18 17 … 12 11 … 6 5…0 001 1 1 ICM ACS HYSTc THRESH3 THRESH2 THRESH1 Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 561/629 V17.0 BSS Parameter User Guide (BPUG) One can see that in this case the hysteresis is coded only on 2 bits (as recommended by the GSM Rec 05.09) thus can only take 4 different values, that are: Set value at the OMC-R 0 / 0,5 / 1 / 1,5 2 / 2,5 3 / 3,5 4 / more than 4 Coded value in the RATSCCH Corresponding value 00 01 10 11 1 dB 2 dB 3 dB 4 dB Please note that this case is only applicable in downlink AND for a change of Active Codec Set via a RATSCCH message (refer to RATSCCH management). Consequently, if one wants to use the customized values in the amrAdaptationSet table (parameter amrXXYYAdaptationSet = 3) it is recommended to set cunningly the related downlink hysteresis in the customized AMR adaptation table,that is to say in order to respect the only 4 values that hysteresis can take via a RATSCCH message. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 562/629 V17.0 BSS Parameter User Guide (BPUG) AMR VERSUS EFR AMR FR VS EFR IN BCCH LAYER IN INTERFERENCE LIMITED ENVIRONMENT The purpose of this test was to characterize AMR performances in a degraded radio environment to show AMR codec performance on the BCCH layer, but it also included comparative results with EFR performance with different adaptation sets. Same BCCH frequency was set for 2 neighboring cells in order to create interference to the victim cell, and the Pessimistic default table has been compared with a customized table proposed by the operator. Observations: • AMR gain is critically dependant on voice quality target. A trade-off capacity-voice quality is found. The lower the voice quality target, the higher is capacity increase available. This capacity increase could be obtained by increasing network frequency load. For a given radio condition, TEPMOS from AMR is better than EFR. AMR increases voice quality or area reliability is improved. In very good radio conditions, e.g. more than 14 dB, lower codecs present worse performances than 10k2 FR Adapting to lower codecs in a higher C/I tends to slightly decrease voice quality but going faster to lower codec in bad radio conditions improve the voice quality performance in bad radio conditions. • • • Note: higher gain is found in AMR in frequency hopping layer than in non-hopping BCCH layer, and frequency diversity adds an extra gain to lower codec robustness. AMR HR VS EFR IN BCCH LAYER IN INTERFERENCE LIMITED ENVIRONMENT The purpose of this test was to evaluate AMR HR performances and to compare them with EFR. Calls were established in very good radio conditions and algorithms to intracell HO from HR to FR were set impossible to be triggered (setting amrHRtoFRIntracellCodecMThresh target to 4k75 AMR HR). Observations: • Test results show how AMR HR presents a very good performance with regard to EFR in good radio conditions. Degradation could be quantified from 3.7 to 3.5 TEPMOS which is neglected by human ear. Moreover, when radio conditions are degraded, AMR HR performance keeps a good performance and even at 3 TEPMOS voice quality target can presents a better performance than EFR This test shows that it would be perfectly possible, when radio conditions allow it, to maximize AMR HR penetration and obtain interesting performance comparable to EFR with the benefit of more resource availability thanks to HR usage • Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 563/629 V17.0 BSS Parameter User Guide (BPUG) AMR FR VS EFR IN COVERAGE LIMITED ENVIRONMENT The purpose of this test was to evaluate the coverage enhancement with AMR feature and to compare its performance with EFR calls. Radio Link TimeOut timer was extended to 64 to allow increasing coverage as much as possible. One mobile was set in AMR FR only mode while another was logged on EFR mode only. Calls were dragged on a coverage limited areas to the limits of the cell. Intercell handovers were disabled to hold them in serving cell. Low ranges of RxLev signal samples were obtained. No interferences are found since tests were done during maintenance window and no traffic was detected at this hour. RxLev measurements are suitable for performance comparison since no interference were found in coverage limited environment. Observations: • More than 3 dB coverage gain can be obtained using low AMR codecs in low signal strengths. EXECUTIVE RESULTS In summary of these tests: • • • • • • • • there is definitely a trade-off between AMR gain versus voice quality. This will be up to the operator to define it PMOS target for voice quality impacts critically AMR gain Adaptation codec set table impacts voice quality and AMR gain Low codec usage in good radio condition degrades voice quality AMR FR could achieve a gain of 3-3.5 dB on BCCH layer AMR FR could achieve a gain of 3.5-4 dB on frequency hopping layer AMR FR could achieve a gain of 3-4 dB on coverage could be obtained AMR HR presents a comparable voice quality compared to EFR Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 564/629 V17.0 BSS Parameter User Guide (BPUG) 6.32.4 HALF RATE PENETRATION ANALYSIS AMR penetration is a trade-off between quality target for HR users and capacity required. The more voice quality the operator is ready to sacrifice, i.e. the lower the C/I thresholds is set to handover from HR to FR, the more HR capacity would be. HR penetration depends on different AMR HR related parameters: adaptation table, HR to FR codec target and HR direct allocation. HALF RATE DIRECT ALLOCATION Even if intracell handover from FR to HR and from HR to FR are found to be efficient, it is important to avoid doing more intracell handovers than necessary. This is why it is important to set HR direct allocation RxLev target to the correct figure to avoid that a call in very good radio conditions is allocated in FR since it will be sent to HR immediately after because of radio conditions. In order to set these parameters in UL and in DL (amrDirectAllocRxLevUL, amrDirectAllocRxLevDL), a Call Path Trace analysis could be done based on the distribution of the amrHRtoFRIntracellCodecMThresh vs. RxLev, bearing in mind also that codec requests depends also on the table that is being used. HALF RATE SETTINGS AMR adaptation tables are the main/critical parameter to define HR penetration. Adaptation table thresholds define radio condition where adaptation from AMR FR to AMR HR and AMR HR to AMR FR occurs. Optimistic table defines low C/I (degraded radio conditions) in order to handover from HR to FR and also a low target to handover from AMR FR to HR. Thus, HR penetration is favored. When pessimistic tables are set, C/I to handover from HR to FR are high, so quickly after radio is degraded, FR is requested. AMR adaptation table and HR to FR intracell handover target are highly related since once both parameters are defined, a target C/I is established and thus, radio conditions where HR is used are set, e.g. in DL, it is the same to set a pessimistic table with a HR to FR target to 5k9 than a typical table with a target 6k7. Two main parameters are related to HR to FR handover: Adaptation table and amrHRtoFRIntracellCodecMThresh while main parameter for FR to HR is the adaptation table: • Parameters like n and p from the (n,p) voting algorithm are found to have a limited impact on intracell HO ratio. In order to maximize overlap, it is recommended to set nCapacityFRRequestedCodec to 100% of P and nHRRequestedCodec to 50% of pRequestedCodec The intracell codec target for HO from FR to HR is hardcoded and set to 12k2 FR codec. Therefore, this threshold is fully defined by the choice of adaptation table. • It is important to check that thresholds for intracell HO HR to FR and FR to HR are correctly set in order to avoid ping-pong handover. It should be check that C/I threshold to adapt from HR to FR is lower than FR to HR and a good overlapped zone is found in order to avoid ping pong intracell HO due to wrong parameter settings. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 565/629 V17.0 BSS Parameter User Guide (BPUG) The figure below is a typical example of a correct setting to guarantee a good overlap for DL intracell handover: HR to FR 6k7 HR 17 dB C/I FR to HR BS 12k2 FR 20,5 dB C/I As AMR HR penetration is a trade-off between radio conditions and voice quality, it is highly dependent on environment since if high interference is found, penetration is only obtained if voice quality is highly jeopardized. Handovering to FR mode too early because parameter are too constraining would provide benefit of HR capacity. On the other hand, handovering to FR mode too late jeopardizes user voice quality as lower codecs might be used too long in lower C/I ranges. Using pessimistic table threshold and 7,4 HR as amrHRtoFRIntracellCodecMThresh, intracell HO HR to FR is done as soon as possible when radio conditions starts to be degraded. Normally this case brings a low HR penetration, around 20 to 25% HR penetration (highly dependent on radio/environment conditions). Increase of HR penetration is obtained setting a lower codec for HR to FR intracell handover (30 to 35% HR penetration can be expected). A more aggressive strategy is to change adaptation set to more optimistic thresholds which would bring a higher HR penetration (50 to 55% HR penetration can be expected). Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 566/629 V17.0 BSS Parameter User Guide (BPUG) HALF RATE MAXIMIZATION ANALYSIS Considering the graph of speech MOS vs C/I, one can see that AMR-HR with link adaptation is in theory slightly worse than EFR. AMR-HR provides fair quality down to 9dB while EFR can go down to 7 dB for the same quality. But both, AMR-HR and EFR are quite poor below 7dB while FACCH and SACCH performance are in a range where the BLER is not very good but still can be handled. This would show that an AMR-HR and EFR user would have “roughly” the same behavior at cell edge, either will drop or will attempt to release the calls as the quality will degrade. In urban area, where the limiting factor is not necessarily the coverage but the C/I, it has been tested to maximize the HR penetration in order to analyze the drop performance. • From a drop performance perspective, AMR FR only has degraded the statistics; but introducing the link adaptation using the full-set of lower codecs did for sure bring a improvement in terms of voice quality. As soon as HR has been activated with a setting maximizing its penetration to a level of 80%, the drop indicator did go downward to a level similar to what it was before. From a voice quality perspective, there has been no real improvement here as the objective was to lower down the drop rate. From a blocking view, HR maximized did improve the blocking rate for call initiation and handovers. • • Maximizing HR in the urban area could definitely reduced the drop performance to the level it was in EFR only and brought big improvement in terms of resource availability related to traffic mobility In order to maximize that HR penetration, one can either: • • • Reduce at maximum the level for the direct allocation in HR favor FR to HR intra cell handover by setting nFRRequestedCodec to 1 avoid HR to FR intracell handover by setting amrHRtoFRIntracellCodecMThresh to 4k75 Of course, these settings are not standard and the maximization of HR could be loosen by changing these parameters along with the intracell ping-pong protection Concerning the adaptation table, it is recommended to use the customized one as HR becomes poor very quickly for low C/I lower. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 567/629 V17.0 BSS Parameter User Guide (BPUG) 6.32.5 AMR USER BEHAVIOUR EFFECT AMR has been implemented to give a better voice quality robustness against radio condition degradation via lower codec usage. Thus, when radio is degraded voice quality is still acceptable for human perception. On the other hand, signaling channels have traditionally given better performance than voice channels since they are transmitted in a more robust channel and because retransmission are allowed. Erroneous packets are more critical for voice quality degradation than signaling, which can be retransmitted a certain time until call is released before it is considered lost, i.e. via RLT counter. Signaling has been found to be, in some specific cases, more constraining than AMR low codecs. This means that in some cases, while signaling is not correctly received and thus RLT counter is decreasing due to radio conditions, AMR low codecs are able to still give a fair voice quality. This effect impacts critically GSM networks KPI since user behavior becomes key factor. In the same radio degraded condition where signaling is not correctly received (or even before for EFR user!), an EFR user would realize its voice quality becoming poor, hangs up, release the call. This release would be pegged as a normal clearing of call from a counter perspective. On the other hand, AMR users do not realize of this radio condition degradation since AMR low codecs allow a fair voice quality at low C/I. AMR user drags the communication until RLT counter reaches 0 or when it tries to hang up, one of the links is lost. This effect has been found to increase call drop ratio from GSM networks. AMR Very Good Voice Quality Good Radio Conditions AMR EFR EFR Very Good Voice Quality Very Bad Radio Conditions AMR Good Voice Quality EFR Signalling Channels Traffic Channels Bad Voice Quality User Hangs Up Correct Released call No Call Drop Signalling channels risks to be lost User keeps talking since VQ is good Call drop is increased CAUTION! Thus, from a counter perspective, this kind of tricky situation is seen as a dropped call in AMR, while it is being pegged as a normal clearing for a EFR user. This problem is intrinsic to AMR standards. While waiting for AMR standard to be improved, one of the work-around is to increase radioLinkTimeout which maximize probability to recover radio conditions without degradation of AMR user perception or leave enough time to clear properly the call when it starts to be very poor in terms of voice quality. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 568/629 V17.0 BSS Parameter User Guide (BPUG) T200 with RLT drops have found to be related. It can happen that a user which realizes radio condition has been degraded tries to hang up when one of the links is lost. This will provoke that network start its procedure to release the call but it is never correctly released since one of the links messages are never correctly released. Thus, T200 drops are pegged. It has been found that when RLT is increased, RLT drops are decreased while T200 drops are slightly increased. In order to validate somehow this effect, EFR and AMR tests have been performed in coverage limited zone. Some monitoring findings supported also that phenomena. Two mobiles were running in parallel in a coverage limited zone. Both mobiles were running in a car moving at 50km/h connected to a single external antenna. Without user behavior intervention, both calls end at the same time. RLT (SACCH performance) is independent from speech codecs, EFR and AMR call ends at the same time. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 569/629 V17.0 BSS Parameter User Guide (BPUG) 6.32.6 VOICE QUALITY ANALYSIS AMR improves voice quality. Figures below show FER evolution depending on speech codec. U p lin k F E R e v o lu tio n 2 .2 5 % 2 .0 0 % 1 .7 5 % 1 .5 0 % AMR power control benefit: 0.5% 1 .2 5 % 1 .0 0 % AMR link adaptation benefit: 0.5% High half rate voice quality 0 .7 5 % F E R U L S ta n d a rd F R 0 .5 0 % FER U L AMR FR FER U L AMR HR 0 .2 5 % 1 0 -M a r 1 2 -M a r 1 6 -M a r 2 3 -M a r 2 7 -M a r 2 9 -M a r • • • • • AMR FR FER is significantly lower than EFR FER EFR FER is also improved due to AMR L1m power control aggressiveness AMR HR FER is very low since it uses robust codecs and it is used in very good radio quality When AMR HR is activated, AMR FR FER increases since AMR FR is used in worst radio conditions than AMR HR When AMR HR is activated, less interferences are found since AMR HR uses half time radio resources and thus, EFR FER slightly improves. USE OF TEPMOS TO ESTIMATE VOICE QUALITY IN AMR ONLY The TEPMOS indicator has been successfully validated for AMR traffic with the proposed link adaptation tables. The indicator provides a very good match versus the pMOS as calculated through the standardized PESQ algorithm. The chart below shows the validation for AMR-FR in TU3 with the typical table. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 570/629 3 1 -M a r 1 4 -M a r 2 5 -M a r 2 5 -F e b 2 7 -F e b 2 9 -F e b 2 8 -J a n 3 0 -J a n 2 -M a r 8 -M a r 4 -M a r 3 -F e b 6 -M a r 1 -F e b 0 .0 0 % V17.0 BSS Parameter User Guide (BPUG) Note that the voice degradation caused by frame losses on the terrestrial links or by the perturbations induced during handovers is not captured by the indicator. The TEPMOS enables to measure the impact of AMR tuning on the user perceived voice quality in various configurations and thus to find ore optimal QoS tradeoff: choice of the adaptation table, AMR-HR allocation triggers, AMR based on traffic, Interference cancellation... However with EFR, the indicator is less accurate. One reason is that the TEPMOS relies mainly on the weighted FER per AMR codec mode. In AMR each codec mode is used in a limited C/I range. For EFR the same encoding is used over the whole working range limiting the accuracy. A second reason is that with EFR, class 2 bits are not protected. Thus the frame erasure rate with EFR does not reflect the voice quality degradation occurring when a speech frame is correct (class 1 bit OK) and some class 2 bits are erroneous. With AMR-FR however there are no class 2 bit defined. Thus the FER or the TEPMOS reflect more accurately the perceived voice quality with AMR. Nortel recommends thus using the TEPMOS with EFR cautiously. Variations in EFR TEPMOS are representative of different voice quality perception enabling comparison between cells or TDMA with EFR traffic. However EFR and AMR TEPMOS shall not be used to compare the voice quality between the two modes. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 571/629 V17.0 BSS Parameter User Guide (BPUG) 6.32.7 AMR MONITORING The purpose of this AMR monitoring section is to provide the reader with observation findings made during the VO and onwards on different live networks. From a tuning and optimization perspective, the AMR feature is not as straightforward as another feature mainly because of the known limitations of the standards, some erratic mobile issues and the dependency with the terrain and user profile. Nevertheless, with all the efforts made on the optimization in several challenging clusters, it is possible today to provide general guidelines for the tuning and optimization of the feature according to the environment and customer’s objectives. Most of the results and trends presented hereafter are based on the monitoring made on different live areas. Each area having specific characteristics in terms of: • • • • • Design and engineering strategy Spectrum available Current traffic profile (numbers, mobility, offered services…) Field morphology AMR mobile penetration For these above reasons, there is no comparison and absolute trends to be considered here when deploying AMR feature. The purpose of this section is to provide some guidelines in terms of monitoring observation and what are the contributors of the changes that could be observed. The performances of the AMR feature were evaluated regarding newly dedicated counters: • • • • • TCH resource: AMR FR and HR allocation, assignment, resource usage, connection duration Handover: AMR FR and HR HO required, executed, completed and failures Drops: AMR FR and HR drops per cause radio, LAPD or Others L1M: AMR level, quality, power control, C/I… Additional counters related to AMR specific mechanisms such as the codec distribution, FER, RATSCCH failures etc… There is also a huge set of already existing counters that are being pegged whether or not the call is in FR, EFR or AMR. All these counters are mostly related to the allocation and the handovers procedures. For more details on these counters, please refer to [R29]. OVERALL FINDINGS After having successfully tested all the procedures and the specific algorithms related to the AMR feature throughout numerous testing in lab and live, AMR have been deployed progressively on live areas under different environments: • • • rural areas with low density of urbanized areas where coverage was the limiting factor suburban areas with spot of dense traffic and where the interference was definitely the constraining factor urban to dense urban areas where interference and coverage (indoor) limitations are mainly the constraining factors. Traffic was also a important constraint. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 572/629 V17.0 BSS Parameter User Guide (BPUG) With the AMR activation over different clusters, it has been proven that all the usual indicators like the resource allocation, the call establishment, the blocking were performing within standard ranges with the exception for the call drop indicator. Many efforts have then been deployed to address this drop call concern. Nortel has been through the testing of different timers impact (T200, NY1, RLT, and T3103) and the changing of some key elements in the AMR algorithm with always the objective to isolate potential software issues. None of them did bring huge improvements in reducing the drop call performance though but many findings were interesting and kept for future settings (TDMA priority, timer T3103 extension, RLT extension). In parallel to these efforts, several papers were submitted by different providers and customers to the GERAN meeting indicating potential issues with actual AMR performance vs signaling performance, i.e. the improved lower codec rates provide voice robustness in areas where signaling channel fails to perform reliably (SACCH and FACCH). Call are being dropped while voice quality is still acceptable. Beside this, we have also observed some differences between EFR and AMR mobiles in their estimation of RxQual under severe interference and DTX situations which may, in some cases, lead to some delays in the decision of handovers. Even if the main driver of all the AMR monitoring activities is the drop call performance for which the variations will depend upon the environment, the mobile penetration and the traffic mobility, the feature has proven many benefits in terms of coverage, voice quality and capacity. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 573/629 V17.0 BSS Parameter User Guide (BPUG) COVERAGE LIMITED AREAS OBSERVATION In this type of environment, RLT drop contribution is usually much higher because calls are being dragged at cell edges and the overlap between neighboring sites is less important than in urban areas. The T200 drops can be also higher than usual but in a lesser extent than the RLT. T3103 drops are less significant than areas where the overlap is more dense since they are directly related to users mobility. In such rural area, RLT drops (and T200 with a less extent) represent more than 45% of the drops while T3103 represents less than 25%. Activating AMR increase the dropped calls with two main contributors, the RLT and the T3103. Extend the DL RLT timer and keep the UL to its original value would lead to a reduction of the drop contribution on RLT cause. The timer extent cannot fully compensate the robustness of the codecs vs. SACCH performance when C/N becomes critical. HR activation does not brig any improvement in the drop performance. In an area where the limiting factor is the coverage and not the traffic, there is no real benefit to have HR activated unless necessary. The excess of T3107 drops is not necessary here. RECOMMENDATION In coverage limited areas with low traffic (rural areas) Nortel recommend to avoid using as much as possible the low codecs in order not to experience any “user behavior” effect. Usage of the optimistic table or a customized table avoiding at least the 4k75 codec is necessary. The DL RLT (radioLinkTimeout) should be increased subsequently to a minimum of 32 SACCH periods. To a certain extent it could be interesting to customize if possible a “10k2 only” table for such environment and keep the RLT to 32 as the 10k2 is bringing a 1-2 dB coverage gain vs EFR. Concerning HR, one should look at the real traffic carried on a cell level to decide whether or not capacity is required. In a general manner, HR should be disabled in such environment as it does not bring any extra benefit. T3107 drops would then be avoided. From a handover perspective, it is recommended to change the timer T3103 (t3103) to a value of 9 seconds in order to offer a wider window of good completion of the procedure at cell edge where the quality might be poorer. INTERFERENCE LIMITED AREAS OBSERVATION In this kind of environment, T3103 drops are dominant; it represents more than 45% of the drops, while RLT is around 25%. This ratio remains the same before and after AMR activation as RLT drops can also be a consequence of T3103 increase: a handover that fails and come back to its original channel in worst radio conditions than before may drop on RLT. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 574/629 V17.0 BSS Parameter User Guide (BPUG) The activation of HR in this environment does not affect the overall drop indicator. The T3107 increase is due to the substantial increase of intra cell handover that occur when HR is activated. That activation usually show some improvement of the T3103 as some intercell HO can occur now in better radio conditions. However, the slight improvement of the T3103 drops is compensated by an increase of T3107 which makes the overall drop not being modified. RECOMMENDATION In urbanized environment, potentially facing spots of interference, it is advisable to enable the legacy HO in order to perform HO on Quality criteria (RxQual) instead of CMR (AMR algorithm). For the same reasons, it is also recommended to have a window of decision for the rescue HO short enough to react for signal degradation. It has been observed in some specific situations and interfered areas differences in the RxQual estimation between EFR and AMR mobiles. If the volume of handover is higher after AMR activation: • • Make sure that the allocation priority threshold (allocPriorityThreshold) is well set on the target cells Extend the T3103 timers (t3103). Usually set to 5s, when this timer is set to 9s, it has been observed some improvement on the HO failures It is also advisable to make sure that TDMA priorities are well set (frAMRPriority & hrAMRPriority). As the allocation in AMR does not take directly the level of interference in the resource classification, a higher priority on hopping TDMA can be set for AMR allocations in order to favor hopping layers. In such environment, it has also been observed that increasing the HR usage may decrease the drop rate to normal values as from a MOS perspective, HR and EFR are similar in low C/I ranges. The gain in such conditions is not on the coverage but on the capacity. CODEC 10K2 ONLY OBSERVATION With today’s AMR performances and according to customer objectives, there are no real benefits to activate AMR in rural environments (or coverage limited areas). However, implementing the 10k2 only is a trade-off between the drop call control and the slight gain in voice quality at cell edges. It can be seen from a drop distribution perspective that an area is coverage limited as the RLT contribution is much higher than T3103. Activating AMR FR would increase the drop rate in a network where the AMR mobile penetration is very important. By changing the AMR adaptation table in such a way to limit the codec usage to only 10k2, the drop rate would clearly decrease. Removing totally HR improve further the drop indicator to a value very close to the EFR period prior to the AMR activation. It can be observed that in rural areas, running AMR with 10k2 only adaptation table and no HR does bring down the drop ratio to a certain extent to standard level. The 10k2 codec gain of 2dB in coverage can still be obtained. The DL RLT extended to 32 SACCH or more may not in all cases compensate the signaling weakness vs the robusteness of the 10k2 at cell edges Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 575/629 V17.0 BSS Parameter User Guide (BPUG) RECOMMENDATION Setting the AMR table to 10k2only usage requires customizing the table at BSC level (class1 change = planned outage). Another solution would be to set the optimistic table or Nortel customized table that is detailed above. On cell basis, HR should be totally avoided unless necessary but with pessimistic settings (see Nortel customized table) RLT should be also kept to 32 in such configuration. ISOLATED AREAS OBSERVATION AMR has been deployed in a cluster of sites totally or partially isolated one to each other. In the particular case where AMR is deployed in a cluster of sites totally or partially isolated one to each other, whether or not the area is urbanized and the level of traffic significant, the majority of the drops will be on RLT as calls are being dragged away or indoor without candidates (or very few). If the radio constraints are more due to C/N here, RLT has to be extended to 32 in order to compensate the robusteness.of the codecs at the border of cells, and it is better to activate an optimistic table. HR can be reasonably activated if necessary as the RF conditions are clean. So in this particular case, one can observe: • • • The overall drop level do not change before and after AMR activation RLT drops represent more than 40% of the drop contribution T200 drops represent more than 22% of the drops which is probably a consequence of the coverage lack with releases of calls made in limited radio conditions HR traffic penetration is close to 55% T3107 drops are quite important T3103 drops are low as there is no real inter-site HO. The only ones being intercell intra site HO where overlapping should be OK. • • • RECOMMENDATION As in coverage limited or rural areas, Nortel would recommend to avoid using as much as possible the low codecs in order not to experience any “user behavior” effect with AMR. A usage of the optimistic table or a customized table avoiding at least the 4.75 codec is necessary. The RLT in the downlink (user perception) should be increased subsequently to a minimum of 32 SACCH period. Concerning HR, one should look at the real traffic carried on a cell level to decide whether or not capacity is required. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 576/629 V17.0 BSS Parameter User Guide (BPUG) If HR is activated, a pessimistic HR table should be implemented in order to limit somehow the HR penetration in order not to have too much T3107 contribution and keep a fair voice quality level. If more penetration is required, there are numerous settings that could be done from the direct allocation, to the ping-pong protection, the change of a table or the triggering of intracell HO thresholds. In such environment where inter-site HOs are limited, there are no real recommendations in terms of the intercell settings. The majority of HOs will occur intra-site where normally the overlap between cells is reasonable. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 577/629 V17.0 BSS Parameter User Guide (BPUG) 6.33. IMPACT OF AUTOMATIC HANDOVER ADAPTATION ACTIVATION The Automatic Handover Adaptation feature adapts handover parameters to radio environment of each call; taking into account mobile speed and frequency hopping with BSCe3 (this BSS feature is available from V14.3). The objective is to minimize call drops and bad quality transients. The feature also has a power control adaptation mechanism in addition to the power budget handover adaptation. For a good understanding of this feature, please refer to the Automatic handover adaptation chapter, or to the Functional Note TF1216 : Automatic handover adaptation ([R17]) 6.33.1 RELATED PARAMETERS All the parameters directly related to this feature are described in the Automatic Handover Adaptation Parameters chapter, but one should also take into account the following parameters to monitor an impact of the feature on an existing network. Parameter Description selfAdaptActivation servingfactorOffset neighDisfavorOffset rxLevHreqave rxNCellHreqave rxLevHreqaveBeg rxLevNCellHreqaveBeg rxQualHreqave rxQualAveBeg hoMargin hoMarginBeg runHandOver Use for activate the Automatic Handover adaptation This attribute defines the offset linked to the serving cell, used to decrease the HO margin This attribute modifies the offset linked to the neighbouring cell, used to increase the HO marging Number of signal strength measurements performed on a serving cell, used to compute arithmetic strength averages in handover and power control algorithms Number of measurement results used in the PBGT algorithm to compute the average neighboring signal strength Number of measurement reports used in short averaging algorithm on current cell for signal strength arithmetic average Number of measurement results used in short averaging algorithm to compute the average neighboring signal strength Number of arithmetic averages taken into account to compute the weighted average bit error rate in handover and power control algorithms. Each is calculated from rxQualHreqave bit error rate (BER) measurements on a radio link This attribute defines the number of quality measures used by the power control mechanism, in case of hopping TS or fast MS Margin to use for PBGT handovers to avoid subsequent handover, in PBGT formula Margin to be added to hoMargin until rxLevHreqave for short averaging algorithm in order to compensate the lack of measurements Number of Measurement Results messages that must be received before the handover algorithm in a cell is triggered Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 578/629 V17.0 BSS Parameter User Guide (BPUG) 6.33.2 DEPLOYMENT OPTIMIZATION AND MONITORING The expected gains when deploying Automatic Handover Adaptation feature are: • • • • Reduce Overall RF Drops Improve HO Drops and HO Failures RLT drops and BER improvement due to automatic power control effects Reduced time at max power due to better efficiency in power control Hereunder is an example of activation of AHA that shows those improvements. FIRST ACTIVATION Activation parameters setting: Parameter Value selfAdaptActivation servingfactorOffset neighDisfavorOffset rxLevHreqave rxNCellHreqave rxLevHreqaveBeg rxLevNCellHreqaveBeg rxQualHreqave rxQualAveBeg hoMargin hoMarginBeg runHandOver enabled 2 2 8 8 2 2 8 2 4 4 1 That activation has proven some good results, mainly on RF drops and Minute Of Usage, but also on HO repartition, as shown below: RF Drop per Erlang Evolution Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 579/629 V17.0 BSS Parameter User Guide (BPUG) Handover Distribution As explained in the feature description the algorithm helps in the Urban areas by making intelligent decisions for Power Budget handovers and reducing interference by more reactive adjustment in attenuation. In coverage limited environment the advantage is highly mitigated. In order to capture the benefits from the feature in the Suburban and Rural areas through reducing rescue handovers; appropriate recommendations should be applied (see chapter Final recommended setting). Hereunde are the general conclusions about AHA activation: • RF MoU/Drop improvement follows more closely the reduction in drop due to handovers. BSCs with good coverage and having interference issues definitely showed improvement in drops. BSCs with good ratio of hopping radios and having reduction in BER showed some considerable improvement in RLT drops. These were areas where the UL BER had shown consistent improvement after the feature activation BSCs with very low ratio of hopping Sectors OR even with high ratio of hopping sectors showed NO considerable improvement in drops if they are coverage limited OR less RF overlap. • • Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 580/629 V17.0 BSS Parameter User Guide (BPUG) FINE TUNING FREQUENCY HOPPING CASE The power Budget handover adaptation in the frequency hopping case ( > 3 SFH per sector) uses servingfactorOffset to favor the server as suppose to the neighbor in two of the four cases. So the setting of “-2” for servingFactorOffset means it will actually favor the server OR in other words disfavor the neighbor greatly. The neighDisfavorOffset is already applied at “2” dB such that the two cases where you have enough measurements of your server the effective HOMargin (eff) will be 8 dB when you have not enough measurements in the neighbor and 6 dB when you have enough measurements in the server as well as from the neighbor. In the expectation of making better and more handovers decisions on PBGT in these two case the HOMargin (eff) should be reduced by 2 dB in both these cases in order not to disfavor the neighbor by effectively HOMargin of “6” OR “4” by tuning the servingFactorOffset from “-2” to “0”. Note: experience results presented in this part are done with 8 SFH per sector. Handover QoS NON FREQUENCY HOPPING CASE The power Budget handover adaptation in the non-frequency hopping case ( < 4 SFH per sector) does not use servingFactorOffset to favor the server as suppose to the neighbor. This case uses the neighborDisfavorOffset and so the HOMargin (eff) remains at 6 and 4 dB for cases with server having enough measurements. However, the other two cases where the neighbor is disfavored when the server is not having enough measurements seems to be very high with the intial settings; HOMargin (eff) ( 4 + 4 = 8 dB). It was recommended to change the HOMargin (eff) by tuning hoMarginBeg from “4” dB to “2” dB to get effective margin of “6” dB. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 581/629 V17.0 BSS Parameter User Guide (BPUG) Handover QoS FINAL RECOMMENDED SETTING The table below provides the recommended setting to take advantage of AHA activation depending on the area characteristics: Parameter Urban area Suburban area Rural area selfAdaptActivation servingfactorOffset neighDisfavorOffset rxLevHreqave rxNCellHreqave rxLevHreqaveBeg rxLevNCellHreqaveBeg rxQualHreqave rxQualAveBeg hoMargin hoMarginBeg runHandOver enabled 0 2 8 8 2 2 8 2 4 2 1 enabled 2 2 8 8 2 2 8 2 4 2 1 enabled 0 2 8 8 2 2 8 2 2 4 1 Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 582/629 V17.0 BSS Parameter User Guide (BPUG) 6.34. HANDOVER FOR TRAFFIC REASONS ACTIVATION GUIDELINE The purpose of this guideline is to define a default activation of the feature “Handovers for traffic reasons” over the whole BSC. This proposal includes also the usage of the feature “Handover decision according to adjacent cell priorities and load” and the default activation of directed retry. We remind that HoTraffic must be favoured for traffic reason instead of using the feature Directed Retry, which is a solution only for occasional cases of congestion. For a better understanding please refer to the following Functional Notes and chapters: • • • • • [R12] Handover for traffic reasons: TF132 Handover for traffic reasons (from V12) [R13] Handover decision according to adjacent cell priorities and load TF716 Handover decision according to adjacent cell priorities and load (from V12) Directed Retry Handover The objectives of a BSC deployment of that feature would be: • • • to reduce current TCH blocking wherever it happens on normal origination and during HO phase to anticipate unexpected TCH blocking in order to improve traffic carried on originating and ongoing calls to facilitate feature activation process by generalising the settings on the whole BSC 6.34.1 ALGORITHMS AND PARAMETERS DEFINITION As the Directed Retry handover is intended to re-direct TCH Allocation on a loaded cell to an other cell, the traffic handover’s objective is to leverage resources blocking when one cell is overloaded by redirecting the most appropriate calls in progress to neighbour cells with a PBGT handover procedure. OVERLOAD CRITERION The overload criterion is defined on a cell basis and can take two expressions according to the operator’s choice : • • If queuing is not activated the number of available TCHs is lower than the defined threshold, If queuing is activated: the number of queued TCH requests is greater than the defined threshold. That mechanism is decribed in the chapter Congestion determination. When overload occurs, the BTS sends, on request from the BSC, HO indications including the list of candidate neighbors n for which the following expression is fullfilled: EXP2Traffic(n) = Pbgt(n) - [hoMargin(n) - hoMarginTrafficOffset(n)] Refer also to the chapter General formulas. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 583/629 V17.0 BSS Parameter User Guide (BPUG) RELATED PARAMETERS Parameter Description hoTraffic (bsc) hoTraffic (bts) hoMarginTrafficOffset numberOfTCHFreeBeforeCongestion numberOfTCHFreeToEndCongestion hoPingpongCombination hoPingpongTimeRejection offsetLoad enable the traffic HO feature at BSC level enable the traffic HO feature at BTS level level strength margin added to compute the neighbor eligibility in case of traffic HO (refer to EXP2Traffic) minimum number of free TCHs which triggers the beginning of the TCH congestion phase and the beginning of the traffic overload condition number of free TCHs which triggers the end of the TCH congestion phase and the end of the traffic overload condition list of couples of causes (HOInitialCause and HONonEssentialCause) to prevent possible HO ping pong due to traffic HO timer associated to the anti ping pong feature level strength offset added to compute the neighbor eligibility depending on its state of congestion (refer to EXP4) Furthermore and as described in the chapter Expected effects and recommended parameters, queuing and directed retry parameters have to be set properly. As a reminder: • • Queuing activation: please refer to chapters Queuing and TCH Allocation Management Parameters Directed retry: please refer to chapters Directed Retry Handover and Directed Retry Handover Parameters FEATURE INTERWORKING In order to avoid blocking the originating calls on congested cells, directed retry with default settings should be enabled, and to avoid a return from non congested to congested cell after HO traffic activation two features should be used: • • prevent « ping-pong » effect by applying a protection timer for all incoming relations onto the congested cell prevent a « snow ball » effect by using the load status conditions through the usage of the offset load parameter in : EXP4(n) = EXP2(n) – [offsetLoad(n) * stateLoad(n)] Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 584/629 V17.0 BSS Parameter User Guide (BPUG) 6.34.2 EXPECTED EFFECTS AND RECOMMENDED PARAMETERS Let’s consider a cell A passing through different states of congestion and the HO interactions in its neighborhood. Normal phase Overload phase Normal phase Cell A Cell A Cell A Normal HO (PBGT, Qual, Lev, …) Traffic HO Prevented HO on load condition Non congested cell Congested cell In a normal phase incoming HO toward cell A can be alarm HO, PBGT HO, or traffic HO coming from congested neighbor cells. As the congestion state is reached on cell A, depending on the cell load state and the associated parameter, some procedures are engaged to try to set back the cell to a non congested state: • • • traffic HO are activated from cell A to its non congested neighbor cells, i.e. PBGT HO with a smaller margin traffic HO are disfavored toward congested cell thanks to Handover decision according to adjacent cell priorities and load feature HO toward cell A are also disfavored When the cell A succeed in balancing the excess of traffic it reaches again a non congested cell and the normal procedures are applicable again. PARAMETER TUNING As described hereabove the expected behaviour takes benefit from the Handover for traffic reasons feature that allows to balance calls in good radio conditions toward neighbor cells via a traffic HO, from the directed retry HO that balance TCH assignment to neighbor cells, and from the Handover decision according to adjacent cell priorities and load feature that prevents from oading the cell with unnecessary incoming HO. Directed retry parameters settings are summarized in the following chapter §4.5.5 and hoMarginTrafficOffset and offsetLoad parameters tuning is explained hereunder. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 585/629 V17.0 BSS Parameter User Guide (BPUG) hoMarginTrafficOffset Cell A congested Cell B non congested Offset load One can observe on the above figure that using traffic HO is likely to simulate an increase in the non congested neighbor cell coverage of hoMarginTrafficOffset dB. In order to prevent outgoing traffic HO from A to B to come back on A an offsetLoad value equal to hoMarginTrafficOffset is recommended. In that case any attempt of HO from “traffic extended” B cell coverage to A would be discarded. offsetLoad ≥ hoMarginTrafficOffset Furthermore, the correct setting of the anti ping pong feature sould harden that behaviour for the PBGT HO from B to A. CAUTION! The following exceptions should be applied: • • Timer protection should not be set from cells like: indoor, microcells, special coverage, or any relation with HOmarginPBGT < 0 Offset load should not be set from cells like: indoor, microcells, special coverage, or any relation with HOmarginPBGT < 0 Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 586/629 V17.0 BSS Parameter User Guide (BPUG) RECOMMENDED PARAMETERS CONGESTION DETECTION Parameter numberOfTCHFreeBeforeCongestion numberOfTCHFreeToEndCongestion Recommended value 10 % of potential ressources for circuit calls including preemptable PDTCH 20 % of potential ressources for circuit calls including preemptable PDTCH Note: potential ressources for circuit calls including preemptable PDTCH cans be deduced from the following metric (C1700 max value (tchFrAveragedAvailableMax) - AllocPriorityThreshold) HANDOVER FOR TRAFFIC REASONS ACTIVATION Parameter Recommended value hoTraffic (bsc) hoTraffic (bts) hoMarginTrafficOffset enabled enabled 6 dB Note: HoMarginTrafficOffset should be tune such as the resulting margin should be equivalent to the one for rescue HO. This margin can be increase case by case for cell with important congestion. At on stage it is preferable to add capacity. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 587/629 V17.0 BSS Parameter User Guide (BPUG) HANDOVER DECISION ACCORDING TO ADJACENT CELL PRIORITIES AND LOAD ACTIVATION Parameter Recommended value offsetLoad ≥ hoMarginTrafficOffset GENERAL PROTECTION AGAINST HO PINGPONG Parameter Recommended value hoPingpongCombination hoPingpongTimeRejection (all, PBGT) at least 20s DIRECTED RETRY HANDOVER ACTIVATION Parameter Recommended value directedRetryModeUsed interBscDirectedRetry intraBscDirectedRetry interBscDirectedRetryFromCell intraBscDirectedRetryFromCell modeModifyMandatory directedRetry bts allowed allowed allowed allowed used - 80 dBm Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 588/629 V17.0 BSS Parameter User Guide (BPUG) 6.35. DISABLING AMR BASED ON TRAFFIC IN V15.1.1 Previously to V15.1.1, if hrCellLoadStart > 0, then HR calls can be allocated as long as the RxLev criterion is matched. To achieve such a behavior in V15.1.1, since AMR based on traffic is automatically activated, it is necessary to set the parameters as following: • • • filteredTrafficCoefficient = 1 hrCellLoadStart = 1 (range [0 to 100]) hrCellLoadEnd = 0 (range [0 to 100]) With this values, the “V15.1 like” behaviour should be reached after nb_of_inService_DRX*10 seconds. Note: the behaviour with this configuration is based on a theoretical study of the AMR based on traffic algorithm. To prevent HR allocation, it is necessary to set the parameters as following : • • hrCellLoadStart = 0 (range [0 to 100]) amrDirectAllocRxLevUL or amrDirectAllocRxLevDL = more than -48 dBm Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 589/629 V17.0 BSS Parameter User Guide (BPUG) 6.36. NETWORK SYNCHRONIZATION IMPACTS 6.36.1 COLLISION PROBABILITY PROBABILITY COLLISION METHOD OF CALCULATION In an asynchronous network or in a burst synchronized network, the probability collision between 2 not co-site cells cannot be precisely calculated. In these two cases, a collision probability average value is usually used when calculating interferences. But in a time synchronized network the exact calculation of the collision probability between 2 cells is possible using the hopping GSM algorithm. Generally, this calculation depends on the following 9 parameters: • • • • HSN1 and HSN2 - range 1 to 63 MAIO1 and MAIO2 - range 0 to Nb of frequencies of MA list1(2) - 1 FNOffset1 and FNOffset2 - range from 0 to 2715647 (the length of a GSM hyperframe). Nb of frequencies of MA list1 and Nb of frequencies of MA list2. Duration over which to compute the collision probability the GSM hyperframe length: 2715647 GSM frames. In the case of 1x1 frequency hopping fractional reuse, as the same MA list is used, the number of parameters goes down to 8. Cell x1, HSN1= 9 MAIO1= 0 FN1 = 150 MA list = 38 Freq Cell x2, HSN2= 10 MAIO2= 26 FN2 = 1450 MA list = 38 Freq F24 F30 F4 F33 F25 F26 F26 F19 collision F22 F16 F22 F5 F2 F26 F37 F36 Duration : d Probability of collision calculation Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 590/629 V17.0 BSS Parameter User Guide (BPUG) The more TDMA, the more the average collision probability will tend to its limit = 1 / Nb. Freq. It leads also to ad hoc plan’s limitation, for which the Collision probability is constant. No change in the parameters of the hopping law (HSN, FN) will bring any difference to the collision probability, for all the MAIO are used by all the TDMA (ad-hoc frequency plan implies number of TDMA is equal to the number of hopping frequencies). SPECIAL PROPERTIES OF THE HOPPING LAWS As it will be detailed below, the hopping GSM laws have some interesting properties which could be used for decreasing and controlling the collision probability when using time synchronization. PERIODICITY Applying the GSM hopping algorithm, the following periodicity can be found concerning the FN and FN Offsets: ARFCN (FN) = ARFCN (FN + 26*51*64). This property implies that the calculation of the collision probability over a duration of 84864 (where 84864 = 26*51*64) TDMA frames is equivalent to the collision probability calculation over a duration of 2715648 TDMA frames Therefore, the computation of the exact value of collision probability requires a shorter duration - 84864 TDMA frames - than the whole GSM hyperframe. It implies also that using the Nortel FN Offset range (0 to 84863) allows the calculation of collision probability with 100% precision. EQUIVALENT HOPPING COMBINATIONS A hopping combination between two cells is defined as the following set of hopping parameters: (HSN1, FNOffset1, MAIO1, HSN2, FNOffset2, MAIO2) Applying again the GSM hopping algorithm, it can be found that the collision probability between the hopping combinations: (HSN1, FN1, MAIO1) and (HSN2, FN2, MAIO2) is equal to the collision probability between hopping combinations: (HSN1, FNOffset1, mod (MAIO1+k, Nb Freq.)) And (HSN2, FNOffset2, mod (MAIO2+k, Nb Freq.)) This property allows that the calculation of the collision probabilities between all hopping combinations that exist between 2 cells needs computing the collision probabilities only for some hopping combinations of these 2 cells - therefore, less computing time than in the general case is needed. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 591/629 V17.0 BSS Parameter User Guide (BPUG) “MAGIC” HOPPING COMBINATIONS In the case of asynchronous hopping networks, the interference between a victim cell and an interferer cell is calculated by using an average collision probability between two cells. This probability is calculated with a simple formula which takes into account the number of common frequencies, the number of TRXs of the interfering cell and the numbers of frequencies of both MA lists. Using the GSM hopping algorithm, it can be found that the hopping combinations for 2 cells have collision probabilities which, depending on the used FN Offsets, HSNs and MAIOs, may be or not be significantly different from the above mentioned average collision probability. This property can be exploited only on Network with low fractional reuse where the chosen hopping combinaisons with very low or low collision probabilities (so called magic Hopping combinaison) could be used throughout the network for decreasing the collision probability and thus the network interference. Time synchronization allows knowing and controlling the FNOffset. Therefore, the existence of those hopping combinations that have significantly different collision probabilities from the average collision probability could be exploited only in the case of time synchronized networks with low fractional reuse. Unfortunately, there are several difficulties about using these special hopping combinations as the multiple matching of the 3 parameters (HSN, FN Offsets, MAIOs) at a network level is very complex. Finding the best global solution through systematic computing is not possible but it is supposed that a satisfactory feasibility can be achieved by using a certain strategy of parameter planning (HSN, FN Offsets, and MAIOs. 6.36.2 TSC IMPACTS The TSC (Training Sequence Code) is used by the GSM equalizer for the characterization of the radio channel. The 8 TSCs were chosen for better combating the random GMSK interference, other types of not GSM interferences or noise. In a synchronized network, if the interferer is a co-channel interference then, the interferer is another TSC and not random bits of GMSK. In this case, depending on the couple victim TSC and interferer TSC, the synchronization may cause further C/I degradation (and in very few cases a slight improvement). As the different synchronized couples of TSCs have not the same de-correlation level this degradation is variable and it is the highest when the victim and the co-channel interferer have the same TSC (when the equalizer considers the interferer as a reflection of the useful signal); this case is called TSC collision. It has to be underlined that an interferer is considered synchronized with a victim only if the time bit offset between them is less or equal to 5 time bit periods. Therefore, if the difference of propagation distance for victim and interferer is greater than 5,5 km then the victim and the interferer are non synchronized and there is no TSC impact. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 592/629 V17.0 BSS Parameter User Guide (BPUG) Also, the TSC impact in a synchronized network depends on the fact if an interference cancellation feature is deployed or not in a network. When an interference cancellation feature is not deployed in the synchronized network, the TSC degradation impact in the case of TSC collision may be up to 3 dB. But this impact is significantly higher when an interference cancellation feature is deployed: if in this case a TSC collision exists between the victim and the strongest co-channel interferer, then all gain due to the interference cancellation is lost and also an extra loss in C/I is produced (the TSC degradation impact may be up to 12 dB). Therefore, synchronization may cause significant network C/I degradation when synchronizing a network without a careful TSC (BCC) planning. In an asynchronous network, the BCC planning is contained in BSIC (NCC&BCC) planning which is done in order to avoid usually co-BCCH & co-BSIC neighboring. This kind of planning is no longer satisfactory for a synchronized network: in this case, a BCC planning has to be done firstly for avoiding the TSC collisions and then a NCC planning has to be done in order to avoid usually co-BCCH & co-BSIC neighboring. BCC planning for avoiding TSC collisions is far from being trivial as only 8 values (0 to 7) are available and TSC collisions have to be avoided on the BCCH channel as well as on the TCH channel (which usually is hopping). Each victim and interferer TSC couple (i, j) has an intrinsic impact value: Ti,j. But the real impact of an interfering TSC on the final value of interference has to be calculated taking also into account a factor characterizing the interference situation. This factor, called DITR (Dominant to Interferer TSC Ratio), reflects how much stronger the co-channel interference with the same TSC as the dominant interferer is comparing to the rest of interference (which is the sum of: interferences with other TSCs, adjacent-channel interferences and thermal noise). 6.36.3 FN OFFSET IMPACTS In a synchronized network without a FN Offset planning, the same types of bursts and channels (FCH, SCH, BCCH, SDCCH, SACCH, and CCCH) will occur simultaneously on different BTS. Using NW synchronization and a FN Offset planning for all neighbors of each optimized cell could bring an improvement on collision probability, an improvement to handovers reactivity and a reduction on interference level on SACCH channels by avoiding (or lowering) the simultaneous SACCH transmissions between interfering cells. SACCH IMPACT In a synchronized network without a FN Offset planning, the SACCH transmission will be simultaneous and, as SACCH channel is always transmitted regardless of the voice activity, it will not benefit from the discontinuous transmission (DTX) mechanism at all, since it is always transmitted. The consequence of this fact is a higher interference level on SACCH channels than on TCH channels. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 593/629 V17.0 BSS Parameter User Guide (BPUG) In a synchronized network with an intelligent FN Offset planning, the simultaneous SACCH transmissions of interfering cells can be avoided (or lowered) and thus the interference level on SACCH channels can be significantly reduced. SCH IMPACT FN Offset has an important role on BSIC decoding reactivity. According to the GSM standard, a mobile should attempt to demodulate SCH on the BCCH carrier of as many neighbor cells as possible, and read the BSIC as often as possible for neighboring cell information and at least once every 10 seconds in dedicated mode or for cell selection or reselection in idle mode. In a synchronized network without a FN Offset planning, the SCH transmission of neighbor cells will be simultaneous and a mobile will need much more time for BSIC reading. Thus, a mobile will read the BSIC of a smaller number of neighbors if FN Offset is not correctly planned. In a synchronized network with an intelligent FN Offset planning, the simultaneous SCH transmission of neighbor cells can be significantly reduced. In this case, a mobile could read the BSIC of a greater number of neighbors in the window of 10 seconds. It has to be underlined that in this case an intelligent scheduling for BSIC refreshing has a very significant impact. Finally, it has to be mentioned that the BSIC searching and decoding speed in active mode depends on the type of TCH channel used by mobiles. During a 26 TDMA frames period, a mobile has only one idle frame for searching and decoding the BSIC of neighbor cells when using a FR TCH channel, whereas it has 12 idle frames when using a HR TCH channel. Consequently, for a synchronized network, the impact of an intelligent FN Offset planning on the BSIC searching and decoding speed in active mode is more significant for the mobiles using FR TCH channels than for the mobiles using HR TCH channels. Neighbor relationships and the Interference Matrix are used as input data for the SCH Color allocation (see [R34]) Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 594/629 V17.0 BSS Parameter User Guide (BPUG) 6.36.4 INTERFERENCE CANCELLATION Network synchronization should allow to optimizing receiver performances in both Uplink (maximizing the gain on interference cancellation algorithms) and Downlink (with the introduction of SAIC mobiles). UPLINK (INTERFERENCE CANCELLATION) Since V9-V10, Nortel’s proprietary algorithm of uplink interference cancellation requires BTS equipped with antenna diversity. It can work with or without frequency hopping and it can remove any kind of interferer that has some spatial or temporal coherence (co-channel, adjacent channel, CDMA signal leaking in the PCS band, TV transmitter, etc...). The number of simultaneous interferers is a limiting factor to the good working of the feature. The feature removes the stronger interference signal and proves to be more efficient when the ratio (Stronger Interferer / Sum of all interferers) is high. Theoretical gain values are summarized bellow: 1 interferer Synchronous interferers Asynchronous interferers 8dB 4.5dB 1dB 0.5dB 5 interferers Potential gains with interference cancellation feature The algorithm uses the window of 26 bits of the TSC in the normal bursts. The table above shows that the gain is higher in case of synchronous interferers. If the stronger interferer uses the same TSC than the useful signal, then, the useful signal will be degraded as well (TSC collision). The TSC collision problem doesn’t happen if, comparing to the victim burst, the interferer burst has a delay greater than 5 symbols. This is the assumption taken for the non synchronized case. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 595/629 V17.0 BSS Parameter User Guide (BPUG) DOWNLINK (SAIC MOBILES) In the same way as for the uplink, SAIC (Single Antenna Interference Cancellation) mobiles may limit the interferences impact in downlink. SAIC mobiles are the DARP (Downlink Advanced Receiver Performance) phase 1 mobiles. One antenna downlink algorithm, based on signal processing in the mobiles takes benefit at the burst level by improving the C/I ratio up to 9 dB gain in first adjacent interferences and up to 2 dB for co channel interferences. Unlike uplink interference cancellation, the benefit of this feature at the network level depends on the penetration of these mobiles. At 75% penetration, 1 dB improvement on C/I can be achieved. Moreover, in non-interfered conditions, these algorithms do not degrade the performances. The real benefit on the network will actually depend on the mobiles performances and their penetration on the market. Since performances are dependent on SAIC mobiles penetration, there is a way to part the requests associated with a mobile type (SAIC or not) on some of the TDMA rather than others in case of TCH allocation. Each TDMA is affected with a property (DARPPh1Priority) that shares the TDMA of a cell in 2 pools: • • TDMA handling preferably SAIC mobiles requests. TDMA handling preferably non SAIC mobiles requests. The BSC radio allocator is modified to include this new type of priority to be combined with all already existing priorities. The BSC chooses the radio TS using the following order: • SAIC : For a SAIC type of request, whatever the type of request (FR, AMR FR, AMR HR, DATA) BSC allocates the MS on a high priority DARPPh1 resource unless there is no free TCH (that copes with the request) in the high priority DARPPh1 pool of resources. For AMR HR request, if there is any hole in the high priority DARPPh1 pool of resources, this one is selected otherwise BSC looks for an available full TS in the high priority DARPPh1 pool of resources. If there is neither available hole nor available full TS in the high priority DARPPh1 pool of resources, BSC looks for first an available hole in the low priority DARPPh1 pool of resources, then an available full TS in this pool of resources. For a non SAIC type of request, whatever the type of request (FR, AMR FR, AMR HR, DATA) BSC allocates the MS on a low priority DARPPh1 resource unless there is no free TCH in the low priority DARPPh1 pool of resources. For AMR HR request, if there is any hole in the low priority DARPPh1 pool of resources, this one is selected otherwise BSC looks for available full TS in the low priority DARPPh1 pool of resources. If there is neither available hole nor available full TS in the low priority DARPPh1 pool of resources, BSC looks for first an available hole in the high priority DARPPh1 pool of resources, then an available full TS in this pool of resources. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 596/629 V17.0 BSS Parameter User Guide (BPUG) • • • • Interference level, TDMA priority, TDMA number (from the smallest to the biggest: 0 to n), TS number (from the biggest to the smallest: TS7 to TS0). Note: For radio resource allocation only SDCCH requests are not differentiated depending if the mobile requesting is SAIC capable or not. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 597/629 V17.0 BSS Parameter User Guide (BPUG) 6.37. NETWORK SYNCHRONIZATION ENGINEERING PLANNING 6.37.1 TSC PLANNING TSC (BCC) planning uses only 8 values of TSC and therefore avoiding the TSC collisions or using intelligently the best TSC couples throughout a network is a complicate task. The TSC planning strategy is to allocate the best TSC couples to the worst interfering cell couples. Nortel Engineering recommends a relatively simple TSC planning which has as input: • • • The Nortel TSC impact matrix Ti,j The Interference matrix (IM) of the network The quantity of interference between cells due the used frequency plan (given by the collision probability and the traffic) Thus, Nortel’s TSC planning strategy is to allocate the best TSC couples, which have the smallest Ti,j values, to the interfering cell couples which have the highest values of IM *Collision probability*Traffic. The TSC planning has then to be used as input for the final BSIC (NCC+BCC) planning. 6.37.2 FN OFFSET PLANNING The FN Offset planning has simultaneously 3 different and independent requirements: • • • Avoiding SACCH collision Avoiding SCH collision (for speeding up BSIC reading) Contributing with the couple HSN and MAIO planning at obtaining a lower collision probability between the hopping laws In order to address independently the 3 requirements of FNOffset planning, Nortel defines FNOffset as a combination of 4 new parameters: • • • • where: Global Color = SACCH Color * 51 + SCH Color * 52 FN Offset = Global Color + Hopping Color* 13 * 51 (for synchronized networks without HR traffic) or FN Offset = Global Color + Hopping Color* 26 * 51 (for synchronized networks without HR traffic) Nortel confidential SACCH Color ( integer from 0 to 12 for HR traffic network or 0 from 0 to 25 for FR traffic network) SCH Color ( integer from 0 to 50 ) Hopping Color ( integer from 0 to 123 for HR traffic networkor 0 from 0 to 61 for FR traffic network) Global Color PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 598/629 V17.0 BSS Parameter User Guide (BPUG) It can be easily verified that: • • • • • The impact of SACCH Color on SACCH collisions is equivalent to the impact of FN Offset (Global Color) on SACCH collisions The impact of SCH Color on SCH collisions is equivalent to the impact of FN Offset (Global Color) on SCH collisions SACCH Color has no impact on SACCH Collisions SCH Color has no impact on SACCH collisions Hopping Color has no impact on SACCH and SCH collisions Therefore, for making an easier FN Offset planning, Nortel obtains the FN Offset planning by making independently: • • • SACCH Color planning SCH Color planning Hopping Color planning It has to be noted that: • • SACCH Color planning is done taking into account the TN Offset planning additionnally Hopping Color planning is useful only for a fractional reuse frequency plan as it has no impact fro adhoc frequency plans For further details concerning the SACCH Color, SCH Color and Hopping color please refer to [R34]) 6.37.3 TN OFFSET PLANNING In a time synchronized network, a TNOffset planning has to be performed in order to spread as much as possible the TNOffsets between neighbor sites. This can be easily obtained if through planning the sites that have the same TNOffset are as far as possible from each another). This planning does not take into account FNOffset planning but it has to be used then as input for the SACCH Color planning Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 599/629 V17.0 BSS Parameter User Guide (BPUG) 6.37.4 SYNCHRONIZATION STRATEGIES The parameter planning in a synchronized network depends strongly on the used frequency plan: ad-hoc or fractional reuse. For each of two frequency plans, 3 different synchronization strategies were envisaged by Nortel Engineering: • • • 100% Synchronization Solution, when the synchronization is applied to a significant part of the network (or all network); Hot Spot Solution, when synchronization is applied for only some couples of cells (sites), representing the network hot spots, which are heavily interfering; Mixed Synchronized/Not Synchronized Solution, when synchronization is applied to clusters of sites of limited size; So far, Nortel has experimented only the 100% Synchronization Solution in a frequency adhoc plan. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 600/629 V17.0 BSS Parameter User Guide (BPUG) 6.38. NETWORK SYNCHRONIZATION FIRST TRIAL RESULTS DEFINITION ENGINEERING TESTS CHARACTERISTICS A network engineering study of only the 100% Synchronization Solution in a frequency adhoc plan was performed during a trial, The trial synchronized zone consisted of 33 synchronized sites which were divided into 2 different clusters: • • KPI Cluster (10 sites) Buffer Cluster (23 sites) Only the cells of KPI Cluster were taken into account when assessing the performances of different test scenarios. Also, initially, the KPI Cluster cells were supposed to not be interfered by any not synchronized cell. Broadly, the impact of the following parameters was tested: • • • • • Burst synchronization with existing BSIC plan (w/o a TSC plan); TSC planning with Burst synchronization; ICA algorithm usage (50% or 100%) with Burst synchronization & TSC plan; Time synchronization with FNOffset planning (SCH + SACCH color) without TNOffset planning (same TSC plan and TNOffset plan as Burst Synchronization); Time synchronization with FNOffset planning (SCH + SACCH color) and TNOffset planning (same TSC plan as Burst Synchronization); Please refer to Network Synchronization handbook [R34] for a complete KPI Results presentation. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 601/629 V17.0 BSS Parameter User Guide (BPUG) ICA 50% VS ICA 100% IN BURST SYNCHRONIZATION In order to determine the best ICA settings, tests were carried out in Burst Synchronization with an existing BSIC plan as well as with a planned TSC. The expectation that ICA 100% performs better than ICA 50% was confirmed. This can be seen in the following charts, where average UL BER and MOU metrics are presented in Burst Synchronization with an existing BSIC plan. Following these tests, it was decided that only ICA 100% will be used in the following tests. AVE RxQual UL 0,53 0,52 0,51 0,5 0,49 0,48 0,47 0,46 0,45 0,44 08 /0 8/ 20 06 09 /0 8/ 20 06 10 /0 8/ 20 06 11 /0 8/ 20 06 12 /0 8/ 20 06 13 /0 8/ 20 06 07 /0 8/ 20 06 14 /0 8/ 20 06 ICA @50% ICA @100% MOU 290 ICA @50% ICA @100% 270 250 230 210 190 170 150 07/08/2006 08/08/2006 09/08/2006 10/08/2006 11/08/2006 12/08/2006 13/08/2006 14/08/2006 Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 602/629 V17.0 BSS Parameter User Guide (BPUG) A gain can be achieved with NW synchronization only when deploying with interference cancellation features (ICA in UL, SAIC in DL) and performing engineering planning of the following parameters: TSC, FN Offset, TNOffset, hopping laws. The interference cancellation features work significantly better in burst or time synchronized networks than in asynchronous networks provided that co-channel TSC collisions are avoided. The impact of interference cancellation is expected to be greater in UL due to a more performing interference cancellation algorithm and 100% penetration. In DL, the interference cancellation algorithm is less performing and, at present, the penetration of mobiles with such a feature is still low in life networks (below 30%). PLANNED TSC VS BSIC PLAN – BURST SYNCHRONIZATION As mentioned before, in an asynchronous network the BSIC planning is done in order to avoid BSIC/BCCH conflict between the neighbors. Evidently, this BSIC planning cannot ensure that there are no harmful TSC when synchronizing the network. Furthermore, this methodology of BSIC planning cannot take in consideration that the TSC couples have different TSC impacts when synchronizing the network and therefore it cannot take advantage of this fact by allocating the best TSC couples to the worst couples of interfering cells. MOU BSIC Plan 290 270 250 MOU 230 210 190 170 150 06 06 06 06 06 06 06 06 06 06 006 06 006 06 06 06 06 20 20 20 20 2 20 20 2 20 20 20 20 20 20 20 20 20 8/ 8/ 8/ 8/ 8/ 8/ 8/ /08/ 8/ /08/ 8/ 8/ 8/ 8/ 8/ /08/ 8/ /0 /0 /0 /0 /0 /0 /0 /0 /0 /0 /0 /0 /0 /0 23 22 12 13 19 15 21 11 18 20 07 14 10 17 16 09 08 310 TRAFFIC CARRIED TSC Plan 8400 7200 6000 4800 High Non RF Drops 3600 2400 1200 0 Traffic The intent behind this test case was to see how much a planned TSC provides improvements in performance against an un-planned TSC (BSIC). As it was expected, the MOU evolution shows an improving trend. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 603/629 V17.0 BSS Parameter User Guide (BPUG) 7. APPENDIX A: MAIN EXCHANGE PROCEDURES AT BSC LEVEL ESTABLISHMENT PROCEDURE 7.1. SABME: frame to set asynchronous balanced mode (initiate a link for numbered information transfer). UA: unnumbered aknowledge Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 604/629 V17.0 BSS Parameter User Guide (BPUG) 7.2. CHANNEL MODE PROCEDURE Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 605/629 V17.0 BSS Parameter User Guide (BPUG) 7.3. DEDICATED CHANNEL ASSIGNMENT Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 606/629 V17.0 BSS Parameter User Guide (BPUG) 7.4. INTRACELL HANDOVER PROCEDURE Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 607/629 V17.0 BSS Parameter User Guide (BPUG) 7.5. INTRABSS HANDOVER PROCEDURE From BTS 1 to BTS 2 Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 608/629 V17.0 BSS Parameter User Guide (BPUG) 7.6. INTERBSS HANDOVER PROCEDURE BTS 1 (from BSC 1) to BTS 2 (from BSC 2) Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 609/629 V17.0 BSS Parameter User Guide (BPUG) 7.7. 2G-3G HANDOVER PROCEDURE Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 610/629 V17.0 BSS Parameter User Guide (BPUG) 7.8. RESOURCE RELEASE PROCEDURE (EXAMPLE) Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 611/629 V17.0 BSS Parameter User Guide (BPUG) 7.9. SACCH DEACTIVATION PROCEDURE Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 612/629 V17.0 BSS Parameter User Guide (BPUG) 7.10. MOBILE TERMINATING CALL Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 613/629 V17.0 BSS Parameter User Guide (BPUG) 7.11. MOBILE ORIGINATING CALL Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 614/629 V17.0 BSS Parameter User Guide (BPUG) 8. APPENDIX B: ERLANG TABLE The table below presents the number of Erlang that are expected with regards to the number of TCH channels on a given cell and considering a blocking rate of 0,01 %. The computation follows the Erlang B law. Additionally, this table gives the number of Erlang expected depending on the AMR Half Rate penetration. CAUTION! The expected number of Erlang with regards to the AMR HR penetration has been calculated based on an estimation of the gain in capactiy provided by AMR HR. It should not be considered as contractual but as a good approximation of the expected gain. % Blocking AMR HR penetration Number of TCH 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 2% 2% 2% 2% 2% 0% 0,021 0,223 0,602 1,092 1,657 2,276 2,935 3,627 4,345 5,084 5,842 6,615 7,401 8,200 9,010 9,829 10,656 11,491 12,333 13,181 14,036 14,896 15,761 16,631 17,504 18,383 19,265 20,150 21,040 21,932 22,827 23,725 25 % 0,021 0,230 0,630 1,158 1,783 2,483 3,208 3,972 4,767 5,589 6,434 7,299 8,182 9,082 9,978 10,885 11,800 12,724 13,656 14,594 15,540 16,525 17,520 18,524 19,536 20,558 21,587 22,624 23,669 24,643 25,617 26,593 50 % 0,022 0,247 0,698 1,324 2,097 3,000 3,882 4,814 5,786 6,794 7,833 8,899 9,991 11,106 12,114 13,119 14,119 15,112 16,099 17,077 18,046 19,272 20,517 21,783 23,068 24,374 25,698 27,041 28,403 29,596 30,791 31,989 75 % 0,023 0,284 0,849 1,688 2,787 4,138 5,299 6,502 7,732 8,982 10,245 11,516 12,790 14,065 15,360 16,655 17,946 19,234 20,516 21,791 23,059 24,579 26,118 27,678 29,257 30,857 32,474 34,112 35,767 37,200 38,629 40,058 100 % 0,027 0,365 1,177 2,482 4,294 6,621 8,377 10,152 11,922 13,669 15,385 17,056 18,677 20,241 22,004 23,747 25,468 27,164 28,834 30,473 32,082 34,075 36,081 38,102 40,135 42,182 44,240 46,310 48,391 50,467 52,551 54,645 Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 615/629 V17.0 BSS Parameter User Guide (BPUG) 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 24,626 25,529 26,435 27,343 28,254 29,166 30,081 30,997 31,916 32,836 33,758 34,682 35,607 36,534 37,462 38,392 39,323 40,255 41,189 42,124 43,060 43,997 44,936 45,876 46,816 47,758 48,700 49,644 50,589 51,534 52,480 53,428 54,376 55,325 56,275 57,226 58,177 59,129 60,082 61,035 61,990 62,945 63,901 64,857 65,813 66,771 67,729 68,688 69,647 70,607 71,568 72,529 27,569 28,545 29,521 30,498 31,534 32,574 33,618 34,664 35,714 36,768 37,825 38,886 39,815 40,741 41,662 42,580 43,493 44,402 45,308 46,426 47,549 48,678 49,812 50,951 52,095 53,245 54,399 55,344 56,285 57,224 58,158 59,091 60,019 61,029 62,039 63,048 64,057 65,065 66,073 67,080 68,087 69,258 70,434 71,614 72,798 73,987 75,179 76,377 77,340 78,300 79,258 80,215 33,191 34,394 35,600 36,808 37,988 39,169 40,349 41,528 42,708 43,886 45,065 46,242 47,306 48,364 49,414 50,458 51,494 52,523 53,546 54,862 56,184 57,513 58,847 60,187 61,533 62,886 64,243 65,345 66,443 67,537 68,626 69,711 70,792 71,867 72,937 74,003 75,065 76,122 77,174 78,222 79,266 80,665 82,071 83,482 84,900 86,325 87,755 89,192 90,276 91,358 92,434 93,508 41,485 42,908 44,329 45,748 47,248 48,750 50,255 51,761 53,269 54,779 56,290 57,803 59,197 60,585 61,968 63,346 64,719 66,085 67,447 68,982 70,519 72,059 73,600 75,144 76,690 78,237 79,786 81,124 82,456 83,782 85,101 86,414 87,720 89,092 90,459 91,822 93,181 94,536 95,886 97,232 98,574 100,154 101,738 103,323 104,912 106,504 108,098 109,696 111,137 112,578 114,017 115,455 56,748 58,857 60,975 63,100 65,077 67,051 69,023 70,990 72,954 74,914 76,870 78,822 80,555 82,272 83,973 85,658 87,327 88,979 90,616 92,628 94,640 96,654 98,667 100,682 102,697 104,712 106,726 108,458 110,181 111,893 113,592 115,282 116,961 118,865 120,765 122,664 124,559 126,452 128,341 130,227 132,109 134,307 136,512 138,723 140,939 143,163 145,392 147,628 149,435 151,237 153,032 154,822 Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 616/629 V17.0 BSS Parameter User Guide (BPUG) 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 73,490 74,452 75,415 76,378 77,342 78,306 79,270 80,235 81,201 82,167 83,133 84,100 85,067 86,035 87,003 87,972 88,941 89,910 90,880 91,850 92,820 93,791 94,763 95,734 96,706 97,678 98,651 99,624 100,597 101,571 102,545 103,519 104,493 105,468 81,169 82,120 83,069 84,016 85,131 86,247 87,365 88,485 89,607 90,732 91,857 92,944 94,033 95,122 96,212 97,303 98,395 99,487 100,581 101,704 102,828 103,955 105,083 106,212 107,342 108,474 109,568 110,663 111,758 112,854 113,951 115,047 116,145 117,244 94,578 95,644 96,706 97,764 99,178 100,596 102,020 103,448 104,882 106,322 107,765 108,975 110,184 111,393 112,601 113,809 115,017 116,223 117,429 118,717 120,005 121,295 122,587 123,880 125,173 126,467 127,684 128,900 130,115 131,331 132,546 133,760 134,974 136,187 116,890 118,324 119,756 121,187 122,918 124,654 126,396 128,144 129,899 131,659 133,424 134,758 136,088 137,415 138,736 140,053 141,366 142,675 143,979 145,583 147,190 148,800 150,412 152,025 153,640 155,257 156,717 158,177 159,634 161,091 162,547 164,001 165,454 166,906 156,606 158,384 160,156 161,922 164,140 166,362 168,590 170,823 173,062 175,307 177,556 179,493 181,428 183,361 185,291 187,220 189,146 191,070 192,993 195,088 197,185 199,284 201,385 203,487 205,590 207,694 209,642 211,588 213,531 215,473 217,414 219,352 221,289 223,224 Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 617/629 V17.0 BSS Parameter User Guide (BPUG) 9. 9.1. ABBREVIATIONS & DEFINITIONS ABBREVIATIONS For other abbreviations, refer to [R3]. AMNU AMR AMR-HR AMR-FR BCC Advanced Management Unit Adaptative Multi-Rate Adaptative Multi-Rate Half Rate Adaptative Multi-Rate Full Rate Base station Colour Code Last three bits of BSIC code. The BCC is used to identify one of the cells sharing the same BCCH frequency. Neighouring cells may, or may not, have different BCC. BCCH Broadcast Control CHannel Common mobile logical channel used for broadcasting system information on the radio interface BCF BDA BDE Base Common Function BSC application database This database contains all the information objects describing the BSS. OMC-R operations database This database contains all the information objects describing the BSS under OMCR management control, and the objects required to manage OMC-R functionalities BER Bit Error Rate Method of measuring the quality of radio link transmission A ratio of the number of digital errors received in a specified period to the total number of bits received in the same period. Usually expressed as a negative exponent, i.e: 10-6 means one bit error in 106 bits of transmission, or one in a million BIFP BSC BSCB Base Interface Front-end Processor Set of BSC functional units managing the interface with BTS Base Station Controller BTS Signalling Concentration Board Board which concentrates 12 LAPD signalling channels between BSC and BTS into 3 channels Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 618/629 V17.0 BSS Parameter User Guide (BPUG) BSIC Base Station Identity Code Code used to identify a base station which allows mobile stations to distinguish the cells sharing the same BCCH frequency. A BSIC is defined by an (NCC, BCC) combination BSS Base Station Subsystem Radio Cellular Network radio subsystem made up of Base Station Controllers, one or more remote TransCoder Units and one or more Base Transceiver Stations BTS CA CBCH Base Transceiver Station Cell Allocation Radio frequency channel allocated to a cell Cell Broadcast CHannel Logical channel used inside a cell to broadcast short messages in unacknowledged mode CC Call Control Sublevel of layer 3 on the radio interface charged with managing call processing CCCH Common Control CHannel Common bidirectional mobile control channel, used for transmitting signalling information on the radio interface CCH CGI Control Channel Common or dedicated control channel Cell Global Identifier Global identifier of a mobile network cell. The CGI contains the Location Area Code (LAC), Mobile Country Code (MCC), Mobile Network Code (MNC) and the cell identifier in the location area CMC CPU CPU-MPU/BIFP dB Codec Mode Command Central Processing Unit Slave BSC processing unit Central BSC processing unit handling MPU and BIFP functions Decibel Measurement unit of relative power level defined as 10 log10 (P1/P2) where P1 and P2 are the power levels. dBm Power in dB relative to 1 mW Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 619/629 V17.0 BSS Parameter User Guide (BPUG) DCCH Dedicated Control CHannel Dedicated radio signalling channel with one SDCCH + one SACCH DITR DLNA DRX DTX EFR EIRP eMLPP FACCH FCCH FCH FER FH FN FP FR GSM GSM 900 GSM 1800 GSM 1900 HO HR HSN ICM L1M LAC LAI Dominant to Interferer TSC Ratio Duplexer Low Noise Amplifier Amplifier installed between BTS and the antenna Driver and Receiver Unit Signal processing unit for radio transmission and reception. Discontinuous Transmission Enhanced Full Rate vocoder Equivalent Isotropic Radiated Power enhanced Multi Level Precedence and Preemption Fast Associated Control CHannel Dedicated signalling channel (Um interface) Frequency Correction CHannel Common frequency synchronization channel Frequency CHannel Common frequency synchronization channel Frame Erasure Rate Frequency Hopping Frame Number Frame Processor Full Rate TCH Global System for Mobile Communications Radio Cellular Network standard adapted for the 900 MHz frequency band. Radio Cellular Network standard adapted for the 1800 MHz frequency band. Radio Cellular Network standard adapted for the 1900 MHz frequency band. HandOver: automatic call transfer between two radio channels Half Rate TCH Hopping Sequence Number Iinitial Codec Mode Processor functional unit handling BTS radio measurements Location Area Code Code used to identify a location area in the GSM network Location Area Identity Geographic identity of a group of cells used to locate a mobile station Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 620/629 V17.0 BSS Parameter User Guide (BPUG) LB LNA MA MAI MAIO MCC MTBF MEU Link Budget Low Noise Amplifier, part of DLNA system Mobile Allocation Mobile Allocation Index Mobile Allocation Index Offset Mobile Country Code Minimum Time Between Failure Masthead Electronics Unit Mini-masthead electronics cabinet. Remote amplifier located between BTS and the antenna MHz MMU MPU MNC Mp MRC MS MSC MCL MTBF MegaHertz Mass Memory Unit (BSC) Main Processor Unit (BSC) Set of BSC functional units charged mainly with call processing functions Mobile Network Code Measurement processing Maximum Radio Combiner Mobile Station Mobile Services Switching Center Minimum Coupling Loss Mathematical Time Between Failure It is a mathematical time expectancy between two successive parts of equipment or unit failure NCC NMC NSS Network Colour Code First three bits of the BSIC code. Each country is assigned a list of NCC. Network Management Centre Network and Switching SubSystem Radio Cellular Network subsystem including an MSC, main HLR, VLR, EIR and AUC NS/EP OMC OMC-R OMC-S OMU OSS National Security and Emergency Preparedness Operation and Maintenance Centre for the radio subsystem Operation and Maintenance Centre - Radio Operation and Maintenance Centre - Switching Central BSC Operation & Maintenance Unit Operation SubSystem Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 621/629 V17.0 BSS Parameter User Guide (BPUG) Radio Cellular Network operations subsystem including the OMC-R and OMC-S PA PBGT PC PCH PLMN PSTN PURQ-AC RACH Power Amplifier Power Budget Power Control Paging CHannel Common subscriber radio paging channel Public Land Mobile Network Public Switched Telephone Network Public Use Reservation for Queuing – All Calls Random Access CHannel Common mobile logical channel, reserved for random access requests transmitted by mobile stations on the radio interface. RF RLC RX RXLEV RXQUAL SACCH Radio Frequency Radio Link Counter BTS receiver Received signal Level Received signal Quality Slow Associated Control CHannel Slow logical control channel associated with a traffic channel during a communication SCH SDCCH Synchronization CHannel Common time division synchronization channel Standalone Dedicated Control CHannel Dedicated radio signalling channel temporarily allocated during call set up. There are 2 types of SDCCH: SDCCH/8 and SDCCH/4, on which the logical channels are grouped by 8 and by 4 respectively and combined with CCH SFH SFH mobile Non SFH mobile SICD Slow Frequency Hopping mobile using an hopping channel mobile using a non hopping channel Serial Interface Controller LAPD BSC board controller for Abis and Ater Interface SNR SPU SUP Signal to Noise Ratio Signal Processing Unit SUPervision unit Functional BSC monitoring unit Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 622/629 V17.0 BSS Parameter User Guide (BPUG) SWC TA SWitching matrix Controller (BSC 6000) Timing Advance Alignment process designed to compensate propagation time between a mobile and base station TCH TCH/F TCH/H TDMA Traffic CHannel Radio traffic channel Traffic CHannel/Full rate Traffic CHannel/Half rate Time Division Multiple Access Abbreviation used to designate a transmission frame on the radio interface, divided into eight time slots (TS) or channels TMU TRX TS TSC TSCB Traffic Management Unit Transmission/reception subsystem of the BTS Time Slot Training Sequence Code Transcoder Signalling Concentration Board (BSC) Board which concentrates LAPD signalling channels between BSC and TCU into a single channel TX WPS BTS transmitter Wireless Priority Service Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 623/629 V17.0 BSS Parameter User Guide (BPUG) 9.2. DEFINITIONS CODEC MODE Codec mode is used to designate one of the 8 AMR vocoder and identified using its rate (12k2, 10k2, 7.95, 7k4, 6k7, 5k9, 5k15, 4k75) give in kbps. CONCENTRIC CELL Two concentric geographical zones delimited by distance and level criteria (outer zone and inner zone). Outerzone BCCH and signalling channels Innerzone traffic channels DUAL BAND CELL Each group of TRXs is dedicated to a frequency band (900 and 1800 MHz for example) with different radio propagation condition; the frequency band used for the largest zone (outer) is the one used by the mono-band MS already existing in the network, since a mono-band MS must still be able to decode the common channels. Outerzone Innerzone / band1 band0 DCS (or GSM) traffic channels BCCH and signalling channels GSM (or DCS) DUAL COUPLING CELL Each group of TRXs is dedicated to a frequency band and the two groups of TRXs are combined with coupling systems with different losses, resulting in different coverage areas with the same TX transmission power. Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 624/629 V17.0 BSS Parameter User Guide (BPUG) Innerzone H4D traffic channels Outerzone H2D BCCH and signalling channels ERLANG Unit of telecommunications traffic intensity. The number of erlangs represents the average number of resources or circuits occupied during the peak traffic hour. FREQUENCY LOAD Defines the load of a frequency hopping pattern and is evaluated as below: fl = Nb of hopping TRX in the cell / Nb of frequencies in the hopping law FREQUENCY HOPPING: AD-HOC The Ad-Hoc frequency hopping does not reproduce a pattern all over the network. Frequency planning is done (HSN, MAIO, MA lists) according to the interference matrix. The particularity is that the number of hopping TRX = the number of hopping frequencies in most of the cases. FREQUENCY HOPPING PATTERNS: 1X1 This frequency pattern is used in case of frequency hopping. Each hopping TRX of 1*1 cell, uses all frequencies of the frequency law: f1,f2,f3,f4 f1,f2,f3,f4 f1,f2,f3,f4 FREQUENCY HOPPING PATTERNS: 1X3 This frequency pattern is used in case of frequency hopping. Each hopping TRX of 1*3 cell, uses 1/3 frequencies of the frequency law: Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 625/629 V17.0 BSS Parameter User Guide (BPUG) f1,f2,f3 f7,f8,f9 f4,f5,f6 MULTIZONE CELL Used in order to refer following kinds of cell: • • • concentric cell (see above) heterogeneous coupling cell (see above) dual-band cell (see above) RADIO INTERFACE Interface between the mobile station (MS) and the BTS. SPEECH FRAME Corresponds to 20 ms of speech on the radio interface and theTRAU interface. TIMING ADVANCE Delay used to compensate propagation time between mobile and base station. UM-INTERFACE See “Radio interface” WPS CALL Call which has priority level set in the Assignment Request or Handover Request between 2 and 6 (3GPP TS 48.008) Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 626/629 V17.0 BSS Parameter User Guide (BPUG) 10. INDEX All the parameters listed in the chapter ALGORITHM PARAMETERS are listed and indexed here below: accessClassCongestion, 344 adaptiveReceiver, 448 adjacent cell umbrella ref, 359 allocPriorityTable, 344 allocPriorityThreshold, 345 allocPriorityTimers, 346 allocWaitThreshold, 347 allOtherCasesPriority, 347 amrAdaptationSet, 425, 426, 427 amrDirectAllocIntRxLevDL, 435 amrDirectAllocIntRxLevUL, 435 amrDirectAllocRxLevDL, 433 amrDirectAllocRxLevUL, 433 amrFRIntercellCodecMThresh, 435 amrFRIntracellCodecMThresh, 436 amrHRIntercellCodecMThresh, 436 amrHRtoFRIntracellCodecMThresh, 436 amriRxLevDLH, 437 amriRxLevULH, 437 amrReserved1, 438 amrReserved2, 438 answerPagingPriority, 348 assignRequestPriority, 348 averagingPeriod, 371 baseColourCode, 446 bCCHFrequency_adjacentCellHandover, 397 bCCHFrequency_adjacentCellReselection, 397 bCCHFrequency_bts, 399 biZonePowerOffset_adjacentCellHandover, 363 biZonePowerOffset_handoverControl, 364 bscHopReconfUse, 387 bscMSAccessClassBarringFunction, 349 bscQueueingOption, 349 bsMsmtProcessingMode, 336 bsPowerControl, 336 bssMapT1, 375 bssMapT12, 375 bssMapT13, 375 bssMapT19, 376 bssMapT20, 376 bssMapT4, 376 bssMapT7, 377 bssMapT8, 377 bssMapTchoke, 377 bssPagingCoordination, 447 bssSccpConnEst, 378 bsTxPwrMax, 336 bts Time Between HO configuration, 310 btsHopReconfRestart, 387 btsIsHopping, 388 Nortel confidential btsMSAccessClassBarringFunction, 350 btsSMSynchroMode, 445 btsThresholdHopReconf, 388 callClearing, 332 callReestablishment, 298 callReestablishmentPriority, 350 capacityTimeRejection, 414 cellAllocation, 389 cellBarQualify, 351 cellBarred, 351 cellDeletionCount, 306 cellDtxDownLink, 402 cellReselectHysteresis, 284 cellReselectOffset, 285 cellReselInd, 285 cellType_adjacentCellHandover, 330 cellType_bts, 330 channelType, 351 cId, 417 coderPoolConfiguration, 428 compressedModeUTRAN, 417 concentAlgoExtMsRange, 365 concentAlgoExtRxLev, 366 concentAlgoIntMsRange, 365 concentAlgoIntRxLev, 366 concentric cell, 367 cypherModeReject, 448 dARPPh1Priority, 446 data mode 14.4 kbit/s, 403 data non transparent mode_bts, 403 data non transparent mode_signalingPoint, 403 data transparent mode_bts, 404 data transparent mode_signalingPoint, 404 Data14_4OnNoHoppingTs, 403 delayBetweenRetrans, 382 directedRetry, 359 directedRetryModeUsed, 360 directedRetryPrio, 354 distHreqt, 308 distWtsList, 308 diversity, 406 diversityUTRAN, 417 dtxMode, 402 early classmark sending, 395 earlyClassmarkSendingUTRAN, 418 emergencyCallPriority, 352 enableRepeatedFacchF, 442 encrypAlgoAssComp, 448 encrypAlgoCiphModComp, 449 encrypAlgoHoPerf, 449 PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 627/629 V17.0 BSS Parameter User Guide (BPUG) encrypAlgoHoReq, 449 encryptionAlgorSupported, 450 enhancedTRAUFrameIndication, 408 enhCellTieringConfiguration, 409 estimatedSiteLoad, 394 extended cell, 332 facchPowerOffset, 442 fDDARFCN, 418 fDDMultiratReporting, 293 fDDreportingThreshold, 293 fDDreportingThreshold2, 294 fhsRef, 390 fnOffset, 445 forced handover algo, 310 frAMRPriority, 430 frPowerControlTargetMode, 431, 432 frPowerControlTargetModeDl, 432 gprsNetworkModeOperation, 447 gprsPreemptionForHR, 442 gsmToUmtsReselection, 289 gsmToUMTSServiceHo, 418 handOver from signalling channel, 311 hoMargin, 311 hoMarginAMR, 441 hoMarginAMRUTRAN, 419 hoMarginBeg, 312 hoMarginDist, 312 hoMarginDistUTRAN, 420 hoMarginRxLev, 313 hoMarginRxLevUTRAN, 419 hoMarginRxQual, 313 hoMarginRxQualUTRAN, 419 hoMarginTiering, 409 hoMarginTrafficOffset, 314 hoMarginTrafficOffsetUTRAN, 420 hoMarginUTRAN, 419 hoPingpongCombination, 314 hoPingpongCombinationUTRAN, 420 hoPingpongTimeRejection, 315 hoPingpongTimeRejectionUTRAN, 421 hoppingSequenceNumber, 391 hoRejectionTimeOverloadUTRAN, 421 hoSecondBestCellConfiguration, 316 hoTraffic_bsc, 316 hoTraffic_bts, 316 hrAMRPriority, 430 hrCellLoadEnd, 427 hrCellLoadStart, 427 hrPowerControlTargetMode, 431, 432 hrPowerControlTargetModeDl, 432 incomingHandOver, 317 interBscDirectedRetry, 360 interBscDirectedRetryFromCell, 360 interCellHOExtPriority, 352 interCellHOIntPriority, 353 interferenceType, 409 interferer cancel algo usage, 406 intraBscDirectedRetry, 361 intraBscDirectedRetryFromCell, 361 Nortel confidential intraCell, 323 intraCellHOIntPriority, 353 intraCellQueueing, 354 intraCellSDCCH, 323 layer3MsgCyphModeComp, 450 locationAreaCodeUTRAN, 421 lRxLevDLH, 326 lRxLevDLP, 337 lRxLevULH, 326 lRxLevULP, 337 lRxQualDLH, 328 lRxQualDLP, 338 lRxQualULH, 328 lRxQualULP, 338 maio, 391 masterBtsSmId, 446 maxNumberRetransmission, 382 measurementProcAlgorithm, 404 microCellCaptureTimer, 331 microCellStability, 331 minNbOfTDMA, 354 minTimeQualityIntraCellHO, 414 missDistWt, 309 missRxLevWt, 303 missRxQualWt, 301 mobileAllocation, 392 mobileCountryCodeUTRAN, 422 mobileNetworkCodeUTRAN, 422 modeModifyMandatory, 361 msBtsDistanceInterCell, 333 msRangeMax, 333 msTxPwrCCH, 285 msTxPwrMax, 317 msTxPwrMax2ndBand, 339 msTxPwrMaxCell, 318 multi band reporting, 395 nbLargeReuseDataChannels, 410 nbOfRepeat, 383 nCapacityFRRequestedCodec, 440 neighDisfavorOffset, 416 new power control algorithm, 339 nFRRequestedCodec, 440 nHRRequestedCodec, 440 noOfBlocksForAccessGrant, 383 noOfMultiframesBetweenPaging, 384 notAllowedAccessClasses, 355 numberOfPwciSamples, 410 numberOfSlotsSpreadTrans, 385 numberOfTCHFreeBeforeCongestion, 355 numberOfTCHFreeToEndCongestion, 356 numberOfTCHQueuedBeforeCongestion, 356 numberOfTCHQueuedToEndCongestion, 356 offsetLoad, 319 offsetPriority, 319 offsetPriorityUTRAN, 422 otherServicesPriority, 357 pagingOnCell, 386 pcmErrorCorrection, 408 penaltyTime, 286 PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 628/629 V17.0 BSS Parameter User Guide (BPUG) powerBudgetInterCell, 320 powerControlIndicator, 292 powerIncrStepSizeDL, 340 powerIncrStepSizeUL, 340 powerRedStepSizeDL, 340 powerRedStepSizeUL, 341 preemptionAuthor, 358 pRequestedCodec, 441 preSynchroTimingAdvance, 334 priority, 357 processorLoadSupConf, 394 pwciHreqave, 411 qsearchC, 294 radChanSelIntThreshold, 372 radioAllocator, 428 radioLinkTimeout, 298 radResSupBusyTimer, 374 radResSupervision, 374 radResSupFreeTimer, 374 reportTypeMeasurement, 296 retransDuration, 386 rlf1, 299 rlf2, 300 rlf3, 300 rNCId, 422 rndAccTimAdvThreshold, 334 runCallClear, 335 runHandOver, 320 runPwrControl, 342 rxLevAccessMin, 287 rxLevDLIH, 324 rxLevDLPBGT, 329 rxLevDLPbgtUTRAN, 423 rxLevHreqave, 303 rxLevHreqaveBeg, 304 rxLevHreqt, 304 rxLevMinCell, 321 rxLevMinCellUTRAN, 423 rxLevNCellHreqaveBeg, 307 rxLevULIH, 324 rxLevWtsList, 305 rxNCellHreqave, 307 rxQualAveBeg, 416 rxQualDLIH, 325 rxQualHreqave, 301 rxQualHreqt, 302 rxQualULIH, 325 rxQualWtsList, 302 sacchPowerOffset, 443 sacchPowerOffsetSelection, 443 scramblingCode, 423 selfAdaptActivation, 415 selfTuningObs, 411 servingBandReporting, 296 servingBandReportingOffset, 297 servingfactorOffset, 415 siteGsmFctList, 405 small to large zone HO priority, 368 smartPowerManagementConfig, 451 smartPowerSwitchOffTimer, 451 smsCB, 413 speechMode_bts, 412 speechMode_signallingPoint, 412 standard indicator AdjC_adjacentCellHandover, 396 standard indicator AdjC_adjacentCellReselection, 397 standardIndicator, 399 synchronized, 322 t3101, 378 t3103, 379 t3107, 379 t3109, 380 t3111, 380 t3121, 424 t3122, 381 temporaryOffset, 288 thresholdInterference, 373 timeBetweenHOConfiguration, 322 timerPeriodicUpdateMS, 381 tnOffset, 445 trafficPCMAllocationPriority, 393 transceiver equipment class_transceiverEquipment, 368 transceiver equipment class_transceiverZone, 369 transceiverZone, 369 uMTSAccessMinLevel, 289 uMTSReselectionARFCN, 290 uMTSReselectionOffset, 290 uMTSSearchLevel, 290 uplinkPowerControl, 342 uRxLevDLP, 342 uRxLevULP, 343 uRxQualDLP, 343 uRxQualULP, 343 wPSManagement, 444 wPSQueueStepRotation, 444 zone Tx power max reduction, 370 zoneFrequencyHopping, 393 zoneFrequencyThreshold, 393 END OF DOCUMENT Nortel confidential PE/DCL/DD/000036 17.03 / EN Standard 03/03/2008 Page 629/629
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