2G3G Interoperability (TDD).pdf

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2G/3G Interoperabili ty (TDD)Feature Parameter Description

Copyright Huawei Technolog ies Co., Ltd. 2011. All rights reserved.

No part of this document may be reproduced or transmitted in any form or by any means without priorwritten 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 respectiveholders.

Notice

The purchased products, services and features are stipulated by the commercial contract made betweenHuawei and the customer. All or partial products, services and features described in this document maynot be within the purchased scope or the usage scope. Unless otherwise agreed by the contract, allstatements, information, and recommendations in this document are provided AS IS without warranties,

guarantees or representations of any kind, either express or implied.

The information in this document is subject to change without notice. Every effort has been made in thepreparation of this document to ensure accuracy of the contents, but all statements, information, andrecommendations in this document do not constitute the warranty of any kind, express or implied.

Issue 01 (2010-06-30)Huawei Proprietary and Confidential

Copyright Huawei Technologies Co., Ltd.i


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2G/3G Interoperability (TDD) Contents

Issue 01 (2010-06-30) Huawei Proprietary and Confidential

Copyright Huawei Technologies Co., Ltd.

ii

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


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2G/3G Interoperability (TDD) 1 Introduction



1-1

1 Introduction

1.1 Scope

This document describes the 2G/3G interoperability feature of Huawei GBSS. It covers the functions ofand technologies related to this feature, including measurement of neighboring 3G cells, inter-RAT cellreselection, 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 ofGSM telecommunication.

This document is intended for:

z

Personnel working on Huawei GSM products or systemsz 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 productversion.

z Editorial change

Editorial change refers to the change in wording or the addition of the information that was notdescribed in the earlier version.

Document Issues

The document issues are as follows:

z 01 (2010-06-30)

z 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 incorporatesthe changes described in the following table.

Change Type Change Descrip tion Parameter Change

Feature change None. None.

Editorial change Parameters are presented in the form of Parameter ID insteadof Parameter Name.

None.


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Draft (2010-03-30)

This is the draft release of GBSS12.0.


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2G/3G Interoperability (TDD) 2 Overview



2-1

2 Overview

The UMTS network and the GSM network will coexist and provide services together for a long time. Tofacilitate the service provision by both the networks, Huawei introduces 2G/3G interoperability into the

BSS, which consists of two functions: inter-RAT handover and inter-RAT cell reselection between GSMand UMTS.

Through 2G/3G interoperability, a smooth evolution from GSM to UMTS can be achieved, thus savingthe investment. For the operator that has both the UMTS network and the GSM network, 2G/3Ginteroperability enables the GSM network and the UMTS network to complement each other, thusexpanding the network coverage and improving the service quality. For example, when a dual-mode MSmoves to an area without UMTS coverage, it can reselect or be handed over to a GSM cell through2G/3G interoperability. The continuous coverage brought by this feature improves the user experience.

For the areas covered by both the GSM network and the UMTS network, 2G/3G interoperability can beperformed to achieve traffic balance between the GSM system and the UMTS system. For example,when the traffic load in a GSM cell is too heavy, 2G/3G interoperability can be performed to hand over

some calls from the GSM cell to a UMTS cell.

With 2G/3G interoperability, the access policy for the GSM network can be different from that for theUMTS network in the areas covered by both the GSM network and the UMTS network. For example, theGSM network can be preferentially selected by CS services and similarly the UMTS network by PSservices. In this way, the advantages of both networks can be achieved.

All the MSs involved in this feature are dual-mode MSs.


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2G/3G Interoperability (TDD) 3 Measurement of Neighboring UMTS Cells



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3 Measurement of Neighboring UMTS Cells

The system information contains the neighboring UMTS cell list and UMTS cell reselection parameters,based on which the MS measures the neighboring cell information and performs cell reselection and

handover. The system information refers to System Information 2ter, System Information 2Quater, andMeasurement Information. System Information 2ter and System Information 2Quater are sent on theBCCH, and Measurement Information is sent on the SACCH. The parameterSend2QuterFlag controlswhether System Information 2Quater should be sent.

The MSs in a GSM cell measure the information of both neighboring GSM cells and neighboring UMTScells. To reduce unnecessary measurements and save power consumption of MSs, the BSS controls theneighboring cell measurement of MSs through parameters. The MSs in idle mode or packet transfermode can perform inter-RAT cell reselection. The MSs in dedicated mode can perform inter-RAThandover. Operators can set measurement parameters to different values for the MSs in different states.

The MSs in idle mode determine whether to measure the information about neighboring UMTS cellsaccording to QI and the receive level of the serving cell. The conditions for triggering the measurement

differ with the value ofQI.

z If the value ofQI ranges from 0 to 6, the measurement is triggered when the receive level of theserving cell is lower than the value ofQI.

z If the value ofQI ranges from 8 to 14, the measurement is triggered when the receive level of theserving cell is higher than the value ofQI.

z If the value ofQI is 7, the MSs always measure the neighboring UMTS cell information regardless ofthe receive level of the serving cell.

z If the value ofQI is 15, the MSs never measure the neighboring UMTS cell information regardless ofthe receive level of the serving cell.

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 themeasurement differ with the value ofQP.

z If the value ofQP ranges from 0 to 6, the measurement is triggered when the receive level of theserving cell is lower than the value ofQP.

z If the value ofQP ranges from 8 to 14, the measurement is triggered when the receive level of theserving cell is higher than the value ofQP.

z If the value ofQP is 7, the MSs always measure the neighboring UMTS cell information regardless ofthe receive level of the serving cell.

z If the value ofQP is 15, the MSs never measure the neighboring UMTS cell information regardless ofthe receive level of the serving cell.

The MSs in dedicated mode determine whether to measure the information about neighboring UMTScells according to QSEARCHC and the receive level of the serving cell. The conditions for triggering themeasurement differ with the value ofQSEARCHC.

z If the value ofQSEARCHC is between 0 and 6, the measurement is triggered when the receive levelof the serving cell is lower than the value ofQSEARCHC.

z If the value ofQSEARCHC is between 8 and 14, the measurement is triggered when the receive levelof the serving cell is higher than the value ofQSEARCHC.

z If the value ofQSEARCHC is 7, the MSs always measure the neighboring UMTS cell informationregardless of the receive level of the serving cell.

z If the value ofQSEARCHC is 15, the MSs never measure the neighboring UMTS cell informationregardless of the receive level of the serving cell.


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QSEARCHC is contained in the Measurement Information. After entering the dedicated mode, MSs tryto obtain the QSEARCHC from the Measurement Information transmitted on the SACCH. BeforeQSEARCHC is obtained, MSs take the value ofQCI that is transmitted on the BCCH as the value ofQSEARCHC.


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2G/3G Interoperability (TDD)

4 Common Measurements and Information

Exchange Based on Iur-g



4-1

4 Common Measurements and Information ExchangeBased on Iur-g

This section describes the feature GBFD-511401 Iur-g Interface Between GSM and TD-SCDMA.

4.1 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. In this case, unnecessary handoverattempts cannot be avoided.

With the development of 3GPP specifications, the Iur-g interface between the RNC and the BSC is usedto achieve common measurement and information exchange between 2G and 3G networks. Thissimplifies the 2G/3G interoperability procedures, reduces the delay caused by handovers, and improvesthe handover success rate.

Figure 4-1 shows the position of the Iur-g interface in the network architecture.

Figure 4-1 Position of the Iur-g interface in the network architecture

CN

A/Gb Iu

Iur-g

BSC RNC

Iu

Iur

RNC

Figure 4-2 shows the protocol stack defined in 3GPP specifications for the Iur-g interface.


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Figure 4-2 Protocol stack defined for the Iur-g interface

Layer

Transport Network

Control Plane

Radio

Network

Layer

Transport

Layer

RNSAP

Transport Network

User Plane

Control Plane

MTP3-B

SCCP

M3UAM3UA

SSCF-NNI SCTPSCTP

SSCOPIP

IP

AAL5

DATA LINKATM

Physical

There is an Iur-g interface between each remote RNC and the local BSC. The Iur-g interface supportsthe common measurement procedure and information exchange procedure. These two procedures areperformed through connection-oriented signaling.

The Iur-g interface is made to carry the control plane data and user plane data to reduce the delaycaused by handovers between GSM and TD-SCDMA and improve the handover success rate. The Iur-ginterface uses IP transmission.

4.2 Common Measurement

The common measurement is based on the Iur-g interface. The procedures of the commonmeasurement are performed through connection-oriented signaling. IfSPTCOMMMEASis set to Yes,the common measurement is enabled.

The source BSC/RNC sends a COMMON MEASUREMENT INITIATION REQUEST message to thetarget RNC/BSC to initialize the common measurement procedure. Through this message, the sourceBSC/RNC requests the target RNC/BSC to periodically report the load information about neighboringcells. If the target RNC/BSC supports the common measurement procedure, it responds with aCOMMON MEASUREMENT INITIATION RESPOSE message. Figure 4-3 shows the successfulcommon measurement initialization procedure.

Figure 4-3 Successful common measurement initialization

SBSC/SRNC

COMMON MEASUREMENT

INITIATION REQUEST

COMMON MEASUREMENT

INITIATION RESPOSE

TRNC/TBSC


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If the target RNC/BSC does not support the common measurement procedure, it responds with aCOMMON MEASUREMENT INITIATION FAILURE message. Figure 4-4 shows the failed commonmeasurement initialization procedure.

Figure 4-4 Failed common measurement initialization

After a common measurement is successfully initialized, the target RNC/BSC periodically sends

COMMON MEASUREMENT REPORT messages to the source BSC/RNC to report the load informationabout neighboring cells. Figure 4-5 shows the common measurement reporting procedure.

Figure 4-5 Common measurement reporting procedure

If a neighboring cell is faulty, blocked, removed, or deactivated, the target RNC/BSC sends a COMMONMEASUREMENT FAILURE INDICATION message to the source BSC/RNC, notifying the sourceBSC/RNC that the common measurement procedure has failed and has to be terminated. Figure 4-6shows the failed common measurement.

Figure 4-6 Failed common measurement

4.3 Information Exchange

The information exchange procedure is based on the Iur-g interface, performed throughconnection-oriented signaling.

IfSPTINFOEXCHG is set to Yes, and INFOEXCHGLIST is set to CELLCAPCLASS, the informationexchange is enabled.

During a common measurement procedure, information is transmitted between 2G and 3G networksthrough the Iur-g interface. Such information includes the load information about 2G and 3G cells,


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inter-RAT CS service handover support flag of a 2G cell, and inter-RAT PS service handover support flagof a 2G cell.

z Load information about 2G or 3G cells

A cell can be in three load states: normal, basic congestion, or overload congestion. Table 4-1

describes the rules for determining the load states of 2G cells.

Table 4-1 Rules for determining the load states of 2G cells

TransmissionDirection

If Then the Load State ofthe Cell Is

Uplink load < UlLdrThrd2GCell Normal

UlLdrThrd2GCell Uplink load < UlOlcThrd2GCell Basic congestion

Uplink

Uplink load UlOlcThrd2GCell Overload congestion

Downlink load < DlLdrThrd2GCell Normal

DlLdrThrd2GCell Downlink load < DlOlcThrd2GCell Basic congestion

Downlink

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 theInterRatCsServiceLoadHoThrd parameter or the INTERRATINBSCHOEN parameter is set toNO(No), the inter-RAT CS service handover support flag is No for a 2G cell. That is, the CS services in3G cells are not 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 issmaller than the value of the InterRatCsServiceLoadHoThrd parameter, the inter-RAT CS servicehandover support flag is Yes for a 2G cell. That is, the CS services in 3G cells are allowed to behanded over to 2G cells.

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 LOADRESELRXTHRSHparameter, the inter-RAT PS service handover support flag is Yes for a 2G cell. That is, the PSservices in 3G cells are allowed to be handed over to 2G cells. Otherwise, the PS services in 3G cellsare not allowed to be handed over to 2G cells.


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5 2G/3G Inter-RAT Cell Reselection

2G/3G inter-RAT cell reselection involves the cell reselection from GSM to UMTS and the cell reselectionfrom UMTS to GSM. Cell reselection is performed mainly by the MS.

For MSs in idle mode, cell reselection is mainly performed to implement 2G/3G interoperability. Adual-mode MS camping on a GSM cell can reselect a UMTS cell. It measures the information of theneighboring UMTS cell, and then decides whether to reselect the UMTS cell according to cell reselectionparameters.

For MSs in packet transfer mode, they can reselect a UMTS cell for data services through autonomouscell reselection, Network Assisted Cell Change (NACC), or Network Control Mode 2 (NC2). The cellreselection procedure in packet transfer mode is the same as that in idle mode. The autonomous cellreselection is performed by the MS without the intervention of the network. In NACC and NC2, thenetwork affects the cell reselection through signaling so that the MS will camp on the desired cell.

The parameterINTERRATCELLRESELEN determines whether cell reselection between GSM andUMTS is enabled. When INTERRATCELLRESELEN is set to No, the BSS does not send theneighboring UMTS cell list and the parameters related to 2G/3G inter-RAT cell reselection. In this way,MSs in a GSM cell cannot select a UMTS cell.

5.1 Inter-RAT Cell Reselection from UMTS to GSM

When an MS moves into the GSM coverage area and reselects a GSM cell, the MS initiates the locationupdate in the GSM network. The GSM network handles the location update regardless of whether theMS is from a UMTS cell or a GSM cell.

For the BSS, the cell reselection procedure from UMTS to GSM is the same as that between GSM cells.Thus, it is not repeated in this document.

5.2 Inter-RAT Cell Reselection from GSM to UMTSThe MSs in a GSM cell obtain the neighboring UMTS cell list and cell reselection parameters throughSystem Information 2ter and System Information 2Quater, and then measure the neighboring UMTScells according to the list and parameters. When the MS is in idle mode or packet transfer mode, themechanism of cell reselection from the GSM cell to the UMTS cell is the same as that between GSMcells. The GSM network controls the cell reselection from the GSM cell to the UMTS cell throughTDDCELLRESELDIV.

TDDCELLRESELDIV indicates the signal strength difference between the candidate UMTS cells andthe serving GSM cell. This parameter is a key factor for controlling the cell reselection from the GSM cellto the UMTS cell.

When TDDCELLRESELDIV is set to a small value, the cell reselection condition is easy to meet. In thiscase, the number of MSs that camp on the GSM cell is reduced. When TDDCELLRESELDIV is set to agreat value, the cell reselection condition is difficult to meet. In this case, the number of MSs that campon the GSM cell is increased.

For the UMTS TDD cell, the measurement quantity to be used is Received Signal Code Power (RSCP)of the Common Pilot Channel (CPICH). If the measurement result meets the following condition withinfive seconds, the MS initiates the cell reselection from GSM to UMTS. If there is more than one UMTScell that meets the condition, the MS selects a cell with the highest RSCP as the target cell.

z CPICH RSCP > RLA_C + TDDCELLRESELDIV

In the preceding condition, RLA_C refers to the average receive level. The RSCP of the neighboringUMTS cell must be greater than the sum of the value ofTDDCELLRESELDIV and the average receive


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level of the serving cell. In addition, the RSCP of the neighboring UMTS cell must be greater than thesum of the value ofTDDCELLRESELDIV 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 reselectionfrom UMTS to GSM. If the inter-RAT cell reselection from GSM to UMTS is triggered within 15s after the

cell reselection from UMTS to GSM, the value ofTDDCELLRESELDIV must be increased by 5 dB.

When the condition for the cell reselection from GSM to UMTS and the condition for the cell reselectionbetween GSM cells are met, the MS selects the UMTS cell as the target cell.

5.3 Fast 3G Reselection at 2G CS Call Release

Overview

Normally, after an MS terminates a call in a GSM cell, it camps on the GSM cell. When a neighboringUMTS cell meets the requirements for cell reselection, the MS camps on the UMTS cell after the cellreselection. Before initiating the UMTS cell reselection, the MS must receive system information andcalculate cell reselection parameters. When the Fast 3G Reselection at 2G CS Call Release feature is

activated, the BSS determines the best neighboring UMTS cell based on the measurement informationon the neighboring UMTS cells after the call termination in a GSM cell. Then, the BSS sends thefrequency information on the neighboring UMTS cell through a Channel Release message to the MS toinstruct it to camp on the UMTS cell. In this way, the MS camps on a UMTS cell without calculating cellreselection parameters, thus accelerating cell reselection. In addition, the MS camps on the UMTS cellfor a longer period, thus increasing the revenue of operators in the UMTS network.

This feature is activated when CELLSELECTAFTERCALLREL is set to YES.

A UMTS cell is classified into the UTRAN FDD cell and the UTRAN TDD cell.

Procedure

Take the case of call termination by the MS as an example. Figure 5-1 shows the cell reselectionprocedure.

Figure 5-1 Cell reselection procedure


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1. After receiving the Release Complete message from the MS, the MSC sends a Clear Commandmessage to the BSC to instructing the BSC to release the occupied resources on the A and Uminterfaces.

2. 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 Channel Release message may carry the information element"Cell selection indicator after release of all TCH and SDCCH", which contains the information on thetarget neighboring UMTS cell.

3. After receiving the Channel Release message, the MS disconnects the uplink signaling link. Then,the MS sends a DISC frame to the BTS to instruct the BTS to release the TCH or SDCCH.

4. After receiving the UA message, the MS switches to idle mode and initiates cell reselection.

If... Then...

The Channel Release message contains theinformation element "Cell selection indicator afterrelease of all TCH and SDCCH",

The MS attempts to camp on the cell indicated inthe Channel Release message.

The Channel Release message does not containthe information element "Cell selection indicatorafter release of all TCH and SDCCH",

The MS attempts to camp on the cell where theTCH or SDCCH is already released.

5. If step4 fails, the MS performs the normal cell reselection procedure. For details on the normal cellreselection procedure, see Inter-RAT Cell Reselection from GSM to UMTS.

Before sending the Channel Release message, the BSC determines whether to carry the informationelement "Cell selection indicator after release of all TCH and SDCCH" in the message.

1. If CELLSELECTAFTERCALLREL is set to YES, the procedure proceeds to 2. Otherwise, the

procedure is complete, and the BSC sends the Channel Release message to the MS. The messagedoes not carry the information element "Cell selection indicator after release of all TCH and SDCCH".

2. The BSC determines whether an MS supports both GSM and UMTS through the classmark. If theclassmark does not indicate the MS capability of supporting the GSM/UMTS, the procedure proceedsto 3. Otherwise, the procedure is completed, and the BSC sends the Channel Release message tothe MS. The message does not carry the information element "Cell selection indicator after release ofall TCH and SDCCH".

3. The BSC figures out the best neighboring UMTS cell based on the related measurement report, andthen the procedure proceeds to 4. If there is no measurement report or the measurement report doesnot contain the information on the neighboring UMTS cell, the procedure is complete, and the BSCsends the Channel Release message to the MS. The message does not carry the informationelement "Cell selection indicator after release of all TCH and SDCCH".

4. If the measurement report indicates a neighboring UMTS FDD cell, Cell Selection Indicator is set toUTRAN FDD Description. If the measurement report indicates a neighboring UTRAN TDD cell, CellSelection Indicator is set to UTRAN TDD Description, and the procedure is complete. Meanwhile, theBSC sends the Channel Release message to the MS. The message contains the informationelement "Cell selection indicator after release of all TCH and SDCCH".

5.4 NACC and NC2

When MS is in packet transfer mode, NACC and NC2 can be performed for inter-RAT cell reselection.

If the Iur-g interface exists between the BSC and RNC, the UMTS-to-GSM NACC procedure is anoptimized NACC procedure. In this case, the MS obtains the SI of the target cell directly over the Iur-g


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interface. The information exchange see 4.3 Information Exchange, and the parameterINFOEXCHGLIST should set to NACCRELATED.

For details, see NACC Parameter Description and NC2 Parameter Description.


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6 2G/3G Inter-RAT Handover

The 2G/3G inter-RAT handover involves the handover from GSM to UMTS and the handover fromUMTS to GSM. The handover is controlled mainly by the network.

For MSs in dedicated mode, inter-RAT handovers can be performed, including the emergency handover,better cell handover, inter-RAT load handover, and inter-RAT service handover.

Emergency handover refers to the handover that is triggered when the call cannot be processed in theserving cell because of poor coverage or other reasons during the CS service of the dual-mode MS. Forexample, when an MS during a call in the GSM cell is moving to the outside of the cell, the emergencyhandover is triggered to avoid call drops.

Better cell handover refers to the handover that is triggered when the signal quality of the neighboringcell is better than that of the serving cell, so that better service quality and user experience can beachieved. For example, when the signal quality of a UMTS cell is better than that of the serving GSM cell,MSs in the serving cell can be handed over to the UMTS cell to achieve better voice quality.

Inter-RAT load handover refers to the handover wherein some calls served by a GSM cell are handedover to a UMTS cell or some calls served by a UMTS cell are handed over to a GSM cell because ofheavy load in the serving cell. For an incoming inter-RAT handover to a GSM cell, if the traffic load in thetarget GSM cell is also heavy, the target cell rejects the handover to avoid ping-pong handovers.

In the inter-RAT service handover, the operator can choose the network that the MS will access throughthe MSC. For a call to be accessed in a GSM cell, if the MSC indicates that the service handover shouldbe performed, the BSS hands over the call to the UMTS cell. Otherwise, the BSS does not hand over thecall to a UMTS cell when a handover is required during the call.

When the cell delivers the neighboring TD-SCDMA cell information, MSs from certain manufacturersmay be restarted because defects exist in MS chips. To solve the problem, Huawei optimizesGSM/TD-SCDMA interoperability.

6.1 Inter-RAT Handover from UMTS to GSM

MSs in dedicated mode can be handed over from a UMTS cell to a GSM cell. The handover decisionand handover procedure are controlled by the RNC. The BSS considers the incoming handover fromUMTS to GSM as a general inter-BSC handover.

The parameterINTERRATINBSCHOEN determines whether inter-RAT handover from UMTS to GSM isenabled. IfINTERRATINBSCHOEN is set to No, the BSS rejects all the requests for the handover fromUMTS to GSM.

6.2 Inter-RAT Handover from GSM to UMTS

The parameterINTERRATINBSCHOEN determines whether the inter-RAT handover from GSM toUMTS is enabled. IfINTERRATINBSCHOEN is set to NO(No), the BSS rejects all the requests for thehandover from GSM to UMTS and does not select a UMTS cell as the target cell.

In dedicated mode, the MS obtains the neighboring UMTS cell list and other information from theMeasurement Information. Then, the MS reports the measurement result to the BSS through themeasurement report. After receiving the measurement result, the BSS determines whether to initiate theinter-RAT handover from GSM to UMTS based on the measurement result and the handover algorithm.

The inter-RAT handover from GSM to UMTS can be classified into emergency handover and better 3Gcell handover. The algorithm for the emergency handover from GSM to UMTS is the same as that for thegeneral emergency handover. For details, see Handover Parameter Description.


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In the GSM network, the parameterHOOPTSEL determines whether the GSM cell or the UMTS cell ispreferentially selected as the target cell.

z When HOOPTSEL is set to Pre_2G_Cell(Preference for 2G cell ), the BSC preferentially selects theGSM cell as the target cell.

z When HOOPTSEL is set to Pre_3G_Cell(Preference for 3G cell ), the BSC preferentially selects theUMTS cell as the target cell.

z When HOOPTSEL is set to Pre_2G_CellThres(Preference 2G cell by thresh), the BSC determinesthe target cell according to the levels of the neighboring GSM cells and the value ofHOPRETH2G. Ifno neighboring GSM cell has a level higher than HOPRETH2G, the BSC selects a UMTS cell as thetarget cell.

Better 3G cell handover can be performed only when both INTERRATOUTBSCHOEN andBET3GHOEN are set to YES(Yes). The system performs a handover decision based on themeasurement result.

z If there is HODURT3GTDD in HOSTAT3GTDD and the measured value meets the following condition,

the better 3G cell handover is triggered.CPICH RSCP > HORSCPTH3G

6.3 2G/3G Service Distribution and Load Balancing in AccessState

Overview

With the co-existence of 2G and 3G networks, operators can provide more diversified services. TheQoS-based service distribution feature is introduced to optimize the utilization of resources in 2G and 3Gnetworks. For example, voice services and low-rate data services are distributed to the 2G network,whereas high-rate data services are distributed to the 3G network to achieve high peak throughput.

In addition, in the case of co-existence of 2G and 3G networks, the traffic load in the two networks isdifferent. The 2G/3G load balancing feature is introduced to balance the load between the two networks.In this manner, the system capacity is increased, but there is no impact of high load on the system, andthe 2G/3G network resources are efficiently used.

When an MS accesses the network through a 2G cell, 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 andretains the low-rate services in the 2G cell. If the MS accesses the network through a 2G cell and the 2Gcell is congested, the BSC redirects the MS to the target 3G cell according to the load in the target 3Gcell.

Related Algorithms

When an MS accesses the network through a 2G cell, the BSC selects an inter-RAT handover algorithmbased on the setting of the InterRatServiceLoadHoSwitch parameter, if theINTERRATOUTBSCHOEN parameter is set to YES(Yes).

z When the InterRatServiceLoadHoSwitch parameter is set to CnService-based(CN Service-based),the BSC performs different processing based on the setting of the Service Handover IE in theASSIGNMENT REQUEST message received from the Core Network (CN). The details are as follows:

If the value of the Service Handover IE is Handover to UTRAN or cdma2000 should be performed,it indicates that the MS should be handed over to a 3G cell. In this case, the BSC selects a target 3Gcell from the list of neighboring cells and starts the handover from 2G to 3G.

If the value of the Service Handover IE is Handover to UTRAN or cdma2000 should not beperformed, it indicates that a 2G cell should be preferentially selected as the serving cell. In this


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case, the BSC does not start the handover from 2G to 3G. If a handover is required during the call, a2G cell is preferentially selected as the target cell.

If the value of the Service Handover IE is Handover to UTRAN or cdma2000 shall not beperformed, it indicates that the MS must not be handed over to a 3G cell. In this case, the BSC will

not hand over the MS to a 3G cell, and will select only a 2G cell as the target cell if a handover isrequired.

z When the InterRatServiceLoadHoSwitch parameter is set to Service-based(Service-based), theBSC removes the candidate 3G cells that experience basic congestion in uplink or downlink andadmits the MS to the 2G cell if the MS performs only CS voice services after accessing the network.

z When the InterRatServiceLoadHoSwitch parameter is set to Load-based(Load-based) and thevalue of the Service Handover IE is handover to UTRAN or cdma2000 should be performed, theBSC selects a candidate 3G cell that meets the following condition in both uplink and downlink as thetarget cell. The details are as follows:

G2GLoadAdjustCoeffx Current load in the serving 2G cell 10 x load in the neighboring 3G cell 10 x G2G3GLdBlcDeltaThrd 1,000

Then, the BSC selects the best neighboring 3G cell as the target cell and starts the directed retry to the3G cell. If there is no 3G cell that meets the preceding condition in uplink and downlink, the BSC admitsthe MS to the 2G cell.

If there are no candidate 3G cells or if the directed retry to the target 3G cell fails, the BSC starts a reassignmentprocedure in a 2G cell.

z When the InterRatServiceLoadHoSwitch parameter is set to Dynamic-based(DynamicService/Load-based) , the BSC selects a proper target cell by using the system service distributionalgorithm if the load in the serving cell is in the normal state. If the load in the serving cell is in otherstates, the BSC selects a target cell by using the system load balancing algorithm.

6.4 Inter-RAT Load-based Handover in Connect StateOverview

In the case of co-existence of 2G and 3G networks, there is a possibility that a network is congested dueto insufficient resources, whereas the other network has only a light traffic. The inter-RAT load-basedhandover in connected state feature is introduced to solve this problem. This feature enables theefficient use of the resources in 2G and 3G networks and balances the load between 2G and 3Gnetworks. In this manner, the system capacity is increased, but there is no impact of high load on thesystem.

Related Algorithms

When the OutSysLoadHoEn parameter is set to YES(Yes) and the MS supports inter-RAT handover, aninter-RAT load-based handover in connected state is triggered when the following conditions are met:

z The CPU usage of the system is smaller than or equal to the value of the SYSFLOWLEV parameter.

z The current load in the serving cell is greater than or equal to the value of the TRIGTHRES parameter.

z The value of the Service Handover IE in the ASSIGNMENT REQUEST message received from the CNis not handover to UTRAN or cdma2000 shall not be performed.

The candidate neighboring 3G cells must meet the following condition:

z G2GLoadAdjustCoeffx Load in the current 2G serving cell 10 x Load in the neighboring 3G cell G2G3GLdBlcDeltaThrd 1,000

z InterRATLoadHoEcNoStart LOADOFFSET < CPICH Ec/No < InterRATLoadHoEcNoStart

z CPICH Ec/No > IntRATLoadHOEcNoThr


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6-4

If a candidate neighboring 3G cell does not meet the preceding condition, the neighboring 3G cell isremoved from the list of candidate cells.

If the load information about a neighboring 3G cell is invalid, the neighboring 3G cell is not considered as a candidate cell.

Resource Reserved Handover Based on

w

escribes the feature GBFD-511402 Radio Resource Reserved Handover Between

rved handover based on Iur-g applies to the scenarios where the

rce reserved handover based on Iur-g only when

If there is at least one candidate 3G cell that meets the preceding condition, the BSC selects the bestcandidate cell as the target cell.

6.5 Enhanced RadioIur-g

Overvie

This section dGSM/TD-SCDMA Based on Iur-g.

The enhanced radio resource reseGSM and TD-SCDMA networks provide coverage for the same area. The enhanced radio resourcereserved handover procedure consists of the standard handover procedure between GSM andTD-SCDMA and the radio resource reservation procedure. The radio resource reservation procedure isachieved through the information exchange over the Iur-g interface between the BSC and the RNC. Thatis, the BSC reserves a channel for the MS to be handed over from the TD-SCDMA network. In this way,the BSC performs the radio resource reservation procedure that originally involves the Core Network(CN) in advance. In this case, delay caused by handovers between GSM and TD-SCDMA is reduced,and the handover success rate is improved.

The BSC supports the enhanced radio resouparameters INTERRATINBSCHOEN and InterRatIurgInBscHoEn are both set to YES.

The RNC must support the enhanced radio resource reserved handover based on Iur-g.

for the enhanced radio resource reserved handover based on Iur-g is described as

NC receives measurement reports (MRs) from the MS and selects an optimum target cell to

4.

5.

e A and Abis interfaces. The BSC also sends the MSC a HANDOVER REQUEST

Procedure

The procedurefollows:

1. The Rperform handover based on the capacity and load of neighboring GSM cells.

2. The RNC requests Iur-g SCCP links for this MS and sends the BSC an ENHANCED RELOCATIONRESOURCE REQUEST message, requesting resources for this MS.

3. After receiving the request from 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 theAMR speech versions supported by the target cell and the MS. Then, the BSC sends the RNC anENHANCED RELOCATION RESOURCE RESPONCE message. The message carries the callinstance information that is allocated to the MS. Meanwhile, the BSC starts the incoming BSC HO Ainterface timer.

The RNC sends the MS a HANDOVER FROM UTRAN COMMAND message to instruct the MS toprepare for the handover, and sends the MSC a RELOCATION REQUIRED message to request thehandover.

The MSC sends the BSC a HANDOVER REQUEST message through the A interface, requesting thehandover.

6. The BSC stops the incoming BSC HO A interface timer and establishes the connections on the user

planes of th


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6-5

ACKNOWLEDGE message over the A interface in response to the handover request of the MSC.Then the BSC waits to receive from the RNC a Relocation Commit message, which is used to ensurethat the MSC sends messages over the A interface in the right sequence in time.

The MS sends the BSC a HANDOVER ACCESS message to start the handover to the BSC.7.

e to the MSC, and releases the related Iur-g resources.

hand r if any of the following conditions is met:

z

z

z ferent from the speech

tween GSM and TD-SCDMA

face is enhanced in such a way that it can carry control plane data as well as user plane

data and user plane data. After the handover is complete, the related resources over the Iu

, and InterRatIurgVoiceCarryEn are all

8. After receiving the Relocation Commit message, the BSC sends the MSC a HANDOVER DETECTmessage over the A interface.

9. After the handover is complete, the MS sends the BSC a HANDOVER COMPLETE message. TheBSC then forwards the messag

10. The MSC sends the RNC an IU RELEASE COMMAND message through the Iu interface, notifyingthe RNC to release the Iu/Iub resources.

The BSC sends the RNC an ENHANCED RELOCATION RESOURCE FAIL message and processes theover as a normal incoming BSC handove

z The RNC does not support the enhanced radio resource reserved handover based on Iur-g.

The BSC considers the resource request message as illegal.

.The BSC detects that the SS7 signaling link on the A interface is faulty

The BSC detects that the speech versions supported by the target cell are difversions supported by the MS.

z The BSC fails to assign or activate a channel.

6.6 Handover Optimization BeBased on Iur-g

Overview

The Iur-g inter

data.

In the optimized handover between GSM and TD-SCDMA based on Iur-g, the Iur-g interface carriescontrol planeinterface between the RNC and the CN are still retained, and the handover between GSM andTD-SCDMA is processed in a way that is similar to the way in which an intra-RNC handover is processed.In this way, the delay caused by the handover is reduced.

The BSC supports the optimized handover between GSM and TD-SCDMA based on Iur-g only whenparameters INTERRATINBSCHOEN, InterRatIurgInBscHoEnset to YES. In addition, the TCTYPE must be set to UTC.

The RNC must support the optimized handover between GSM and TD-SCDMA based on Iur-g.

for the optimized handover between GSM and TD-SCDMA based on Iur-g is described

dover based on the capacity and load of neighboring GSM cells.

eived and the AMR speech

Procedure

The procedureas follows:

z The RNC receives measurement reports (MRs) from the MS and selects an optimum target cell toperform han

z The RNC requests Iur-g SCCP links for this MS and sends the BSC an ENHANCED RELOCATIONRESOURCE REQMSST message, requesting resources for this MS.

zAfter receiving the message from the RNC, the BSC assigns and activates a channel for the MS to bhanded over form the TD-SCDMA network based on the message rece


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6-6

versions supported by the target cell and the MS. The BSC establishes the connections on the userplanes of the Iur-g and Abis interfaces.

The BSC sends the RNC an ENHANCED RELOCATION RESOURCE RESPONCE message. Themessage carries the call instance inform

z

ation that is allocated to the MS.

z sends the RNC anage.

BSC ahandover is complete.

Afest The BSC

z The RNC sends the MS a HANDOVER FROM UTRAN COMMAND message, instructing the MS tohand over to the BSC.

z The MS sends the BSC a HANDOVER ACCESS message.

After receiving the HANDOVER ACCESS message from the MS, the BSCENHANCED RELOCATION RESOURCE RESPONSE mess

z The MS is handed over to the BSC. The Iur-g interface carries speech data. The MS sends theHANDOVER COMPLETE message through the Um interface. The

ter the handover is complete, the connection on the Iu interface is released, and a connection isablished on the A interface to prevent repeated handover decisions over the Iur-g interface.

receives a handover request message from the CN through the A interface and requests A interfaceresources accordingly. Meanwhile, the BSC responds to the handover request message, and waits for

the RELOCATION COMMIT message from the RNC. On receiving the RELOCATION COMMITmessage, the BSC establishes the connections on the user planes of the A and Abis interfaces, andreleases the connection on the user plane of the Iur-g interface.


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2G/3G Interoperability (TDD) 7 GSM/TD-SCDMA Interoperability Optimization



7-1

7 GSM/TD-SCDMA Interoperability Optimization

After the GSM cell is configured with neighboring TD-SCDMA cells, some MSs restart or stop working.This is because these MSs have defects in system information decoding. To solve this problem, Huawei

optimizes GSM/TD-SCDMA interoperability. The parameterTDDSIOPTIMIZEDALLOWED determineswhether to enable GSM/TD-SCDMA interoperability optimization.

IfTDDSIOPTIMIZEDALLOWED is set to YES(Yes) and the neighboring UMTS cell of the )GSM cell is aTDD cell, the BSS adds a virtual FDD cell description before the TDD cell description when deliveringthe System Information 2Quater and Measurement Information. In addition, the BSS delivers only thefrequency information of the TDD cell in the TDD cell description without scrambling code information. Ifthe GSM cell has multiple neighboring TDD cells with the same frequency and different scramblingcodes, the BSS delivers the description of only one cell in the System Information 2Quater andMeasurement Information to the MS, that is, these neighboring TDD cells are regarded as oneneighboring cell. The neighboring TDD cell of a GSM cell can be configured with a maximum of 16different frequencies.

During network planning, different frequencies must be planned for the neighboring TDD cells of each GSM cell.Otherwise, the handover from the GSM cell to the TD-SCDMA cell may fail.

In addition, the parameterTDDMIPROHIBIT determines whether the BSS delivers the MeasurementInformation that contains the neighboring 3G cell information to avoid faults occurring in some MSs withdecoding defects.


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8 PS GSM and TD-SCDMA Interoperability

Optimization



8-1

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 cellreselection procedure in idle mode.

During the PS service, if the MS performs autonomous cell reselection from GSM to TD-SCDMA, theKPIs may deteriorate after the cell reselection. To solve this problem, the BSC sends the PACKETMEASUREMENT ORDER message to the MS, instructing the MS to filter the neighboring TDD cell list.In this way, the MS in packet transfer mode does not reselect a neighboring TDD cell.

z Prohibiting cell reselection from GSM to TD-SCDMA

When TDDSIOPTIMIZEDALLOWED is set to NO(No), the BSC sends the PACKET MEASUREMENTORDER message to the MS after the PS service access is successful. The cell reselection parameterQP is set to 15 to prohibit the MS from listening to the neighboring TDD cell list, thus prohibiting theMS from reselecting the neighboring TDD cell.

z Modifying parameter settings

When the value ofTDDMIPROHIBIT, NCO, orRPTPERIODT is changed, the BSC sends thePACKET MEASUREMENT ORDER message to all the MSs in packet transfer mode in the cell,instructing the MSs to update the parameter value dynamically.


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2G/3G Interoperability (TDD) 9 Engineering Guidelines



9-1

9 Engineering Guidelines

Related Parameters in the System Information

2G/3G interoperability requires the support of MSs. After 2G/3G interoperability is enabled, the systemshould obtain the support capability of MSs. Therefore, the early classmark sending function should beenabled so that MSs report their support capability as soon as possible. It is recommended that ECSCbe set to YES(Yes).

During the configuration of the inter-RAT cell reselection parameters and handover thresholds, theconsistency between the GSM parameters and the UMTS parameters should be taken into account toavoid ping-pong handovers.

The network can control the cell reselection between GSM and UMTS through related parameters in thesystem information. If the operator requires that MSs access the UMTS network preferentially in theareas covered by the UMTS network, it is recommended that QI be set to 7. IfQI be set to 7, the UMTScell searching is performed.

The value ofTDDCELLRESELDIV determines cell reselection. If MSs are expected to camp on theUMTS network, the value ofTDDCELLRESELDIV should be changed so that the actual offset is anegative value.

When the value ofTDDCELLRESELDIV is smaller than 8, the corresponding actual offset is smaller than 0.

Neighboring UMTS Cell Configuration

Currently, the BSC6900 supports two types of neighboring UMTS cells using different accesstechnologies. One is the neighboring WCDMA cell, a neighboring UMTS cell using FDD, which is calledneighboring FDD cell. The other is the neighboring TD-SCDMA cell, a neighboring UMTS cell using TDD,

which is called neighboring TDD cell. The neighboring UMTS cells of a cell must be all the neighboringFDD cells or neighboring TDD cells. The neighboring FDD cells and neighboring TDD cells cannot beconfigured for a GSM cell simultaneously.

Before 2G/3G interoperability is enabled, neighboring UMTS cells must be configured. The UMTS cellcan be configured on the BSS side through the addition of external 3G cells. If the UMTS cell is aTD-SCDMA cell, UTRANCELLTYPE is set to TDD(TDD).

When GSM/TD-SCDMA interoperability optimization is not enabled, a GSM cell can be configured with amaximum of 64 neighboring TDD cells. These neighboring cells can have a maximum of 3 differentfrequencies, and a maximum of 32 neighboring TDD cells can have the same frequency.

When GSM/TD-SCDMA interoperability optimization is enabled, the neighboring TDD cells of a GSM cell

can have a maximum of 16 different frequencies. In addition, a maximum of 64 neighboring TDD cellscan be configured. When GSM/TD-SCDMA interoperability optimization is enabled, the scrambling codeinformation of TD-SCDMA cells is not delivered in the system information. If multiple neighboringTD-SCDMA cells of the GSM cell have the same frequency, the BSS cannot determine the mappingbetween the measurement information and the neighboring cells. This may cause handover failureseasily. Therefore, when GSM/TD-SCDMA interoperability optimization is enabled, a GSM cell should notbe configured with neighboring TDD cells that have the same frequency and different scrambling codes.

GSM/TD-SCDMA Interoperabili ty Optimization

To avoid communication failures due to MS chip defects, both TDDSIOPTIMIZEDALLOWED andTDDMIPROHIBIT are set to YES(Yes) in the cell configured with neighboring TDD cells.


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2G/3G Interoperability (TDD) 10 Parameters



10-1

10 Parameters

Table 10-1 Parameter description

Parameter ID NE MML DescriptionTDDCELLRESELDIV

BSC6900 SETGCELLCCUTRANSYS(Optional)

Meaning: A TDD cell can become a candidate cellonly when the average receive level of the TDDcell is greater than the TDD Cell ReselectDiversity of the serving cell.The value of this parameter corresponds to thefollowing decibel value:0: negative infinity1: -28 dB2: -24 dB...15: 28 dB

GUI Value Range: 0~15Actual Value Range: Negative infinity, -28~28,step: 4Unit: dBDefault Value: 8

INTERRATINBSCHOEN

BSC6900 SETGCELLHOBASIC(Optional)

Meaning: This parameter specifies whether thehandover from 3G cells to 2G cells is allowed.GUI Value Range: NO(No), YES(Yes)Actual Value Range: NO, YESUnit: NoneDefault Value: NO

HOOPTSEL BSC6900 SETGCELLHOUTRANFDD(Optional)

Meaning: This parameter specifies whether a 2Gcell or to a 3G cell is preferentially selected as thetarget cell for handover. When this parameter isset to Pre_2G_Cell, the BSC preferentially selectsa 2G candidate cell as the target cell forhandover. When this parameter is set toPre_3G_Cell, the BSC preferentially selects a 3Gcandidate cell as the target cell for handover.When this parameter is set toPre_2G_CellThres, the BSC preferentially selectsa neighboring 3G cell as the handover target cell

if the receive level of the neighboring 2G cell thatranks the first in the candidate cell list is equal toor smaller than "HO Preference Threshold for 2GCell". Otherwise, the BSC preferentially selects aneighboring 2G cell as the handover target cell.GUI Value Range: Pre_2G_Cell(Preference for2G cell), Pre_3G_Cell(Preference for 3G cell),Pre_2G_CellThres(Preference 2G cell by thresh)Actual Value Range: Pre_2G_Cell, Pre_3G_Cell,Pre_2G_CellThresUnit: NoneDefault Value: Pre_2G_CellThres

HOOPTSEL BSC6900 SET Meaning: This parameter specifies whether a 2G


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10-2

GCELLHOUTRANTDD(Optional)

cell or to a 3G cell is preferentially selected as thetarget cell for handover. When this parameter isset to Pre_2G_Cell, the BSC preferentially selectsa 2G candidate cell as the target cell forhandover. When this parameter is set to

Pre_3G_Cell, the BSC preferentially selects a 3Gcandidate cell as the target cell for handover.When this parameter is set toPre_2G_CellThres, the BSC preferentially selectsa neighboring 3G cell as the handover target cellif the receive level of the neighboring 2G cell thatranks the first in the candidate cell list is equal toor smaller than "HO Preference Threshold for 2GCell". Otherwise, the BSC preferentially selects aneighboring 2G cell as the handover target cell.GUI Value Range: Pre_2G_Cell(Preference for2G cell), Pre_3G_Cell(Preference for 3G cell),

Pre_2G_CellThres(Preference 2G cell by thresh)Actual Value Range: Pre_2G_Cell, Pre_3G_Cell,Pre_2G_CellThresUnit: NoneDefault Value: Pre_2G_CellThres

HOPRETH2G BSC6900 SETGCELLHOUTRANFDD(Optional)

Meaning: If the receive level of the neighboring2G cell that ranks the first in the candidate cell listis equal to or smaller than this threshold, the BSCpreferentially selects a neighboring 3G cell as thehandover target cell. Otherwise, the BSCpreferentially selects a neighboring 2G cell as thehandover target cell.GUI Value Range: 0~63Actual Value Range: 0~63Unit: dBDefault Value: 25

HOPRETH2G BSC6900 SETGCELLHOUTRANTDD(Optional)

Meaning: If the receive level of the neighboring2G cell that ranks the first in the candidate cell listis equal to or smaller than this threshold, the BSCpreferentially selects a neighboring 3G cell as thehandover target cell. Otherwise, the BSCpreferentially selects a neighboring 2G cell as thehandover target cell.

GUI Value Range: 0~63Actual Value Range: 0~63Unit: dBDefault Value: 25

INTERRATOUTBSCHOEN


Meaning: This parameter specifies whether thehandover from 2G cells to 3G cells is allowed.GUI Value Range: NO(No), YES(Yes)Actual Value Range: NO, YESUnit: NoneDefault Value: NO

BET3GHOEN BSC6900 SET

GCELLHOUTRANF

Meaning: This parameter specifies whether to

allow 3G better cell handover algorithm.


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DD(Optional) GUI Value Range: NO(No), YES(Yes)Actual Value Range: NO, YESUnit: NoneDefault Value: NO

BET3GHOEN BSC6900 SETGCELLHOUTRANTDD(Optional)

Meaning: This parameter specifies whether toallow 3G better cell handover algorithm.GUI Value Range: NO(No), YES(Yes)Actual Value Range: NO, YESUnit: NoneDefault Value: NO

HODURT3GTDD BSC6900 ADDG3GNCELL(Optional)MODG3GNCELL(Optional)

Meaning: According to the P/N rule, if theconditions for the handover to a better 3G cell aremet for P seconds within N seconds, thehandover is triggered.This parameter specifies the number P.GUI Value Range: 1~32Actual Value Range: 0.5~16, step:0.5Unit: sDefault Value: 8

HOSTAT3GTDD BSC6900 ADDG3GNCELL(Optional)MODG3GNCELL(Optional)

Meaning: According to the P/N rule, if theconditions for the handover to a better 3G cell aremet in P of N measurement reports, the handoveris triggered.This parameter specifies the number N.GUI Value Range: 1~32Actual Value Range: 0.5~16, step:0.5Unit: s

Default Value: 10

HORSCPTH3G BSC6900 SETGCELLHOUTRANFDD(Optional)

Meaning: The 3G better cell handover is triggeredonly when the RSCP of a neighboring 3G cell isgreater than this threshold for a period of time.GUI Value Range: 0~63Actual Value Range: 0~63Unit: dBDefault Value: 50

HORSCPTH3G BSC6900 SETGCELLHOUTRANTDD(Optional)

Meaning: The 3G better cell handover is triggeredonly when the RSCP of a neighboring 3G cell isgreater than this threshold for a period of time.

GUI Value Range: 0~63Actual Value Range: 0~63Unit: dBDefault Value: 50

OutSysLoadHoEn BSC6900 SETGCELLHOINTERRATLDB(Optional)

Meaning: This parameter specifies whether toallow the inter-RAT load handover in connectionmode (after the assignment is complete).GUI Value Range: NO(No), YES(Yes)Actual Value Range: NO, YESUnit: NoneDefault Value: NO

SYSFLOWLEV BSC6900 SET Meaning: System flux thresholds correspond to


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10-4

GCELLHOAD(Optional)

the system flux obtained based on messagepackets, CPU load, and FID queuing load. Thesystem flux level is the current flux control level ofthe system.0-11: There are 12 flow control levels. Where, 0

indicates the lowest level and 11 indicates thehighest level.A load handover is allowed only when the systemflux is lower than the value of this parameter. Thehandover performed over the maximum thresholdmay have tremendous impacts on the system.Thus, this parameter should not be set to a highervalue. 1) The flow control level algorithm for theassigned system messages: [(Average MessageUsage - Inner Flow Control Discard BeginThreshold)/(Inner Flow Control Discard AllThreshold - Inner Flow Control Discard Begin

Threshold) x 100]/10+1 (round-down for divisionoperation). If the value is smaller than Inner FlowControl Discard Begin Threshold, Level 0 is used.If the value is equal to or greater than Inner FlowControl Discard Begin Threshold, the level iscalculated. The value range is from 0 to 11.2) Flow control threshold for the CPU to start todiscard the channel access messages and pagingmessages: 80%. Flow control threshold for the CPU to discard allchannel access messages and paging messages:100%

. CPU usage smaller than 80% corresponds tolevel 0. CPU usage equal to or greater than CPUflow control threshold 80% corresponds to level 2.An increase of 5% means an increase of 2 levels.Level 10 is the highest. The level value can be 0,2, 4, 6, 8, and 10.GUI Value Range: 0, 8~11Actual Value Range: 0, 8~11Unit: NoneDefault Value: 10

TRIGTHRES BSC6900 SETGCELLHOAD(Optio

nal)

Meaning: The load handover is triggered whenthe traffic load in a cell is greater than the value of

this parameter.GUI Value Range: 0~100Actual Value Range: 0~100Unit: NoneDefault Value: 90

G2GLoadAdjustCoeff

BSC6900 SETGCELLHOINTERRATLDB(Optional)

Meaning: Coefficient used to modulate the loadlevel of a 2G system so that the load level of the2G system can be compared with that of a 3Gsystem.GUI Value Range: 0~100Actual Value Range: 0~100

Unit: None


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10-5

Default Value: 10

G2G3GLdBlcDeltaThrd

BSC6900 SETOTHSOFTPARA(Optional)

Meaning: If the load balance between a 2G celland a 3G cell is greater than the threshold, loadbalance is triggered.

GUI Value Range: 0~200Actual Value Range: -100~100Unit: %Default Value: 110

InterRATLoadHoEcNoStart


Meaning: Initial EcNo value of the inter-RATload-based handover bandGUI Value Range: 0~49Actual Value Range: 0~49Unit: dBDefault Value: 49

LOADOFFSET BSC6900 SET

GCELLHOAD(Optional)

Meaning: In the handover algorithm of the first

generation, load handovers can be performedonly when the receive level of the current servingcell is in the range "Edge HO DL RX_LEVThreshold" to "Edge HO DL RX_LEV Threshold"+ "Load HO Bandwidth".In the handover algorithm of the secondgeneration, load handovers can be performedonly when the level difference between theneighboring cell and the serving cell is between("Inter-cell HO Hysteresis" - 64) - "Load HOBandwidth" and ("Inter-cell HO Hysteresis" - 64).GUI Value Range: 0~63

Actual Value Range: 0~63Unit: dBDefault Value: 25

IntRATLoadHOEcNoThr


Meaning: Minimum Ec/No value of a 3G cellduring the load-based GSM-to-UMTS handoverGUI Value Range: 0~49Actual Value Range: 0~49Unit: dBDefault Value: 25

InterRatIurgInBscHoEn

BSC6900 SETGCELLHOBASIC(O

ptional)

Meaning: Whether to reserve resources for theincoming BSC handover on the Iur-g interface

GUI Value Range: NO(No), YES(Yes)Actual Value Range: NO, YESUnit: NoneDefault Value: NO

InterRatIurgVoiceCarryEn


Meaning: Whether to carry the speech data onthe Iur-g interface. If this parameter is set to YES,the speech data is still carried on the Iur-ginterface and then transmitted through the Iuinterface when the 3G service is switched to the2G network.GUI Value Range: NO(No), YES(Yes)Actual Value Range: NO, YESUnit: None


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Default Value: NO

TCTYPE BSC6900 SETTCTYPE(Mandatory)

Meaning: The type of TC resourceGTC: TC resources that support normal voicecoding/decoding and packet conversion

UTC: TC resources that support only theoptimized handover on the Iur-g interfaceITC: TC resources that support only packetconversionGUI Value Range: GTC(Normal voicecoding/decoding), UTC(Optimized handover onthe Iur-g interface), ITC(Packet Conversion)Actual Value Range: GTC, UTC, ITCUnit: NoneDefault Value: None

TDDSIOPTIMIZEDALLOWED

BSC6900 SETGCELLCCUTRANSYS(Optional)

Meaning: This parameter specifies whether tooptimize the system information 2Quater and MIof the TDD neighboring cell. That is, to add anFDD neighboring cell information before the TDDneighboring cell information to solve thecompatibility problem of some dual-mode MSs.


TDDMIPROHIBIT BSC6900 SETGCELLCCUTRANS

YS(Optional)

Meaning: This parameter specifies whether tosend the system information MI which contains

the 3G neighboring cell information in the TDDneighboring cell. The value YES(YES) indicatesthat the MI is sent, and the value NO(NO)indicates that the MI is not sent.


QP BSC6900 SETGCELLCCUTRANSYS(Optional)

Meaning: This parameter specifies one thresholdof the signal level for cell reselection in packettransfer mode.

In packet transfer mode, if the signal level of theserving cell is below [0, 7] or above [8, 15], theMS starts to search for 3G cells.For example, if this parameter is set to 5 and if thesignal level of the serving cell is lower than 5, theMS starts to search for 3G cells; if this parameteris set to 10 and if the signal level of the servingcell is above 10, then the MS starts to search for3G cells.The values of this parameter correspond to thefollowing decibel values:0: -98 dBm

1: -94 dBm


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...6: -74 dBm7: (always)8: -78 dBm9: -74 dBm

...14: -54 dBm15: Positive infinity (never)

GUI Value Range: 0~15Actual Value Range: -98, -94, -90, -86, -82, -78,-74, (always), -78, -74, -70, -66, -62, -58, -54,Positive infinity(never)Unit: NoneDefault Value: 15

NCO BSC6900 SET

GCELLPSBASE(Optional)

Meaning: Network control mode for cell

reselection of the MS. There are three modes.NC0: normal MS control. The MS shall performautonomous cell re-selection. NC1: MS controlwith measurement reports. The MS shall sendmeasurement reports to the network and the MSshall perform autonomous cell re-selection. NC2:network control. The MS shall send measurementreports to the network. The MS shall only performautonomous cell re-selection when thereselection is triggered by a downlink signalingfailure or a random access failure. When thisparameter is set to NC2 and "Support NC2" in"SET GCELLGPRS" is set to "YES", the networkside can control the cell reselection for the MS.

GUI Value Range: NC0(NC0), NC1(NC1),NC2(NC2)Actual Value Range: NC0, NC1, NC2Unit: NoneDefault Value: NC0

RPTPERIODT BSC6900 SETGCELLNWCTRLMSRPARA(Optional)

Meaning: Cell reselection measurement reportperiod in packet transmission mode

GUI Value Range: 0.48sec(0.48sec),

0.96sec(0.96sec), 1.92sec(1.92sec),3.84sec(3.84sec), 7.68sec(7.68sec),15.36sec(15.36sec), 30.72sec(30.72sec),61.44sec(61.44sec)Actual Value Range: 0.48sec, 0.96sec, 1.92sec,3.84sec, 7.68sec, 15.36sec, 30.72sec, 61.44secUnit: sDefault Value: 0.96sec

ECSC BSC6900 SETGCELLCCBASIC(Optional)

Meaning: The early classmark sending control(ECSC) parameter specifies whether the MSs in acell use early classmark sending. After asuccessful immediate assignment, the MS sends

additional classmark information to the network


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as early as possible. The additional classmarkinformation mainly contains the CM3 (classmark3) information. The CM3 (classmark 3)information contains the frequency band supportcapability of the MS (used for the future channel

assignment), power information about eachfrequency band supported by the MS (used forthe handover between different frequency bands),and encryption capability of the MS.

GUI Value Range: NO(No), YES(Yes)Actual Value Range: NO, YESUnit: NoneDefault Value: YES

QI BSC6900 SETGCELLCCUTRANS

YS(Optional)

Meaning: This parameter specifies the levelthreshold for cell reselection in idle mode.

In idle mode, if the signal level of the serving cellis below [0, 7] or above [8, 15], the MS starts tosearch for 3G cells.For example, if this parameter is set to 5 and ifthe signal level of the serving cell is lower than 5,the MS starts to search for 3G cells; if thisparameter is set to 10 and if the signal level of theserving cell is above 10, then the MS starts tosearch for 3G cells.The values of this parameter correspond to thefollowing decibel values:0: -98 dBm1: -94 dBm2: -90 dBm3: -86 dBm4: -82 dBm5: -78 dBm6: -74 dBm7: (always), that is, the MS keeps searching for3G cells8: -78 dBm9: -74 dBm10: -70 dBm11: -66 dBm12: -62 dBm

13: -58 dBm14: -54 dBm15: Positive infinity (never), that is, the MS doesnot search for 3G cells.

GUI Value Range: 0~15Actual Value Range: -98, -94, -90, -86, -82, -78,-74, (always), -78, -74, -70, -66, -62, -58, -54,Positive infinity(never)Unit: NoneDefault Value: 15

UTRANCELLTYPE BSC6900 ADDGEXT3GCELL(MandMeaning: This parameter specifies the type of a3G cell. A cell type can be Frequency Division


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atory)MODGEXT3GCELL(Optional)

Duplex (FDD) or Time Division Duplex (TDD).

GUI Value Range: FDD(FDD), TDD(TDD)Actual Value Range: FDD, TDDUnit: None

Default Value: None

SPTCOMMMEAS BSC6900 ADDGNRNC(Optional)MODGNRNC(Optional)

Meaning: Whether to support the commonbidirectional measurement procedure on the Iur-ginterface.

GUI Value Range: NO(No Support),YES(Support)Actual Value Range: NO, YESUnit: NoneDefault Value: NO

SPTINFOEXCHG BSC6900 ADDGNRNC(Optional)MODGNRNC(Optional)

Meaning: Whether to support the bidirectionalinformation exchange procedure on the Iur-ginterface.

GUI Value Range: NO(No Support),YES(Support)Actual Value Range: NO, YESUnit: NoneDefault Value: NO

INFOEXCHGLIST BSC6900 ADDGNRNC(Mandatory)MOD

GNRNC(Mandatory)

Meaning: Information exchange content to besupported

GUI Value Range: CELLCAPCLASS(CellCapacity Info), NACCRELATED(NACC Info)Actual Value Range: CELLCAPCLASS,NACCRELATEDUnit: NoneDefault Value: CELLCAPCLASS


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2G/3G Interoperability (TDD) 11 Counters



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11 Counters

For the counters, see the BSC6900 GSM Performance Counter Reference.


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2G/3G Interoperability (TDD) 12 Glossary



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12 Glossary

For the acronyms, abbreviations, terms, and definitions, see the Glossary.


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2G/3G Interoperability (TDD) 13 Reference Documents

13 Reference Documents

[1] 3GPP TS 45.008 Radio subsystem link control

[2] 3GPP TS 44.018 Mobile radio interface layer 3 specification; Radio Resource Control (RRC)

protocol

[3] 3GPP TS 48.008 Mobile Switching Centre - Base Station system (MSC-BSS) interface; Layer 3specification

[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

2G3G Interoperability (TDD).pdf

Documents

Transcript of 2G3G Interoperability (TDD).pdf