ZTE GSM BSS Basic Feature Description V10R1.pdf

GSM BSSDescription V10R1 Basic Feature GSM BSS Basic Feature Description V10R1 GSM BSS Basic Feature Description Version Date Author Approved By Remarks V1.0 2010-8-15 Not open to the Third Party V1.1 2010-12-20 Not open to the Third Party © 2010 ZTE Corporation. All rights reserved. ZTE CONFIDENTIAL: This document contains proprietary information of ZTE and is not to be disclosed or used without the prior written permission of ZTE. Due to update and improvement of ZTE products and technologies, information of the document is subjected to change without notice. ZTE Confidential Proprietary © 2010 ZTE Corporation. All rights reserved. I ZTE GSM BSS Basic Feature Descripiton V10R1 TABLE OF CONTENTS 1 Instruction ....................................................................................................... 1 2 2.1 2.1.1 2.2 2.2.1 2.3 2.3.1 2.3.2 2.3.3 Service............................................................................................................. 2 Voice Service.................................................................................................... 2 ZGB-01-01-001 Full Rate (FR) Speech Codec ............................................... 2 Data Service ..................................................................................................... 3 ZGB-01-02-001 Quality of Service (QoS) ....................................................... 3 Supplementary Service ..................................................................................... 4 ZGB-01-03-001 Emergency Call Handling ..................................................... 4 ZGB-01-03-002 Data Traffic Channels ........................................................... 5 ZGB-01-03-003 Short Message Service (SMS) .............................................. 5 3 3.1 3.1.1 3.2 3.2.1 3.2.2 3.2.3 3.2.4 Mobility Management ..................................................................................... 7 Paging .............................................................................................................. 7 ZGB-02-01-001 Paging .................................................................................. 7 Handover and Reselection................................................................................ 8 ZGB-02-02-001 Basic Handover .................................................................... 8 ZGB-02-02-004 Support 64 Neighboring Cells ............................................. 11 ZGB-02-02-006 Cell Reselection.................................................................. 12 ZGB-02-02-007 Cell Selection...................................................................... 13 4 4.1 4.1.1 4.1.2 4.1.3 4.1.4 4.2 4.2.1 4.2.2 4.2.3 4.2.4 4.2.5 4.2.6 4.2.7 4.2.8 4.2.9 4.3 4.3.1 4.3.2 4.3.3 4.3.4 4.3.5 4.4 4.4.1 4.4.2 4.4.3 Resource Management ................................................................................ 15 Access Control ............................................................................................... 15 ZGB-03-01-001 MS Access Control ............................................................. 15 ZGB-03-01-002 Directed Retry..................................................................... 16 ZGB-03-01-003 Queuing .............................................................................. 17 ZGB-03-01-004 Immediate TCH Assignment ............................................... 18 Channel Allocation .......................................................................................... 20 ZGB-03-02-001 Support of SDCCH/4 and SDCCH/8 ................................... 20 ZGB-03-02-002 Flexible SDCCH Configuration ........................................... 20 ZGB-03-02-003 Dynamic Configuration of SDCCH ...................................... 21 ZGB-03-02-004 MAC Dynamic Allocation Mode .......................................... 22 ZGB-03-02-005 Static Channel Management............................................... 23 ZGB-03-02-006 Dynamic Channel Management .......................................... 23 ZGO-03-02-001 Idle Channel Measurement ................................................ 24 ZGO-03-02-002 Enhancement on CS Channel Allocation ............................ 25 ZGO-03-02-003 Enhancement on PS Channel Allocation ............................ 27 Circuit Management........................................................................................ 29 ZGB-03-03-001 2M High Speed Signaling Link ............................................ 29 ZGB-03-03-002 Enhanced E1 Link between BSC and BTS ......................... 30 ZGB-03-03-003 LAPD Cluster ...................................................................... 30 ZGB-03-03-004 TC Resource Dynamic Sharing .......................................... 31 ZGB-03-03-005 PCU Resource Dynamic Allocation..................................... 32 Reliability ........................................................................................................ 33 ZGB-03-04-001 BSC Load Control............................................................... 33 ZGB-03-04-003 BTS Recovery .................................................................... 34 ZGB-03-04-004 Dry Contact Alarm .............................................................. 35 II © 2010 ZTE Corporation. All rights reserved. ZTE Confidential Proprietary ...................................................5................ 62 ZGB-06-01-005 BSC Monitor Functions ...1....................................................... C MS .................................................. 38 ZGB-03-05-005 8/11 bit Access Burst .......................................................1 5..... 46 ZGB-03-05-015 RLC Acknowledged/ Unacknowledged Mode ... 72 ZTE Confidential Proprietary © 2010 ZTE Corporation............5.....5........................... 36 GPRS/EDGE ........... 61 ZGB-06-01-003 Performance Data Measurement .1.................................................1. 47 ZGB-03-05-016 Downlink BVC Flow Control ................................8 7......3 Network Performance................2 6.........................11 4.4 7..................... 45 ZGB-03-05-013 Delayed TBF Release in DL .................................. 45 ZGB-03-05-014 Delayed TBF Release in UL ............................. 70 ZGB-06-02-001 A5/1 and A5/2 Ciphering Algorithm ................ III .............................................2 5..................................................................................................................... All rights reserved.....5.5...................9 4. 52 Network Quality Improvement.....................1.......... 64 ZGB-06-01-007 Cell Traffic Statistics ...1..................16 ZGB-03-04-006 Backward Compatibility for BTS ......7 7....................1 Others ........... 70 8 Acronyms and Abbreviations ..................1.......15 4.....2 7...2 7............ 49 ZGO-03-05-003 EGPRS Packet Channel Request on CCCH ............ 55 ZGB-05-02-001 Automatic Bridge in BTS Chain Networking .....1................................ 50 5 5.................5.................GSM BSS Basic Feature Description V10R1 4.......1 4......... 67 ZGO-06-01-003 BSC LMT .... 51 ZGB-04-01-001 Receiving Diversity ..............................5........................................................7 4....................................5....... 40 ZGB-03-05-008 Two Phase Access ..............................8 4......5 4.......................1 7......... 36 ZGB-03-05-001 Coding Scheme CS1~CS4 .........................5 4. 54 6 6..........................2 5........................................................ 38 ZGB-03-05-006 Class A...............................2......................................... and Chain Networking ..1 6.1 Transmission .................................2...................................................2.......................................................5................2........1 5...12 4.13 4..................................4 4..... 60 ZGB-06-01-001 Monitoring Um Interface .................................2 6............1................ 48 ZGB-03-05-017 Downlink MS Flow Control .............1....14 4...2 4.. 57 Synchronization ................ 51 ZGB-04-01-002 Support Tower Mounted Amplifier (TMA) .........2 5............................... 60 O&M ......5..5 7.............1 7.............................5.............................................................................................4 4........................ 41 ZGB-03-05-009 Network Mode of Operation (NMO) 1~3 ....................... 63 ZGB-06-01-006 BTS Software Loading ................. 69 Security ....................... 58 7 7........................ 44 ZGB-03-05-012 GPRS Link Adaptation ................ 54 ZG0-04-02-019 Discontinuous Reception (DRX) ...................................................................................................... 60 ZGB-06-01-002 Abis Interface Monitoring .....................1................................... 36 ZGB-03-05-002 Initial Coding Scheme Per Cell Settable ...........5................... 67 ZGB-06-01-008 BSC Diagnostic Tests ............................1..................1 6...............1...........5........................................ 53 ZGB-04-02-001 Traffic Hold at Channel Blocking ................ 53 ZGB-04-02-002 Static BTS Power Control ........................................5.......................... 50 ZGO-03-05-007 EGPRS Activation per Cell ......................... 51 Coverage Enhancement .... 56 ZGO-05-02-031 Distributed Architecture of BTS ..... B........... 39 ZGB-03-05-007 One Phase Access . Tree........... 55 Flexible Networking .................................................2............1 5... 55 ZGB-05-02-002 Star.................................................................................3 4.5.....................3 6........3 7..............5..............................................4......................6 4........ 58 ZGB-05-03-001 Clock Synchronization .................... 42 ZGB-03-05-011 Timeslot Multiplexing ....6 7............................1..........................................10 4........ ...................................................................................................... 57 TABLES Table 2-1 RLC transmission modes corresponding to reliability class ................ 3 Table 4-1 Bandwidth Requirement of LADP Cluster .. 31 Table 4-2 Coding Scheme CS1-CS4 ......................................................................................... 43 IV © 2010 ZTE Corporation..................... tree and Chain Networking .......................................................... ZTE Confidential Proprietary .... All rights reserved............ 19 Figure 6-1 Star.............................................ZTE GSM BSS Basic Feature Descripiton V10R1 FIGURES Figure 4-1 Immediate Assignment of TCH ................... 37 Table 4-3 Three Network Operation Modes........................... ZTE GSM BSS Feature ID number is in the format of ZGx-xx-xx-xxx.GSM BSS Basic Feature Description V10R1 1 Instruction The complete set of feature description for radio access part of ZTE GSM consists of three documents: ZTE GSM BSS Basic Feature Description. ZTE GSM BSS Optional Feature Description. All rights reserved. This document contains the basic features of ZTE GSM BSS. ZTE NetNumen-M31 Feature Description. The header “ZG” stands for ZTE GSM. ZTE Confidential Proprietary © 2010 ZTE Corporation. 1 . ZTE GSM BSS Basic Feature Description V10R1 2 Service 2.1 Voice Service 2.1.1 ZGB-01-01-001 Full Rate (FR) Speech Codec Benefits This feature is a speech codec that gives good speech quality used for Full Rate traffic channels and makes the user have better experience. Description Full rate speech coder is the basic coding scheme of GSM system. It uses Linear Predictive Coding with Regular Pulse Excitation (LPC-RPE codec). It is a full rate speech codec and operates at 13 kbps. Full Rate Speech Codec is based on RPE-LTP. 160 speech samples in 13-bit PCM are mapped to 260bit (interval is 20ms and sampling rate is 8KHz), which is called coding. Decoding refers to the mapping relation between the 160 reconstructed speech samples from 260bit coding packet to export packet. The coding stream is 13kbit/s. The traffic channel using FR speech codec is usually expressed by TCH/F. One TRX supports maximum 8 TCH/F time slots. It can give good speech quality with Mean Opinion Score (MOS) 3.8. Introduced Version Before V09R1 Enhancement None 2 © 2010 ZTE Corporation. All rights reserved. ZTE Confidential Proprietary GSM BSS Basic Feature Description V10R1 2.2 Data Service 2.2.1 ZGB-01-02-001 Quality of Service (QoS) Benefits This feature enhances high-end subscribers’ service experience in the case of restricted radio resource for packet service. Description GPRS QoS includes the parameters as follows: Delay class: 1 (short delay) ~ 4 (background) Reliability class: 1 ( 10-5) ~ 5 (>5*10-4) Peak throughput class: 1 (<16Kb/s) ~ 9 (M2Mb/s) Precedence class: 1 ~ 3 Mean throughput class: 1 (lowest, 0.22kbps) ~ 18 (highest, 111kbps), 31 (best effort). These QoS parameters are negotiated by MS and SGSN in the process of PDP activation. BSC obtains QoS parameters from SGSN downlink data. On the Best Effort principle, BSC processes reliability class and precedence class as follows: Table 2-1 RLC transmission modes corresponding to reliability class Reliability class LLC Mode RLC Mode 1 Acknowledged Acknowledged 2 Acknowledged Acknowledged 3 Unacknowledged Acknowledged 4 Unacknowledged Unacknowledged ZTE Confidential Proprietary © 2010 ZTE Corporation. All rights reserved. 3 ZTE GSM BSS Basic Feature Description V10R1 5 Unacknowledged Unacknowledged The RLC mode of uplink TBF is determined by mobile phones, while the RLC mode of downlink TBF is determined by BSC. According to the wireless transmission features, BSC sets the RLC mode to acknowledged mode for all reliability classes in the downlink. Introduced Version Before V09R1 Enhancement None 2.3 Supplementary Service 2.3.1 ZGB-01-03-001 Emergency Call Handling Benefits Emergency calls have the highest priority, even if the system congests or overloads, emergency calls will be handled rapidly and guaranteed good service quality. This enhances emergency call handling efficiency and user satisfaction. Description Emergency call is a basic voice service of the GSM system. When the MS accesses the network using an emergency call, the BSS treats and provides higher priority and faster service to it. So TCH channel will be allocated with higher priority. Allocation of SDCCH channel will be considered if the TCH channel is busy. Emergency calls have highest priority, even if the MS does not have any SIM card or the SIM card is locked, he/she still can dial emergency calls successfully, even if the system congests or overloads, emergency calls will be handled rapidly and guaranteed good service quality. Introduced version Before V09R1 4 © 2010 ZTE Corporation. All rights reserved. ZTE Confidential Proprietary GSM BSS Basic Feature Description V10R1 Enhancement None 2.3.2 ZGB-01-03-002 Data Traffic Channels Benefits Circuit Switched Data services (CSD) shows more ways to support dada services for 2G operators. Operators can provide diversified services on the data platform of CSD to attract more subscribers and achieve more profits. Description ZTE GSM BSS adopts TCH/F9.6 (transparent and non-transparent) data channels to deliver circuit switched data services at a rate of 9.6 Kbits/s. The BSS provides the lower-layer bearer service but does not process the upper-layer services. In nontransparent data services, a set of radio link protocol is used for data correction and retransmission between Mobile Station (MS) and Core Network (CN). Introduced version Before V09R1 Enhancement None 2.3.3 ZGB-01-03-003 Short Message Service (SMS) Benefits This feature has great potential in attracting target subscribers and increasing revenue. Many services can be deployed with short messages, such as stock information, current exchange rate and weather forecast. ZTE Confidential Proprietary © 2010 ZTE Corporation. All rights reserved. 5 BSS establishes links (SAPI =3) to transmit SMS. ZTE Confidential Proprietary . short messages are carried on SACCH channel. Introduced version Before V09R1 Enhancement None 6 © 2010 ZTE Corporation. The text should not exceed 160 (English) letters or 80 (Chinese) characters. operator can send advertisement. MS still can receive short message.ZTE GSM BSS Basic Feature Description V10R1 In addition. MS sends and receives SMS in either busy or idle state. One MS sends text to another MS (point to point. which makes them charge on not only subscribers. When MS is in idle state. PTP) through network and SMC. Even if a call is coming. BSC then transmits the short message to MS after a successful setup. MS sets up a link (SAPI = 3) at Abis interface before sending or receiving short messages. bill and charge information to specific subscribers by SMS. short messages can be carried on SDCCH channel or FACCH channel according to the network state. When MS is going through a call. but also for fixed network users that are able to receive short messages as well. After BSC receives the short message from SMC. All rights reserved. it will send ‘Establish Request’ message to set up a link at Abis interface first. In idle state. This transmission procedure is transparent to BSS. SMC is in charge of short message storing and forwarding. but also the enterprise that needs the service. This service is not only for GSM users. Then it will set up SAPI connection at Abis interface to send or receive short messages. Description Support bi-directional (MT/MO) message transmission between MS and SMC. Description Paging procedure is initialized by MSC or SGSN to locate the MS. Paging is sent via CCCH. ZTE Confidential Proprietary © 2010 ZTE Corporation.1. When the paging message is not replied within certain duration. while four TMSI can be packed in one paging message. it will be retransmitted. one paging message can contain two IMSI numbers. and there are 9 paging groups when CCCH and SDCCH are configured individually.1 Paging 3. Among them. There are three paging types: CS call paging. and SMS paging. PCH. PS paging. 7 . The paging group in one multi-frame is shared by PCH and AGCH.1 ZGB-02-01-001 Paging Benefits This feature is a basic step to setup a call and send a SMS. the paging capacity depends on the configuration method of CCCH. Downlink CCCH is shared by PCH and AGCH. ZTE BSC supports a flexible channel configuration to provide different paging capacity. When IMSI is used for paging. there are 3 paging groups in one multi-frame when the CCCH and SDCCH share one control channel. According to GSM specification. The maximal paging capacity for one LAC is 400. and the ratio of IMSI paging to TMSI paging. ZTE BSS also supports paging retransmission. All rights reserved. BSC sends the paging request to all cells in specified LA.000 times per hour. After receiving the paging message from CN. Large paging capacity and flexible process avoids congestion caused by paging overload and improves the call setup success rate. There are two kinds of paging: IMSI paging and TMSI paging. Usually all these paging messages are sent via CCCH.GSM BSS Basic Feature Description V10R1 3 Mobility Management 3. In order to avoid paging congestion. Thus. all these traffics should be considered so that the LAC can be defined properly. and AGCH sends immediate assignment and immediate assignment rejection message. AGCH. PCH sends paging message. the target cell based on the layer strategy and the handover decision criterion is selected. BSC updates the BCCH Allocation (BA) list first. First. The determinant factor of the target cells’ sequencing is load. for the inter-cell handover. the suitable carrier and the timeslot of the minimum interference band is selected.ZTE GSM BSS Basic Feature Description V10R1 Introduced Version Before V09R1 Enhancement None 3. Description This feature enables the basic function related to the mobility management. ZTE Confidential Proprietary . which is handover. and then selects the suitable cell to handover after the handover decision is made. and then BSC decides whether the terminals need to handover according to the measurement reports. ZTE GSM supports BSC in dealing with the measurement reports with the sliding window mechanism and the weighted average algorithm. The terminals report the measurement reports every 480 ms during the voice conversation. In order to avoid the frequent handover failure. For the intra-cell handover.2 Handover and Reselection 3. which decreases the signaling load and increases the handover successful ratio. sequence and filter the target cells’ list according to the traffic: the cell with full 8 © 2010 ZTE Corporation. All rights reserved. so as to guarantee the users’ voice quality during handover as well. priority and power margin. relevant failure penalty is adopted. allowing the terminals to keep talking while moving in the cell or to the other cells.2. and then selects the higher priority handover algorithm according to the different handover reasons.1 ZGB-02-02-001 Basic Handover Benefits This feature enables the basic handover. and the handover decision is the same. the radio link maybe abnormal to release the occupied channel. which is composed of uplink and downlink. The details are shown as follows: Signal Quality (Uplink/Downlink) Handover Signal quality handover is a basic criterion for inter-cell handover. BSC deducts the offset value based on the signal level of the cell. BSC restrains the user not to attempt handover during the penalty time of handover failure. signal interference (uplink/downlink) handover. which avoids the repeated handover failure. if not. When the channel quality is getting worse. For the intracell handover. and then select the suitable target cell for this handover. when the mean error rate is greater than the quality threshold for P times in N times. sequence all target cells with the same priority based on the power margin. BSC compares the current time point with the time point of last successful handover. and increases the successful handover ratio. the synchronous handover is used for the inter-cell handover in the same site. leading to the user’s call drop. ultra-distance and Power Budget (PBGT) handover. If the difference between the two time point exceeds the penalty time of repeated handover. In order to prevent the repeated handover. the handover procedure is going on. Basic handover algorithm includes: signal quality (uplink/downlink) handover.GSM BSS Basic Feature Description V10R1 traffic or exceeding the traffic threshold should be deleted from the list. the source cell of last handover should be deleted from the target cells’ list of this handover first. The handover mode is divided into the synchronous handover and the asynchronous handover. Then sequence all the target cells based on the priority. At last. All rights reserved. In order to avoid this situation. 9 . BSC triggers the signal quality handover to save this call. signal level (uplink/downlink) handover. the handover failure penalty should be adopted. Signal Level (Uplink/Downlink) Handover ZTE Confidential Proprietary © 2010 ZTE Corporation. For the inter-cell handover. Select the first cell in the list as the target cell to handover. If handover fails. ZTE GSM supports basic and optional handover algorithms. and the asynchronous handover is used for the handover between the different sites. which reduces the possibility of the user handover to the last failed target cell during the penalty time of handover failure. which is composed of uplink and downlink. So the handover in the different channel of the same cell solves the interference problem. Signal Interference (Uplink/Downlink) Handover Signal Interference handover is the basic criterion for intra-cell handover. ZTE Confidential Proprietary . and the handover decision is the same.ZTE GSM BSS Basic Feature Description V10R1 Signal level handover is a basic criterion for inter-cell handover. When the signal quality is getting worse but the signal level is higher. the handover should be converted to the signal quality handover to try the inter-cell handover. the interference degree of every channel in the cell is different. If there is not idle channel in the serving cell. When the Time Advance (TA) is greater than the distance threshold for P times in N times. In order to avoid this situation. If the terminal is far from BTS. PBGT is gained from the signal level of the neighboring cell subtracting that of the serving cell. so as to keep the call in the suitable cell. the terminal enters the pre-defined interference area for P times in N times. the ultra-distance handover is done to the nearest neighboring cell. and the handover decision is the same. Ultra-Distance Handover Ultra-distance handover is a basic criterion for inter-cell handover. PBGT Handover PBGT handover is a basic criterion for inter-cell handover. All rights reserved. When the interference occurs. The difference between the signal interference handover and the signal quality handover is: when the signal interference handover occurs. the signal quality isn’t worse to influence the call and the signal level is high at present. when the signal lever is lower than the level threshold for P times in N times. leading to the users’ call drop. When the interference is too low to trigger the interference or quality handover even the level fading is serious. which is composed of uplink and downlink. BSC triggers the signal interference handover to save this call. BSC triggers the ultra-distance handover to save this call. BSC triggers the signal level handover to save this call. if the PBGT of the neighboring cell is greater than the preset PBGT 10 © 2010 ZTE Corporation. When the downlink level of the neighboring cell is lower than the initial threshold. If the inter-layer timer isn’t out. the normal PBGT handover is executed.2. In order to make the PBGT occur in the same layer.2 ZGB-02-02-004 Support 64 Neighboring Cells Benefits This feature improves radio network performance and reduces call drop rate by providing enough neighboring cells. Introduced Version Before V09R1 Enhancement ZTE Confidential Proprietary © 2010 ZTE Corporation. If the timer is out. All rights reserved. and maximum 96 GSM/UMTS neighboring cells. meeting the demand from growing network capacity and complexity. 64 GSM cell reselection cells. and the neighboring cell’s level should add the offset value of the lower layer for PBGT handover to the lower layer. Description This feature increases GSM neighboring cells from original 32 to 64 ones. BSS sends neighboring cell list to MS by system information. the neighboring cell’s level should add the offset value of the upper layer for PBGT handover to the upper layer. the inter-layer timer should be set when the terminal accesses the network. BSC triggers the PBGT handover. Introduced Version Before V09R1 Enhancement None 3. 11 . BSC supports handover and cell reselection between different frequency bands with maximum 64 GSM handover neighboring cells. and the neighboring cell’s level of other layers is strong enough to execute the inter-layer PBGT handover. PBGT handover is a non-saving handover.GSM BSS Basic Feature Description V10R1 threshold for P times in N times. The terminal implements the cell reselection through the measurement of the radio signal in BCCH carriers for the serving cell and the neighboring cells. All rights reserved. CELL_RESELECT_OFFSET applies an offset to the C2 reselection criterion for the cell.ZTE GSM BSS Basic Feature Description V10R1 None 3. ensuring the terminal to offer the best radio connection. Description This feature enables the cell reselection algorithm. PENALTY_TIME is the duration for which TEMPORARY_OFFSET applies.TEMPORARY_OFFSET * H (PENALTY_TIME . The signal quality criterion parameter C2 is only used for cell reselection and is defined by: C2 = C1 + CELL_RESELECT_OFFSET .3 ZGB-02-02-006 Cell Reselection Benefits This feature enables the reselection to the suitable neighboring cell in the idle mode and the connected mode for the terminal. 12 © 2010 ZTE Corporation. TEMPORARY_OFFSET applies a negative offset to C2 for the duration of PENALTY_TIME after the timer T has started for the cell. ZTE Confidential Proprietary .2. which is defined in 3GPP protocol. If one of the following conditions is satisfied.T) C2 = for PENALTY_TIME <> 11111 C1 .CELL_RESELECT_OFFSET for PENALTY_TIME = 11111 Where T is a timer implemented for each cell in the list of strongest carriers. the cell reselection is triggered: If C1<0 lasts for 5s. If the cell reselection occurs before the previous 15s. ZTE GSM supports the terminals controlled cell reselection. if not. Introduced Version Before V09R1 Enhancement None 3. C2 (s) is the C2 value of the serving cell. Where C2 (n) is the C2 value of the neighboring cell. when C2 (n) > C2 (s) the cell reselection occurs.2. Description When the MS is switched on or following recovery from lack of coverage. it finds available GSM PLMN. All rights reserved. the cell reselection occurs. and then the terminal selects the cell satisfied with the reselection conditions to reselect in the searching neighboring cells. and selects an appropriate cell for residence." ZTE Confidential Proprietary © 2010 ZTE Corporation. 13 . BSC sends the cell reselection parameters to the terminal through the system information SI 2quater. CRH applies the hysteresis of cell reselection.4 ZGB-02-02-007 Cell Selection Benefits This feature is the basic feature of GSM radio network. and C2 (n) > C2 (s) + CRH the cell reselection occurs. and C2 (n) > C2 (s) + 5dB. This process is called "cell selection.GSM BSS Basic Feature Description V10R1 During 5s. if the serving cell and the neighboring cell are in the same Location Area Code (LAC). ZTE Confidential Proprietary . whether the cell is prohibited from accessing or not. The MS can only reside in the cell if the MS correctly decodes BCCH data the cell belongs to the selected PLMN. If an MS stores BCCH carrier information before last power-off. the cell priority. only emergency calls can be made. such as whether the cell belongs to selected network. to demonstrate RF channel quality. If the MS can decode BCCH data of the cell but cannot reside in the cell. which is the important factor for cell selection. If so. All rights reserved. the path loss criterion parameter. If it still fails to find an appropriate cell after searching all BCCH carriers in the BA list. the MS attempts to decode SCH to synchronize with this carrier and reads system broadcast message on BCCH. C1 is larger than 0 and the cell access is not barred. it confirms whether it is BCCH carrier or not. reads received signal strength of each channel and calculates average signal level. whether MS access level is prohibited by the cell and whether RF channel quality is good enough. it continues monitoring the signal strength of all RF channels and searches BCCHs with access not barred and C1 larger than 0. If MS does not store BCCH message. it checks the BCCH Allocation (BA) list of the cell. Introduced Version Before V09R1 Enhancement None 14 © 2010 ZTE Corporation. If the MS fails to find an appropriate cell after searching 30 RF channels with best signal strength. After finding an appropriate carrier. After MS tunes to the carrier with highest receiving level. it searches all the 124 RF channels (for dualmode MS. the MS selects the cell without taking into account PLMN identification. it also needs to search 374 GSM1800 RF channels). the MS will initiate cell selection procedure in the way described above. Otherwise. The path loss criterion is satisfied if C1 > 0. GSM standard defines C1. In such a mode.ZTE GSM BSS Basic Feature Description V10R1 To select one appropriate cell is constrained by many factors. it first searches the stored BCCH carrier. MS is tuned to the next maximum carrier until it finds an available cell. 5 classes (11-15) are allocated to specific high priority subscribers.1 ZGB-03-01-001 MS Access Control Benefits This feature allows the operator to classify the subscribers to provide preferential service.1 Access Control 4. With Access Class Control (ACC).1. This feature can also be used to ensure telecommunication for staffs from special sections in case of emergency. ZTE Confidential Proprietary © 2010 ZTE Corporation. Every MS is assigned an ACC. and additional income might be obtained. If the bit is set to 1.GSM BSS Basic Feature Description V10R1 4 Resource Management 4. network operators can define some cells to be only accessed by authorized subscribers. So the operators can ensure better service for these subscribers in busy hour. For example. but only authorized subscribers can access the cell. The GSM protocols define 16 classes: 10 classes (0-9) are randomly allocated to normal subscribers. All rights reserved. which is saved in SIM card. operators offer the additional cell to enforce the traffic abilities. 15 . ACC information is included in system information. the MS with the corresponding ACC will be forbidden. Every class is indicated by one bit in system information. an important function of this message is to indicate the MS how to access this cell. Description BTS continually broadcasts system information message to all MSs in the cell. Class 10 is dedicated to emergency call. in traffic hotspot area. forced handover or queuing attempt according to calling priority. effectively relieving the network congestion and the unbalanced usage of wireless resources and greatly enhancing the assigning success rate. 2 sets of access control parameters for normal scenario. while the other users can always access. barred classes window size and window sliding time interval. if network doesn’t have available TCH resource. So it is possible for some users to be always forbidden to access in case of radio resource congestion. Each set of access control parameters consists of the first barred access class.2 ZGB-03-01-002 Directed Retry Benefits Directed retry realizes wireless resources sharing among neighboring cells during assignment. operator can enable some ACCs to access special cells. MS Access Control function applies sliding window method to decide the forbidden MS classes. which access classes of users are forbidden to access in case of radio resource congestion are configured statically on OMCR. cell will make forced release. Which set of access control parameters to be used can be configured on OMCR. All rights reserved.1. These configurations are set in OMCR and included in system information broadcasted by BTS. In V09R2. ZTE Confidential Proprietary . 4. Description During TCH assignment. MS turns to serving cell for TCH channel resource. which avoids forbidding some fixed classes of MS. queuing 16 © 2010 ZTE Corporation.ZTE GSM BSS Basic Feature Description V10R1 By setting the different ACCs. There are 2 sets of access control parameters for resource congestion scenario. preemption vulnerability indicator. Introduced Version Before V09R1 Enhancement In ZTE BSS version before V09R2. If the attempted cells of directed retry belong to the BSC. All rights reserved.GSM BSS Basic Feature Description V10R1 permission indicator and preemption capability indicator in assignment request. Afterwards. and the remaining cells are sorted in accordance with the dynamic priorities and power budget surplus. If the attempted cells do not belong to the BSC. When TCH channel is allocated from target cell. according to whether the attempted cells in directed retry cells list belong to the BSC. directed retry is divided into internal and external directed retry. if the attempt fails. the cells overloaded compared to load threshold are filtered out first. MS then accesses to target cell. directed retry procedure is initiated. if “Yes” is selected. Introduced Version Before V09R1 Enhancement None 4. it sends to MSC the failure message and waits for clear command from MSC. External directed retry in BSC part may select whether to send request failure to MSC. network sorts the adjacent cells which meet the rule 1 for handover to get the directed retry target cell list. then releases wireless resources. In addition. When sorting adjacent cells. request failure will be delivered to MSC firstly before sending handover request with cause labeled as directed retry.1. according to measurement reports sent by MSs. 17 . MS has to send handover request to MSC through A interface and make external directed retry via inter-BSC external handover flow. BSC turns to the first cell in the target cell list for TCH channel. when MS fails to initiate forced release. forced handover and queue. Then. channel description of target cell are sent to MS through assignment or handover command.3 ZGB-03-01-003 Queuing Benefits ZTE Confidential Proprietary © 2010 ZTE Corporation. then MS can directly apply channels to the cell and make internal directed retry. If network doesn’t support directed retry function. if the serving cell has no idle TCHs. All rights reserved. channel type and frequency band. then the call setup or handover procedure continues.1. When queuing time is set to zero. Reduce call failures caused by unavailable idle SDCCH in the serving cell.4 ZGB-03-01-004 Immediate TCH Assignment Benefits This feature reduces the call setup time. If some other MS releases a call or hands over to another cell and the serving cell has idle TCHs. it will be assigned to the MS in the queue. and MSC indicates in the assignment message that this MS is allowed to be queued. Description 18 © 2010 ZTE Corporation. then the MS is put in a queue. ZTE Confidential Proprietary . Description In the assignment procedure of call setup or handover. Introduced Version Before V09R1 Enhancement None 4. Queuing time can be set individually for call attempts and for handover. By putting subscribers in queue instead of rejecting it when the radio resources are busy. If there is such an idle channel that matches. this feature increases the success ratio of call setup and handover. BSC will check if there is idle channel that can match some MS’s request in the queue in respect of subcell. and the queuing is allowed in this cell. the queuing function is deactivated. improves the ratio of successful assignment.ZTE GSM BSS Basic Feature Description V10R1 This feature improves the usage of the radio resources. Then in assignment procedure.GSM BSS Basic Feature Description V10R1 When this feature is activated. BSS assigns a TCH channel for MS in immediate assignment procedure. Figure 4-1 Immediate Assignment of TCH On OMCR. All rights reserved. 19 . This is shown in the following graphic. Usually emergent call and call re-establishment are configured to apply this feature. This TCH channel is used as SDCCH to carry the dedicated signallings. Introduced Version Before V09R1 Enhancement None ZTE Confidential Proprietary © 2010 ZTE Corporation. the operator can configure which kind of call can initiate immediate assignment. this channel is modified to a TCH channel to carry user voice data. 2.2 Channel Allocation 4. Description SDCCH is used to transmit system signaling before TCH assignment.1 ZGB-03-02-001 Support of SDCCH/4 and SDCCH/8 Benefits This feature improves the channel utilization ratio by configuring different SDCCH type according to cell traffic. One is combination with BCCH. Description 20 © 2010 ZTE Corporation. 4 SDCCH can be configured in the TS0 of BCCH TRX. Normally SDCCH/4 is only used for a cell with no more than two TRXs. SDCCH/4 and SDCCH/8 can be configured in a cell at the same time or individually. several SDCCH channels can be mapped to one physical channel.2 ZGB-03-02-002 Flexible SDCCH Configuration Benefits This feature allows operator to configure any number of SDCCH in one cell to reduce the risk of SDCCH congestion. In this configuration. such as MS register. while SDCCH/8 means that a whole physical channel is configured to eight SDCCH channels. Introduced Version Before V09R1 Enhancement None 4. and Location Update. In ZTE BSS system. All rights reserved. This kind of SDCCH is called SDCCH/.2. There are two different ways to configure SDCCH. ZTE Confidential Proprietary . As one kind of low data rate logical channel. Authentication.ZTE GSM BSS Basic Feature Description V10R1 4. Which kind of configuration should be used depends on the capacity of a cell. 2. All rights reserved. With the methods provided above. ZTE Confidential Proprietary © 2010 ZTE Corporation. SDCCH can be configured on every TS of one TRX. BSC adjusts the SDCCH number in a cell automatically according to the load of SDCCH. SDCCH can be allocated to every TRX in a cell. and TCH channels are idle according to another threshold set on OMCR. BSC changes one TCH into 8 SDCCHs automatically.GSM BSS Basic Feature Description V10R1 ZTE BSS supports flexible configuration of SDCCH. It reduces the risk of SDCCH congestion and improves the network performance. When the SDCCH channels in a cell are overloaded referring to the threshold set on OMCR. 21 . For an extended coverage cell. Description When this feature is activated. Whether a cell supports frequency hopping or not has no effect on SDCCH.3 ZGB-03-02-003 Dynamic Configuration of SDCCH Benefits This feature reduces call attempt failure caused by busy SDCCH. operator is able to configure SDCCH flexibly according to cell traffic. Introduced Version Before V09R1 Enhancement None 4. SDCCH can be configured on both extended and ordinary TRXs. 4 ZGB-03-02-004 MAC Dynamic Allocation Mode Benefits Dynamic Allocation Mode is defined in 3GPP which is the primary function to introduced PS service. please refer to ZGO-03-02-007 MAC Extended Dynamic Allocation. Introduced Version Before V09R1 Enhancement None 4. Only those SDCCH channels formerly obtained from TCH can be combined into TCH channels. Introduced Version Before V09R1 Enhancement 22 © 2010 ZTE Corporation. This feature supports dynamic allocation. In this way. Description ZTE GSM BSS supports two MAC modes: Dynamic Allocation and Extended Dynamic Allocation. ZTE Confidential Proprietary . The number of downlink PDCHs should be more than uplink PDCHs in Dynamic Allocation mode. the BSS controls the uplink access of multiple MS on a timeslot. BSC combines 8 redundant SDCCH channels into 1 TCH channel to provide more traffic channels. Network allocates one timeslot to more than one MS with specified USF.2.ZTE GSM BSS Basic Feature Description V10R1 When SDCCH channels are idle. With Dynamic Allocation. All rights reserved. For downlink data. the USF information is decoded in RLC/MAC headers to determine which MS is assigned to send radio block in the uplink. For Extended Dynamic Allocation. please refer to ZGB-03-02-005 Static Channel Management. For static channel management. All rights reserved. ZTE Confidential Proprietary © 2010 ZTE Corporation. Likewise.GSM BSS Basic Feature Description V10R1 None 4. There are two kinds of static channels: static TCH and static PDCH. Introduced Version Before V09R1 Enhancement None 4. Description ZTE GSM BSS supports static channel and dynamic channel. not PS service. Description ZTE GSM BSS supports static channel and dynamic channel. please refer to ZGB-03-02-006 Dynamic Channel Management.2. For dynamic channel management. 23 .2. This feature only describes static channel management.5 ZGB-03-02-005 Static Channel Management Benefits This feature provides basic channel management for GSM service. Static TCH is only used for CS service. static PDCH is only used for PS service.6 ZGB-03-02-006 Dynamic Channel Management Benefits This feature provides flexible channel management to improve channel resource utilization. This feature only describes dynamic channel management. channel with degree 1 is assigned first. For example.7 ZGO-03-02-001 Idle Channel Measurement Benefits This feature improves network quality and user satisfaction by providing interference measurement result to assign suitable channel to establish new calls. For dynamic channel allocation priority of PS service. BSS allocates channel dynamically to CS service or PS service based on traffic load. 4. Description BTS measures the idle channel’s interference level and classifies the results into 5 levels. The channel with lowest interference level is considered to be the best. BSC assigns the channel with lowest interference level first. Dynamic channels are allocated to CS service while CS traffic load is high or allocated to PS service while PS traffic is high. please refer to ZGO-03-02-009 Flexible Priority Handling of Packet Data Channel.2. All rights reserved. ZTE Confidential Proprietary . If CS and PS traffic are both high in the same time. Introduced Version Before V09R1 Enhancement None 24 © 2010 ZTE Corporation. During the channel assignment procedure. 3. 5. Introduced Version Before V09R1 Enhancement None 4.ZTE GSM BSS Basic Feature Description V10R1 With this feature. the dynamic channel is assigned to CS service with priority. then reports it to BSC. then degree 2. The optional priority based managements are as following: FR priority HR priority Only FR channel to be allocated Only HR channel to be allocated Transceivers selected according to priority Transceivers are separated into five classes according to the radio parameter and the channels in the transceivers: 1 is the highest priority. ZTE Confidential Proprietary © 2010 ZTE Corporation.2. levels for different users or applications will be in the initial cut into channel management to ensure maximum utilization of spectrum resources. All rights reserved. Channel allocation on speech channel with different rates Several channel allocation manners can be selected in order to control and use the FR and HR channels flexibly. Description This feature supports following channel allocation methods. Different allocation functions have different emphases in order to improve network stability and system capability. 5 is the lowest priority and the default value is 3.GSM BSS Basic Feature Description V10R1 4. The channels of transceivers with high priority are selected by the system first. The operator can optimize the network with customized parameters. 25 . The priority is configured in OMCR. The system supports channel allocation according to the subscriber’s priority.8 ZGO-03-02-002 Enhancement on CS Channel Allocation Benefits With this feature. and the BCCH transceivers are set as the highest priority 1 and other transceivers are set 2 to 5 according the priority in general condition. and handover completion ratio. All rights reserved. followed by level 2. Level 1 is the highest priority. and sets a punishment period in which the interference band will not be updated. call completion ratio. see “ZGO-03-02-001 Idle Channel Measurement”. Channel allocation on interference band The BTS measures the receiving level values of idle channels. It converts the interference averages to the information of corresponding interference bands and sends it to BSC. the channel with interference band 0 will be assigned at last in the channel allocation. 4. As the origin of the handover decision is 26 © 2010 ZTE Corporation. and 5 orderly. BSS always prefers to allocate the high priority TRX when MS requests to access the network. the channel in the different transceivers is selected in priority. Level 1 is the highest priority. When problems such as radio channel cause the channel exception release. the interference band information of the channel is a major factor which should be considered preferentially in the enhanced channel allocation. the BSC sets the interference band of the channel to 0.ZTE GSM BSS Basic Feature Description V10R1 Channel Allocation on TRX Priority The TRX priority is divided into five levels: level 1 to level 5. channels with level 1 interference band will be assigned with priority. ZTE Confidential Proprietary . call drop rate. that is. For example. The priority is divided into five levels: level 1 to level 5. such as call quality. The channel interference affects the key indices of this channel. and calculates the average value in the measurement period (480 ms). Channel allocation on intra-cell handover When handover is caused by the interference in the uplink or downlink. Low-interference channel is preferred in the channel allocation. Therefore. TRX priority is set by operator on OMCR. Channel allocation on TRX priority The enhanced channel allocation algorithm sorts the intra-cell carriers by the background configuration parameter “Same Type Carrier Allocation Priority” (carrier with high priority precedes). It acts as an assignment history record to affect the current channel allocation. 3. The BSC classifies the interference bands of the channel into five levels: level 1 to level 5. For details. Then the channels on other transceivers are allocated according to priority. High priority subscribers can select normal channels allocation in priority or reserved channels allocation in priority. Description ZTE Confidential Proprietary © 2010 ZTE Corporation. which improves the handover success rate. the system is allowed to set several reserved channels. the possibility of interference on the other channels in the transceivers is large.GSM BSS Basic Feature Description V10R1 interference. To control the utilization of the reserved channels flexibly and satisfy the demands of the different subscribers. Channel allocation on reserved channel When service with high user priority is used. but in the feature of eMLPP. channels are reserved only for high priority subscribers. all the subscribers can use the channel.2. The difference from eMLPP is that in this feature. Introduced Version Before V09R1 Enhancement None 4. increases frequency efficiency. and enhances system performance and capacity. The purpose is to decrease the risk of call failure because of the network congestion. system provides two ways: reserved channels are allocated in priority. in another word. All rights reserved. the channel is not reserved.9 ZGO-03-02-003 Enhancement on PS Channel Allocation Benefits Enhanced PS channel allocation improves PS user’s throughput. but high priority subscriber will be allocated first when congests. and other channels are allocated in priority. 27 . there is interference in the current transceivers. The operator can optimize the network with customized parameters. the EDGE downlink rate will be limited due to the limitation of coding method (8 psk to GSMK). With this way. increasing user throughput. For empty and queue on GBR service. BSS always prefers to allocate the high priority TRX when MS requests to access the network. reduces requirement on the other dynamic channel and avoids the PDCH preemption by CS service when traffic load is high.ZTE GSM BSS Basic Feature Description V10R1 This feature supports following channel allocation methods. please refer to ZGO-03-02-009 Flexible Priority Handling of Packet Data Channel. PCU tries empty and queue as eMLPP. When current available resource is hard to satisfy the GBR. secondly. Introduced Version 28 © 2010 ZTE Corporation. Level 1 is the highest priority. For PS preference dynamic channel. allocate static PDCH. In order to avoid this scenario. ZTE Confidential Proprietary . Channel allocation on TRX priority The TRX priority is divided into five levels: level 1 to level 5. This method improves the utilization on static and PS preference channel. please refer to ZGO-01-02-004 Streaming Service Policies. New TRX will be allocated for PS service only when service TRX load exceeds the load threshold. All rights reserved. allocate other dynamic channel. Firstly. BSS balances the CS/PS service and resource. Channel allocation on EGPRS/GPRS scheduling conflict When the GPRS uplink and EDGE downlink multiplex the same radio channel. BSS allocates the channel with following order. Channel allocation on user’s throughput maximum PCU allocates channel resource as much as possible according to the MS multi-slot class and system capacity. avoiding PS service occurred TRX overly. allocate dynamic channel with PS preference. and assigns the channel to MS without conflict. and last. Channel allocation on PDCH preference For PS service. Channel allocation on Guarantee Bit Rate (GBR) PCU allocates the channel resource to fulfill the GBR of streaming or conversational service. TRX priority is set by operator on OMCR. Channel allcocation on TRX load BSS limits TRX number that allocated to MS by TRX load. BSS allocates the channel considering the conflict preferentially. ZTE BSS system supports 2Mbps high speed signaling link. 29 . and meets the requirement of large capacity networking. Maximal 16 high speed links can be configured for one signaling point pair. which means there are maximal 16 signaling links between two signaling points.1 ZGB-03-03-001 2M High Speed Signaling Link Benefits This feature extends the bandwidth of system signaling link on A/Ater interface. When the narrowband 64Kbps signaling link is used. TS0 is used for synchronization. Introduced Version Before V09R1 Enhancement None ZTE Confidential Proprietary © 2010 ZTE Corporation.GSM BSS Basic Feature Description V10R1 Before V09R1 Enhancement None 4. This field has 4 bits. the signaling link between different signaling points is identified by the Signaling Link Selection (SLS) field of signaling routing label. All rights reserved. In one 2M signaling link.984M bandwidth. It limits the processing capacity of one BSC. It extends the bandwidth of signaling link and meets the requirement of large capacity networking. the total bandwidth between BSC and MSC is only 16*64Kbps.3. Description In GSM network. TS1-TS31 is combined as one signaling link with 1.3 Circuit Management 4. With this feature. in chain network.ZTE GSM BSS Basic Feature Description V10R1 4.3 ZGB-03-03-003 LAPD Cluster Benefits This feature saves the transmission resource of Abis interface. Introduced Version Before V09R1 Enhancement None 4. especially for large capacity sites. E1 interface can hop to next BTS interface unit automatically to ensure the normal function of other BTSs. Description Enhanced E1 link between BSC and BTS supports the 75Ωand 125Ωimpedance input. and E1 link impedance).3. This feature supports more E1 links.3.2 ZGB-03-03-002 Enhanced E1 Link between BSC and BTS Benefits This feature enhances E1 transmission function (the number of E1 link. Description 30 © 2010 ZTE Corporation. ZTE Confidential Proprietary . This feature also supports automatic bridge function of E1 interface. supports 2km-transmission or even longer distance with unbalanced E1. E1 link distance. This feature enhances E1 transmission. For example. if BTS interface fails. All rights reserved. as many as 16 E1 links. network planning and implementation becomes easier. 3. As a result. According to the LAPD signaling traffic. Description ZTE Confidential Proprietary © 2010 ZTE Corporation. The time slots used for LAPD cluster work in load-sharing mode. The detailed bandwidth requirement of LADP Cluster is shown in following table. the signalling on other time slots are not affected. 31 .GSM BSS Basic Feature Description V10R1 After this feature is deployed. the LAPD links of the two racks are multiplexed together. Table 4-1 Bandwidth Requirement of LADP Cluster TRX Timeslot Number Number Bandwidth Peak Rate of Signaling 6 1 64kbps 0~30kbps 7~16 2 128kbps 30~75kbps 17~26 3 192kbps 75kbps~120kbps 27~36 4 256kbps 120kbps~180kbps Introduced Version Before V09R1 Enhancement None 4. 1 to 4 64kbps time slots are allocated to one site. all LAPD signaling of one site is multiplexed on several 64kbps time slots rather than allocating one LAPD time slot for one TRX.4 ZGB-03-03-004 TC Resource Dynamic Sharing Benefits This feature makes the configuration of TC irrelevant to the codec types and distribution of MSs in the network. When one of the time slots fail. This feature enhances the LAPD processing capability of BSC and saves the transmission of Abis interface. All rights reserved. the configuration of TC is simplified and the hardware cost of TC is reduced. If a site has two racks. And the processing ability for these codec types is the same. If Remote Transcoder feature is deployed. When fault process is recovered. Description PCU process resources are dynamically allocated to cell when BSS is initialized. TC resources are dynamically shared not only in one BSS. MSC informs BSS of the voice rate and voice codec type supported by this MS in Assignment Request or Handover Request message. BSC chooses a codec type for this call and allocates TC resource. With this feature.5 ZGB-03-03-005 PCU Resource Dynamic Allocation Benefits PCU resource dynamic sharing saves the PCU resources. cell and PCU resources are not fixedly mapping anymore. TC configuration is irrelevant to the distribution of MSs in the network. All rights reserved. ZTE BSS TC resources are not allocated to radio channel resource statically. but also in multiple BSSs. When some of the PCU processing resources break down. but are shared by all radio channels. If a PCU process resource fails. which increases reliability of PCU.3. the PS service of cell attached on the processing resource will be dynamically switched to other processing resources. Introduced Version Before V09R1 Enhancement None 4. the system re-assigns the cell 32 © 2010 ZTE Corporation. As a result. When a call is initiated.ZTE GSM BSS Basic Feature Description V10R1 ZTE BSS TC unit supports 5 codec types: FR/EFR/HR/AMR-FR/AMR-HR. the system attaches new PCU process resource to take over the fault process. the MS reports its bearer capability and the Class Mark to the network. reduces the cost of PCU resource. and saves investment. ZTE Confidential Proprietary . when BSC detects that the CPU usage is too high. when BSC application layer receives overload message from BSC signalling transportation layer. 33 . BSS selects the lowest load process to serve the cells one by one till every cell is attached completely. Description This feature deals with these 3 types of overload: MSC overload: that is. The number of cell serving this process does not exceed the maximum capacity. Signalling overload: that is. ZTE Confidential Proprietary © 2010 ZTE Corporation. CPU overload: that is.4.1 ZGB-03-04-001 BSC Load Control Benefits This feature guarantees the BSS system stability during the traffic surge by means of selective rejection of service requests.4 Reliability 4. All rights reserved.GSM BSS Basic Feature Description V10R1 with load balance. when BSC receives OVERLOAD message via A interface. Introduced Version V09R2 Enhancement None 4. The number of PDCH serving this process does not exceed the maximum capacity. no failure. BSS performs dynamic allocation when the target process fulfills the following conditions: The process is working normally. 4. BSC sets the threshold that how many paging can be dealt with. the FUC module of BTS stops some MSs from accessing the network according to the RACH random value of MSs The BSC load control function adopts ZTE patent algorithm. BSC applies the following 2 methods to reject some service requests to maintain system stability: Access class control: that is.4.ZTE GSM BSS Basic Feature Description V10R1 In overload cases. new request received later will be discarded. stop some MSs from accessing the network by sending (Access Control Class N ACCN) in system information FUC control: that is. BHCA control. new paging messages will be discarded. All rights reserved. Introduced Version Before V09R1 Enhancement In V10R1 BSC load control is enhanced by paging flow control and BHCA control. There are two methods used to do paging flow control. Description 34 © 2010 ZTE Corporation. ZTE Confidential Proprietary .2 ZGB-03-04-003 BTS Recovery Benefits This feature enables BTS to restore the service immediately after the recovery of broken Abis transmission link. channel request threshold can be set via OMC-R. when BSC receives more channel requests from Abis. It reduces the service outage time. Priority based paging flow control. BSC will discard paging messages of low priority subscribers when CPU load reaches the threshold set via OMC-R Paging message number based flow control. if paging messages reach this threshold. 4. BTS provides Dry Contact Alarm input and output interfaces. The OMCR’s Alarm Management terminal shows these alarms. BSC can monitor whether other equipments are functioning well without extra transmission. system monitors other equipments to ensure the BSS system stability.3 ZGB-03-04-004 Dry Contact Alarm Benefits With this feature. and sends to BSC. Description With this feature. Introduced Version Before V09R1 Enhancement None 4. Alarm type includes water alarm. fire alarm. BTS sets the service status as “unblock”. BTS collects these alarm messages. smoke alarm and intruder alarm. 35 . All rights reserved. Introduced Version Before V09R1 Enhancement None ZTE Confidential Proprietary © 2010 ZTE Corporation. When Abis transmission recovers.GSM BSS Basic Feature Description V10R1 BTS detects Abis status automatically and sets the service status as “block” after Abis transmission is broken. Thus the service recovers. etc. After the check. Operator can define Dry Contact Alarm type in alarm management module. All these alarm signals are connected with BTS through Dry Contact Alarm connector. BTS applies parameter refresh for BSC and checks the parameter with that locally set. Network can choose the Coding Scheme depend on data rate requirement and radio channel quality.ZTE GSM BSS Basic Feature Description V10R1 4. Description GPRS offers a number of coding schemes with different levels of error detection and correction.4.1 ZGB-03-05-001 Coding Scheme CS1~CS4 Benefit This feature provides basic Packet Service for GPRS network. CS-1 has the strongest error correction capability and has lowest requirement 36 © 2010 ZTE Corporation. BTSs of different versions can co-exist in the same network. This procedure helps BSS to keep compatible to all previous versions of BTS. CS-2. ZTE Confidential Proprietary . Introduced Version Before V09R1 Enhancement None 4. Description BTS reports current software version to BSC via Abis interface after reboot.5 GPRS/EDGE 4. CS-3 and CS-4 four types of coding scheme.4 ZGB-03-04-006 Backward Compatibility for BTS Benefits This feature saves the investment on upgrading and reduces the impact on the existing network.5. All rights reserved. The operator can upgrade BSC and some BTSs to deploy new features in some area without upgrading the BTSs in other parts of the network. There are CS-1. The following data rates are calculated theoretically based on the selected coding scheme depending on C/I: Table 4-2 Coding Scheme CS1-CS4 Coding Scheme Modulation Data throughput per timeslot (kbps) RLC/MAC data throughput per timeslot (kbps) CS-1 CS-2 CS-3 CS-4 GMSK GMSK GMSK GMSK 9. It effectively uses a 2/3 encoder and results in data throughput of 13. and results in data throughput of 9. 171.2kpbs data throughput can be achieved. It is used in scenarios when interference levels are high or signal levels are low. CS-4 offer highest data throughput and have the weakest error correction capability. CS-2: This coding scheme is used for better channel quality. CS-3: This coding scheme uses 3/4 encoder.4 20 CS-1: This coding scheme applies for the highest level of error detection and correction. All rights reserved.05 kbps. Introduced Version BeforeV09R1 Enhancement None ZTE Confidential Proprietary © 2010 ZTE Corporation.GSM BSS Basic Feature Description V10R1 for radio environment. To the opposite. data is not necessarily been re-sent too often.4kbps data throughput.4 kbps.4 8 12 14. without error correction it can result in 21. So for MS using maximum 8 timeslots. CS-1 uses 1/2 encoder.4 15.05 13. CS-4: This coding scheme is used in good channel condition which has very weak interference. When applying CS-1. to result in 15. but it offers the minimum data throughput. 37 .6 21.6kbps data throughput. so it needs highest C/I. It can reduce the time to adjust to the optimal coding scheme and increase the data rate.5. the coding scheme will be optimized according to the quality information reported by the MS and BTS. When the MS set up the Temporary Block Flow (TBF) connection. Description The initial coding scheme of PS user assignment can be set from OMCR based on cell level. Introduced Version BeforeV09R1 Enhancement None 4. All rights reserved. The coding scheme settable can provide MS with optimized access data rate and make fully use of network resources. by cell level configuration to differentiate GPRS and EGPRS service parameters. network user can set an initial coding scheme which is very close to optimal coding scheme for the cell. By analyzing the overall channel quality condition. ZTE Confidential Proprietary . the link quality and C/I are reported to BSC after a period of time. thus improving subscriber satisfaction.2 ZGB-03-05-002 Initial Coding Scheme Per Cell Settable Benefit This feature offers operator capability to set initial coding scheme of MS based on network condition.3 ZGB-03-05-005 8/11 bit Access Burst Benefits 8 bit access is the primary access mode of PS service and 11 bit access shortens the access delay and increases the throughput of EGPRS MS.5. And after the period. Description 38 © 2010 ZTE Corporation. during which the MS will use the coding scheme initially settled by the network.ZTE GSM BSS Basic Feature Description V10R1 4. A Class B mobile can make or receive a ZTE Confidential Proprietary © 2010 ZTE Corporation. B and C. The MS shall support both random access bursts. thus can use one phase access to reduce the access delay. Introduced Version Before V09R1 Enhancement None 4. All rights reserved. 11 bit access burst includes extend parameters such as MS multi-slot class.5. Please refer to ZGB-03-05-007 One Phase Access for the description on the one phase access. Class B: This class mobile can be attached to both GPRS and GSM services but they can be used with only one service at a time. The three types of mobiles are Class A. C MS Benefit This feature provides support for PS basic service. 39 . PSI13 and SI13 to indicate which access type MS shall adopted. Description Not all GPRS mobiles are designed to offer the same levels of service. 8 bit access is the primary access burst. B. BSS broadcasts the access type in system message PSI1. GPRS network can support the three types of mobiles connection and provides differentiated services to different types of MSs. which are described as the following: Class A: This class describes mobile phones that can be connected to both GPRS and GSM services at the same time.4 ZGB-03-05-006 Class A.GSM BSS Basic Feature Description V10R1 Two types of packet random access burst are supported in GERAN network: 8 bits random access burst and 11 bits random access burst called the extended packet random access burst. In fact they are split into three basic categories according to their capabilities to connect to GSM and GPRS network. to allow MS with certain capability to quick access to packet network. the MS is asked to send the TLLI in the begin RLC block after it receives the uplink assignment message. MS initiates one phase access mode and requests one phase access in the “Channel Request” or “Packet Channel Request” message. the GPRS service will be suspended and will be re-established automatically after the voice call or SMS session is completed. If this TLLI value is 40 © 2010 ZTE Corporation. For the uplink direction. After receiving the first RLC block. to reduce latency.5. During voice call or SMS session. ZTE Confidential Proprietary . network side will fill the TLLI in PACKET UPLINK ACK and send to MS. Description The packet access procedure using CCCH may be used to establish a Temporary Block Flow (TBF) to support the transfer of LLC PDUs in the direction from MS to network or from network to MS. Network sends MS a packet uplink assignment message carrying information about resources allocated to MS.ZTE GSM BSS Basic Feature Description V10R1 voice call. Class C: This classification covers mobiles that can be attached to either GPRS or GSM services but user needs to switch manually between the two different types. MS receives this ACK message and get the TLLI value. All rights reserved. or send or receive a SMS message during a GPRS connection. To handle the competition. Introduced Version Before V09R1 Enhancement None 4.5 ZGB-03-05-007 One Phase Access Benefit This feature provides support for PS basic service. One phase access reduces initial TBF setup time by reducing signalling procedure and to improved packet access speed. Resource competition may be happened when different MSs request the channel at same time. there are two types of packet access: one phase access and two phase access. they are chosen based on MS access reason or network can force MS to use two phase access. to ensure GPRS/EGPRS capable MS access to network. Description The packet access procedure using CCCH may be used to establish a Temporary Block Flow (TBF) to support the transfer of LLC PDUs in the direction from MS to network or from network to MS. All rights reserved. Introduced Version BeforeV09R1 Enhancement None 4. Then the one phase access procedure is completed. it means the radio resource is allocated to this MS.5. Two phase access has complexer signalling procedure than one phase access. If two phase access is initiated by MS. MS with one phase access conditions can quick access to GPRS network to have improved performance on latency. Normally. cell update and MM layer messages through TBF establishment By this feature. The network sends a “Packet Uplink Assignment” message containing single block assignment to MS to instruct second ZTE Confidential Proprietary © 2010 ZTE Corporation. For the uplink direction. there are two types of packet access: one phase access and two phase access. One phase access can be used directly if the requested RLC mode is acknowledged mode and the amount of data need to be transferred is less than 8 RLC/MAC blocks. MS requests one phase access when transmitting paging response. MS turns to packet transfer mode. MS send two phase access request in the “Channel Request” or “Packet Channel Request” message.GSM BSS Basic Feature Description V10R1 identical with its own value sent to network side.6 ZGB-03-05-008 Two Phase Access Benefit This feature provides support for PS basic service. 41 . ZTE GSM BSS Basic Feature Description V10R1 phase access. Description 42 © 2010 ZTE Corporation. ZTE Confidential Proprietary . System can also be configured as “Force Two Phase Access”. the competition solution on the MS side also ends if TLLI in this message is identical with that in the “Packet Resource Request” message from MS.. Then MS sends a “Packet Resource Request” message on the allocated single block. the MS can choose. by the information to effectively allocate radio resources. two phase access procedure ends and MS switches to packet transmission mode. The competition solution on the network side ends after the network receives TLLI used to identify MS. then MS has to use two phase access no matter acknowledge mode or unacknowledged mode. After MS receives the “Packet Uplink Assignment” message.5. The two phase access will be used in situations when the requested RLC mode is unacknowledged mode or the RLC mode is acknowledge mode and the data need to be translated is more than 8 RLC/MAC blocks. Introduced Version BeforeV09R1 Enhancement None 4. for EGPRS TBF mode capable MSs (in an EGPRS capable cell). by the second phase access. to attach to GPRS services. network can acquire the MS capability such as Extended Uplink TBF Mode etc. according to its capabilities. Comparing with one phase access. the network returns a “Packet Uplink Assignment” message in response. After the competition solution succeeds. All rights reserved. or to both. In addition. Upon receiving the message. the network will force MS to adopt two phase access mode after receiving the “Channel Request” or “Packet Channel Request” message from MS and ignore the request reason of MS.7 ZGB-03-05-009 Network Mode of Operation (NMO) 1~3 Benefits Based on the mode of operation provided by the network. if the cell does not support EGPRS PACKET CHANNEL REQUEST. to non-GPRS services. and is provided ZTE Confidential Proprietary © 2010 ZTE Corporation. Table 4-3 Three Network Operation Modes Mode I II III Circuit Paging Channel Paging Co- GPRS Paging Channel Packet Paging Channel Packet Paging Channel CCCH Paging Channel CCCH Paging Channel Packet Data Channel Not Applicable CCCH Paging Channel CCCH Paging Channel CCCH Paging Channel Packet Paging Channel CCCH Paging Channel CCCH Paging Channel ordination Yes No No When the Gs interface is available. all MSC-originated paging of GPRS-attached MSs shall go via the SGSN.GSM BSS Basic Feature Description V10R1 According to 3GPP standards. and that CS paging continues on this paging channel even if the MS has been assigned a packet data channel.Network operation mode III: the network sends a CS paging message for a GPRSattached MS on the CCCH paging channel.e. the packet paging channel or the CCCH paging channel). This means that the MS needs only to monitor the CCCH paging channel.. . All rights reserved.Network operation mode I: the network sends a CS paging message for a GPRSattached MS. and this channel is also used for GPRS paging. This means that the MS needs only to monitor one paging channel. either on the same channel as the GPRS paging channel (i. .Network operation mode II: the network sends a CS paging message for a GPRSattached MS on the CCCH paging channel. three network operation modes are defined. Paging coordination shall be made by the SGSN based on the IMSI. or on a GPRS traffic channel. This means that an MS that wants to receive paging for both circuit-switched and packet-switched services shall monitor both paging channels if the packet paging channel is configured in the cell. and sends a GPRS paging message on either the packet paging channel (if configured in the cell) or on the CCCH paging channel. thus allowing network co-ordination of paging. and that it receives CS paging messages on the packet data channel when it has been assigned a packet data channel. 43 . . No paging co-ordination is performed by the network. II. which helps to improve efficiency of timeslot.5. the mode of network operation should be the same in all cells of a routing area. all MSC-originated paging of GPRS-attached MSs shall go via the A interface. and co-ordination of paging cannot be performed.8 ZGB-03-05-011 Timeslot Multiplexing Benefits GPRS service has different timeslot allocation strategies from voice service. When the Gs interface is not available.ZTE GSM BSS Basic Feature Description V10R1 independently of whether the MS is in STANDBY or in READY state. meaning that the packet common control channel shall be used for GPRS paging when the packet paging channel is configured in the cell. All rights reserved. The network operation mode (mode I. Description GPRS timeslot allocation is different from voice service. For proper operation. ZTE Confidential Proprietary . Introduced Version Before V09R1 Enhancement None 4.operate in mode III. meaning that the packet common control channel shall not be configured in the cell. And several MSs are able to use one time slot simultaneously to maximize the timeslot efficiency. or III) is indicated in system information to MSs. While GPRS time slots are allocated on uplink and downlink respectively according to data transfer requirements. or .operate in mode II. 44 © 2010 ZTE Corporation. The network shall then either: . The time slots for uplink and downlink voice are allocated simultaneously and they will be used exclusively by a MS till the call is terminated to release them. The network operates in mode I. 9 ZGB-03-05-012 GPRS Link Adaptation Benefits This feature improves the adaptation of the link and increases the system throughput efficiently. All rights reserved. different link adaptation algorithm models are designed The threshold consists of the switching points between four coding schemes: CS-1.GSM BSS Basic Feature Description V10R1 Introduced Version Before V09R1 Enhancement None 4. Introduced Version Before V09R1 Enhancement None 4. to make the user choose an optimal link adaptation algorithm model according to the overall conditions of channel quality.10 ZGB-03-05-013 Delayed TBF Release in DL Benefits ZTE Confidential Proprietary © 2010 ZTE Corporation. CS-3 and CS-4. BLER and BER. 45 improving . These switching points between coding schemes are configurable.5. According to different evaluated parameters: C/I. Description The link adaptation algorithm compares the estimated channel quality with threshold preset in the OMC-R in order to select appropriate coding scheme.5. It is set in BSC parameters settings. CS2. hence the efficiency of link adaptation. During this period of time. and the idle BIT in the RLC block is filled with filling bit. the connection will be released. Otherwise the TBF connection will be released. After a period of time. it sets up and releases the radio resource frequently. if it doesn’t yet have any new downlink or uplink traffic request. it postpones sending PACKET UPLINK ACK with FAI=1 message. Introduced Version Before V09R1 Enhancement None 4. ZTE Confidential Proprietary .11 ZGB-03-05-014 Delayed TBF Release in UL Benefits When the GPRS channel carries the burst IP traffic. Description When BSS receives RLC block with CV=0 sent by MS. while TBF’s release and setup takes some time and occupies radio interface resource. it immediately transfers the data over the existing RLC link. FBI is not set to 1.5. which causes high signaling load and decreases the data transfer efficiency. it sets up and releases the radio resource frequently. TBF’s release and setup takes some time and occupies radio interface resource. 46 © 2010 ZTE Corporation. Description When BSS sends the last RLC block.ZTE GSM BSS Basic Feature Description V10R1 When the GPRS channel carries the burst IP traffic. sending the virtual LLC frame periodically to keep connection. Otherwise it will transfer the data over the existing RLC link immediately. which causes high signaling load and decreases the data transfer efficiency. The delayed TBF release in DL avoids the unnecessary procedure of TBF setup and release so as to improve the GPRS data transfer performance. All rights reserved. if there is new downlink or uplink traffic request. The delayed TBF release in DL avoids the unnecessary procedure of TBF setup and release so as to improve the GPRS data transfer performance. Description ZTE GSM BSS support two RLC modes defined in 3GPP: RLC acknowledged mode and RLC unacknowledged mode. This mechanism ensures the transmission reliability of the RLC data blocks. TBF can’t be released until each data block transmitted on the TBF is complete and acknowledged. All rights reserved. is not required to be resent by sender. The RLC mode of the uplink TBF is dependent on the service type requested by the MS and the RLC mode of the downlink TBF is dependent on the RLC mode in the QoS parameters contained in the downlink LLC PDU. Introduced Version Before V09R1 Enhancement ZTE Confidential Proprietary © 2010 ZTE Corporation. 47 .12 ZGB-03-05-015 RLC Acknowledged/ Unacknowledged Mode Benefits The feature is the basis for introduction of PS service.5. RLC acknowledged mode: each data block transmitted on the TBF should be acknowledged by receiver. The sender shall resend the blocks indicated lost by receiver. The data block. however. RLC unacknowledged mode: the receiving party acknowledges the received RLC data blocks as in RLC acknowledged mode. The TBF is released after the data transmission is complete although maybe some data are lost during the transmission.GSM BSS Basic Feature Description V10R1 Introduced Version Before V09R1 Enhancement None 4. the downlink flow control is introduced. In order to balance the throughput between Gb interface and Um interface. Downlink flow control includes downlink BVC flow control and downlink MS flow control. Description Gb interface and Um interface have different data transmission rate. the default MS bucket size. There is a downlink buffer for each BVC. The principle of the downlink flow control procedure is that PCU sends flow control parameters to SGSN which allow SGSN to locally control its transmission output in the direction from SGSN to PCU.5. the default MS leak rate and etc. identified as BVCI. PCU reports to SGSN the flow control parameters including the size of the maximum bucket of each BVC cell. Based on the reported parameters. For downlink MS flow control. Furthermore.13 ZGB-03-05-016 Downlink BVC Flow Control Benefits This feature is a basic feature of PS services. in a PCU. The BVC flow control mechanism controls the loading of the BSS LLC PDU queues per BVCI between SGSN and BSC in the downlink direction. Introduced Version Before V09R1 48 © 2010 ZTE Corporation.ZTE GSM BSS Basic Feature Description V10R1 None 4. SGSN adjusts the downlink data rate of the cell to implement the flow control to prevent frequent data loss caused by congestion or transmission interruption due to insufficient flow. All rights reserved. the multi-slot capability of the MS and traffic load in the cell. the cell leak rate. ZTE Confidential Proprietary . the downlink throughput on the Um interface is unstable that is impacted by various factors such as radio quality. Throughput on the Gb interface is greater than that on the Um interface. please refer to “ZGB-03-05-017 Downlink MS Flow Control”. It prevents link congestion and improves service quality. This feature only describes the downlink BVC flow control. the size of the maximum bucket of each MS and MS leak rate. The downlink data from SGSN to MS is buffered by PCU. 49 . Downlink flow control includes downlink BVC flow control and downlink MS flow control.GSM BSS Basic Feature Description V10R1 Enhancement None 4. Introduced Version Before V09R1 ZTE Confidential Proprietary © 2010 ZTE Corporation. It prevents link congestion and improves service quality. the downlink flow control is introduced. the multi-slot capability of the MS and traffic load in the cell. For downlink BVC flow control. SGSN adjusts the downlink data rate of the MS to implement the flow control to prevent frequent data loss caused by congestion or transmission interruption due to insufficient flow. Description Gb interface and Um interface have different data transmission rate. the downlink throughput on the Um interface is unstable that is impacted by various factors such as radio quality. PCU reports to SGSN the flow control parameters. All rights reserved.5. Based on the reported parameters. Furthermore. including the TLLI identifying the MS. In order to balance the throughput between Gb interface and Um interface. The throughput on the Gb interface is greater than that on the Um interface.14 ZGB-03-05-017 Downlink MS Flow Control Benefits This feature is a basic feature of PS services. please refer to ZGB-03-05-016 Downlink BVC Flow Control. This feature only describes the downlink MS flow control. The MS flow control mechanism controls the loading of the BSS LLC PDU queues per MS between SGSN and BSC in the downlink direction. The principle of the downlink flow control procedure is that PCU sends flow control parameters to SGSN which allows SGSN to locally control its transmission output in the direction from SGSN to BSC. Because access on CCCH does not need dedicated PCCCH channel. An MS initiates PS access by sending a (Packet) channel request on RACH.ZTE GSM BSS Basic Feature Description V10R1 Enhancement None 4. Description 50 © 2010 ZTE Corporation. and the network responds on AGCH to start PS transfer. ZTE Confidential Proprietary . providing more timeslots for traffic and increasing system capacity. so the control channel can be reduced and more timeslots can be used for traffic. All rights reserved. and the other is on PCCCH. Introduced Version Before V09R1 Enhancement None 4.15 ZGO-03-05-003 EGPRS Packet Channel Request on CCCH Benefits This feature enables MS to access the network with packet channel request on CCCH.5. and cell configuration is optimized. one is on CCCH. Description There are two ways to access the network for PS service.16 ZGO-03-05-007 EGPRS Activation per Cell Benefits This feature enables EGPRS network configured flexibly to make use of radio resource more effectively and efficiently. the number of traffic channel is increased to carry more PS traffic.5. This improves the signal quality and diminishes the effects of fading. With the flexible mechanism. According to ZTE’s receiving diversity algorithm.1 ZGB-04-01-001 Receiving Diversity Benefits This feature relieves the impact of interference due to fading as well as smoothes the received signal and contributes to a more reliable and cost efficient network.GSM BSS Basic Feature Description V10R1 Each cell managed by BSS can be configured to support EGPRS when EGPRS function is introduced. it improves the receiving sensitivity and system voice service quality. All rights reserved. which means some cells can be enabled for EGPRS service while some cells are disabled for EGPRS service. Description Receiving Diversity is a coverage enhancement technology. Introduced Version Before V09R1 Enhancement None 5 Network Performance 5.1 Coverage Enhancement 5. the operator can select whether or not to activate the EGPRS function in every cell according to subscribers’ request. Each cell has two antennas independently to receive the same signal. ZTE Confidential Proprietary © 2010 ZTE Corporation.1. 51 . Each signal is independently influenced by fading. It achieves by having two antennas independently receive the same signal. It amplifies the received signals before they go into the cable. This feature can be used with ZGO-04-01-002 Delay Diversity Transmission (DDT) or ZGO-04-01-003 Dual Power Combining Transmission (DPCT) to keep the balance of uplink and downlink. and blocks the corresponding carrier when alarms occur. Together with downlink coverage enhancement technology. BTS provides external interface to TMA and monitors the TMA working status. IRC technology is more suitable for environment where uplink interference is very strong.2 ZGB-04-01-002 Support Tower Mounted Amplifier (TMA) Benefits This feature enhances uplink receiving sensitivity. All rights reserved. BTS reports the alarm to OMCR. TMA will give 2-3 dB uplink gain to enlarge the coverage. For example: in an urban area where there is frequent frequency multiplexing. When the voltage is abnormal. ZTE Confidential Proprietary .1. Introduced Version Before V09R1 Enhancement None 5. BTS provides power supply to TMA and monitors the TMA working voltage.ZTE GSM BSS Basic Feature Description V10R1 There are two algorithms for the receiving diversity: Max Rate Combining (MRC) and Interference Rejection Combining (IRC). it enlarges the coverage of the site. Introduced Version Before V09R1 52 © 2010 ZTE Corporation. Description Tower Mounted Amplifier (TMA) is a low noise amplifier device which is installed close to receiving antenna on the top of the tower. and quickly optimizes the whole network. If merely TCH timeslots or some certain TRXs are to be blocked. service will be handed over to other unblocked TRXs in this cell with priority. but if the cell is blocked entirely. Blocking will not start until there is no service in these pending cells. When the channel is detected an error. Introduced version Before V09R1 Enhancement None ZTE Confidential Proprietary © 2010 ZTE Corporation. TRXs or TCH timeslots. The length of time delay to block can be set.GSM BSS Basic Feature Description V10R1 Enhancement None 5. All rights reserved. forced handover to other TCH timeslots will be executed to hold the ongoing calls and delay the blocking. service will be handed over to its best neighboring cell only. Description When blocking cells. TRXs or TCH timeslots manually. TRXs or TCH timeslots.2 Network Quality Improvement 5. TRXs or TCH timeslots and if there are ongoing calls in these pending cells.2. 53 .1 ZGB-04-02-001 Traffic Hold at Channel Blocking Benefits This feature increases the service performance of the network and decreases the call drops caused by system maintenance. the ongoing call on the channel will be released before channel blocking. new calls will not be assigned to these pending cells. after the delay the failed handover calls will be forced release. the power level 0 means the maximum output power.ZTE GSM BSS Basic Feature Description V10R1 5. Description The purpose of static power control is to meet the requirement of various coverage scenarios and reduce the interference. the static power of one TRX can be configure from 1W to 80W if the maximal allowed power of this TRX is 80W.2 ZGB-04-02-002 Static BTS Power Control Benefits This feature allows the operator to adjust the cell coverage according to the requirement of network planning and optimization. If dynamic power control is enabled.3 ZG0-04-02-019 Discontinuous Reception (DRX) Benefits This feature helps to save the battery power of MS in idle mode. For example. Introduced Version Before V09R1 Enhancement From V09R2. ZTE BTS supports downward adjustment of its maximum output power with 6 levels by 2dB/per step within an error of ± 1dB. The actual absolute output power of each level of static RF power (N) must be 2 × NdB lower than the absolute output power of the static RF power level 0. the static power of ZTE SDR can be adjusted by step of one watt. BTS can further adjust the output power according to the radio link quality. static power usually remains unchanged. 54 © 2010 ZTE Corporation. It reduces the interference between different cells and improves the efficiency of frequency utilization. All rights reserved. but certainly allows necessary adjustment yet.2. Upon completion of network planning and configuration. TRX transmits signal with the configured output power. Static power control is configured according to the maximum BTS output power and network planning results. ZTE Confidential Proprietary . 5.2. All rights reserved.1 ZGB-05-02-001 Automatic Bridge in BTS Chain Networking Benefits The Chain networking saves transport resources compared to star or tree connection.1 Flexible Networking 6. The group in which an MS resides is known locally at both the MS and the BSS. Description ZTE Confidential Proprietary © 2010 ZTE Corporation.1. Introduced Version Before V09R1 Enhancement None 6 Transmission 6. This feature improves the reliability of the transport resources by decreasing impact of faults.GSM BSS Basic Feature Description V10R1 Description The BSS divides the MSs within a cell into groups. thus the battery power of MS is saved. Thus both the BSS and the MS know when relevant page requests will be sent and the MS can power down for the period when it knows that page requests will not occur. All paging requests to each group are scheduled and sent at a particular time which is derived from the TDMA frame number in conjunction with the IMSI of the MS and some BCCH transmitted data. 55 . The IMSI is always used to identify the paging population. The page request contain the IMSI or the TMSI in order to identify the MS concerned. But compared to star networking. Star networking is most commonly seen in the actual network which is also mostly recommended. The following figure shows the possible link configurations on Abis interface between BSC and BTS: star. ZTE Confidential Proprietary . tree and chain networking. Description ZTE GSM BSS supports Star. Automatic Bridge Circuit over E1 link is activated to bypass the failing BTS and ensures that the downstream BTS can run normally. Introduced Version Before V09R1 Enhancement None 6. etc. BTS communicates with BSC by E1 interface. Then the E1 link bypasses the failed BTS and ensures the connection of downstream BTSs to BSC without any impact.2 ZGB-05-02-002 Star.ZTE GSM BSS Basic Feature Description V10R1 BTS supports Chain networking to BSC.1. A suitable connection type is to be chosen to save the leased line costs according to actual situation. All rights reserved. the Automatic Bridge Circuit is activated. If an upstream BTS is in severe failure. Star networking has simple topology and most reliable on transmission. In case one BTS is failing. tree and chain networking are of less reliablity and more complicated which are often used for situations with restricted transmission. and Chain Networking Benefit This feature provides flexible networking topology for BSC and BTS. Tree. tree and Chain connection on Abis interface between BTS and BSC. The depth of chain is less than 8. 56 © 2010 ZTE Corporation. such as transmission path and BTS location and capacity. whereas tree and chain networking are of higher multiplexing of the transmission resources and cost saving on it. Distributed BTS uses fiber to connect baseband processing parts and radio processing parts.1. Baseband processing parts are set in equipment room to make maintenance easily. tree and Chain Networking Introduced Version Before V09R1 Enhancement None 6. Description Distributed BTS consists of baseband processing parts and radio processing parts.3 ZGO-05-02-031 Distributed Architecture of BTS Benefits This feature saves equipment room and reduces cable loss and increases power output in antenna port. ZTE Confidential Proprietary © 2010 ZTE Corporation. Digital technology is adopted and no signal distortion happened in between two parts. 57 transmission . All rights reserved. and radio parts are set close to antenna to reduce cable loss.GSM BSS Basic Feature Description V10R1 Figure 6-1 Star. 703. GPS Clock Synchronization BSC supports GPS clock synchronization. Description In order to satisfy different application scenarios’ demands. including E1/T1.544Mbps.2 Synchronization 6. BITS clock reference quality should be in accordance with ITU G. 58 © 2010 ZTE Corporation. It traces and locks the clock. BITS Clock Synchronization Electrical interface of Building Integrated Timing Supply System (BITS) is required being coincided with ITU G. All rights reserved.2.048Mbps/1.812. refer to “ZGO-05-03-001 GPS Synchronization”. BSC and BTS support multiple clock synchronization methods. BSC supports BITS reference input with 2. ZTE BSC supports following clock synchronization methods: Clock Synchronization Extraction from Traffic Interfaces BSC extracts line recovered clock from the message that contains synchronization timer information at traffic interface.048MHz/2. so as to meet such kind of requirement for various transmission modes and ensure system performance.ZTE GSM BSS Basic Feature Description V10R1 Introduced Version Before V09R1 Enhanced Function None 6. which owns a special FD. ZTE Confidential Proprietary . For details. Different clock reference sources are configured as per actual application scenario to synchronize BSC and BTS.1 ZGB-05-03-001 Clock Synchronization Benefits This feature enables BSS to realize clock synchronization. While BITS-2Mbps clock is directly connected to BTS by E1. BITS-2MHz clock is firstly to access to the top of the cabinet. ZTE BTS supports following clock synchronization methods: Clock Synchronization Extraction from Abis Interfaces If Abis interface adopts E1/T1 transmission.048 Mbps clock signals via E1 interfaces. only one of them can be selected. then connect to rear board to enter CMB. The clock complies with ITU-T G. For V3 BTS. The SMA interface and GPS interface are shared. the physical layer must be comply with the requirement of interface E12 in Chapter 9. BTS automatically selects one E1/T1 in ascending order to extract clock. Hence BITS2Mbps and the 8th E1 are also mutex. For BITS-2MHz. BSC switches to available reference clock with lower priority automatically. the physical layer must be comply with the requirement of interface T12 in Chapter 13. extract synchronization from Abis interface. All rights reserved. BITS-2Mbps clock is accessed from the 8th E1 receiver. When current reference clock is lost. Abis interface of BTS is available to be configured with multiple E1/T1 to connect to BSC. BITS Clock Synchronization BTS supports BITS-2MHz and BITS-2Mbps clock. which clock references to use and the master clock reference can all be set on OMC. For SDR BTS. only one of them can be configured the reference clock. If line recovered clock reference source is configured. 59 .703 and is provided as a clock reference to the other NodeB/BTS or other equipment located in the same site. BSC can maintain the normal system services. which means BITS-2MHz and GPS is a pair of mutex reference clock. When one of the links fails. GPS Clock Synchronization ZTE Confidential Proprietary © 2010 ZTE Corporation.GSM BSS Basic Feature Description V10R1 whether BSC to use clock references. BTS is also able to output 2. it automatically switches to another working link so as to realize redundancy backup. which should be decided when configuring the site. BITS-2MHz clock is accessed from SMA interface in front panel of CC board. if all the reference clocks are lost. As for BITS-2Mbps. Each reference clock is allowed to be specified with certain priority. ZTE Confidential Proprietary . while the MS monitors radio channel in the downlink.1 O&M 7. thus increasing the efficiency of radio resource utility.ZTE GSM BSS Basic Feature Description V10R1 BTS supports GPS clock synchronization. IEEE1588 IP Clock Synchronization Only SDR BTS supports IEEE1588 IP clock synchronization. 60 © 2010 ZTE Corporation.1 ZGB-06-01-001 Monitoring Um Interface Benefits This feature detects and releases faulty radio channels in time. Introduced Version V09R1 Enhancement None 7 Others 7. refer to “ZGO-05-03-002 IEEE1588 V2 IP Clock Synchronization”. For details. system then selects one with highest priority as its reference clock. For details. which owns a special FD. Description The BTS monitors radio channel in the uplink. BSC can maintain the normal system services. When current reference clock is lost. if all the reference clocks are lost. BSC switches to available reference clock with lower priority automatically. refer to “ZGO-05-03-001 GPS Synchronization”. All rights reserved.1. BTS reference clock is configured on OMC. which owns a special FD. counter S is increased by 2.1. BTS decides that this radio channel is faulty and initiates a channel release procedure. When the counter S is deduced to zero. the BTS calculates the average value of uplink signal level and quality. counter S decrements. If the second criterion is applied. Introduced Version Before V09R1 Enhancement None 7. Which criterion to apply is configured on OMCR. When the LAPD board of BSC detects LAPD links failure or the main processing board of BSC ZTE Confidential Proprietary © 2010 ZTE Corporation. a counter S is in work. When E1/T1 access is adopted. Abis signaling fault detection and alarming are provided for all these three methods. All rights reserved.GSM BSS Basic Feature Description V10R1 The BTS monitors radio channel in the uplink according to two criteria. BTS decides that this radio channel is faulty and initiates a channel release procedure. so that they can take measures quickly. 61 . every time the BTS successfully decodes an uplink SACCH frame. Description In ZTE GSM BSS the Abis interface adopts E1. When the average value of uplink signal level or quality is worse than a threshold. Every time the BTS fails to decode an uplink SACCH frame. T1 or IP access methods. The second criterion is the uplink signal level and quality. Counter S has an initial value above zero. If the first criterion is applied.2 ZGB-06-01-002 Abis Interface Monitoring Benefits This feature enables the network operation and maintenance staff to detect the Abis interface failure in time. The first criterion is the ratio of SACCH channel failure. the Abis signaling is carried on LAPD links. 30min. handover measurement. etc. 1h. OMCR adds up the counter values according to the frequency and stores the results into data base. 12h and 24h. etc. When protocol module of BSC detects SCTP links failure. TBF procedure measurement. BSC collects the performance data and sends it to OMCR periodically. analysis and report of performance data. 62 © 2010 ZTE Corporation. Description ZTE GSM BSS supports the collection. the Abis signaling is carried on SCTP protocol.3 ZGB-06-01-003 Performance Data Measurement Benefits This feature is a basic function and helps the operator to supervise the state and performance of the whole BSS network.ZTE GSM BSS Basic Feature Description V10R1 detects communication failure with the LAPD board. O&M staff can set the measurement objects.7 signaling office. When IP access is adopted. storage. No.1. Measurement objects include cell. Every type of measurement consists of many counters. Measurement frequency includes 15min. measurement types and measurement frequency on OMCR. TCH/H measurement. Abis interface failure alarms are sent to OMCR. channel. Measurement types include TCH/F measurement. ZTE Confidential Proprietary . BVC. TRX. All rights reserved. Introduced Version Before V09R1 Enhancement None 7. The SCTP protocol module of BSC manages the SCTP link state according to RFC 2960 specification. LAPD link failure alarms are sent to OMCR. If a problem occurs. If it detects a fatal error. If a board fails. If a problem occurs. ZTE Confidential Proprietary © 2010 ZTE Corporation. ensuring service not to be interrupted. the system is capable of being resumed within 8 minutes because the parameters access is local style instead of remote access from OMCR. then to be rebooted. for example: The OMP continuously monitors the running of TC unit.1. Description BSC monitors the process sources and wireless resources. the board is to be automatically rebooted. OMP also monitors the overall business process. and the boards are rebooted.GSM BSS Basic Feature Description V10R1 Introduced Version Before V09R1 Enhancement None 7. it is to be blocked and diagnosed immediately. the BSC is to be restarted. and the service process goes to the backup board. The process of new service wouldn’t be assigned to the failure board until the fault is recovered or the board is replaced. All rights reserved. BSC's control plane processing board CMP adopts 1 +1 backup mode. If the system detects failure of the active board. The problem caused by software or data processing can be solved automatically. And an alarm is sent to the OMCR to remind the network maintenance engineer. This feature improves the stability of the BSS system and increases the quality of the radio network. it easily detects and locates. 63 . alarm is sent to the OMCR. OMP continuously monitors the boards.4 ZGB-06-01-005 BSC Monitor Functions Benefits This feature enables the operator to continuously monitor the BSC. number of SDCCH seizure failure counter. the non-traffic alarm. number of DL/UL TBF establishment success counter and number of DL/UL TBF establishment failure counter.ZTE GSM BSS Basic Feature Description V10R1 BSC continuously monitors the states of the cells. serious interference alarm and other alarms will be send to the OMCR to notify maintenance person. None-traffic and other abnormal conditions of the cell can be detected. if the free channel rate of a cell is lower than the threshold pre-configured.1. Introduced version Before V09R1 Enhancement None 7. Once a cell of the interference exceeds the threshold pre-configured. If the cell is abnormal. None-traffic alarm will be send to OMCR and maintenance engineer is able to check the reason. serious interference alarm is to be sent to OMCR to inform maintenance engineer.5 ZGB-06-01-006 BTS Software Loading Benefits 64 © 2010 ZTE Corporation. In this case. ZTE Confidential Proprietary . low availability channel alarm is to be sent to OMCR to inform maintenance engineer. Logical Channel Usage Monitoring: System periodically checks the availability of the logical channels (TCH / SDCCH / PDCH). All rights reserved. Serious Interference Alarm: System periodically checks the wireless interference counters. None-traffic Alarm: System periodically checks the performance counters of cells and analyzes the related counters such as number of SDCCH seizure success counter . Meanwhile. and synchronized to NEs. Major version is the normal method to update software. This step is called version packet warehousing. this software should be added into the network management server through the network management system. OMCB can extract a set of related board software versions correctly by analyzing the packet. The OMCB resolves the major version packet into multiple separate version files and stores them into its own hard disk. and has the capability of describing its own format. ZTE Confidential Proprietary © 2010 ZTE Corporation. The special version is often used to verify the validity of single software instead of acting as the main method to update the version. leading to less network congestion and interference when loading the software. and improves loading efficiency. Special version is some board software version independent of the major version. a major version packet contains all required board software versions. Description The SDR BTS software version can be categorized into two types: major version and special version. that is. to ensure that the BTS can use the latest software. So the process is safer and more reliable. 2 Version downloading When the major version is warehoused. 65 . to be loaded into OMCB.GSM BSS Basic Feature Description V10R1 ZTE GSM BTS’s modules are highly integrated. All rights reserved. The installation of BTS software contains the following steps: 1 Version warehousing When new software version is released for the BTS. the OMCB will record these software versions in the database. the version object can be opened on the version tree to download the version packet. The major version is a packet delivered to a binary file when the foreground version is released. It complies with standard naming conventions and format definition. For a specific BTS type. When the major version is activated. the activation fails. All rights reserved. This feature also includes other version commands. 3 Version activation The major version supports non-compatible activation only.ZTE GSM BSS Basic Feature Description V10R1 Loading the major version. Successful loading means successful activation. the process is stopped. If problems occur in the loading process. and the version file is restored. This method speeds the version downloading and relieves the network congestion. you can use the original version through the handover of version packet. Introduced Version V09R1 Enhancement Null 66 © 2010 ZTE Corporation. Version query etc. that is. Thus. is loading all the board software in the major version. Version query can be used to query the currently running version information of BTS through the network management system. only download the required board software after comparing the version information. Version deletion can be used to delete the whole packet of the major version or a single file in the version packet. The major version packet should be downloaded by using the differentiated method. such as Version deletion. the original version packet will act as the spare version file. in fact. ZTE Confidential Proprietary . The new version file will be loaded in the restart process of BTS. All the downloading operations either fail or succeed. This operation must be atomic. If required. The activation of the major version includes two parts: table data configuration command and BTS activation. 7 ZGB-06-01-008 BSC Diagnostic Tests Benefits This feature enhances the efficiency of system maintenance. it’s specifically used in the following scenarios. And the operator can also check the effect of network optimization by this feature. and the other is for TCH. System generates traffic reports every hour to compare the traffic difference of different equipments in different time period. ZTE Confidential Proprietary © 2010 ZTE Corporation. as well as the load condition of equipment resources. Traffic statistical data reflects whether the network resource is optimally configured or not. The operator then can determine if it is necessary to expand system capacity or adjust equipment parameters and resources according to the result.1. 67 . one is for SDCCH. Introduced Version Before V09R1 Enhancement None 7. Description The traffic load of cell can be reported to operator through the performance statistics BSC gathers the information of cell traffic and reports them to OMM by hour.1.6 ZGB-06-01-007 Cell Traffic Statistics Benefits This feature is very important input for network analyses. According to traffic changes. OMM will store them in the database and prepare report forms.GSM BSS Basic Feature Description V10R1 7. There are two kinds of traffic statistics. All rights reserved. the operator can also monitor performance of the network to identify potential problems in a timely manner. so as to analyze network traffic changing trend. Therefore. refresh. Immediate Test: Maintenance engineer is able to select the test objects at any time and test items in the network management client and triggers the test. Both immediate test and routine test results are automatically saved. Description This feature includes immediate test and routine test. All rights reserved. Routine testing is generally used for routine maintenance in order to reduce the workload. clean up. Routine Test: Maintenance engineer is able to select test objects and test items. The system runs the task and the test results can be observed immediately. delete. export. Troubleshooting: Users can set the immediate task.ZTE GSM BSS Basic Feature Description V10R1 Routine Maintenance: Users can set the routine tasks of equipment physical test and communication links test. the maintenance engineer needs to pay attention to it and eliminate hidden dangers to avoid the real fault occurred. When test time arrives. BSC Version Information: 68 © 2010 ZTE Corporation. print the results and customize the results list. the users can check the test results when needed. This feature includes the following test categories: BSC TDM Link Loop Test: BSC is enabled to set both E1 or 64K time slot loopback and send test packets whether the TDM link works normally. and pre-set the test time. the diagnostic test will be triggered and the test results are automatically saved in OMCR server. to help maintenance engineer identifies the cause of the failure and locats fault position as soon as possible. If the test results close to the outlier. ZTE Confidential Proprietary . Users can also inquire. BSC Board Test: This test comprehensively diagnoses whether the board to be tested encounters hardware faults.1. Media stream test checks whether the media stream flows are working properly. and the main communications link between the main and standby board test. are working properly. the hardware version. 69 . All rights reserved. Introduction Version Before V09R1 Enhancement None 7. The test includes the CS and PS domain media flow diagnostic tests.8 ZGO-06-01-003 BSC LMT Benefits ZTE Confidential Proprietary © 2010 ZTE Corporation. the firmware version information and other information to facilitate the users to determine whether to support the feature which requires special hardware and firmware version. The system generates test packets in the source boards. interfaces. Control flow test checks whether the internal control links are working properly. and the target boards receive and return the test packets to the source boards. It also checks whether the major functional units. The system generates test packets in the source boards. BSC Media Stream Test: Media stream test is to test the media flow state between two service boards. etc.GSM BSS Basic Feature Description V10R1 This function gets the board types. the link between the external boards test. and the target boards receive and return the test packets to the source boards. BSC Control Flow Test: Control flow test contains the control link between OMP and the external boards test. All rights reserved. even if the OMCR is not reachable. Diagnostic test: Provide the test of NE object to get more detailed information for the convenience to locate the fault for users. It provides the following functions: Configuration management: Satisfy the commissioning requirements of the BSC.2. activate/deactivate. Status Management: View the status and statistics of various physical and radio resources and perform the operations such as block/unblock. as well as maintenance of BSC. By installing the LMT client in a PC. thus commissioning the BSC. users can connect the LMT client to the BSC LMT to commission the BSC.2 Security 7.1 ZGB-06-02-001 A5/1 and A5/2 Ciphering Algorithm Benefits 70 © 2010 ZTE Corporation. users can directly connect the display and mouse to the LMT server and start the LMT client directly. Operators can view the BSC through the LMT to check the current status and alarms. Alarm management: View the current alarm of the BSC. ZTE Confidential Proprietary .ZTE GSM BSS Basic Feature Description V10R1 This feature reduces construction investment because of more convenient construction. Description BSC LMT is the commission and maintenance tool when the OMCR is not reachable. Alternatively. Introduced version Before V09R1 Enhancement None 7. the BSC is commissioned. All rights reserved. which is one of the input parameters in A5/1. BTS and the terminal to support it. The realization of A5/2 is the same as that of A5/1. which are defined in 3GPP protocol. and this function is initiated when MSC/VLR sending the message Cipher Mode Command to BSC. Before the ciphering procedure. while A5/2 is used in other countries with weak intensity. all information over the air interface is ciphered.GSM BSS Basic Feature Description V10R1 This feature enables the A5/1 and A5/2 ciphering algorithm to send all information during the air interface encrypted. Since A5/2 is decrypted already. The other inputs include the Time Division Multiple Access (TDMA) frame number. so as to provide sufficient security and stability of service. thus providing sufficient security and stability of service. 71 . Kc changes along with the TDMA frame number. The message “Cipher Mode Command” together with Kc and TDMA frame number is sent to BTS via the BSC. This feature requires CN. then sends the message “Cipher Mode Complete” to BSC and MSC. The terminal encrypts the message “Cipher Mode Complete” by using A5/1. GSM association allows all countries to use A5/1 and operators are suggested to use A5/1 as well. A5/1 lies at BTS and the terminal. Description This feature enables two ciphering algorithms A5/1 and A5/2. guaranteeing the private information and signal of the user. and then is sent to the terminal forward. which is sent via the radio path to BTS. there is an authentication procedure first. The authentication procedure evaluates a ciphering key (Kc). Introduced Version Before V09R1 Enhancement None ZTE Confidential Proprietary © 2010 ZTE Corporation. After this procedure. A5/1 is an algorithm with high intensity used in Europe. ZTE GSM supports A5/1 and A5/2 ciphering algorithm to guarantee the private information and signal of the user. BTS decrypts the message “Cipher Mode Complete” with Kc and TDMA frame number by using A5/1. ZTE Confidential Proprietary . All rights reserved.ZTE GSM BSS Basic Feature Description V10R1 8 Acronyms and Abbreviations Abbreviations 72 Full names ACC Access Control Classes ACCN Access Control Class ADPCM Adaptive Differential Pulse Code Modulation AGPS Assisted GPS AH Antenna Hopping AIU Air Interface Unit AMPS Advanced Mobile Phone System AMR Adaptive Multi-Rate ARQ Automatic Repeat request ASAP As Soon As Possible BA BCCH Allocation BCCH Broadcast Control Channel BER Bit Error Rate BSS Base Station Subsystem BTS Base Transceiver Station CAPEX Capital Expenditure CBCH Cell Broadcast Channel CCCH Common Control Channel CDMA Code Division Multiple Access CDU Combiner Distribution Unit CGI Cell Global Identity CMB Controller & Maintenance Board CMIS Common Manage Information Service CMM Control and Maintenance Module CPU Central Processing Unit CRO Cell Reselection Offset DCME Digital Circuit Multiplication Equipment DD Delay Diversity © 2010 ZTE Corporation. All rights reserved. 73 .GSM BSS Basic Feature Description V10R1 DDT Delay Diversity Transmission DRT Dual Rate Transcoder DSL Digital Subscriber Line DSP Digital Signal Processor DTM Dual Transfer Mode DTX Discontinuous Transmission EGPRS Enhanced Data rate for Global Evolution EDRT Enhanced Dual Rate Transcoder EFR Enhanced Full Rate EGPRS Enhanced General packet Radio Service FACCH Fast Associated Control Channels FEC Forward Error Correction FR Full Rate FRSC Full Rate Speech Codec FSMU Far Sub-multiplexing Unit FTP File Transfer Protocol FUC Frame Unit Controller GERAN GPRS EGPRS Radio Access Network GGSN Gateway GPRS Support Node GPP General Peripheral Processor GPS Global Positioning System GSM Global System for Mobile Communication HLR Home Location Register HR Half Rate ICE Integrated Configuration Environment IMSI International Mobile Subscriber Identity IP Internet Protocol IRC Interference Rejection Combining ISDN Integrated Services Digital Network ISP In Service Performance LAC Location Area Code LAN Local Area Network ZTE Confidential Proprietary © 2010 ZTE Corporation. Radio OPEX Operational Expenditure PBGT Power Budget PCH Paging Channel PCM Pulse Code Modulation PCU Packet Control Unit PDU Power Distribution Unit PH Phase Hopping PIE Priority Information Element PLMN Public Land Mobile Network PoC Push to talk over Cellular © 2010 ZTE Corporation. All rights reserved.ZTE GSM BSS Basic Feature Description V10R1 74 LAPD Link Access Protocol for D-Channel MAIO Mobile Allocation Index Offset MCPC Multiple Channels Per Carrier MIT Managed object Instance Tree MMI Man Machine Interface MO Mobile Originating MOC Mobile Originated Call MOS Mean Opinion Score MRC Macro Ratio Combining MS Mobile Station MSC Mobile Switching Center MT Mobile Terminating MTBF Mean Time Before Failure MTC Mobile Terminated Call NACC Network Assisted Cell Change NECI New Establishment Cause Indicator NIU Network Interface Unit NSEI Network Service Entity Identifier NSMU Near Sub-multiplexing Unit NSS Network Switching Subsystem NS-VC Network Service Virtual Channel OMC-R Operation and Maintenance Center . ZTE Confidential Proprietary . 75 . All rights reserved.GSM BSS Basic Feature Description V10R1 PREC Preemption Recommendation PTP Point to Point PTT Push To Talk QoS Quality of Service QRI Queuing Recommendation Indicator RACH Request Access Channel RLP Radio Link Protocol RMM Radio Management Module RNC Radio Network Controller RR Radio Resource RTP Real Time Protocol SACCH Slow Associated Control Channel SAPI Service Access Point Identifier SCM Switching Control Module SCPC Single Channel Per Carrier SDCCH Stand-alone Dedicated Control Channel SDH Synchronous Digital Hierarchy SGSN Serving GPRS Support Node SID Silence Descriptor SMC Short Message Center SNM Switching Network Module STM Synchronous Transport module TA Timing Advance TC Transcoder TCH Traffic Channels TCH Traffic Channel TCPP Transcoder Peripheral Processor TCU Transcoder Unit TDD Time Division Duplexing TDMA Time Division Multiple Access TD-SCDMA Time Division Synchronous CDMA TFO Tandem Free Operation ZTE Confidential Proprietary © 2010 ZTE Corporation. ZTE Confidential Proprietary . All rights reserved.ZTE GSM BSS Basic Feature Description V10R1 76 TIC Trunk Interface Card TO Temporary Offset TRA Transcoder Rate Adaptation TRA Trunk circuit Resource of A interface TRAU Transcoder and Rate Adaptation Unit TRM Transceiver Module TRANCEIVER Transceriver TS Time Slot TSC Training Sequence Code UDP User Datagram Protocol UIR Uplink Incremental redundancy UNC Universal Nodes Controller UTRAN Universal Terrestrial Radio Access Network VAD Voice Activity Detector VLR Visitor Location Register VSWR Voltage Standing Wave Ratio WCDMA Wideband Code Division Multiple Access WPA Wireless Packet Access © 2010 ZTE Corporation.