2G3G Interoperability (TDD).pdf

GSM BSS2G/3G Interoperability (TDD) Feature Parameter Description Copyright © Huawei Technologies Co., Ltd. 2011. All rights reserved. No part of this document may be reproduced or transmitted in any form or by any means without prior written consent of Huawei Technologies Co., Ltd. Trademarks and Permissions and other Huawei trademarks are trademarks of Huawei Technologies Co., Ltd. All other trademarks and trade names mentioned in this document are the property of their respective holders. Notice The purchased products, services and features are stipulated by the commercial contract made between Huawei and the customer. All or partial products, services and features described in this document may not be within the purchased scope or the usage scope. Unless otherwise agreed by the contract, all statements, information, and recommendations in this document are provided “AS IS” without warranties, guarantees or representations of any kind, either express or implied. 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Issue 01 (2010-06-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd. i GSM BSS 2G/3G Interoperability (TDD) Contents Contents GSM BSS .................................................................................................................................................i 1 Introduction ................................................................................................................................1-1 1.1 Scope ............................................................................................................................................ 1-1 1.2 Intended Audience ........................................................................................................................ 1-1 1.3 Change History.............................................................................................................................. 1-1 2 Overview .....................................................................................................................................2-1 3 Measurement of Neighboring UMTS Cells .........................................................................3-1 4 Common Measurements and Information Exchange Based on Iur-g ........................4-1 4.1 Introduction to Iur-g Interface ........................................................................................................ 4-1 4.2 Common Measurement................................................................................................................. 4-2 4.3 Information Exchange ................................................................................................................... 4-3 5 2G/3G Inter-RAT Cell Reselection ........................................................................................5-1 5.1 Inter-RAT Cell Reselection from UMTS to GSM ........................................................................... 5-1 5.2 Inter-RAT Cell Reselection from GSM to UMTS ........................................................................... 5-1 5.3 Fast 3G Reselection at 2G CS Call Release ................................................................................ 5-2 5.4 NACC and NC2 ............................................................................................................................. 5-3 6 2G/3G Inter-RAT Handover .....................................................................................................6-1 6.1 Inter-RAT Handover from UMTS to GSM...................................................................................... 6-1 6.2 Inter-RAT Handover from GSM to UMTS...................................................................................... 6-1 6.3 2G/3G Service Distribution and Load Balancing in Access State ................................................. 6-2 6.4 Inter-RAT Load-based Handover in Connect State....................................................................... 6-3 6.5 Enhanced Radio Resource Reserved Handover Based on Iur-g ................................................. 6-4 6.6 Handover Optimization Between GSM and TD-SCDMA Based on Iur-g...................................... 6-5 7 GSM/TD-SCDMA Interoperability Optimization.................................................................7-1 8 PS GSM and TD-SCDMA Interoperability Optimization ..................................................8-1 9 Engineering Guidelines...........................................................................................................9-1 10 Parameters .............................................................................................................................10-1 11 Counters ..................................................................................................................................11-1 12 Glossary ..................................................................................................................................12-1 13 Reference Documents .........................................................................................................13-1 Issue 01 (2010-06-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd. ii GSM BSS 2G/3G Interoperability (TDD) 1 Introduction 1 Introduction 1.1 Scope This document describes the 2G/3G interoperability feature of Huawei GBSS. It covers the functions of and technologies related to this feature, including measurement of neighboring 3G cells, inter-RAT cell reselection, and inter-RAT handover. The feature involved is GBFD-114302 GSM and TD-SCDMA Interoperability. 1.2 Intended Audience It is assumed that users of this document are familiar with GSM basics and have a working knowledge of GSM telecommunication. This document is intended for: z z Personnel working on Huawei GSM products or systems System operators who need a general understanding of this feature 1.3 Change History The change history provides information on the changes made to the 2G/3G interoperability (TDD) feature in different document versions. There are two types of changes, which are defined as follows: z Feature change Feature change refers to the change in the 2G/3G interoperability (TDD) feature of a specific product version. z Editorial change Editorial change refers to the change in wording or the addition of the information that was not described in the earlier version. Document Issues The document issues are as follows: z z 01 (2010-06-30) Draft (2010-03-30) 01 (2010-6-30) This is the first release of GBSS12.0. Compared with issue Draft (2010-03-30) of GBSS12.0, issue 01 (2010-06-30) of GBSS12.0 incorporates the changes described in the following table. Change Type Feature change Change Description None. Parameter Change None. Editorial change Parameters are presented in the form of Parameter ID instead None. of Parameter Name. Issue 01 (2010-06-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd. 1-1 1-2 .0. Issue 01 (2010-06-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co. Ltd..GSM BSS 2G/3G Interoperability (TDD) 1 Introduction Draft (2010-03-30) This is the draft release of GBSS12. 2-1 . when a dual-mode MS moves to an area without UMTS coverage. For the operator that has both the UMTS network and the GSM network. Huawei introduces 2G/3G interoperability into the BSS. which consists of two functions: inter-RAT handover and inter-RAT cell reselection between GSM and UMTS.. the access policy for the GSM network can be different from that for the UMTS network in the areas covered by both the GSM network and the UMTS network. Through 2G/3G interoperability. it can reselect or be handed over to a GSM cell through 2G/3G interoperability. 2G/3G interoperability can be performed to hand over some calls from the GSM cell to a UMTS cell. To facilitate the service provision by both the networks. thus saving the investment. Ltd.GSM BSS 2G/3G Interoperability (TDD) 2 Overview 2 Overview The UMTS network and the GSM network will coexist and provide services together for a long time. For example. With 2G/3G interoperability. Issue 01 (2010-06-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co. For example. 2G/3G interoperability enables the GSM network and the UMTS network to complement each other. 2G/3G interoperability can be performed to achieve traffic balance between the GSM system and the UMTS system. the GSM network can be preferentially selected by CS services and similarly the UMTS network by PS services. For example. For the areas covered by both the GSM network and the UMTS network. thus expanding the network coverage and improving the service quality. In this way. All the MSs involved in this feature are dual-mode MSs. a smooth evolution from GSM to UMTS can be achieved. The continuous coverage brought by this feature improves the user experience. the advantages of both networks can be achieved. when the traffic load in a GSM cell is too heavy. If the value of QSEARCHC is between 8 and 14. System Information 2ter and System Information 2Quater are sent on the BCCH. The conditions for triggering the measurement differ with the value of QI. and Measurement Information. Operators can set measurement parameters to different values for the MSs in different states. The conditions for triggering the measurement differ with the value of QSEARCHC. The parameter Send2QuterFlag controls whether System Information 2Quater should be sent. the MSs never measure the neighboring UMTS cell information regardless of the receive level of the serving cell. If the value of QP is 7. the MSs always measure the neighboring UMTS cell information regardless of the receive level of the serving cell. The MSs in a GSM cell measure the information of both neighboring GSM cells and neighboring UMTS cells. the measurement is triggered when the receive level of the serving cell is lower than the value of QP. the MSs never measure the neighboring UMTS cell information regardless of the receive level of the serving cell. z z z z If the value of QI ranges from 0 to 6. Issue 01 (2010-06-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co. the BSS controls the neighboring cell measurement of MSs through parameters. If the value of QSEARCHC is 7. If the value of QSEARCHC is 15. the MSs never measure the neighboring UMTS cell information regardless of the receive level of the serving cell. the measurement is triggered when the receive level of the serving cell is lower than the value of QSEARCHC. z z z z If the value of QSEARCHC is between 0 and 6. Ltd. The system information refers to System Information 2ter. The MSs in packet transfer mode determine whether to measure the information about neighboring UMTS cells according to QP and the receive level of the serving cell. The conditions for triggering the measurement differ with the value of QP. the measurement is triggered when the receive level of the serving cell is higher than the value of QP. The MSs in dedicated mode can perform inter-RAT handover. based on which the MS measures the neighboring cell information and performs cell reselection and handover. The MSs in idle mode determine whether to measure the information about neighboring UMTS cells according to QI and the receive level of the serving cell.GSM BSS 2G/3G Interoperability (TDD) 3 Measurement of Neighboring UMTS Cells 3 Measurement of Neighboring UMTS Cells The system information contains the neighboring UMTS cell list and UMTS cell reselection parameters. If the value of QP ranges from 8 to 14. To reduce unnecessary measurements and save power consumption of MSs. If the value of QI ranges from 8 to 14. If the value of QP is 15. the measurement is triggered when the receive level of the serving cell is higher than the value of QI.. The MSs in idle mode or packet transfer mode can perform inter-RAT cell reselection. the MSs always measure the neighboring UMTS cell information regardless of the receive level of the serving cell. If the value of QI is 7. If the value of QI is 15. the MSs always measure the neighboring UMTS cell information regardless of the receive level of the serving cell. The MSs in dedicated mode determine whether to measure the information about neighboring UMTS cells according to QSEARCHC and the receive level of the serving cell. System Information 2Quater. z z z z If the value of QP ranges from 0 to 6. and Measurement Information is sent on the SACCH. the measurement is triggered when the receive level of the serving cell is higher than the value of QSEARCHC. 3-1 . the measurement is triggered when the receive level of the serving cell is lower than the value of QI. After entering the dedicated mode. Before QSEARCHC is obtained. MSs take the value of QCI that is transmitted on the BCCH as the value of QSEARCHC. 3-2 . Ltd.GSM BSS 2G/3G Interoperability (TDD) 3 Measurement of Neighboring UMTS Cells QSEARCHC is contained in the Measurement Information.. Issue 01 (2010-06-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co. MSs try to obtain the QSEARCHC from the Measurement Information transmitted on the SACCH. Issue 01 (2010-06-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co. Figure 4-1 Position of the Iur-g interface in the network architecture CN A/Gb Iu Iu Iur-g Iur BSC RNC RNC Figure 4-2 shows the protocol stack defined in 3GPP specifications for the Iur-g interface. and improves the handover success rate. This simplifies the 2G/3G interoperability procedures.1 Introduction to Iur-g Interface The load information exchanged between 2G and 3G networks is carried in the information elements (IEs) of the handover procedures over the A and Iu interfaces. Ltd.GSM BSS 2G/3G Interoperability (TDD) 4 Common Measurements and Information Exchange Based on Iur-g 4 Common Measurements and Information Exchange Based on Iur-g This section describes the feature GBFD-511401 Iur-g Interface Between GSM and TD-SCDMA. In this case. With the development of 3GPP specifications. reduces the delay caused by handovers. Figure 4-1 shows the position of the Iur-g interface in the network architecture. 4. 4-1 .. unnecessary handover attempts cannot be avoided. the Iur-g interface between the RNC and the BSC is used to achieve common measurement and information exchange between 2G and 3G networks. The Iur-g interface is made to carry the control plane data and user plane data to reduce the delay caused by handovers between GSM and TD-SCDMA and improve the handover success rate. The Iur-g interface uses IP transmission. If the target RNC/BSC supports the common measurement procedure. the common measurement is enabled. If SPTCOMMMEAS is set to Yes. the source BSC/RNC requests the target RNC/BSC to periodically report the load information about neighboring cells.GSM BSS 2G/3G Interoperability (TDD) 4 Common Measurements and Information Exchange Based on Iur-g Figure 4-2 Protocol stack defined for the Iur-g interface Radio Network Layer Control Plane RNSAP Transport Layer Transport Network User Plane SCCP MTP3-B SSCF-NNI SSCOP AAL5 ATM M3UA SCTP IP M3UA SCTP IP DATA LINK Transport Network Control Plane Physical Layer There is an Iur-g interface between each remote RNC and the local BSC. The Iur-g interface supports the common measurement procedure and information exchange procedure. it responds with a COMMON MEASUREMENT INITIATION RESPOSE message. Ltd. 4-2 . 4. Figure 4-3 Successful common measurement initialization SBSC/SRNC TRNC/TBSC COMMON MEASUREMENT INITIATION REQUEST COMMON MEASUREMENT INITIATION RESPOSE Issue 01 (2010-06-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co. The source BSC/RNC sends a COMMON MEASUREMENT INITIATION REQUEST message to the target RNC/BSC to initialize the common measurement procedure. The procedures of the common measurement are performed through connection-oriented signaling.. These two procedures are performed through connection-oriented signaling.2 Common Measurement The common measurement is based on the Iur-g interface. Figure 4-3 shows the successful common measurement initialization procedure. Through this message. 4-3 . If SPTINFOEXCHG is set to Yes. Such information includes the load information about 2G and 3G cells.3 Information Exchange The information exchange procedure is based on the Iur-g interface. and INFOEXCHGLIST is set to CELLCAPCLASS. blocked. the information exchange is enabled. Figure 4-6 shows the failed common measurement. the target RNC/BSC sends a COMMON MEASUREMENT FAILURE INDICATION message to the source BSC/RNC. Ltd. the target RNC/BSC periodically sends COMMON MEASUREMENT REPORT messages to the source BSC/RNC to report the load information about neighboring cells. During a common measurement procedure. it responds with a COMMON MEASUREMENT INITIATION FAILURE message. Figure 4-5 shows the common measurement reporting procedure. Figure 4-6 Failed common measurement 4. or deactivated.. Figure 4-4 Failed common measurement initialization After a common measurement is successfully initialized. Figure 4-5 Common measurement reporting procedure If a neighboring cell is faulty. removed. notifying the source BSC/RNC that the common measurement procedure has failed and has to be terminated. Issue 01 (2010-06-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co. Figure 4-4 shows the failed common measurement initialization procedure. information is transmitted between 2G and 3G networks through the Iur-g interface.GSM BSS 2G/3G Interoperability (TDD) 4 Common Measurements and Information Exchange Based on Iur-g If the target RNC/BSC does not support the common measurement procedure. performed through connection-oriented signaling. the inter-RAT PS service handover support flag is Yes for a 2G cell. Table 4-1 Rules for determining the load states of 2G cells Transmission Direction Uplink If… Uplink load < UlLdrThrd2GCell UlLdrThrd2GCell ≤ Uplink load < UlOlcThrd2GCell Uplink load ≥ UlOlcThrd2GCell Downlink Downlink load < DlLdrThrd2GCell Then the Load State of the Cell Is… Normal Basic congestion Overload congestion Normal DlLdrThrd2GCell ≤ Downlink load < DlOlcThrd2GCell Basic congestion Downlink load ≥ DlOlcThrd2GCell Overload congestion z Inter-RAT CS service handover support flag of a 2G cell When the TCH usage of a 2G cell is greater than or equal to the value of the InterRatCsServiceLoadHoThrd parameter or the INTERRATINBSCHOEN parameter is set to NO(No). That is. z Inter-RAT PS service handover support flag of a 2G cell When the TBF multiplexing rate of s 2G cell is lower than the value of the LOADRESELRXTHRSH parameter. the inter-RAT CS service handover support flag is No for a 2G cell. the CS services in 3G cells are allowed to be handed over to 2G cells. Ltd. 4-4 . Table 4-1 describes the rules for determining the load states of 2G cells. Issue 01 (2010-06-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co. the PS services in 3G cells are not allowed to be handed over to 2G cells. z Load information about 2G or 3G cells A cell can be in three load states: normal. the PS services in 3G cells are allowed to be handed over to 2G cells. When the INTERRATINBSCHOEN parameter is set to YES(Yes) and the TCH usage of a 2G cell is smaller than the value of the InterRatCsServiceLoadHoThrd parameter. Otherwise. That is. the inter-RAT CS service handover support flag is Yes for a 2G cell. and inter-RAT PS service handover support flag of a 2G cell. That is. the CS services in 3G cells are not allowed to be handed over to 2G cells. basic congestion. or overload congestion.GSM BSS 2G/3G Interoperability (TDD) 4 Common Measurements and Information Exchange Based on Iur-g inter-RAT CS service handover support flag of a 2G cell.. they can reselect a UMTS cell for data services through autonomous cell reselection. It measures the information of the neighboring UMTS cell. the network affects the cell reselection through signaling so that the MS will camp on the desired cell. the number of MSs that camp on the GSM cell is increased.. When INTERRATCELLRESELEN is set to No. The parameter INTERRATCELLRESELEN determines whether cell reselection between GSM and UMTS is enabled.GSM BSS 2G/3G Interoperability (TDD) 5 2G/3G Inter-RAT Cell Reselection 5 2G/3G Inter-RAT Cell Reselection 2G/3G inter-RAT cell reselection involves the cell reselection from GSM to UMTS and the cell reselection from UMTS to GSM. RLA_C refers to the average receive level. z CPICH RSCP > RLA_C + TDDCELLRESELDIV In the preceding condition. In this case. For MSs in idle mode. For the BSS. the MS initiates the cell reselection from GSM to UMTS. the cell reselection condition is difficult to meet. Cell reselection is performed mainly by the MS. 5-1 . Network Assisted Cell Change (NACC). The GSM network handles the location update regardless of whether the MS is from a UMTS cell or a GSM cell. TDDCELLRESELDIV indicates the signal strength difference between the candidate UMTS cells and the serving GSM cell. it is not repeated in this document.2 Inter-RAT Cell Reselection from GSM to UMTS The MSs in a GSM cell obtain the neighboring UMTS cell list and cell reselection parameters through System Information 2ter and System Information 2Quater. the mechanism of cell reselection from the GSM cell to the UMTS cell is the same as that between GSM cells. The RSCP of the neighboring UMTS cell must be greater than the sum of the value of TDDCELLRESELDIV and the average receive Issue 01 (2010-06-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co. the MS selects a cell with the highest RSCP as the target cell. the MS initiates the location update in the GSM network. or Network Control Mode 2 (NC2). In this case. and then decides whether to reselect the UMTS cell according to cell reselection parameters. MSs in a GSM cell cannot select a UMTS cell. For the UMTS TDD cell. When TDDCELLRESELDIV is set to a great value. The GSM network controls the cell reselection from the GSM cell to the UMTS cell through TDDCELLRESELDIV. the number of MSs that camp on the GSM cell is reduced. 5. Thus. Ltd. When the MS is in idle mode or packet transfer mode. and then measure the neighboring UMTS cells according to the list and parameters. For MSs in packet transfer mode. In this way. In NACC and NC2. The autonomous cell reselection is performed by the MS without the intervention of the network.1 Inter-RAT Cell Reselection from UMTS to GSM When an MS moves into the GSM coverage area and reselects a GSM cell. The cell reselection procedure in packet transfer mode is the same as that in idle mode. A dual-mode MS camping on a GSM cell can reselect a UMTS cell. the measurement quantity to be used is Received Signal Code Power (RSCP) of the Common Pilot Channel (CPICH). the cell reselection condition is easy to meet. When TDDCELLRESELDIV is set to a small value. This parameter is a key factor for controlling the cell reselection from the GSM cell to the UMTS cell. the cell reselection procedure from UMTS to GSM is the same as that between GSM cells. If the measurement result meets the following condition within five seconds. cell reselection is mainly performed to implement 2G/3G interoperability. If there is more than one UMTS cell that meets the condition. 5. the BSS does not send the neighboring UMTS cell list and the parameters related to 2G/3G inter-RAT cell reselection. the MS camps on a UMTS cell without calculating cell reselection parameters. after an MS terminates a call in a GSM cell. Ltd. the RSCP of the neighboring UMTS cell must be greater than the sum of the value of TDDCELLRESELDIV and the receive level of each GSM neighboring cell. The inter-RAT cell reselection from GSM to UMTS cannot be triggered within 5s after the cell reselection from UMTS to GSM. When the Fast 3G Reselection at 2G CS Call Release feature is activated. the MS camps on the UMTS cell for a longer period. When a neighboring UMTS cell meets the requirements for cell reselection.GSM BSS 2G/3G Interoperability (TDD) 5 2G/3G Inter-RAT Cell Reselection level of the serving cell.3 Fast 3G Reselection at 2G CS Call Release Overview Normally.. If the inter-RAT cell reselection from GSM to UMTS is triggered within 15s after the cell reselection from UMTS to GSM. When the condition for the cell reselection from GSM to UMTS and the condition for the cell reselection between GSM cells are met. 5-2 . the BSS sends the frequency information on the neighboring UMTS cell through a Channel Release message to the MS to instruct it to camp on the UMTS cell. In this way. 5. Before initiating the UMTS cell reselection. Then. the value of TDDCELLRESELDIV must be increased by 5 dB. In addition. Figure 5-1 Cell reselection procedure Issue 01 (2010-06-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co. thus accelerating cell reselection. the MS must receive system information and calculate cell reselection parameters. the MS selects the UMTS cell as the target cell. Figure 5-1 shows the cell reselection procedure. Procedure Take the case of call termination by the MS as an example. In addition. it camps on the GSM cell. A UMTS cell is classified into the UTRAN FDD cell and the UTRAN TDD cell. the BSS determines the best neighboring UMTS cell based on the measurement information on the neighboring UMTS cells after the call termination in a GSM cell. This feature is activated when CELLSELECTAFTERCALLREL is set to YES. thus increasing the revenue of operators in the UMTS network. the MS camps on the UMTS cell after the cell reselection. The message contains the information element "Cell selection indicator after release of all TCH and SDCCH". After receiving the Channel Release message. the BSC sends the Channel Release message to the MS. Otherwise. After receiving the UA message. The BSC sends a Channel Release message to the MS to instruct the MS to release the TCH or SDCCH on the Um interface. The MS attempts to camp on the cell indicated in the Channel Release message. the procedure proceeds to 2. and the BSC sends the Channel Release message to the MS.. For details on the normal cell reselection procedure. the MS obtains the SI of the target cell directly over the Iur-g Issue 01 (2010-06-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co. If step 4 fails. The Channel Release message contains the information element "Cell selection indicator after release of all TCH and SDCCH". which contains the information on the target neighboring UMTS cell. Otherwise. 5.. The BSC figures out the best neighboring UMTS cell based on the related measurement report. the MS switches to idle mode and initiates cell reselection. Meanwhile. The Channel Release message does not contain the information element "Cell selection indicator after release of all TCH and SDCCH". the MSC sends a Clear Command message to the BSC to instructing the BSC to release the occupied resources on the A and Um interfaces. 5-3 . 4. 2. the MS performs the normal cell reselection procedure. If the classmark does not indicate the MS capability of supporting the GSM/UMTS. Ltd. The message does not carry the information element "Cell selection indicator after release of all TCH and SDCCH". 3. NACC and NC2 can be performed for inter-RAT cell reselection. If there is no measurement report or the measurement report does not contain the information on the neighboring UMTS cell. The message does not carry the information element "Cell selection indicator after release of all TCH and SDCCH". 2. The MS attempts to camp on the cell where the TCH or SDCCH is already released. 1. If. The message does not carry the information element "Cell selection indicator after release of all TCH and SDCCH". If the measurement report indicates a neighboring UTRAN TDD cell.. and the BSC sends the Channel Release message to the MS. the procedure is complete. the MS sends a DISC frame to the BTS to instruct the BTS to release the TCH or SDCCH. 3. and then the procedure proceeds to 4. If CELLSELECTAFTERCALLREL is set to YES. the procedure is complete. 5. the UMTS-to-GSM NACC procedure is an optimized NACC procedure. the procedure is completed. Cell Selection Indicator is set to UTRAN FDD Description. see Inter-RAT Cell Reselection from GSM to UMTS. the MS disconnects the uplink signaling link.4 NACC and NC2 When MS is in packet transfer mode. and the procedure is complete.GSM BSS 2G/3G Interoperability (TDD) 5 2G/3G Inter-RAT Cell Reselection 1. 4. If the measurement report indicates a neighboring UMTS FDD cell. the procedure proceeds to 3.. If the Iur-g interface exists between the BSC and RNC. The Channel Release message may carry the information element "Cell selection indicator after release of all TCH and SDCCH". Before sending the Channel Release message. After receiving the Release Complete message from the MS. Then. and the BSC sends the Channel Release message to the MS. the BSC determines whether to carry the information element "Cell selection indicator after release of all TCH and SDCCH" in the message. In this case. Cell Selection Indicator is set to UTRAN TDD Description.. The BSC determines whether an MS supports both GSM and UMTS through the classmark. Then. For details.. Ltd. and the parameter INFOEXCHGLIST should set to NACCRELATED. see NACC Parameter Description and NC2 Parameter Description. 5-4 . Issue 01 (2010-06-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co.GSM BSS 2G/3G Interoperability (TDD) 5 2G/3G Inter-RAT Cell Reselection interface.3 Information Exchange. The information exchange see 4. To solve the problem. The handover is controlled mainly by the network. if the traffic load in the target GSM cell is also heavy. Emergency handover refers to the handover that is triggered when the call cannot be processed in the serving cell because of poor coverage or other reasons during the CS service of the dual-mode MS.2 Inter-RAT Handover from GSM to UMTS The parameter INTERRATINBSCHOEN determines whether the inter-RAT handover from GSM to UMTS is enabled. For a call to be accessed in a GSM cell. the target cell rejects the handover to avoid ping-pong handovers. 6. Otherwise. the emergency handover is triggered to avoid call drops. inter-RAT load handover. including the emergency handover. After receiving the measurement result. Then. the BSS determines whether to initiate the inter-RAT handover from GSM to UMTS based on the measurement result and the handover algorithm. the BSS hands over the call to the UMTS cell. MSs in the serving cell can be handed over to the UMTS cell to achieve better voice quality. when an MS during a call in the GSM cell is moving to the outside of the cell. Issue 01 (2010-06-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co.. the BSS rejects all the requests for the handover from UMTS to GSM. and inter-RAT service handover. If INTERRATINBSCHOEN is set to NO(No). The BSS considers the incoming handover from UMTS to GSM as a general inter-BSC handover.1 Inter-RAT Handover from UMTS to GSM MSs in dedicated mode can be handed over from a UMTS cell to a GSM cell. 6. the BSS rejects all the requests for the handover from GSM to UMTS and does not select a UMTS cell as the target cell. When the cell delivers the neighboring TD-SCDMA cell information. inter-RAT handovers can be performed. 6-1 . The inter-RAT handover from GSM to UMTS can be classified into emergency handover and better 3G cell handover. Better cell handover refers to the handover that is triggered when the signal quality of the neighboring cell is better than that of the serving cell.GSM BSS 2G/3G Interoperability (TDD) 6 2G/3G Inter-RAT Handover 6 2G/3G Inter-RAT Handover The 2G/3G inter-RAT handover involves the handover from GSM to UMTS and the handover from UMTS to GSM. The parameter INTERRATINBSCHOEN determines whether inter-RAT handover from UMTS to GSM is enabled. the MS obtains the neighboring UMTS cell list and other information from the Measurement Information. Inter-RAT load handover refers to the handover wherein some calls served by a GSM cell are handed over to a UMTS cell or some calls served by a UMTS cell are handed over to a GSM cell because of heavy load in the serving cell. In dedicated mode. For example. see Handover Parameter Description. the MS reports the measurement result to the BSS through the measurement report. For example. If INTERRATINBSCHOEN is set to No. the operator can choose the network that the MS will access through the MSC. when the signal quality of a UMTS cell is better than that of the serving GSM cell. better cell handover. MSs from certain manufacturers may be restarted because defects exist in MS chips. if the MSC indicates that the service handover should be performed. For MSs in dedicated mode. Huawei optimizes GSM/TD-SCDMA interoperability. For an incoming inter-RAT handover to a GSM cell. so that better service quality and user experience can be achieved. For details. The algorithm for the emergency handover from GSM to UMTS is the same as that for the general emergency handover. The handover decision and handover procedure are controlled by the RNC. In the inter-RAT service handover. Ltd. the BSS does not hand over the call to a UMTS cell when a handover is required during the call. In this Issue 01 (2010-06-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co. the BSC performs different processing based on the setting of the Service Handover IE in the ASSIGNMENT REQUEST message received from the Core Network (CN). it indicates that a 2G cell should be preferentially selected as the serving cell. In addition. the BSC selects a target 3G cell from the list of neighboring cells and starts the handover from 2G to 3G. operators can provide more diversified services. the better 3G cell handover is triggered. but there is no impact of high load on the system. the parameter HOOPTSEL determines whether the GSM cell or the UMTS cell is preferentially selected as the target cell. If the MS accesses the network through a 2G cell and the 2G cell is congested. the BSC preferentially selects the GSM cell as the target cell. z z z When HOOPTSEL is set to Pre_2G_Cell(Preference for 2G cell). The system performs a handover decision based on the measurement result. the BSC redirects the MS to the target 3G cell according to the load in the target 3G cell. if the INTERRATOUTBSCHOEN parameter is set to YES(Yes). and the 2G/3G network resources are efficiently used. In this manner. z When the InterRatServiceLoadHoSwitch parameter is set to CnService-based(CN Service-based). the BSC hands over the MS (a dual-mode MS) performing high-rate data service to the target 3G cell according to the load in the target 3G cell and retains the low-rate services in the 2G cell. When HOOPTSEL is set to Pre_3G_Cell(Preference for 3G cell). Ltd. Better 3G cell handover can be performed only when both INTERRATOUTBSCHOEN and BET3GHOEN are set to YES(Yes). When an MS accesses the network through a 2G cell. the BSC selects an inter-RAT handover algorithm based on the setting of the InterRatServiceLoadHoSwitch parameter. voice services and low-rate data services are distributed to the 2G network. The QoS-based service distribution feature is introduced to optimize the utilization of resources in 2G and 3G networks. z If there is HODURT3GTDD in HOSTAT3GTDD and the measured value meets the following condition. the BSC preferentially selects the UMTS cell as the target cell. the BSC selects a UMTS cell as the target cell. In this case. The 2G/3G load balancing feature is introduced to balance the load between the two networks. the traffic load in the two networks is different.. CPICH RSCP > HORSCPTH3G 6. the system capacity is increased. For example. in the case of co-existence of 2G and 3G networks. The details are as follows: − If the value of the Service Handover IE is Handover to UTRAN or cdma2000 should be performed.3 2G/3G Service Distribution and Load Balancing in Access State Overview With the co-existence of 2G and 3G networks. 6-2 . the BSC determines the target cell according to the levels of the neighboring GSM cells and the value of HOPRETH2G. whereas high-rate data services are distributed to the 3G network to achieve high peak throughput. If no neighboring GSM cell has a level higher than HOPRETH2G.GSM BSS 2G/3G Interoperability (TDD) 6 2G/3G Inter-RAT Handover In the GSM network. it indicates that the MS should be handed over to a 3G cell. Related Algorithms When an MS accesses the network through a 2G cell. When HOOPTSEL is set to Pre_2G_CellThres(Preference 2G cell by thresh). − If the value of the Service Handover IE is Handover to UTRAN or cdma2000 should not be performed. the BSC selects a proper target cell by using the system service distribution algorithm if the load in the serving cell is in the normal state. and will select only a 2G cell as the target cell if a handover is required. 6-3 Issue 01 (2010-06-30) . The inter-RAT load-based handover in connected state feature is introduced to solve this problem. 6. but there is no impact of high load on the system.4 Inter-RAT Load-based Handover in Connect State Overview In the case of co-existence of 2G and 3G networks. the BSC selects a candidate 3G cell that meets the following condition in both uplink and downlink as the target cell. In this manner.GSM BSS 2G/3G Interoperability (TDD) 6 2G/3G Inter-RAT Handover case. If the load in the serving cell is in other states. If there are no candidate 3G cells or if the directed retry to the target 3G cell fails. there is a possibility that a network is congested due to insufficient resources. it indicates that the MS must not be handed over to a 3G cell.000 Then. This feature enables the efficient use of the resources in 2G and 3G networks and balances the load between 2G and 3G networks. The candidate neighboring 3G cells must meet the following condition: z z z G2GLoadAdjustCoeff x Load in the current 2G serving cell – 10 x Load in the neighboring 3G cell ≥ G2G3GLdBlcDeltaThrd – 1. whereas the other network has only a light traffic. In this case. z When the InterRatServiceLoadHoSwitch parameter is set to Service-based(Service-based).. The current load in the serving cell is greater than or equal to the value of the TRIGTHRES parameter. − If the value of the Service Handover IE is Handover to UTRAN or cdma2000 shall not be performed. the BSC selects the best neighboring 3G cell as the target cell and starts the directed retry to the 3G cell. The value of the Service Handover IE in the ASSIGNMENT REQUEST message received from the CN is not handover to UTRAN or cdma2000 shall not be performed. an inter-RAT load-based handover in connected state is triggered when the following conditions are met: z z z The CPU usage of the system is smaller than or equal to the value of the SYSFLOWLEV parameter. the BSC will not hand over the MS to a 3G cell. the system capacity is increased. the BSC selects a target cell by using the system load balancing algorithm. If there is no 3G cell that meets the preceding condition in uplink and downlink. If a handover is required during the call. the BSC starts a reassignment procedure in a 2G cell. the BSC admits the MS to the 2G cell. When the InterRatServiceLoadHoSwitch parameter is set to Load-based(Load-based) and the value of the Service Handover IE is handover to UTRAN or cdma2000 should be performed. a 2G cell is preferentially selected as the target cell. Related Algorithms When the OutSysLoadHoEn parameter is set to YES(Yes) and the MS supports inter-RAT handover. the BSC removes the candidate 3G cells that experience basic congestion in uplink or downlink and admits the MS to the 2G cell if the MS performs only CS voice services after accessing the network. The details are as follows: − G2GLoadAdjustCoeff z x Current load in the serving 2G cell – 10 x load in the neighboring 3G cell ≥ 10 x G2G3GLdBlcDeltaThrd – 1.000 InterRATLoadHoEcNoStart – LOADOFFSET < CPICH Ec/No < InterRATLoadHoEcNoStart CPICH Ec/No > IntRATLoadHOEcNoThr Huawei Proprietary and Confidential Copyright © Huawei Technologies Co. z When the InterRatServiceLoadHoSwitch parameter is set to Dynamic-based(Dynamic Service/Load-based). Ltd. the BSC does not start the handover from 2G to 3G. 4. 6. the neighboring 3G cell is not considered as a candidate cell. delay caused by handovers between GSM and TD-SCDMA is reduced.GSM BSS 2G/3G Interoperability (TDD) 6 2G/3G Inter-RAT Handover If a candidate neighboring 3G cell does not meet the preceding condition. the BSC reserves a channel for the MS to be handed over from the TD-SCDMA network. The radio resource reservation procedure is achieved through the information exchange over the Iur-g interface between the BSC and the RNC. the BSC assigns and activates a channel for the MS to be handed over from the TD-SCDMA network based on the resource request message received and the AMR speech versions supported by the target cell and the MS. the BSC performs the radio resource reservation procedure that originally involves the Core Network (CN) in advance. 2. Meanwhile. requesting resources for this MS. 6-4 . The BSC supports the enhanced radio resource reserved handover based on Iur-g only when parameters INTERRATINBSCHOEN and InterRatIurgInBscHoEn are both set to YES. The RNC requests Iur-g SCCP links for this MS and sends the BSC an ENHANCED RELOCATION RESOURCE REQUEST message. If there is at least one candidate 3G cell that meets the preceding condition. The RNC receives measurement reports (MRs) from the MS and selects an optimum target cell to perform handover based on the capacity and load of neighboring GSM cells. The RNC must support the enhanced radio resource reserved handover based on Iur-g. The enhanced radio resource reserved handover procedure consists of the standard handover procedure between GSM and TD-SCDMA and the radio resource reservation procedure. requesting the handover. The BSC stops the incoming BSC HO A interface timer and establishes the connections on the user planes of the A and Abis interfaces. and sends the MSC a RELOCATION REQUIRED message to request the handover. the BSC selects the best candidate cell as the target cell. the BSC sends the RNC an ENHANCED RELOCATION RESOURCE RESPONCE message. If the load information about a neighboring 3G cell is invalid. After receiving the request from the RNC. 5. and the handover success rate is improved. The enhanced radio resource reserved handover based on Iur-g applies to the scenarios where the GSM and TD-SCDMA networks provide coverage for the same area. 6. The MSC sends the BSC a HANDOVER REQUEST message through the A interface. The message carries the call instance information that is allocated to the MS. In this case. the BSC starts the incoming BSC HO A interface timer. That is. In this way. Ltd. Procedure The procedure for the enhanced radio resource reserved handover based on Iur-g is described as follows: 1.. the neighboring 3G cell is removed from the list of candidate cells. The BSC also sends the MSC a HANDOVER REQUEST Issue 01 (2010-06-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co.5 Enhanced Radio Resource Reserved Handover Based on Iur-g Overview This section describes the feature GBFD-511402 Radio Resource Reserved Handover Between GSM/TD-SCDMA Based on Iur-g. The RNC sends the MS a HANDOVER FROM UTRAN COMMAND message to instruct the MS to prepare for the handover. 3. Then. 8. 6-5 . Ltd. 10. requesting resources for this MS. In this way. 7. The MSC sends the RNC an IU RELEASE COMMAND message through the Iu interface. The BSC detects that the SS7 signaling link on the A interface is faulty. notifying the RNC to release the Iu/Iub resources. In addition. the related resources over the Iu interface between the RNC and the CN are still retained. and InterRatIurgVoiceCarryEn are all set to YES. The RNC requests Iur-g SCCP links for this MS and sends the BSC an ENHANCED RELOCATION RESOURCE REQMSST message. The RNC must support the optimized handover between GSM and TD-SCDMA based on Iur-g. The MS sends the BSC a HANDOVER ACCESS message to start the handover to the BSC.GSM BSS 2G/3G Interoperability (TDD) 6 2G/3G Inter-RAT Handover ACKNOWLEDGE message over the A interface in response to the handover request of the MSC. the BSC sends the MSC a HANDOVER DETECT message over the A interface. The BSC detects that the speech versions supported by the target cell are different from the speech versions supported by the MS.6 Handover Optimization Between GSM and TD-SCDMA Based on Iur-g Overview The Iur-g interface is enhanced in such a way that it can carry control plane data as well as user plane data. After receiving the Relocation Commit message. After the handover is complete. In the optimized handover between GSM and TD-SCDMA based on Iur-g. 6. After receiving the message from the RNC. Procedure The procedure for the optimized handover between GSM and TD-SCDMA based on Iur-g is described as follows: z z z The RNC receives measurement reports (MRs) from the MS and selects an optimum target cell to perform handover based on the capacity and load of neighboring GSM cells. and releases the related Iur-g resources. the TCTYPE must be set to UTC. the BSC assigns and activates a channel for the MS to be handed over form the TD-SCDMA network based on the message received and the AMR speech Issue 01 (2010-06-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co. InterRatIurgInBscHoEn. The BSC then forwards the message to the MSC.. The BSC fails to assign or activate a channel. the Iur-g interface carries control plane data and user plane data. and the handover between GSM and TD-SCDMA is processed in a way that is similar to the way in which an intra-RNC handover is processed. After the handover is complete. The BSC considers the resource request message as illegal. the MS sends the BSC a HANDOVER COMPLETE message. The BSC sends the RNC an ENHANCED RELOCATION RESOURCE FAIL message and processes the handover as a normal incoming BSC handover if any of the following conditions is met: z z z z z The RNC does not support the enhanced radio resource reserved handover based on Iur-g. The BSC supports the optimized handover between GSM and TD-SCDMA based on Iur-g only when parameters INTERRATINBSCHOEN. which is used to ensure that the MSC sends messages over the A interface in the right sequence in time. the delay caused by the handover is reduced. Then the BSC waits to receive from the RNC a Relocation Commit message. 9. The handover is complete. After receiving the HANDOVER ACCESS message from the MS. The BSC receives a handover request message from the CN through the A interface and requests A interface resources accordingly. The MS is handed over to the BSC. the BSC responds to the handover request message.GSM BSS 2G/3G Interoperability (TDD) 6 2G/3G Inter-RAT Handover versions supported by the target cell and the MS. On receiving the RELOCATION COMMIT message. The message carries the call instance information that is allocated to the MS. instructing the MS to hand over to the BSC.. the connection on the Iu interface is released. The MS sends the BSC a HANDOVER COMPLETE message through the Um interface. Meanwhile. Ltd. and waits for the RELOCATION COMMIT message from the RNC. the BSC establishes the connections on the user planes of the A and Abis interfaces. z z z z z The BSC sends the RNC an ENHANCED RELOCATION RESOURCE RESPONCE message. The BSC establishes the connections on the user planes of the Iur-g and Abis interfaces. The RNC sends the MS a HANDOVER FROM UTRAN COMMAND message. and a connection is established on the A interface to prevent repeated handover decisions over the Iur-g interface. The MS sends the BSC a HANDOVER ACCESS message. Issue 01 (2010-06-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co. and releases the connection on the user plane of the Iur-g interface. the BSC sends the RNC an ENHANCED RELOCATION RESOURCE RESPONSE message. After the handover is complete. The Iur-g interface carries speech data. 6-6 . To solve this problem. In addition.. In addition. these neighboring TDD cells are regarded as one neighboring cell. Otherwise. During network planning. If the GSM cell has multiple neighboring TDD cells with the same frequency and different scrambling codes. Huawei optimizes GSM/TD-SCDMA interoperability. the BSS delivers the description of only one cell in the System Information 2Quater and Measurement Information to the MS. The parameter TDDSIOPTIMIZEDALLOWED determines whether to enable GSM/TD-SCDMA interoperability optimization. If TDDSIOPTIMIZEDALLOWED is set to YES(Yes) and the neighboring UMTS cell of the )GSM cell is a TDD cell. This is because these MSs have defects in system information decoding. different frequencies must be planned for the neighboring TDD cells of each GSM cell. 7-1 . Ltd. the BSS delivers only the frequency information of the TDD cell in the TDD cell description without scrambling code information. the parameter TDDMIPROHIBIT determines whether the BSS delivers the Measurement Information that contains the neighboring 3G cell information to avoid faults occurring in some MSs with decoding defects.GSM BSS 2G/3G Interoperability (TDD) 7 GSM/TD-SCDMA Interoperability Optimization 7 GSM/TD-SCDMA Interoperability Optimization After the GSM cell is configured with neighboring TD-SCDMA cells. some MSs restart or stop working. the BSS adds a virtual FDD cell description before the TDD cell description when delivering the System Information 2Quater and Measurement Information. the handover from the GSM cell to the TD-SCDMA cell may fail. The neighboring TDD cell of a GSM cell can be configured with a maximum of 16 different frequencies. Issue 01 (2010-06-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co. that is. the BSC sends the PACKET MEASUREMENT ORDER message to the MS. In this way. instructing the MS to filter the neighboring TDD cell list. or RPTPERIODT is changed. NCO. thus prohibiting the MS from reselecting the neighboring TDD cell.. Issue 01 (2010-06-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co. the BSC sends the PACKET MEASUREMENT ORDER message to the MS after the PS service access is successful. the MS in packet transfer mode does not reselect a neighboring TDD cell. Ltd. The cell reselection parameter QP is set to 15 to prohibit the MS from listening to the neighboring TDD cell list. z Modifying parameter settings When the value of TDDMIPROHIBIT. During the PS service. 8-1 . To solve this problem. the KPIs may deteriorate after the cell reselection. the BSC sends the PACKET MEASUREMENT ORDER message to all the MSs in packet transfer mode in the cell.GSM BSS 2G/3G Interoperability (TDD) 8 PS GSM and TD-SCDMA Interoperability Optimization 8 PS GSM and TD-SCDMA Interoperability Optimization When the network is not configured with the PBCCH. the MS in packet transfer mode performs the cell reselection procedure in idle mode. z Prohibiting cell reselection from GSM to TD-SCDMA When TDDSIOPTIMIZEDALLOWED is set to NO(No). instructing the MSs to update the parameter value dynamically. if the MS performs autonomous cell reselection from GSM to TD-SCDMA. . Neighboring UMTS Cell Configuration Currently. Issue 01 (2010-06-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co. a neighboring UMTS cell using FDD. Therefore. a GSM cell can be configured with a maximum of 64 neighboring TDD cells. the BSS cannot determine the mapping between the measurement information and the neighboring cells. the early classmark sending function should be enabled so that MSs report their support capability as soon as possible. When the value of TDDCELLRESELDIV is smaller than 8. the consistency between the GSM parameters and the UMTS parameters should be taken into account to avoid ping-pong handovers. If the operator requires that MSs access the UMTS network preferentially in the areas covered by the UMTS network. The value of TDDCELLRESELDIV determines cell reselection. Therefore. the value of TDDCELLRESELDIV should be changed so that the actual offset is a negative value. This may cause handover failures easily. the neighboring TDD cells of a GSM cell can have a maximum of 16 different frequencies. It is recommended that ECSC be set to YES(Yes). the UMTS cell searching is performed. 9-1 . One is the neighboring WCDMA cell. neighboring UMTS cells must be configured. The neighboring FDD cells and neighboring TDD cells cannot be configured for a GSM cell simultaneously. When GSM/TD-SCDMA interoperability optimization is enabled. the corresponding actual offset is smaller than 0. After 2G/3G interoperability is enabled. When GSM/TD-SCDMA interoperability optimization is not enabled. the system should obtain the support capability of MSs. When GSM/TD-SCDMA interoperability optimization is enabled. which is called neighboring TDD cell. If multiple neighboring TD-SCDMA cells of the GSM cell have the same frequency. GSM/TD-SCDMA Interoperability Optimization To avoid communication failures due to MS chip defects. it is recommended that QI be set to 7. the BSC6900 supports two types of neighboring UMTS cells using different access technologies. Before 2G/3G interoperability is enabled. a neighboring UMTS cell using TDD. when GSM/TD-SCDMA interoperability optimization is enabled. a maximum of 64 neighboring TDD cells can be configured. If QI be set to 7. a GSM cell should not be configured with neighboring TDD cells that have the same frequency and different scrambling codes. both TDDSIOPTIMIZEDALLOWED and TDDMIPROHIBIT are set to YES(Yes) in the cell configured with neighboring TDD cells. The network can control the cell reselection between GSM and UMTS through related parameters in the system information. The neighboring UMTS cells of a cell must be all the neighboring FDD cells or neighboring TDD cells. These neighboring cells can have a maximum of 3 different frequencies. In addition. Ltd.GSM BSS 2G/3G Interoperability (TDD) 9 Engineering Guidelines 9 Engineering Guidelines Related Parameters in the System Information 2G/3G interoperability requires the support of MSs. which is called neighboring FDD cell. If MSs are expected to camp on the UMTS network. The other is the neighboring TD-SCDMA cell. UTRANCELLTYPE is set to TDD(TDD). the scrambling code information of TD-SCDMA cells is not delivered in the system information. If the UMTS cell is a TD-SCDMA cell. The UMTS cell can be configured on the BSS side through the addition of external 3G cells. and a maximum of 32 neighboring TDD cells can have the same frequency. During the configuration of the inter-RAT cell reselection parameters and handover thresholds. YES Unit: None Default Value: NO HOOPTSEL BSC6900 SET Meaning: This parameter specifies whether a 2G GCELLHOUTRANF cell or to a 3G cell is preferentially selected as the DD(Optional) target cell for handover. the BSC preferentially selects a neighboring 2G cell as the handover target cell.. ptional) GUI Value Range: NO(No). YES(Yes) Actual Value Range: NO. the BSC preferentially selects a 2G candidate cell as the target cell for handover. step: 4 Unit: dB Default Value: 8 INTERRATINBSCH BSC6900 SET Meaning: This parameter specifies whether the OEN GCELLHOBASIC(O handover from 3G cells to 2G cells is allowed. Pre_3G_Cell. When this parameter is set to Pre_3G_Cell. -28~28. 10-1 . 15: 28 dB GUI Value Range: 0~15 Actual Value Range: Negative infinity.. When this parameter is set to Pre_2G_Cell. Pre_2G_CellThres Unit: None Default Value: Pre_2G_CellThres BSC6900 SET Meaning: This parameter specifies whether a 2G HOOPTSEL Issue 01 (2010-06-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co. Pre_3G_Cell(Preference for 3G cell).GSM BSS 2G/3G Interoperability (TDD) 10 Parameters 10 Parameters Table 10-1 Parameter description Parameter ID NE MML Description TDDCELLRESELDI BSC6900 SET Meaning: A TDD cell can become a candidate cell V GCELLCCUTRANS only when the average receive level of the TDD YS(Optional) cell is greater than the TDD Cell Reselect Diversity of the serving cell. Ltd. the BSC preferentially selects a neighboring 3G cell as the handover target cell if the receive level of the neighboring 2G cell that ranks the first in the candidate cell list is equal to or smaller than "HO Preference Threshold for 2G Cell". The value of this parameter corresponds to the following decibel value: 0: negative infinity 1: -28 dB 2: -24 dB . Pre_2G_CellThres(Preference 2G cell by thresh) Actual Value Range: Pre_2G_Cell. Otherwise. When this parameter is set to Pre_2G_CellThres. the BSC preferentially selects a 3G candidate cell as the target cell for handover. GUI Value Range: Pre_2G_Cell(Preference for 2G cell).. Pre_2G_CellThres(Preference 2G cell by thresh) Actual Value Range: Pre_2G_Cell. GUI Value Range: 0~63 Actual Value Range: 0~63 Unit: dB Default Value: 25 HOPRETH2G INTERRATOUTBSC BSC6900 SET Meaning: This parameter specifies whether the HOEN GCELLHOBASIC(O handover from 2G cells to 3G cells is allowed. the BSC preferentially selects a neighboring 2G cell as the handover target cell. Otherwise. When this parameter is set to Pre_3G_Cell. the BSC preferentially selects a 3G candidate cell as the target cell for handover. YES Unit: None Default Value: NO BET3GHOEN BSC6900 SET Meaning: This parameter specifies whether to GCELLHOUTRANF allow 3G better cell handover algorithm.GSM BSS 2G/3G Interoperability (TDD) 10 Parameters GCELLHOUTRANT cell or to a 3G cell is preferentially selected as the DD(Optional) target cell for handover. 10-2 . When this parameter is set to Pre_2G_CellThres. Pre_3G_Cell. ptional) GUI Value Range: NO(No). Otherwise. Pre_3G_Cell(Preference for 3G cell). the BSC preferentially selects a neighboring 3G cell as the handover target cell. the BSC preferentially selects a neighboring 3G cell as the handover target cell. Issue 01 (2010-06-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co. When this parameter is set to Pre_2G_Cell. Ltd. YES(Yes) Actual Value Range: NO. Otherwise. GUI Value Range: 0~63 Actual Value Range: 0~63 Unit: dB Default Value: 25 BSC6900 SET Meaning: If the receive level of the neighboring GCELLHOUTRANT 2G cell that ranks the first in the candidate cell list DD(Optional) is equal to or smaller than this threshold. the BSC preferentially selects a neighboring 2G cell as the handover target cell. the BSC preferentially selects a neighboring 2G cell as the handover target cell.. GUI Value Range: Pre_2G_Cell(Preference for 2G cell). Pre_2G_CellThres Unit: None Default Value: Pre_2G_CellThres HOPRETH2G BSC6900 SET Meaning: If the receive level of the neighboring GCELLHOUTRANF 2G cell that ranks the first in the candidate cell list DD(Optional) is equal to or smaller than this threshold. the BSC preferentially selects a neighboring 3G cell as the handover target cell if the receive level of the neighboring 2G cell that ranks the first in the candidate cell list is equal to or smaller than "HO Preference Threshold for 2G Cell". the BSC preferentially selects a 2G candidate cell as the target cell for handover. 5~16. the MOD handover is triggered. ) GUI Value Range: 1~32 Actual Value Range: 0. Ltd. the handover MOD is triggered. if the G3GNCELL(Optional conditions for the handover to a better 3G cell are ) met in P of N measurement reports.. G3GNCELL(Optional This parameter specifies the number P. GUI Value Range: NO(No). YES(Yes) Actual Value Range: NO. YES(Yes) Actual Value Range: NO. 10-3 . ) GUI Value Range: 1~32 Actual Value Range: 0. YES Unit: None Default Value: NO BET3GHOEN BSC6900 SET Meaning: This parameter specifies whether to GCELLHOUTRANT allow 3G better cell handover algorithm.5 Unit: s Default Value: 10 BSC6900 SET Meaning: The 3G better cell handover is triggered GCELLHOUTRANF only when the RSCP of a neighboring 3G cell is DD(Optional) greater than this threshold for a period of time. step:0.5 Unit: s Default Value: 8 BSC6900 ADD Meaning: According to the P/N rule.GSM BSS 2G/3G Interoperability (TDD) 10 Parameters DD(Optional) GUI Value Range: NO(No).5~16. GUI Value Range: 0~63 Actual Value Range: 0~63 Unit: dB Default Value: 50 BSC6900 SET Meaning: This parameter specifies whether to GCELLHOINTERRA allow the inter-RAT load handover in connection TLDB(Optional) mode (after the assignment is complete). DD(Optional) GUI Value Range: NO(No). YES(Yes) Actual Value Range: NO. GUI Value Range: 0~63 Actual Value Range: 0~63 Unit: dB Default Value: 50 BSC6900 SET Meaning: The 3G better cell handover is triggered GCELLHOUTRANT only when the RSCP of a neighboring 3G cell is DD(Optional) greater than this threshold for a period of time. step:0. YES Unit: None Default Value: NO BSC6900 SET Meaning: System flux thresholds correspond to HODURT3GTDD HOSTAT3GTDD HORSCPTH3G HORSCPTH3G OutSysLoadHoEn SYSFLOWLEV Issue 01 (2010-06-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co. if the G3GNCELL(Optional conditions for the handover to a better 3G cell are ) met for P seconds within N seconds. YES Unit: None Default Value: NO BSC6900 ADD Meaning: According to the P/N rule. G3GNCELL(Optional This parameter specifies the number N. Where.Inner Flow Control Discard Begin Threshold) x 100]/10+1 (round-down for division operation). If the value is smaller than Inner Flow Control Discard Begin Threshold. 2) Flow control threshold for the CPU to start to discard the channel access messages and paging messages: 80% . Thus. GUI Value Range: 0~100 Actual Value Range: 0~100 Unit: None Default Value: 90 G2GLoadAdjustCoef BSC6900 SET Meaning: Coefficient used to modulate the load f GCELLHOINTERRA level of a 2G system so that the load level of the TLDB(Optional) 2G system can be compared with that of a 3G system. An increase of 5% means an increase of 2 levels. 8. and FID queuing load. Ltd. 8~11 Unit: None Default Value: 10 TRIGTHRES BSC6900 SET Meaning: The load handover is triggered when GCELLHOAD(Optio the traffic load in a cell is greater than the value of nal) this parameter. 6. GUI Value Range: 0. If the value is equal to or greater than Inner Flow Control Discard Begin Threshold. The system flux level is the current flux control level of the system. 2. GUI Value Range: 0~100 Actual Value Range: 0~100 Unit: None Issue 01 (2010-06-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co. The handover performed over the maximum threshold may have tremendous impacts on the system. 1) The flow control level algorithm for the assigned system messages: [(Average Message Usage . CPU load. 8~11 Actual Value Range: 0.Inner Flow Control Discard Begin Threshold)/(Inner Flow Control Discard All Threshold .GSM BSS 2G/3G Interoperability (TDD) 10 Parameters GCELLHOAD(Optio the system flux obtained based on message nal) packets. 10-4 . 0 indicates the lowest level and 11 indicates the highest level. The level value can be 0. the level is calculated. 4. and 10. CPU usage smaller than 80% corresponds to level 0. this parameter should not be set to a higher value.. 0-11: There are 12 flow control levels. The value range is from 0 to 11. Flow control threshold for the CPU to discard all channel access messages and paging messages: 100% . Level 10 is the highest. CPU usage equal to or greater than CPU flow control threshold 80% corresponds to level 2. A load handover is allowed only when the system flux is lower than the value of this parameter. Level 0 is used. In the handover algorithm of the second generation."Load HO Bandwidth" and ("Inter-cell HO Hysteresis" . YES Unit: None Default Value: NO InterRatIurgVoiceCar BSC6900 SET Meaning: Whether to carry the speech data on ryEn GCELLHOBASIC(O the Iur-g interface. 10-5 . GUI Value Range: 0~200 Actual Value Range: -100~100 Unit: % Default Value: 110 InterRATLoadHoEcN BSC6900 SET Meaning: Initial EcNo value of the inter-RAT oStart GCELLHOINTERRA load-based handover band TLDB(Optional) GUI Value Range: 0~49 Actual Value Range: 0~49 Unit: dB Default Value: 49 LOADOFFSET BSC6900 SET Meaning: In the handover algorithm of the first GCELLHOAD(Optio generation. GUI Value Range: NO(No).. YES Unit: None Issue 01 (2010-06-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co.64) . Ltd.64). load handovers can be performed nal) only when the receive level of the current serving cell is in the range "Edge HO DL RX_LEV Threshold" to "Edge HO DL RX_LEV Threshold" + "Load HO Bandwidth". load tional) balance is triggered.GSM BSS 2G/3G Interoperability (TDD) 10 Parameters Default Value: 10 G2G3GLdBlcDeltaTh BSC6900 SET Meaning: If the load balance between a 2G cell rd OTHSOFTPARA(Op and a 3G cell is greater than the threshold. If this parameter is set to YES. ptional) the speech data is still carried on the Iur-g interface and then transmitted through the Iu interface when the 3G service is switched to the 2G network. YES(Yes) Actual Value Range: NO. GUI Value Range: 0~63 Actual Value Range: 0~63 Unit: dB Default Value: 25 IntRATLoadHOEcNo BSC6900 SET Meaning: Minimum Ec/No value of a 3G cell Thr GCELLHOINTERRA during the load-based GSM-to-UMTS handover TLDB(Optional) GUI Value Range: 0~49 Actual Value Range: 0~49 Unit: dB Default Value: 25 InterRatIurgInBscHo BSC6900 SET Meaning: Whether to reserve resources for the En GCELLHOBASIC(O incoming BSC handover on the Iur-g interface ptional) GUI Value Range: NO(No). YES(Yes) Actual Value Range: NO. load handovers can be performed only when the level difference between the neighboring cell and the serving cell is between ("Inter-cell HO Hysteresis" . YES Unit: None Default Value: NO TDDMIPROHIBIT BSC6900 SET Meaning: This parameter specifies whether to GCELLCCUTRANS send the system information MI which contains YS(Optional) the 3G neighboring cell information in the TDD neighboring cell. GUI Value Range: NO(No). then the MS starts to search for 3G cells. The value YES(YES) indicates that the MI is sent. if this parameter is set to 10 and if the signal level of the serving cell is above 10. Ltd. 10-6 . UTC. if this parameter is set to 5 and if the signal level of the serving cell is lower than 5. 7] or above [8. the MS starts to search for 3G cells. the MS starts to search for 3G cells. 15]. ITC(Packet Conversion) Actual Value Range: GTC. YES Unit: None Default Value: NO QP BSC6900 SET Meaning: This parameter specifies one threshold GCELLCCUTRANS of the signal level for cell reselection in packet YS(Optional) transfer mode.. The values of this parameter correspond to the following decibel values: 0: -98 dBm 1: -94 dBm Issue 01 (2010-06-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co. if the signal level of the serving cell is below [0. That is. GUI Value Range: NO(No). In packet transfer mode. YES(Yes) Actual Value Range: NO. to add an FDD neighboring cell information before the TDD neighboring cell information to solve the compatibility problem of some dual-mode MSs. and the value NO(NO) indicates that the MI is not sent.GSM BSS 2G/3G Interoperability (TDD) 10 Parameters Default Value: NO TCTYPE BSC6900 SET Meaning: The type of TC resource TCTYPE(Mandatory) GTC: TC resources that support normal voice coding/decoding and packet conversion UTC: TC resources that support only the optimized handover on the Iur-g interface ITC: TC resources that support only packet conversion GUI Value Range: GTC(Normal voice coding/decoding). For example. UTC(Optimized handover on the Iur-g interface). YES(Yes) Actual Value Range: NO. ITC Unit: None Default Value: None TDDSIOPTIMIZEDA BSC6900 SET Meaning: This parameter specifies whether to LLOWED GCELLCCUTRANS optimize the system information 2Quater and MI YS(Optional) of the TDD neighboring cell. Ltd. When this parameter is set to NC2 and "Support NC2" in "SET GCELLGPRS" is set to "YES". 30. The MS shall send measurement reports to the network.68sec). -66. NC1(NC1).72sec. 6: -74 dBm 7: (always) 8: -78 dBm 9: -74 dBm .84sec(3. NC2 Unit: None Default Value: NC0 RPTPERIODT BSC6900 SET Meaning: Cell reselection measurement report GCELLNWCTRLMS period in packet transmission mode RPARA(Optional) GUI Value Range: 0.96sec). -86. 30. -78. 1. ional) NC0: normal MS control.68sec(7. 0. -82. -90. 0. the MS sends additional classmark information to the network ECSC Issue 01 (2010-06-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co. -58. 3.36sec. 10-7 . -74. NC1. (always).72sec(30.48sec(0. 15.84sec. the network side can control the cell reselection for the MS.68sec. 7. Positive infinity(never) Unit: None Default Value: 15 NCO BSC6900 SET Meaning: Network control mode for cell GCELLPSBASE(Opt reselection of the MS..44sec Unit: s Default Value: 0.44sec(61. The MS shall send measurement reports to the network and the MS shall perform autonomous cell re-selection. 14: -54 dBm 15: Positive infinity (never) GUI Value Range: 0~15 Actual Value Range: -98.92sec). The MS shall only perform autonomous cell re-selection when the reselection is triggered by a downlink signaling failure or a random access failure.36sec). -70.72sec).48sec). -74. -62.. 1.92sec(1.84sec).GSM BSS 2G/3G Interoperability (TDD) 10 Parameters . NC2(NC2) Actual Value Range: NC0. There are three modes. 3.96sec BSC6900 SET Meaning: The early classmark sending control GCELLCCBASIC(Op (ECSC) parameter specifies whether the MSs in a tional) cell use early classmark sending. NC2: network control.. The MS shall perform autonomous cell re-selection.96sec. 15.48sec.92sec. -78. 61.36sec(15. NC1: MS control with measurement reports.. -94. 61. 7. GUI Value Range: NC0(NC0). -54.44sec) Actual Value Range: 0. After a successful immediate assignment.96sec(0.. YES Unit: None Default Value: YES QI BSC6900 SET Meaning: This parameter specifies the level GCELLCCUTRANS threshold for cell reselection in idle mode. -94. 15]. the MS keeps searching for 3G cells 8: -78 dBm 9: -74 dBm 10: -70 dBm 11: -66 dBm 12: -62 dBm 13: -58 dBm 14: -54 dBm 15: Positive infinity (never). -86.. For example. -78. YES(Yes) Actual Value Range: NO. if this parameter is set to 5 and if the signal level of the serving cell is lower than 5. The values of this parameter correspond to the following decibel values: 0: -98 dBm 1: -94 dBm 2: -90 dBm 3: -86 dBm 4: -82 dBm 5: -78 dBm 6: -74 dBm 7: (always). -62. -70. -74. if this parameter is set to 10 and if the signal level of the serving cell is above 10. (always). the MS starts to search for 3G cells. Positive infinity(never) Unit: None Default Value: 15 UTRANCELLTYPE BSC6900 ADD Meaning: This parameter specifies the type of a GEXT3GCELL(Mand 3G cell. that is. 7] or above [8. The additional classmark information mainly contains the CM3 (classmark 3) information. -74. the MS starts to search for 3G cells. GUI Value Range: NO(No). -90. -82. 10-8 .GSM BSS 2G/3G Interoperability (TDD) 10 Parameters as early as possible. Ltd. A cell type can be Frequency Division Issue 01 (2010-06-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co. The CM3 (classmark 3) information contains the frequency band support capability of the MS (used for the future channel assignment). the MS does not search for 3G cells. and encryption capability of the MS. if the signal level of the serving cell is below [0. power information about each frequency band supported by the MS (used for the handover between different frequency bands). that is. -66. -78. YS(Optional) In idle mode. GUI Value Range: 0~15 Actual Value Range: -98. then the MS starts to search for 3G cells. -54. -58. GSM BSS 2G/3G Interoperability (TDD) 10 Parameters atory) Duplex (FDD) or Time Division Duplex (TDD).. NACCRELATED Unit: None Default Value: CELLCAPCLASS Issue 01 (2010-06-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co. YES Unit: None Default Value: NO SPTINFOEXCHG BSC6900 ADD GNRNC(Optional) MOD GNRNC(Optional) Meaning: Whether to support the bidirectional information exchange procedure on the Iur-g interface. YES(Support) Actual Value Range: NO. TDD Unit: None Default Value: None SPTCOMMMEAS BSC6900 ADD GNRNC(Optional) MOD GNRNC(Optional) Meaning: Whether to support the common bidirectional measurement procedure on the Iur-g interface. Ltd. GUI Value Range: NO(No Support). 10-9 . NACCRELATED(NACC Info) Actual Value Range: CELLCAPCLASS. MOD GEXT3GCELL(Optio GUI Value Range: FDD(FDD). GUI Value Range: NO(No Support). YES Unit: None Default Value: NO INFOEXCHGLIST BSC6900 ADD Meaning: Information exchange content to be GNRNC(Mandatory) supported MOD GNRNC(Mandatory) GUI Value Range: CELLCAPCLASS(Cell Capacity Info). TDD(TDD) nal) Actual Value Range: FDD. YES(Support) Actual Value Range: NO. GSM BSS 2G/3G Interoperability (TDD) 11 Counters 11 Counters For the counters. see the BSC6900 GSM Performance Counter Reference. 11-1 .. Issue 01 (2010-06-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co. Ltd. and definitions.GSM BSS 2G/3G Interoperability (TDD) 12 Glossary 12 Glossary For the acronyms.. 12-1 . Ltd. abbreviations. Issue 01 (2010-06-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co. see the Glossary. terms. 018 Mobile radio interface layer 3 specification.008 Radio subsystem link control [2] 3GPP TS 44.Base Station system (MSC-BSS) interface. 13-1 . Radio Resource Control (RRC) protocol [3] 3GPP TS 48..008 Mobile Switching Centre . Ltd. Layer 3 specification [4] BSC6900 Feature List [5] BSC6900 Optional Feature Description [6] GBSS Reconfiguration Guide [7] BSC6900 GSM Parameter Reference [8] BSC6900 GSM MML Command Reference [9] BSC6900 GSM Performance Counter Reference Issue 01 (2010-06-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co.GSM BSS 2G/3G Interoperability (TDD) 13 Reference Documents 13 Reference Documents [1] 3GPP TS 45.