gbss15.0 optional feature description 01

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GBSS15.0 Optional FeatureDescription

Issue 01

Date 2013-2-18

HUAWEI TECHNOLOGIES CO., LTD.


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Issue 01 (2013-2-18) Huawei Proprietary and Confidential

Copyright Huawei Technologies Co., Ltd

i

Copyright Huawei Technologies Co., Ltd. 2013. 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 contract made between Huawei and

the customer. All or part of the products, services and features described in this document may not be

within the purchase scope or the usage scope. Unless otherwise specified in the contract, all statements,

information, and recommendations in this document are provided "AS IS" without warranties, guarantees orrepresentations of any kind, either express or implied.

The information in this document is subject to change without notice. Every effort has been made in the

preparation of this document to ensure accuracy of the contents, but all statements, information, and

recommendations in this document do not constitute a warranty of any kind, express or implied.

Huawei Technologies Co., Ltd.

Address: Huawei Industrial Base

Bantian, Longgang

Shenzhen 518129

People's Republic of China

Website: http://www.huawei.com

Email: [email protected]
http://www.huawei.com/http://www.huawei.com/mailto:[email protected]:[email protected]:[email protected]://www.huawei.com/


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GBSS15.0 Optional Feature Description Contents



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Contents

1 Voice& Other Services ................................................................................................................. 1

1.1 Crystal Voice ........................................................................... ............................................................... .......... 1

1.1.1 GBFD-115701 TFO ........................................................................................................... ..................... 1

1.1.2 GBFD-115711 EVAD ......................................... ............................................................... ..................... 3

1.1.3 GBFD-116801 Voice Quality Index (VQI) ................................................................ ............................. 4

1.1.4 GBFD-115708 Um Interface Speech Frame Repairing ....................... ................................................... 5

1.1.5 GBFD-115709 Smooth Voice Call Handover .................................................................... ..................... 6

1.2 AMR ........................................................ ................................................................. ........................................ 7

1.2.1 GBFD-115501 AMR FR ............................................................................................ ............................. 7

1.2.2 GBFD-115502 AMR HR ............................................... ............................................................... .......... 9

1.2.3 GBFD-115503 AMR Power Control ............................................................... ...................................... 11

1.2.4 GBFD-115504 AMR FR/HR Dynamic Adjustment .............................................................. ................ 12

1.2.5 GBFD-115506 AMR Coding Rate Threshold Adaptive Adjustment .................................................... 14

1.2.6 GBFD-115507 WB AMR.................................... ............................................................... ................... 16

1.3 Voice Capacity ............................................................... ................................................................. ................ 17

1.3.1 GBFD-113401 Half Rate Speech .................................................................................................. ........ 17

1.3.2 GBFD-113402 Dynamic Adjustment Between FR and HR .......................................................... ........ 18

1.3.3 GBFD-115830 VAMOS ................................................................................................................ ........ 20

1.3.4 GBFD-115831 Mute SAIC MS Identification ........................................................... ........................... 22

1.3.5 GBFD-115832 VAMOS Call Drop Solution ......................................................................................... 24

1.4 Cell Broadcast .......................................................................................................... ...................................... 25

1.4.1 GBFD-113601 Short Message Service Cell Broadcast (TS23) ..................................................... ........ 25

1.4.2 GBFD-113602 Simplified Cell Broadcast ................................ ............................................................ 26

1.5 GSM Trunking ............................................................................................................................................... 28

1.5.1 GBFD-510301 Public Voice Group Call Service .................................................................................. 28

1.5.2 GBFD-510303 Late Group Channel Assignment ........................................... ...................................... 29

1.5.3 GBFD-510305 Single Channel Group Call Originating ......................................... .............................. 30

1.5.4 GBFD-510306 Talker Identification ..................................................................................................... 31

1.5.5 GBFD-510307 Group Call EMLPP ........................................................................ .............................. 32

1.5.6 GBFD-510308 Fast Group Call Setup .................................................................................................. 33

1.5.7 GBFD-510309 Group Call Reliability Enhancing ........................................................................ ........ 34

1.5.8 GBFD-510302 Public Voice Broadcast Service ......................................................... ........................... 36

1.5.9 GBFD-510304 Late Broadcast Channel Assignment ......................................................... ................... 37


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1.5.10 GBFD-510310 GSM-T Relay ............................................................ ................................................. 38

1.6 LCS ................................................................................................................................................................ 39

1.6.1 GBFD-115404 Lb Interface ................................................................................................ .................. 39

1.6.2 GBFD-510902 High-Precision TA ....................................................... ................................................. 42

1.6.3 GBFD-511701 Radio Measurement Data Interface for Navigation ...................................................... 43

1.7 Voice Priority ...................................................... ................................................................. ........................... 44

1.7.1 GBFD-116001 Resource Reservation ..................................................................... .............................. 44

1.7.2 GBFD-115001 Enhanced Multi Level Precedence and Preemption (EMLPP) ..................................... 45

1.7.3 GBFD-115002 Flow Control Based on Cell Priority ......................................................... ................... 47

1.7.4 GBFD-115003 Flow control based on User priority .......................................................... ................... 48

1.7.5 GBFD-511002 Access Control Class (ACC) .................................................. ...................................... 49

1.8 CS domain data service ............................................................................................ ...................................... 50

1.81 GBFD-119405 14.4kbit/s Circuit Switched Data ........................................................ ........................... 50

1.8.2 GBFD-119406 High Speed Circuit Switched Data ............................................................... ................ 51

2 Data Services ................................................................................................................................ 54

2.1 PS Rate Increase ............................................................ .............................................................. ................... 54

2.1.1 GBFD-114201 EGPRS ................................................................................... ...................................... 54

2.1.2 GBFD-119201 11-Bit EGPRS Access .................................................................... .............................. 57

2.1.3 GBFD-119302 Packet Channel Dispatching .............................................................. ........................... 58

2.1.4 GBFD-119509 GPRS Fast Transmission ...................................................................................... ........ 59

2.1.5 GBFD-119503 Early TBF Establishment ................................. ............................................................ 60

2.1.6 GBFD-119506 GPRS/EGPRS Time slot multiplexing priority ............................................................ 62

2.1.7 GBFD-119401 Extended Dynamic Allocation (EDA) ....................................................... ................... 63

2.1.8 GBFD-119402 MS High Multislot Classes ................................................................ ........................... 64

2.1.9 GBFD-119407 Active TBF Allocation ............................................................ ...................................... 66

2.1.10 GBFD-119505 PDCH Dynamic Adjustment with Two Thresholds .................................................... 68

2.1.11 GBFD-510801 MSRD ........................................................................................................................ 69

2.1.12 GBFD-510802 Dual Carriers in Downlink ......................................................................................... 70

2.1.13 GBFD-510803 Uplink EGPRS2-A ............................................................... ...................................... 71

2.1.14 GBFD-510804 Downlink EGPRS2-A ............................................................................. ................... 72

2.1.15 GBFD-510805 Latency Reduction...................................................................................................... 74

2.2 PS QoS ........................................................................................................................................................... 77

2.2.1 GBFD-119901 Streaming QoS(GBR) ............................................................. ...................................... 77

2.2.2 GBFD-119902 QoS ARP&THP......................................................................................... ................... 78

2.2.3 GBFD-119905 PoC QoS ........................................................... ............................................................ 80

2.2.4 GBFD-119906 Conversational QoS ................................................................ ...................................... 81

2.2.5 GBFD-119907 PS Service in Priority .................................................. ................................................. 83

2.2.6 GBFD-119904 PS Active Package Management .................................................................................. 84

2.3 PS Service Enhancement .......................................................... .............................................................. ........ 86

2.3.1 GBFD-114151 DTM .......................................................................................................... ................... 86

2.3.2 GBFD-119403 Class11 DTM .............................................................. ................................................. 88


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2.3.3 GBFD-119404 HMC DTM ....................................................... ............................................................ 89

2.4 Smart Pipe .......................................................... ................................................................. ........................... 91

2.4.1 GBFD-511603 IM Service Efficiency Improvement ............................................................................ 91

2.4.2 GBFD-511604 Web Browsing Service Efficiency Improvement ................... ...................................... 92

2.4.3 GBFD-511605 Email Service Efficiency Improvement ...................... ................................................. 94

2.4.4 GBFD-511606 Streaming Media Service Resource Balancing..................................................... ........ 95

2.4.5 GBFD-511607 P2P Resource Balancing ......................................................... ...................................... 97

2.4.6 GBFD-119408 PS Access Congestion Balancing ......................................................................... ........ 98

2.4.7 GBFD-511610 Small Packet Resource Balancing ................................................................ .............. 100

3 Radio & Performance ............................................................................................................... 102

3.1 Paging Enhancement ........................................................................................................ ............................ 102

3.1.1 GBFD-511501 Multiple CCCHs .......................................................... ............................................... 102

3.1.2 GBFD-511502 Layered Paging ............................................................ ............................................... 103

3.1.3 GBFD-511503 Dynamic Multiple CCCH ....................................................... .................................... 104

3.1.4 GBFD-511505 RACH Storm Filtration ............................................................................. ................. 106

3.1.5 GBFD-510001 Network Operation Mode I ........................................................................................ 107

3.1.6 GBFD-119305 BSS Paging Coordination ....................................................... .................................... 109

3.2 Mobility Management .............................................................. .............................................................. ...... 110

3.2.1 GBFD-116201 Network-Controlled Cell Reselection (NC2) ............................................................. 110

3.2.2 GBFD-116301 Network Assisted Cell Change (NACC) ................................ .................................... 111

3.2.3 GBFD-119801 Packet SI Status (PSI) ............................................................. .................................... 113

3.2.4 GBFD-510502 Handover Re-establishment ................................................... .................................... 113

3.2.5 GBFD-117501 Enhanced Measurement Report (EMR) ...................... ............................................... 114

3.2.6 GBFD-119502 PS Handover ................................................................ ............................................... 116

3.2.1 GBFD-114402 Enhanced Dual-Band Network .......................................................... ......................... 117

3.2.1 GBFD-510101 Automatic Frequency Correction (AFC) .................................................................... 118

3.2.2 GBFD-510102 Fast Move Handover ................................................................................. ................. 119

3.2.3 GBFD-510103 Chain Cell Handover .............................................................. .................................... 121

3.2.4 GBFD-510105 PS AFC ............................................................. .......................................................... 122

3.3 Interference Suppression ............................................................................................................. ................. 123

3.3.1 GBFD-119504 PS Power Control ........................................................ ............................................... 123

3.3.2 GBFD-115801 ICC ............................................................................................................ ................. 125

3.3.3 GBFD-115821 EICC ................................................................. .......................................................... 126

3.3.4 GBFD-113701 Frequency Hopping (RF hopping, baseband hopping) ............................................... 127

3.3.5 GBFD-113702 BCCH Carrier Frequency Hopping .............................................................. .............. 129

3.3.6 GBFD-113703 Antenna Frequency Hopping ............................................................. ......................... 130

3.3.7 GBFD-119507 PS Downlink DTX ................................................................ ..................................... 131

3.3.8 GBFD-119508 PS Uplink DTX ......................................................................................... ................. 133

3.3.9 GBFD-119510 Um Adaptive Interference Suppression ..................................................... ................. 134

3.3.10 GBFD-118201 Soft-Synchronized Network ..................................................................................... 135

3.3.11 GBFD-113721 Robust Air Interface Signalling ................................................................................ 137


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3.4 Coverage Enhancement ............................................................ .............................................................. ...... 139

3.4.1 GBFD-115901 PBT(Power Boost Technology) ......................................................... ......................... 139

3.4.2 GBFD-115902 Transmit Diversity ....................................................... ............................................... 140

3.4.3 GBFD-115903 4-Way Receiver Diversity ................................................................ .......................... 141

3.4.4 GBFD-118101 Dynamic Transmit Diversity .................................................. .................................... 142

3.4.5 GBFD-118102 Dynamic PBT (Power Boost Technology) ............................. .................................... 143

3.4.6 GBFD-118104 Enhanced EDGE Coverage .................................................................................. ...... 145

3.4.7 GBFD-118106 Dynamic Power Sharing ......................................................... .................................... 146

3.4.8 GBFD-114001 Extended Cell .................................................................................... ......................... 148

3.4.9 GBFD-510104 Multi-site Cell ............................................................................................................ 150

3.5 Capacity Improvement ................................................................................................................ ................. 152

3.5.1 GBFD-511611 Duty-Cycle-based PDCH Management ..................................................... ................. 152

3.5.2 GBFD-114501 Co-BCCH Cell .......................................................................................... ................. 153

3.5.3 GBFD-117001 Flex MAIO ............................................................................. .................................... 155

3.5.4 GBFD-118001 BCCH Dense Frequency Multiplexing........................................... ............................ 156

3.5.5 GBFD-117002 IBCA (Interference Based Channel Allocation) ......................................................... 157

3.5.6 GBFD-113706 Mega BSC ............................................................................................................ ...... 159

3.6 GSM/UMTS Interoperability ....................................................................................................................... 161

3.6.1 GBFD-114301 GSM/WCDMA Interoperability ........................................................ ......................... 161

3.6.2 GBFD-114321 GSM/WCDMA Service Based Handover .............................. .................................... 163

3.6.3 GBFD-114322 GSM/WCDMA Load Based Handover ...................................................................... 164

3.6.4 GBFD-114323 GSM/WCDMA Cell Reselection Based on MS State ................................................ 165

3.6.5 GBFD-114325 Fast WCDMA Reselection at 2G CS Call Release ..................................................... 167

3.6.6 GBFD-511101 Load Based Handover Enhancement on Iur-g ...................................................... ...... 168

3.6.7 GBFD-511102 NACC Procedure Optimization Based on Iur-g between GSM and WCDMA .......... 169

3.6.8 GBFD-511103 GSM and WCDMA Load Balancing Based on Iur-g ................................ ................. 171

3.6.9 GBFD-511104 GSM and WCDMA Traffic Steering Based on Iur-g .................................................. 173

3.6.10 GBFD-511110 BSC supporting Blind Search .......................................................... ......................... 175

3.7 GSM/LTE Interoperability ....................................................... .............................................................. ...... 176

3.7.1 GBFD-511301 Cell Reselection Between GSM and LTE ............................................................ ...... 176

3.7.2 GBFD-511302 PS Handover Between GSM and LTE Based on Coverage ........................................ 177

3.7.3 GBFD-511303 PS Handover Between GSM and LTE Based on Quality ........................................... 179

3.7.4 GBFD-511304 PS Handover Between GSM and LTE Based on Cell Load ....................................... 180

3.7.5 GBFD-511305 PS Handover Between GSM and LTE Based on Mode Priority................................. 182

3.7.6 GBFD-511306 GSM/LTE Service Based PS Handover ................................ ..................................... 183

3.7.7 GBFD-511307 eNC2 Between GSM and LTE .................................... ............................................... 185

3.7.8 GBFD-511308 eNACC Between GSM and LTE ................................................................ ................ 187

3.7.9 GBFD-511309 SRVCC ................................................................................................................. ...... 188

3.7.10 GBFD-511310 Multi Technology Neighbour Cell Based Handover ................................................ 189

3.7.11 GBFD-511312 Fast LTE Reselection at 2G CS Call Release ..................................................... ...... 190

3.7.12 GBFD-511313 CSFB .............................................................. .......................................................... 192

3.8 GSM/TD-SCDMA Interoperability ............................................................... ............................................... 193


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3.8.1 GBFD-114302 GSM/TD-SCDMA Interoperability .............................................................. .............. 193

3.8.2 GBFD-511401 Iur-g Interface Between GSM and TD-SCDMA ........................................................ 194

3.8.3 GBFD-511402 Radio Resource Reserved Handover Between GSM/TD-SCDMA Based on Iur-g ... 196

3.8.4 GBFD-511403 Extended BCCH .......................................................... ............................................... 197

3.8.5 GBFD-511405 NC2 between GSM and TD-SCDMA ........................................................................ 198

3.9 GSM/WiFi Interoperability ................................................................................................ .......................... 200

3.9.1 GBFD- 511608 WLAN Hot Spot Notification............... ............................................................... ...... 200

3.9.2 GBFD-511609 Intelligent Wi-Fi Detection and Selection .................................................................. 201

4 Networking & Transmission & Security .............................................................................. 203

4.1 TDM Transmission ........................................................ .............................................................. ................. 203

4.1.1 GBFD-510002 Gb Over FR .......................................................................................................... ...... 203

4.1.2 GBFD-115301 Local Multiple Signaling Points ........................................................ ......................... 204

4.1.3 GBFD-116701 16Kbit RSL and OML on Abis Interface .............................................................. ...... 205

4.1.4 GBFD-117301 Flex Abis ................................................................................................... ................. 206

4.1.5 GBFD-118401 Abis Transmission Optimization .......................................................................... ...... 208

4.1.6 GBFD-112013 Abis Congestion Trigger HR Distribution .................................................................. 210

4.1.7 GBFD-116902 Ater Compression Transmission ........................................................ ......................... 211

4.1.8 GBFD-118611 Abis IP over E1/T1 ......................................................................... ............................ 213

4.1.9 GBFD-118622 A IP over E1/T1 ......................................................................................... ................. 215

4.1.10 GBFD-117801 Ring Topology ........................................................... ............................................... 217

4.2 IP Transmission ............................................................. ................................................................. .............. 220

4.2.1 GBFD-118620 Clock over IP support 1588v2 .................................................................................... 220

4.2.2 GBFD-118202 Synchronous Ethernet................................................................................................. 222

4.2.3 GBFD-118601 Abis over IP ................................................................. ............................................... 224

4.2.4 GBFD-118602 A over IP ........................................................... .......................................................... 227

4.2.5 GBFD-118610 UDP MUX for A Transmission ......................................................... ......................... 231

4.2.6 GBFD-118623 TDM/IP Dual Transmission over A Interface ............................................................. 232

4.2.7 GBFD-118603 Gb over IP ........................................................ .......................................................... 233

4.2.8 GBFD-118605 IP QoS ....................................................................................................... ................. 235

4.2.9 GBFD-118631 A Interface Transmission Pool ........................................................... ......................... 239

4.2.10 GBFD-150201 A over IP Based on Dynamic Load Balancing ................................................... ...... 241

4.3 Transmission Efficiency ........................................................... .............................................................. ...... 245

4.3.1 GBFD-117705 PS Dummy Frame Compression ....................................................... ......................... 245

4.3.2 GBFD-117702 BTS Local Switch ............................................ .......................................................... 246

4.3.3 GBFD-117701 BSC Local Switch ................................................................................................ ...... 249

4.3.4 GBFD-118604 Abis MUX ................................................................................................. ................. 252

4.3.5 GBFD-118612 Abis IPHC .................................. ............................................................... ................. 254

4.4 Satellite Transmission .................................................................................................................................. 255

4.4.1 GBFD-113901 Satellite Transmission over Abis Interface ........................................................... ...... 255

4.4.2 GBFD-113902 Satellite Transmission over A Interface ..................................................... ................. 256

4.4.3 GBFD-113903 Satellite Transmission over Ater Interface ............................................................ ...... 257


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4.4.4 GBFD-113905 Satellite Transmission over Gb Interface................................ .................................... 258

4.5 RAN Sharing ...................................................... ................................................................. ......................... 259

4.5.1 GBFD-118701 RAN Sharing ........................................................................................................ ...... 259

4.5.2 GBFD-118702 MOCN Shared Cell .............................................................................................. ...... 261

4.5.3 GBFD-118703 IMSI-Based Handover ............................................................ .................................... 262

4.5.4 GBFD-118704 Abis Independent Transmission ......................................................... ......................... 264

4.6 Security ........................................................................................................................................................ 265

4.6.1 GBFD-113503 A5/3 Ciphering Algorithm ................................................................ .......................... 265

4.6.2 GBFD-113521 A5/1 Encryption Flow Optimization ................................... ....................................... 266

4.6.3 GBFD-113524 BTS Integrated IPsec .............................................................. .................................... 267

4.6.4 GBFD-113526 BTS Supporting PKI .................................................................................................. 268

4.7 Reliability ........................................................... ................................................................. ......................... 270

4.7.1 GBFD-117401 MSC Pool ............................................................................... .................................... 270

4.7.2 GBFD-119701 SGSN Pool ............................................................................. .................................... 273

4.7.3 GBFD-116601 Abis Bypass ................................................................................................ ................ 274

4.7.4 GBFD-117803 Abis Transmission Backup ................................................................ ......................... 276

4.7.5 GBFD-113725 BSC Node Redundancy .......................................................... .................................... 278

4.7.6 GBFD-113726 TC POOL ............................................................................... .................................... 279

4.7.7 GBFD-113728 OML Backup ........................................................................................................ ...... 281

5 O&M ............................................................................................................................................ 283

5.1 Power Saving ............................................................................................................................................... 283

5.1.1 GBFD-117602 Active Power Control ................................................................................................. 283

5.1.2 GBFD-111602 TRX Power Amplifier Intelligent Shutdown .............................................................. 284

5.1.3 GBFD-111603 TRX Power Amplifier Intelligent Shutdown on Timeslot Level ................................ 286

5.1.4 GBFD-111605 Active Backup Power Control ................................................ .................................... 287

5.1.5 GBFD-111606 Power Optimization Based on Channel Type ............................................................. 288

5.1.6 GBFD-111608 PSU Smart Control ............................................................................................... ...... 290

5.1.7 GBFD-111609 Enhanced BCCH Power Consumption Optimization ................................................. 291

5.1.8 GBFD-111610 Dynamic Cell Power Off ................................................................ ............................ 292

5.1.9 GBFD-111611 TRX Working Voltage Adjustment ................... .......................................................... 293

5.1.10 GBFD-111612 Multi-Carrier Intelligent Voltage Regulation ............................................................ 295

5.2 PICO Management ........................................................ .............................................................. ................. 297

5.2.1 GBFD-510601 PICO Automatic Configuration and Planning ...................................................... ...... 297

5.2.2 GBFD-510602 PICO Synchronization.................................................................... ............................ 298

5.2.3 GBFD-510603 PICO Dual-band Auto-planning ........................................................ ......................... 299

5.2.4 GBFD-510605 PICO Access Control List (ACL) ................................................................ ............... 300

5.2.5 GBFD-510606 PICO Sleeping Mode ..................................................................... ............................ 301

5.2.6 GBFD-510607 PICO Automatic Optimization ................................................................................... 302

5.2.7 GBFD-510608 PICO Transceiver Redundancy ................................................................. ................. 303

5.3 Micro Management ...................................................................................................................................... 304

5.3.1 GBFD-111613 Weather Adaptive Power Management ...................................................... ................. 304


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5.3.2 GBFD-510701 Compact BTS Automatic Configuration and Planning ........................................ ...... 305

5.3.3 GBFD-510702 Compact BTS Automatic Capacity Planning ............................................................. 306

5.3.4 GBFD-510704 Compact BTS Automatic Neighbor Cell Planning and Optimization ........................ 307

5.3.5 GBFD-510705 Compact BTS Timing Power Off ............................................................................... 309

5.3.6 GBFD-510706 Local User Management ............................................................................................ 310

5.4 O&M ............................................................................................................................................................ 312

5.4.1 GBFD-510710 Intelligent Battery Management ........................................................ ......................... 312

5.4.2 GBFD-113729 Adaptive Transmission Link Blocking ........................ ............................................... 314

5.4.3 GBFD-114701 Semi-Permanent Connection ............................................................. ......................... 315

5.4.4 GBFD-510901 2G/3G Neighboring Cell Automatic Optimization ..................................................... 318

6 Acronyms and Abbreviations ................................................................................................. 320


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GBSS15.0 Optional Feature Description 1 Voice& Other Services



1

1 Voice& Other Services1.1 Crystal Voice

1.1.1 GBFD-115701 TFO

Availability

This feature was introduced in GBSS6.1.

Summary

With this feature, TFO frames are transparently transmitted and encoding/decoding isbypassed using the bit stealing scheme between the TCs at two ends. Therefore, the

encoding/decoding process is reduced once.

Benefits

Speech signals deteriorate with each encoding/decoding. Therefore, using TFO to bypass

encoding/decoding can improve the voice quality. In the case of encoding/decoding lowerrates, the voice quality improves more evidently.

Description

In a mobile network system without TFO, speech signals are encoded by the MS on one side

and transmitted over the Um interface. The signals are then decoded by the first TC unit. The

decoded PCM data flow is transmitted to the second TC unit on the 64 kbit/s transmission linkfor encoding. After being encoded, the data is transmitted to the MS on the other side over the

Um interface for decoding. As a result, speech signals are transcoded twice during aconversation, which is called tandem operation.

MS/UEMS/UE

PLMN A PLMN BTranscoding

Function

En c o d in g Deco d in g Dec o d in g E n c o d i n g Compressed Speech Compressed SpeechITU-T G.711 A-Law/-Law

Transcoding Functions

Transcoding

Function


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The TFO feature can reduce the speech signal degradation caused by tandem operation,improving the voice quality. When the calling MS and the called MS use the same speech

version, in-band signaling negotiation is performed to establish TFO links. In addition, the

least significant bit and the second least significant bit are stolen to seize the 8 kbit/s (or 16kbit/s) sublink of the PCM transmission link to transparently transmit TFO frames so that TC

encoding/decoding is invalidated. In this manner, speech signals are encoded at the MSinitiating the call and decoded at the MS terminating the call for only once. Therefore, thedegradation of the speech signals due to tandem operation is reduced and the voice quality

improves. This process is called tandem free operation (TFO).

Enhancement

GBSS8.1

The AMR TFO is supported.

GBSS9.0

Conversion between the FR and HR in the TFO:

During the TFO negotiation, if the channel (FR or HR) used by the called party is differentfrom the channel (HR or FR) used by the calling party, the call is handed over from the FR

channel to an HR channel before the TFO. This feature improves the voice quality of HRcalls.

GBSS14.0

The number of TFO setup failures and the TFO setup duration are measured. This introduces

new methods for network optimization and maintenance.

Dependency

Dependency on BSC hardware

For the dependency on BSC hardware, see GBSS15.0 Feature List.

Dependency on BTS hardware

For the dependency on BTS hardware, see GBSS15.0 Feature List.

Dependency on other GBSS features

This feature cannot be used with the following features:

GBFD-115601 Automatic Level Control (ALC)

GBFD-115602 Acoustic Echo Cancellation (AEC)

GBFD-115603 Automatic Noise Restraint (ANR)

GBFD-115703 Automatic Noise Compensation (ANC)

Transcoding

Function

Transcoding

Function

Transcoding Functions Bypassed

MS/UEMS/UE

PLMN A PLMN B

En c o d i n g Dec o d i n g Compressed Speech


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3

GBFD-115704 Enhancement Packet Loss Concealment (EPLC)

GBFD-115711 EVAD

GBFD-115506 AMR Coding Rate Threshold Adaptive Adjustment

AMR Rate Adaptation in GBFD-117702 BTS Local Switch

AMR Rate Adaptation in GBFD-117701 BSC Local Switch

This feature is mutually exclusive with the following features:

GBFD-118602 A over IP

GBFD-150201 A over IP Based on Dynamic Load Balancing

GBFD-118622 A IP over E1/T1

GBFD-115702 TrFO

Dependency on other NEsNone

1.1.2 GBFD-115711 EVAD

Availability


Summary

This feature enhances the encoding effect of downlink music (such as ring back tone (RBT)service and voice information service) that uses the EFR, AMR FR, or AMR HR speech

versions, improving user experience with regard to the downlink music.

Benefits

This feature helps telecom operators promote their value-added music services.

Description

The earlier Voice Activity Detection (VAD) algorithm may consider soft music as silence andmistakenly encode music in the downlink. This affects user experience.

The Huawei proprietary Enhanced VAD (EVAD) algorithm increases music recognitionaccuracy. It greatly reduces the probability that music is mistakenly considered as silence,

improving user experience.

Enhancement

None

Dependency




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This feature depends on any of the following features:

GBFD-115501 AMR FR

GBFD-115502 AMR HR

GBFD-113301 EFR

GBFD-114801 Discontinuous Transmission (DTX)-Downlink

If EVAD is enabled for a call, the following features cannot be enabled at the same time:

GBFD-115701 TFO

GBFD-117701 BSC Local SwitchGBFD-117702 BTS Local Switch


GBFD-115702 TrFO


GBFD-150201 A over IP Based on Dynamic Load Balancing


Dependency on other NEs

None

1.1.3 GBFD-116801 Voice Quality Index (VQI)

Availability


Summary

The voice quality index (VQI) feature provides a direct method of measuring the voice quality

of the radio network. By measuring the uplink VQI and downlink VQI, the voice quality ofthe network is quantified, which provides a reference for future network optimization.

Benefits

The VQI can measure the voice quality of the network rapidly and effectively and thereforeprovides a reference for network optimization.

Description

The VQI establishes the mapping between the radio network performance and voice quality.

The VQI value, which helps learn the voice quality, is calculated based on the parameters

related to the radio quality of uplink/downlink speech signals.


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The MOS analysis method is applied in VQI to measure the voice quality. The MOS is used toassess the quality of the middle-rate and low-rate voice coding. The MOS value ranges from 1

to 5. Based on the MOS analysis method, Huawei further divides the voice quality into 11

VQI levels. The VQI is obtained by analyzing the bit error rate (BER), frame error rate (FER),longest consecutive sequence of frame losses (LFE), and speech codec mode of

uplink/downlink speech signals. In this manner, the voice quality is quantified to facilitatevoice problem location and network optimization.

Enhancement

None

Dependency






Downlink VQI depends on the following feature:

GBFD-117501 Enhanced Measurement Report (EMR)


None

1.1.4 GBFD-115708 Um Interface Speech Frame Repairing

Availability


Summary

This feature applies an enhanced decoding technique to the Um interface to automaticallyrepair bit-error speech frames over the Um interface, improving the voice quality.

Benefits

This feature helps improve the voice quality. The improvement is more significant when thecarrier-to-interference ratio (CIR) is low.

Description

When the bit error rate (BER) is high and the CIR is low, voice quality will deteriorate if

bit-error speech frames are discarded. To solve this problem, an enhanced decoding technique

is used to repair the bit-error speech frames over the Um interface. This technique increasesthe success rate of voice decoding, improving the voice quality under a low CIR. After this

feature is applied, the mean opinion score (MOS) increases by 0.1 to 0.2 points under a low

CIR.


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Enhancement

None

DependencyDependency on BTS hardware





None


None

1.1.5 GBFD-115709 Smooth Voice Call Handover

Availability

This feature is introduced in GBSS15.0.

Summary

The Smooth Voice Call Handover feature enables the BTS to send handover commands toMSs at the most appropriate time when:

A narrowband AMR or enhanced full rate (EFR) voice call is in the discontinuoustransmission (DTX) mode.

Unimportant or no speech frames are transmitted.

Unimportant speech frames refer to frames that have minor impacts on the mean opinion score (MOS).

Benefits

This feature increases the average MOS on the entire network by 0.03 to 0.1 points andincreases the proportion of MOSs higher than 2.8 points by 1% to 3%.

Description

This feature enables the BTS to monitor the types and importance of uplink and downlink

speech frames in real time. The BTS sends handover commands to MSs when unimportant or

no speech frames are transmitted. This reduces the handover's impact on voice calls andimproves voice quality.

After this feature is enabled on the entire network, the proportion of downlink low quality

indicators (LQIs) increases slightly, but the maximum increase is 0.05%.


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This feature does not take effect during full rate (FR), half-rate (HR), and wideband AMRvoice calls.

Enhancement

None

Dependency






This feature depends on the following features:


GBFD-114803 Discontinuous Transmission (DTX)-Uplink


None

1.2 AMR

1.2.1 GBFD-115501 AMR FR

Availability


Summary

The AMR FR feature provides better voice quality when interference is likely to occur. Under

same conditions, the voice quality in AMR FR is the same as or better than the voice quality

in EFR.

Benefits

This feature provides the following benefits:

Increases system capacity.

Enhances the anti-interference capability to adapt to tight frequency reuse patterns.

Improves the network performance counters in an increasingly complex radioenvironment in combination with the frequency hopping technology.

Provides better voice quality.


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Description

The AMR is an integration of multiple voice encoding/decoding rates. Differentencoding/decoding rates yield different voice code streams. This enables the BTS and MSs toselect an appropriate encoding/decoding algorithm and to adjust the encoding rate in a

specific radio environment. Therefore, the AMR improves voice quality of the entire wirelesscommunication system.

When radio channels experience severe interference, better voice quality can be provided inAMR FR than in EFR or FR. In addition, the system in AMR FR has a higheranti-interference capability to adapt to tight frequency reuse patterns.

In the wireless communication system, the higher the original speech rate involved in channel

encoding, the more the information about the speech characteristics carried in the coded

stream, and therefore the higher the speech fidelity. However, the redundant information inthe coded stream decreases, and therefore the coded stream becomes more interference

sensitive. In a poor wireless communication environment, bit errors occur easily and thespeech frames may be lost, leading to discontinuous voices. If the original speech rate

involved in channel encoding is reduced, more redundant information is carried in the codedstream. Then the coded stream has stronger anti-interference and error correction capabilities,improving voice continuity.

The AMR FR provides multiple coding rates, as listed in the following table.

Channel Coding Rate

TCH/Adaptive full rate speech

(AFS)12.2 kbit/s

10.2 kbit/s

7.95 kbit/s

7.40 kbit/s

6.70 kbit/s

5.90 kbit/s

5.15 kbit/s

4.75 kbit/s

EnhancementGBSS8.1

The anti-interference capability of signaling transmission is enhanced.

If the original speech rate involved in channel encoding is reduced, more redundantinformation is carried in the coded stream. Then the coded stream has stronger

anti-interference and error correction capabilities, improving voice continuity. The signaling

transmission performance, however, is not improved. After this feature is enabled, thetransmit power is increased during signaling transmission to increase the success rate of

signaling transmission. This can avoid voice interruption concerned with signaling

transmission in poor radio environment.

GBSS13.0


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E-coder is introduced in GBSS13.0 and it is used in A over TDM transmission mode.

E-coder improves the AMR FR speech quality by using the filter enhancement technique

during preprocessing and the Linear Spectral Pairs (LSP) exact-calculate technique. In thisway, E-coder increases the mean opinion score (MOS) by 0.05 to 0.12 points.

E-coder is not supported in A over IP mode or when TFO is enabled.

Dependency






It is recommended that this feature work with the following feature:

GBFD-115503 AMR Power Control


MSs and the CN must support this feature.

Professional Service

It is recommended that this feature be used with the AMR feature introduction service.

1.2.2 GBFD-115502 AMR HR

Availability


Summary

The AMR HR feature provides better voice quality when interference is likely to occur. Under

same conditions, the voice quality in AMR HR is the same as or better than that in HR. Thisfeature must be used with the Half Rate Speech feature.

Benefits


Increases system capacity.

Enhances the anti-interference capability to adapt to tight frequency reuse patterns.

Improves the network performance counters in an increasingly complex radioenvironment in combination with the frequency hopping technology.

Provides better voice quality.


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Description

The AMR HR feature provides better voice quality when interference is likely to occur. Undersame conditions, the voice quality in AMR HR is the same as or better than that in HR.Therefore, as long as the voice quality meets the requirements, this feature can be widely used

to increase system capacity. When the network experiences much interference and the voicequality deteriorates, the system automatically switches to the AMR FR so that the voice

quality and the system capacity are balanced in real time. In this manner, the system can

provide good voice quality to subscribers while expanding system capacity.

The AMR HR provides multiple coding rates, as listed in the following table.

Channel Coding Rate

TCH/AHS 7.40 kbit/s

6.70 kbit/s

5.90 kbit/s

5.15 kbit/s

4.75 kbit/s

Enhancement

GBSS8.1

TCH/AHS 7.95 kbit/s coding rate.

The BTS using the Abis over IP or Abis transmission optimization function can provide theCS services at the rate of AMR HR 7.95 kbit/s. The following table lists multiple coding rates

provided by AMR HR.

Channel Coding Rate

TCH/AHS 7.95 kbit/s

7.40 kbit/s

6.70 kbit/s

5.90 kbit/s

5.15 kbit/s

4.75 kbit/s

Enhanced anti-interference capability of signaling transmission

If the original speech rate involved in channel encoding is reduced, the coded stream can

contain more redundant information. Then the coded stream has stronger anti-interference and

error correction capabilities and the voice continuity is improved as a result. The signalingtransmission performance, however, is not improved. After this feature is enabled, the

transmit power is increased during signaling transmission to increase the success rate of


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signaling transmission. This prevents voice interruption due to signaling transmission in poorradio environment.

GBSS13.0

E-coder is introduced in GBSS13.0 and it is used in A over TDM transmission mode.E-coder improves the AMR HR speech quality by using the filter enhancement technique

during preprocessing and the Linear Spectral Pairs (LSP) exact-calculate technique. In thisway, E-coder increases the mean opinion score (MOS) by 0.05 to 0.12 points.

E-coder is not supported in A over IP mode or when TFO is enabled.

Dependency






This feature depends on the following feature:

GBFD-113401 Half Rate Speech

It is recommended that this feature work with the following feature:

GBFD-115503 AMR Power Control


MSs and the MSC must support this feature.



1.2.3 GBFD-115503 AMR Power Control

Availability


Summary

The AMR Power Control features uses different AMR power control algorithm to provide

better anti-interference capability, larger network capacity, and better voice quality.

Benefits


Reduces the transmit power and prolongs the MS standby time.

Reduces the network interference and improves the frequency usage.


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Improves the network quality.

Description

The AMR speech codec can select one of the coding rates according to the radio channel

quality to achieve an optimized combination of speech coding rate and channel coding rate. In

this manner, the AMR speech coding scheme can provide the best voice quality in the currentradio environment and meet the communication requirements in various radio environments.The coded stream contains more redundant information. Then the coded stream has stronger

anti-interference and error correction capabilities, improving voice continuity. The systemautomatically determines whether to use the AMR. If the system uses the AMR, the power

control strategy for AMR calls is different from that for non-AMR calls. This reduces the

network interference and the BTS transmit power, and prolongs the MS standby time.

Enhancement

None

Dependency






It is recommended that this feature work with the following features:GBFD-115501 AMR FR

GBFD-115502 AMR HR


None



1.2.4 GBFD-115504 AMR FR/HR Dynamic Adjustment

Availability


Summary

The AMR FR/HR Dynamic Adjustment feature dynamically adjusts AMR HR and AMR FR

in a cell to balance the cell capacity and voice quality.


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Benefits


Requires less maintenance workload because the system can automatically adjust the

ratio of AMR FR to AMR HR based on the network capacity and quality. Expands the network capacity and reduces the network deployment cost without

deteriorating the voice quality.

Description

This feature dynamically adjusts AMR HR and AMR FR in a cell to balance the cell capacity

and voice quality.

After the initial speech coding is used to set up a call, the BSS calculates the radio quality

index (RQI) based on the uplink signal quality measured by the BTS. The BSS then

determines the encoding/decoding scheme used for the uplink based on the uplink quality, the

code sets activated by the BSC, and the corresponding thresholds. In addition, the BSSdynamically adjusts the voice coding rate in the uplink, and instructs MSs to use the selectedvoice coding rate. According to the RQI and parameters such as network capacity, the BSSdetermines whether to enable the AMR FR/HR dynamic adjustment in a cell to balance the

voice quality and cell capacity.

This feature applied in different radio environments and capacity configurations helps tobalance the voice quality and cell capacity. Before enabling this feature, ensure that the Half

Rate Speech and AMR HR features have been enabled.

Enhancement

None

Dependency






None


None




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1.2.5 GBFD-115506 AMR Coding Rate Threshold AdaptiveAdjustment

AvailabilityThis feature was introduced in GBSS8.1.

Summary

By setting a target voice quality and monitoring the voice quality in real time, GBSS devicescan adaptively adjust the coding rate adjustment thresholds so that the AMR speech can select

an appropriate coding rate. This enables the voice quality to approach the target voice quality.

Benefits

This feature provides the following benefits: Enables the AMR speech to select an appropriate coding rate.

Ensures the AMR speech performance.

Description

The AMR speech rate set consists of multiple coding rates. Based on the measured receive

level, receive quality, and carrier-to-interference ratio (CIR), and in combination with a

specific algorithm, the BTS and MS adjust the AMR call control parameters to select a sourcespeech coding rate that adapts to the current radio environment. This helps achieve an optimal

combination of the channel quality and speech coding rate, maximally improving the voice

quality.Generally, network planners evaluate the radio channel quality and then set the AMR speech

coding rate adjustment thresholds to fixed values. If the radio channel quality changes or thenetwork planners' evaluation is inaccurate, the AMR speech will fail to select an appropriate

coding rate and the AMR voice quality is then affected.

With this feature, BSS devices set a target voice quality and monitor the voice quality in real

time. The GBSS devices then adaptively adjust the coding rate adjustment thresholds so thatthe AMR speech can select an appropriate coding rate. This ensures the AMR voice quality.

AMR coding rate adjustment thresholds consist of uplink and downlink adjustmentthresholds.

Uplink: After comparing the uplink quality indicator with the coding rate adjustmentthreshold, the BTS obtains an appropriate coding rate for an MS. Then, the BTS sends

the coding rate to the MS by using in-band signaling, instructing the MS to adjust thecoding rate.

Downlink: After comparing the downlink quality indicator with the coding rateadjustment threshold, an MS obtains an appropriate coding rate for the BTS. Then, the

MS sends the coding rate to the BTS by using in-band signaling. The BTS

comprehensively considers the restrictions on the network side and then adjusts thedownlink coding rate. Meanwhile, the BTS notifies the MS of the selected downlink

coding rate, instructing the MS to use the same coding rate for decoding.

GBSS8.1 only supports the AMR coding rate threshold adaptive adjustment on the uplink.


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Enhancement

GBSS9.0

GBSS9.0 supports the AMR coding rate threshold adaptive adjustment on the downlink. The

details are as follows:

The BTS obtains the frame erase ratio (FER) of the current call from the enhanced

measurement report (EMR) reported by an MS and then estimates the speech quality. If theestimated speech quality is distinct from the target speech quality, the configured threshold is

inappropriate. When this occurs, the GBSS adjusts the threshold based on a specific algorithm.The BTS sends the adjusted AMR coding rate threshold to the MS on the robust AMR trafficsynchronized control channel (RATSCCH). Subsequently, the MS adjusts the AMR coding

rate during the call on the basis of this coding rate adjustment threshold.

Dependency






AMR coding rate threshold adaptive adjustment on the downlink depends on the following

features:


AMR coding rate threshold adaptive adjustment on the uplink and downlink depends on anyof the following features:

GBFD-115501 AMR FR

GBFD-115502 AMR HR

GBFD-115507 WB AMR




This feature does not take effect if any of the following feature is used in a call:

GBFD-115701 TFO

GBFD-117701 BSC Local Switch

GBFD-117702 BTS Local Switch


None




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1.2.6 GBFD-115507 WB AMR

Availability


Summary

Wideband AMR (WB AMR) is a coding scheme that significantly improves the speech quality.

WB AMR supports the rates of 6.60 kbit/s, 8.85 kbit/s, and 12.65 kbit/s.

Benefits


Provides better speech quality than the narrowband AMR.

Increases the operators' revenue because the speech quality improves and subscriberstend to spend more time on calls.

Attracts subscribers to wireless networks from fixed networks because the WB AMR

speech quality is better than that of PSTN.

Description

WB AMR can significantly improve speech quality. With WB AMR, the sampling rate is

increased to 16 kHz and the speech frequency range is extended to 50 Hz7 kHz. WB AMRprovides clear and loud voice and high-quality speech compared with the narrowband AMR

(sampling rate: 8 kHz; speech frequency range: 2003400 Hz.

WB AMR uses the Guassian Minimum Shift Keying (GMSK) mode and supports the rates of

6.60 kbit/s, 8.85 kbit/s, and 12.65 kbit/s on full-rate TCHs.

End-to-end WB AMR calls are required to achieve ideal speech quality. A one-end WB AMRcall requires PCM coding and decoding twice, which adversely affects the speech quality.When the end-to-end WB AMR and the TFO are used together, a call only requires coding

once, which helps maintain good speech quality. If an end-to-end WB AMR call cannot be setup, the BSC will set up an AMR FR call instead of a one-end WB AMR call because the

speech quality and robustness of an AMR FR call is better than a one-end WB AMR call.

Huawei BSS equipment supports the WB AMR feature in Abis over TDM, Abis over IP, andAbis over HDLC transmission modes.

Enhancement

None

Dependency







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None


MSs must support this feature. The MGW/MSC server must support this feature.



1.3 Voice Capacity

1.3.1 GBFD-113401 Half Rate Speech

AvailabilityThis feature was introduced in GBSS6.1.

Summary

This feature reduces the speech coding rate to half the full-rate speech coding rate using a newspeech coding algorithm. In this manner, a physical channel carrying the service of one MS isable to carry the services of two MSs.

Benefits

This feature enables operators to expand the network capacity and improve the frequency

usage without increasing the hardware investment. In addition, this feature enables an E1 tocarry a higher traffic volume.

Description

With the increase of GSM subscribers, the frequency resources of the existing GSM network

become insufficient. The half-rate service helps increase the number of speech channelsconfigured for one TRX. This increases the frequency usage without greatly reducing the

voice quality and expands the network capacity without increasing the hardware investment.

The half-rate service saves resources in the following aspects:

Saving resources on the Um interface

The half-rate speech coding rate is reduced to half the full-rate speech coding rate usinga new coding algorithm. In addition, multiframes on the Um interface are used by two

MSs: One MS receives the even-numbered multiframes and the other MS receives the

odd-numbered multiframes. In this manner, a physical channel that supports one MS inthe full-rate service can carry two MSs in the half-rate service. This requires fewer

timeslots, reducing the entire network interference.

Saving resources on the Abis interface

In half-rate service, one 16 kbit/s channel carries two calls on the Abis terrestrial circuit.In this manner, a higher traffic volume is carried on the terrestrial link. The load on the

radio signaling link (RSL), however, is heavy because one TRX carries a higher traffic

volume. Therefore, when configuring signaling multiplexing, use the 2:1 mode instead of

the 4:1 mode.


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Enhancement

GBSS7.0

The half-rate service is enhanced to save resources on the Ater interface.

When the Flex Ater feature is enabled, the 8 kbit/s circuit is allocated to the half-rate call overthe Ater interface. In this manner, the transmission resources on the Ater interface are saved.

GBSS8.1

Half-rate channels are preferentially allocated when transmission resource congestionoccurs on the Abis interface.

Half-rate channels are allocated based on the resource congestion condition on the Abisinterface. The load on the Abis interface is calculated in real time. When the resources on the

Abis interface are congested, the BSC preferentially allocates a half-rate speech channel to a

call to relieve the resource congestion.

Dynamic conversion between half-rate and full-rate channels is triggered when resourcecongestion occurs on the Um or Abis interface.

The dynamic conversion between half-rate and full-rate channels is triggered based on theresource congestion condition on the Um or Abis interface. When the resources are congested,

Certain full-rate calls are converted to half-rate calls to relieve the congestion.

Dependency






It is recommended that this feature work with the following features:

GBFD-117301 Flex Abis

GBFD-116901 Flex Ater


MSs and the MSC must support this feature.


It is recommended that this feature be used with the VAMOS features introduction service.

1.3.2 GBFD-113402 Dynamic Adjustment Between FR and HR

Availability



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Summary

With this feature, full-rate (FR) channels and half-rate (HR) channels are dynamicallyconverted to automatically adapt to the proportions of FR channels and HR channels in a cell.This prevents the situation in which one type of channel is congested whereas the other type

of channel is idle.

Benefits


Improves the channel usage because channels are adjusted according to the requirement

of the call.

Improves the voice quality because calls are handed over from half-rate channels tofull-rate channels when the traffic volume is low.

Increase cell capacity because calls are handed over from full-rate channels to half-rate

channels when channels in a cell are insufficient.

Description

If HR channels are configured, the HR and FR channels are dynamically converted to

automatically adapt to the proportions of FR and HR channels in a cell. This prevents the

situation in which one type of channel is congested whereas the other type of channel is idle.

In addition, this helps control the proportions of FR and HR channels in a cell by using relatedparameters.

During a call, channels are allocated based on the resources in the MS, MSC, and BSC. If an

HR channel is required but is unavailable, an FR channel is converted into two HR channels.If an FR channel is required but is unavailable, two HR channels are converted into an FR

channel.

Each time a call is released, the channel attributes are not changed. If the load of a cell isnormal, call automatic adjustment ensures that the proportions of FR and HR channels in the

cell are maintained. If the load of a cell is very heavy or light, HR and FR channels areconverted back and forth.

Enhancement

GBSS8.1

During call establishment, the network assigns a half-rate or a full-rate channel to a call basedon the usage of cell resources. If a call lasts for a long period of time, the usage of cell

resources may change:

If the TCH usage is high during call establishment, a half-rate channel is assigned to thecall. After the call lasts for a period, many calls have been released and the TCH usagedecreases. In this case, TCHs in the cell are sufficient and a full-rate channel can be

assigned to the call to improve the voice quality.

If the TCH usage is low during call establishment, a full-rate channel may be assigned toa call. After the call lasts for a period, many calls access the cell and the TCH usageincreases. In this case, available TCHs in the cell are insufficient.

If this feature is enabled, the half-rate or full-rate channels for established calls can beadjusted based on the usage of cell resources. The details are as follows:


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When the TCHs in a cell are sufficient, full-rate channels are preferably assigned to newcalls and poor-quality calls are handed over from half-rate channels to full-rate channels,

This improves voice quality.

When the TCHs in a cell are insufficient, half-rate channels are preferably assigned to

new calls and good-quality calls are handed over from full-rate channels to half-ratechannels. This increases cell capacity.

Before enabling this feature, ensure that the Half Rate Speech feature has been enabled.

GBSS14.0

If a policy is used that preferentially allocates HR channels to an MS, the BSC determineswhether the receive level is higher than the preset threshold during a handover or a channel

assignment. If the receive level is higher than the threshold, the BSC allocates HR channels tothe MS. If the receive level is lower than the threshold, the BSC preferentially allocates FRchannels to the MS.

Dependency






This feature depends on the following feature:

GBFD-113401 Half Rate Speech


None



1.3.3 GBFD-115830 VAMOS

Availability


Summary

Voice services over Adaptive Multi-user Orthogonal Subchannels (VAMOS) enables two

users to be multiplexed onto one half-rate (HR) channel to increase network capacity.


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Benefits

In a network where refarming is applied and speech channels are insufficient, the GSMnetwork capacity can be increased by using software without changing the existing GSMnetwork architecture. Assuming that the SAIC MS penetration rate is 100% and the 4x3

frequency reuse pattern is used, VAMOS increases the network capacity by 20%.

Description

VAMOS is a technology to increase GSM network capacity. The network capacity is

increased by using HR channels and can be increased further by VAMOS applied on the FRchannels. VAMOS introduces a new modulation mode and training sequence, which imposes

new requirements on MSs. Tests tell that the VAMOS performance depends on the penetrationrate of SAIC MSs and the frequency reuse pattern in use.

VAMOS reduces network quality while increasing network capacity. The reduced networkquality should be tolerable for operators because the quality standards for a GSM network

with VAMOS are lower than those for a legacy GSM network, as defined in 3GPPspecifications. The following table lists the VAMOS gains.

Frequency Reuse

PatternSAIC MS Ratio (%) VAMOS Gain (%)

4x3

50% 10%-15%

75% 15%-22%

100% 20%-30%

3x3

50% 7%-12%

75% 10%-18%

100% 15%-25%

1x3

50% 5%-10%

75% 7%-15%

100% 10%-20%

The preceding table tells that the network capacity is not increased when a tight frequency

reuse pattern is used. Therefore, it is recommended that VAMOS be enabled only when aloose frequency reuse pattern is used.

Enhancement

GBSS14.0

The radio resource management (RRM) algorithm is optimized for networks deployed withVAMOS. The optimization reduces the negative impact of VAMOS on the call drop rate and

handover success rate. In addition, the channel preemption and timeslot combination policies

are modified to reduce the negative impact of VAMOS on ongoing services while increasingresource usage efficiency.


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Dependency






This feature depends on the following features:

GBFD-115502 AMR HR or GBFD-113401 Half Rate Speech

GBFD-118103 Network Support SAIC

GBFD-117301 Flex Abis (in TDM transmission mode)

GBFD-118601 Abis over IP or GBFD-118611 Abis IP over E1/T1 (in IP transmission mode)

GBFD-117601 HUAWEI III Power Control Algorithm


GBFD-113501 A5/1 and A5/2 Ciphering Algorithm

GBFD-113503 A5/3 Ciphering Algorithm


GBFD-114803 Discontinuous Transmission (DTX)-Uplink



GBFD-117001 Flex MAIO

GBFD-510104 Multi-site Cell

GBFD-113521 A5/1 Encryption Flow Optimization

GBFD-510101 Automatic Frequency Correction (AFC)

GBFD-114001 Extended Cell


MSs must support this feature.



1.3.4 GBFD-115831 Mute SAIC MS Identification

Availability



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Summary

The Mute SAIC MS Identification feature identifies SAIC-capable MSs that do not reporttheir SAIC capability to the BSS so that the MSs can use VAMOS.

Benefits

This feature helps increase the number of MSs that use VAMOS, increasing network capacity.

Description

Some mute SAIC MSs support SAIC but do not report the SAIC capability to the BSS. As a

result, the number of MSs that can be multiplexed by VAMOS is smaller than what it actuallyis, and therefore the network capacity is limited.

This feature helps distinguish SAIC-capable MSs from SAIC-incapable MSs so that the

SAIC-capable MSs can use VAMOS.

Enhancement

GBSS14.0

VAMOS is enhanced for the Mute SAIC MS Identification feature in GBSS13.0. The M2000is used to share SAIC MS capability data between BSCs. This minimizes the impact of the

Mute SAIC MS Identification feature on KPIs and improves system reliability by reducing

manual workload.

Dependency





Dependency on other GBSS/RAN features

This feature is used with the following feature:

GBFD-115830 VAMOS


GBFD-113501 A5/1 and A5/2 Ciphering Algorithm

GBFD-113503 A5/3 Ciphering

gbss15.0 optional feature description 01

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