Alcatel BSS Description

7/27/2019 Alcatel BSS Description

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Alcatel BSS

BSS System Description

Descriptive Documentation

BSS Concepts

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Status RELEASED

Short title System Description

All rights reserved. Passing on and copying of this document, useand communication of its contents not permitted without writtenauthorization from Alcatel/Evolium.

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Contents

Contents

Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

1.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141.2 BSS Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

1.2.1 Call Set Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161.2.2 Call Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171.2.3 Call Release . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171.2.4 Operations & Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

1.3 BSS Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181.3.1 Base Station Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181.3.2 Base Transceiver Station . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191.3.3 Transcoder And Transmission Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 221.3.4 The Multi-BSS Fast Packet Server . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231.3.5 Multi-GPU per BSS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

1.4 Extended GSM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

1.5 External Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 281.5.1 Network Subsystem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 291.5.2 Mobile Stations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301.5.3 Phase 2 Mobile Support in a Phase 1 Infrastructure . . . . . . . . . . . . . . . . . . . . . . . 331.5.4 Operations and Maintenance Center-Radio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

1.6 Network Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 341.6.1 Telecommunications Management Network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 341.6.2 Q3 Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

1.7 BSS Telecommunications Layers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 361.7.1 Call Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 361.7.2 Mobility Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 361.7.3 Radio Resource Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

1.7.4 The A Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 381.7.5 The Abis Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 391.7.6 Satellite Links . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 391.7.7 The Air Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

2 GPRS in the BSS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

2.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 482.1.1 Packet Switching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 482.1.2 GPRS Elements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

2.2 GPRS Channels and System Information Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 522.2.1 Master Channels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 522.2.2 Static Allocation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 522.2.3 Dynamic Allocation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

2.2.4 Multiple PCCCH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 542.2.5 Logical Channels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 562.2.6 Virtual Channels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 562.2.7 System Information Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

2.3 GPRS Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 592.3.1 The Gb Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 592.3.2 The BSCGP Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 602.3.3 The GCH Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

2.4 GPRS Network Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 622.4.1 Mobility Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 632.4.2 Paging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 642.4.3 Radio Power Control and Radio Link Measurement . . . . . . . . . . . . . . . . . . . . . . . . 64

2.5 Resource Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

2.5.1 Time Slot Allocation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

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2.5.2 Frequency Hopping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 662.5.3 PCM Link Sharing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 662.5.4 Resource Reallocation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

2.6 Traffic Load Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 682.6.1 Congestion Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 692.6.2 Smooth PDCH Traffic Adaption to Cell Load Variation . . . . . . . . . . . . . . . . . . . . . . 70

2.6.3 GPRS Overload Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 702.6.4 Delayed Downlink TBF Release . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

2.7 Data Transmission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 722.7.1 GPRS Attach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 722.7.2 Packet Data Protocol Context Activation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 742.7.3 Data Transfer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 762.7.4 Packet Data Protocol Context De-activation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 782.7.5 GPRS Suspend . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 812.7.6 GPRS Resume . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 822.7.7 GPRS Detach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

3 Call Set Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

3.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

3.2 Mobile Originated Call . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 903.2.1 Radio and Link Establishment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 903.2.2 Authentication and Ciphering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 963.2.3 Normal Assignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

3.3 Mobile Terminated Call . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1023.3.1 Radio and Link Establishment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1033.3.2 Authentication and Ciphering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1033.3.3 Normal Assignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1043.3.4 IMSI Attach-Detach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105

3.4 Paging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1063.4.1 Paging Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1083.4.2 Discontinuous Reception . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110

3.5 Congestion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1113.5.1 Queueing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1113.5.2 In-queue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1123.5.3 Pre-emption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115

3.6 Classmark Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1173.6.1 Classmark IE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1173.6.2 Classmark Updating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1193.6.3 Location Updating with Classmark Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120

3.7 Authentication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1223.8 Ciphering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124

3.8.1 Ciphering Keys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1253.8.2 Ciphering Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125

3.9 Tandem Free Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128

3.9.1 TFO Functional Architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1303.9.2 TFO Optimization and Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131

4 Call Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133

4.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1344.2 In-Call Modification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134

4.2.1 In-Call Modification Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1354.2.2 Circuit-switched Group 3 Fax Data Rate Change . . . . . . . . . . . . . . . . . . . . . . . . . 1364.2.3 Error Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136

4.3 Frequency Hopping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1374.3.1 Baseband Frequency Hopping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1384.3.2 Synthesized Frequency Hopping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139

4.4 Discontinuous Transmission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140

4.4.1 Speech Transmission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140

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4.4.2 BSS Discontinuous Transmission Towards Mobile Station . . . . . . . . . . . . . . . . . 1414.4.3 Mobile Station Discontinuous Transmission Towards BSS . . . . . . . . . . . . . . . . . 142

4.5 Radio Power Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1444.5.1 BTS Radio Power Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1444.5.2 Mobile Station Radio Power Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1444.5.3 Radio Link Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145

4.5.4 Power Control Decision and Handover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1464.5.5 Change Power Levels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148

4.6 Handover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1494.6.1 Radio Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1514.6.2 Handover Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1524.6.3 Target Cell Evaluation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1594.6.4 Synchronous and Asynchronous Handover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160

4.7 Overload Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1674.7.1 BTS Overload . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1674.7.2 BSC Overload . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168

4.8 Call Re-establishment by the Mobile Station . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170

5 Call Release . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171

5.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1725.2 Call Release Procedures in Normal Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173

5.2.1 Normal Release . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1735.2.2 Calls Terminated Following a Channel Change . . . . . . . . . . . . . . . . . . . . . . . . . . . 178

5.3 Call Release - Special Cases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1795.3.1 Call Release Following Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1795.3.2 BSC-Initiated Release . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1805.3.3 BSC-Initiated SCCP Release . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1825.3.4 BTS-Initiated Call Release . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1835.3.5 Mobile Station-Initiated Call Release . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1855.3.6 Remote Transcoder Alarms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186

6 Handling User Traffic Across the BSS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187

6.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1886.2 Speech . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188

6.2.1 Enhanced Full-Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1906.2.2 Half-Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1916.2.3 Adaptive Multiple Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1926.2.4 Channel Mode Adaption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194

6.3 Circuit-Switched Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1956.3.1 Transparent Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1966.3.2 Non-Transparent Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197

6.4 Short Message Service - Cell Broadcast . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1986.5 Support of Localized Service Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2006.6 PLMNs Interworking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200

7 Cell Environments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2037.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2047.2 Concentric Cell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2067.3 Sectored Site . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2077.4 Extended Cell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2087.5 Umbrella Cell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210

7.5.1 Mini Cell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2107.5.2 Microcell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211

7.6 Cell Shared by Two BTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215

8 Operations & Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 217

8.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2188.2 O&M Architecture and Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 218

8.2.1 O&M Architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 219

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8.2.2 O&M Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2208.3 O&M Control - The OMC-R . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 221

8.3.1 Multiple Human-Machine Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2228.3.2 ACO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2238.3.3 Secured X.25 Connection From BSC to OMC-R . . . . . . . . . . . . . . . . . . . . . . . . . . 2248.3.4 Electronic Documentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226

8.4 Configuration Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2278.4.1 Hardware Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2288.4.2 Logical Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2288.4.3 Software Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2288.4.4 Auto Identification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2298.4.5 OML Auto-detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2308.4.6 NE Provisioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231

8.5 Fault Management - Alarms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2328.5.1 Alarm Generation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2348.5.2 Alarm Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2348.5.3 BSC Alarms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2358.5.4 BTS Alarms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238

8.5.5 Alarms Detected by the TSC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2408.5.6 MFS Alarms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2408.5.7 Recovery Example: Carrier Unit Failures with BCCH . . . . . . . . . . . . . . . . . . . . . . 2418.5.8 Automatic Power-Down . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2438.5.9 BSC Alerter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243

8.6 Performance Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2448.6.1 Traces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2448.6.2 Performance Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2458.6.3 Radio Measurements Statistics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2468.6.4 Results Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 247

8.7 Audits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2488.8 Remote Inventory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250

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Figures

Figure 1: BSS in the PLMN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Figure 2: Antenna Diversity on G1 and G2 BTSs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Figure 3: Antenna Diversity on the BTS A9100 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Figure 4: Transmission Components in the BSS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Figure 5: Cell Mapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Figure 6: Logical Position of External Components Associated with BSS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Figure 7: Location Update . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Figure 8: TMN System Hierarchy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Figure 9: General Telecommunication Layers within GSM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Figure 10: BSS Application, Transmission Layers and Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Figure 11: Time Slot 4 of a Time Division Multiple Access Frame Supporting Access Grant Channels . . . 41

Figure 12: Model LLC Packet Data Unit used in GPRS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49Figure 13: The Alcatel GPRS solution in the PLMN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

Figure 14: GPRS Traffic Load Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

Figure 15: GPRS Attach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

Figure 16: Mobile Station-Originating Packet Data Protocol Context Activation . . . . . . . . . . . . . . . . . . . . . . . . 74

Figure 17: GGSN-Originating Packet Data Protocol Context Activation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

Figure 18: Mobile-Originated Data Transfer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76

Figure 19: Mobile-Terminated Data Transfer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

Figure 20: Mobile Station Originating Packet Data Protocol Context De-activation . . . . . . . . . . . . . . . . . . . . . 78

Figure 21: Network-Originating Packet Data Protocol Context De-activation Processes . . . . . . . . . . . . . . . . 79

Figure 22: GPRS Suspend . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

Figure 23: GPRS Resume . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82

Figure 24: Mobile Station-Originating GPRS Detach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

Figure 25: Network-Originating GPRS Detach Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

Figure 26: Radio and Link Establishment for Mobile Originated Call . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

Figure 27: SDCCH Channel Activation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

Figure 28: Immediate Assignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

Figure 29: Connection for Mobile Originated Call . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

Figure 30: Normal Assignment for Mobile Originated Call . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

Figure 31: Channel Activation Process for the Traffic Channel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99

Figure 32: Channel Assignment Process for the Traffic Channel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100

Figure 33: Call Connection for Mobile Originated Call . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101

Figure 34: Radio and Link Establishment for Mobile Terminated Call . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102

Figure 35: Normal Assignment for Mobile Terminated Call . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104

Figure 36: CCCH with Three Blocks Reserved for AGCH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106

Figure 37: Four TDMA Frame Cycles Providing 24 Paging Sub-channels . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107

Figure 38: Paging Message Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

Figure 39: Location Update with Classmark Update . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120

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Figure 40: Location Update with Mobile Station Sending Location Area Identity of Previous VLR . . . . . . . 122

Figure 41: Ciphering Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127

Figure 42: Example of TFO Establishment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129

Figure 43: Frequency Hopping within an FHS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138

Figure 44: Different Forms of Discontinuous Transmission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143Figure 45: Power Control Flow of Measurement and Decision Action . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146

Figure 46: Power Output Balancing Based on Received Quality and Signal Levels . . . . . . . . . . . . . . . . . . . . 147

Figure 47: Quality and Level Handover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153

Figure 48: Better Zone Handover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154

Figure 49: Better Cell Handover (Power Budget) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155

Figure 50: Distance Handover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156

Figure 51: Umbrella Cell Load in Mobile Velocity Dependent Handover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157

Figure 52: Synchronous Internal Handover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161

Figure 53: Asynchronous External Handover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164

Figure 54: Mobile Station Disconnecting a Call . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173

Figure 55: Normal Call Release . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174

Figure 56: Initiation of Normal Release by MSC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175

Figure 57: BSC/BTS/Mobile Station interactions in Normal Call Release . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176

Figure 58: Normal Release Final Steps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177

Figure 59: Call Release Following a Channel Change . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178

Figure 60: Call Release Following Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180

Figure 61: BSC-initiated Call Release toward the MSC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181Figure 62: BTS-initiated Call Release following LAPD failure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184

Figure 63: Call Release due to Mobile Station initiated Radio Link Failure . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185

Figure 64: Call Release due to Communication Failure detected by Transcoder . . . . . . . . . . . . . . . . . . . . . . 186

Figure 65: Encoded Speech Transmission Across the BSS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188

Figure 66: Multiplexed Ater Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189

Figure 67: Data Transmission Across the BSS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195

Figure 68: Short Message Service - Cell Broadcast . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198

Figure 69: Example: Cell Configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205

Figure 70: Sectored site configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207

Figure 71: Example of Extended Cell Topology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208

Figure 72: Umbrella Cell with Mini Cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210

Figure 73: Example: Handovers due to Threshold Triggering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212

Figure 74: Indoor cell example network hierarchy with three layers and two bands . . . . . . . . . . . . . . . . . . . . 213

Figure 75: Multiple HMI Access to OMC-Rs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222

Figure 76: ACO Links . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223

Figure 77: X.25 Without Redundancy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224

Figure 78: X.25 With Redundancy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225

Figure 79: RSL Correlation on the Abis Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 236

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Figure 80: Example: Alarm Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237

Figure 81: Example: Loss of Carrier Unit Holding BCCH. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242

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Tables

Tables

Table 1: System Information Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

Table 2: GPRS System Information Message . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

Table 3: GPRS System Information Messages Used with MPDCH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

Table 4: Gb Interface Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

Table 5: BSCGP Interface Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

Table 6: Network Operation Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

Table 7: Time Slot Allocation Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

Table 8: PDCH Traffic Load States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

Table 9: Types of Calls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

Table 10: Call Set Up Phases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

Table 11: Cell List Identifier and Paging Performed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108

Table 12: Paging Request Message and Mobile Station Identification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

Table 13: Classmark Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117

Table 14: Classmark Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119

Table 15: Mobile Station Ciphering Capabilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124

Table 16: Downlink Discontinuous Transmission Status in Channel_activation . . . . . . . . . . . . . . . . . . . . . . . . 141

Table 17: Operator Discontinuous Transmission Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142

Table 18: Radio Link Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145

Table 19: Mobile Station Maximum and Minimum Power Ranges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148

Table 20: Circuit-Switched Data Rate Conversions Across the Air Interface . . . . . . . . . . . . . . . . . . . . . . . . . . 196

Table 21: Configuration Management Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227

Table 22: Fault Management Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 233

Table 23: BTS Alarm Hardware Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238

Table 24: BTS Alarms Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238

Table 25: Performance Management Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244

Table 26: Audit Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 248

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Preface

Preface

Purpose This document provides detailed descriptions of the functions and featuresof the Alcatel BSS. Some functions and features may not be available onthe system installed at your location.

The technical information in this document covers:

Mobile Communications SupportThese areas describe how the BSS handles communications between amobile station and the NSS. It follows a call through the Alcatel BSS, anddescribes how each element in the system functions individually and withother elements. This shows how the BSS and its units react as a system.

Operations and MaintenanceThese areas describe the O&M functions within the system. It describesboth local and distributed O&M functions in a BSS.

Audience This manual is for people requiring an in-depth understanding of the functionsof the Alcatel BSS:

Network decision makers who require an understanding of the underlying

functions of the system, including:

Network planners

Technical design staff

Trainers.

Operations and support staff who need to know how the system operates in

normal conditions, including:

Operators

Support engineers

Maintenance staff

Client Help Desk personnel.

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Preface

Assumed Knowledge The document assumes that the reader has an understanding of:

GSM

GPRS

Mobile Telecommunications

Network Management concepts and terminology.

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1 Introduction

1 Introduction

This chapter gives a brief overview of the Alcatel BSS, its functions andfeatures. It describes:

Overview

BSS functions

Internal and external components and interfaces

BSS Network Management

The distribution of telecommunications software in the BSS.

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1 Introduction

1.1 Overview

The BSS provides radio coverage for GSM subscribers in a defined area. Itsprincipal role is to provide and support signalling and traffic channels betweenmobile stations and the NSS.

The following figure shows the BSS within the PLMN, and its links to the PSTNand the PSDN in a fixed network.

Base Station Subsystem

MobileStations

NetworkSubsystem

FixedNetwork

PLMN

OMCR

NMC

MFS

BTS

SGSN

MSC PSTN

TC

BSC

PSDN

GGSN : Gateway GRPS Support NodeHLR : Home Location Register

MFS : Multi-BSS Fast Packet Server

NMC : Network Management Center

PSDN : Packet Switched Data Network

PSTN : Public Switched Telephone Network

SGSN : Serving GRPS Support Node

Figure 1: BSS in the PLMN

EVOLIUM RadioSolutions

To respond to the swiftly evolving needs in BSSs, Alcatel offers the EVOLIUMRadio Solutions.

The Alcatel EVOLIUM Radio Solutions includes the following BSS equipment

described in this document:

G2 BSC

G2 Transcoder

G2.5 Transcoder

BTS A9100

BTS A910

A935 MFS.

Note: BTS G1 and BTS G2 are still supported by EVOLIUM.

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1 Introduction

Extended GSM Band(E-GSM)

The Alcatel BSS supports the E-GSM band. E-GSM consists of:

The 900 MHz primary band, called the P-GSM band. This uses 890-915

MHz for uplink, and 935-960 MHz for downlink.

The 900 MHz extended band, called the G1 band. This uses 880-890 MHz

for uplink, and 925-935 MHz for downlink.

This corresponds to a total number of 174 addressable frequencies.

GSM 850 The GSM 850 MHz band has been introduced in the Release 1999 of the 3GPPStandard in 1999 to allow operators to replace progressively the D-AMPS andCDMA technologies that were using these frequencies. Besides certain Asiancountries, the GSM 850 MHz band concerns in particular the Latin Americancountries where many operators already use in their network the GSM systemwith the GSM 1900 MHz to extend or replace their D-AMPS existing network.The term GSM 850 is used for any GSM system which operates in 824 MHz to849 MHz band for the uplink direction and in the 869 MHz to 894 MHz band forthe downlink direction. The GSM 850 band is defined by 124 absolute radio

frequency channel numbers (ARFCN) among the 1024 ARFCNs available inthe GSM standard.

Frequency BandConfigurations

The Alcatel BSS supports the following multiband network configurations:

BSS with a mix of GSM 850 and GSM 1900 cells

BSS with a mix of GSM 850 and GSM 1800 cells

BSS with a mix of GSM 900 and GSM 1800 cells.

Refer also to Basic GSM System Specifications.

GPRS GPRS, the solution chosen by European Telecommunication StandardsInstitute to answer the demand for increased data transmission rates, is nowavailable in the Alcatel BSS. This means there are now two parallel systemsin the PLMN: circuit-switched transmission for voice, and packet-switchedtransmission for data. For information on how GPRS functions within the BSS,see GPRS in the BSS (Chapter 2).

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1 Introduction

1.2 BSS Functions

Functions are defined by the International Telecommunications Union andEuropean Telecommunication Standards Institute recommendations.

This section describes the BSS functions with a system-wide view; that is, how

the BSS functions work together within the system. Network elements andfunctional units are indicated where applicable, but are not described. For moreinformation, refer to the specific network element description manuals, suchas the BTS Functional Description.

The BSS provides signalling and traffic channels between the mobile stationand the NSS. To ensure a high level of service to the subscribers, the BSSoffers the following functions:

Call Set Up

Call Handling

Call Release

Operations & Maintenance.

1.2.1 Call Set Up

The Call Setup function is used for speech and data calls. The three basictypes of call are:

Mobility Management

Supplementary service

User traffic.

Mobility ManagementCalls

Mobility Management calls, such as location update, are used by the systemto gather mobile station information. The exchanges are protocol messagesonly. Therefore, only a signalling channel is used.

Supplementary Service

Calls

Supplementary service calls, such as SMS, allows the mobile station to sendand receive messages to and from the BTS. These calls pass small amounts ofinformation. Therefore, only a signalling channel is used.

User Traffic Calls User traffic calls, such as speech or data calls to a correspondent, can passlarge amounts of information. Therefore, they require greater bandwidth than asignalling channel. These calls use traffic channels.

Call set up processes include:

Radio and Link Establishment to assign a signalling channel between

the mobile station and the NSS

Classmark handling to manage different mobile station power and ciphering

capabilities

Ciphering to ensure data security on the Air Interface

The normal assignment process to assign a traffic channel between the

mobile station and the NSS.

See Call Set Up (Chapter 3) for more information.

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1 Introduction

1.2.2 Call Handling

The call handling function is used to supervise and maintain calls which arein progress. Call handling involves:

In-call channel modification during a call

Maintenance of call integrity and quality through features such as Frequency

Hopping, Discontinuous Transmission or Radio Power Control

Handover to change channels when a mobile station moves from one

cell to another

Handover when the quality of the current channel drops below an acceptable

level

Ciphering to ensure data security on the Air Interface

Overload control to manage the call load on the system.

See Call Handling (Chapter 4) for more information.

1.2.3 Call Release

The call release function ensures that resources allocated to a call are free forreuse when they are no longer required by the current call.

Specifically the Call Release function includes:

Call Release in normal service:

Calls terminated by call management

Calls terminated following a channel change.

Special Cases:

Call release following a reset

BSC-initiated release

BTS-initiated release

Mobile station-initiated release.

See Call Release (Chapter 5) for more information.

1.2.4 Operations & Maintenance

O&M provides the operator interface for the management and control of theBSS, and its interconnection to the NSS. O&M is divided into three principalareas:

Configuration Management

Fault Management

Performance Management.

See Operations & Maintenance (Chapter 8) for more information.

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1.3 BSS Components

There are three main units in the BSS:

The BTS, which provides the radio transmission and reception functions

for a cell

The BSC, which acts as the controller of the BSS. The BSC provides

control of the BTSs and their resources, and performs switching functions

within the BSS

The Transcoder, which performs rate adaptation and encoding/decoding of

speech and data between the MSC and the BSC.

The BSS shown in Figure 1 is supervised by the OMC-R. In a large network,one or more high-level supervisors, such as NMCs, can exist to centralizenetwork management activities. The NMC has the authority to send directivesto the OMC-R.

For more information about the NMC, refer to documentation supplied withthe NMC.

1.3.1 Base Station Controller

The BSC provides control of the BTSs and manages radio resources and radioparameters. From a transmission point of view, the BSC also performs aconcentration function if more radio traffic channels than terrestrial channels areconnected to the MSC. A single BSC can control a large number of BTSs. Theexact number is a function of the BSC equipment and the configurations used.

The BSC provides:

Resource management

Database management

Radio measurement processing

Channel management

Operations and maintenance functions within the BSS

Communication with the OMC-R

Switching between the Air Interface channels (and their associated Abis

channels), and the A Interface channels. Further information concerning

these interfaces can be found in The A Interface (Section 1.7.4), The AbisInterface(Section 1.7.5) and The Air Interface (Section 1.7.7).

The BSC also incorporates the following transmission equipment:

The Base Station Interface Equipment, which performs signalling and

submultiplexing on the Abis Interface

The Transcoder Submultiplexer Controller, which collects and processes

transmission data. It also provides an operator interface to certain

transmission functions via a Local Maintenance Terminal.

For a more detailed description of the BSC, refer to the EVOLIUM BSC/TCOverall Description document.

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1 Introduction

1.3.2 Base Transceiver Station

The BTS provides radio transmission, control and baseband functions for acell. The BTS also supports the Air Interface with the mobile stations. Alcatelfurnishes two families of BTS:

BTS G1 or G2 (includes Micro-BTS M1M and M2M)

BTS A9100 or BTS A910.

These families of BTS have different architectures, and are not functionallyidentical, (e.g. only the BTS A9100 or BTS A910 can support GPRS).

The BTS performs the following functions under the control of the BSC:

Transmit and receive functions

Antenna diversity

Frequency hopping

Radio channel measurements

Radio frequency testing.

The BTS also includes BIEs which enable it to communicate with the BSC overthe Abis interface. In the BTS A9100 and BTS A910, the BIE is integratedinto the SUM.

For a more detailed description of the BTS, refer to the BTS FunctionalDescription or the EVOLIUM BTS A9100/A910 Functional Descriptiondocuments.

1.3.2.1 Antenna Diversity

Antenna Diversity is a BTS feature that protects against multipath fading. Thisis achieved by duplicating the receive antenna and receive path up to the FrameUnit of the BTS (or the TRE for a BTS A9100 or BTS A910). The Frame Unit(or TRE) uses the data burst which has the fewest errors. This increases thelow-power mobile station range, thereby allowing larger cells.

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1.3.2.2 G1 and G2 BTS Antenna Diversity

Antenna diversity on G1 and G2 BTSs duplicates the receive antenna andreceive path up to the Frame Unit. The Frame Unit uses the data burst whichhas the fewest errors. This increases low-power mobile station range, thusallowing larger cells and lowering infrastructure investment.

The following figure shows the antenna diversity path through the G1 andG2 BTS.

BASEBANDCONTROL

CONTROL

BASEBAND RADIO COUPLING

OMU

B

IE

F

HU

OTHER ANTENNAS

TX

CUFU

a

aa

b bb

abbest of a&b

COUPLIN

G

UNIT

aRX

RX

(option)b

BIE : Base Station Interface Equipment

CU : Carrier Unit

FHU : Frequency Hopping Unit

FU : Frame Unit

OMU : Operations and Maintenance Unit

RX : Receiver

TX : Transmitter

Figure 2: Antenna Diversity on G1 and G2 BTSs

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1 Introduction

1.3.2.3 BTS A9100/A910 Antenna Diversity

Antenna diversity on the BTS A9100 or BTS A910 follows the same principle asin the G1 and G2 BTSs. The antennas are used for both transmit and receive,and the receive path is duplicated up to the TRE, providing the same gain inefficiency and low-power mobile station range.

The following figure shows the antenna diversity path through the BTS A9100.

TRE 1

TRE 2

TRE 3

TRE 4

BASEBAND

CONTROL

RADIO

SUM

ANy ANx

RADIO

COMBINING DUPLEXING

ANT a

ANT b

ab

Tx / Rx

Tx / Rx

b

b

b

a

a

a

best ofa&b

best ofa&b

best ofa&b

best ofa&b

b

a

b

a

b

a

b

a

ab

ab

ab

ab

BASEBAND

ANC

ANT : Antenna

ANx : Antenna Network Type x

ANy : Antenna Network Type y

SUM : Station Unit Module

TRE : Transmitter/Receiver Equipment

Figure 3: Antenna Diversity on the BTS A9100

Note: The configuration shown above (1 Sector, 3X4 Transceivers) is one exampleonly. Other combinations of Antennas and TREs are possible. There is noantenna network y in the BTS A910, and the antenna network y is not needed if

the sector has two TREs.

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1 Introduction

1.3.3 Transcoder And Transmission Function

The Transcoder is the key component for the transmission function, whichprovides efficient use of the terrestrial links between the equipment of the BSS.

The Transcoder provides:

Conversion between A-law and Radio Test Equipment-Long Term Prediction

encoded traffic (speech)

Conversion between A-law and Algebraic Code Excited Linear Prediction

encoded traffic (speech)

Rate adaptation (data)

O&M control of the transmission function.

The Transcoder is normally located next to the MSC.

Submultiplexers The Submultiplexer performs submultiplexing on the Ater Interface, between

the MSC and the BSC. When submultiplexing is used, a Submultiplexer islocated at each end of the link.

The following figure shows how transmission components are distributed inthe BSS.

BTS BSC

MSC

BSC

TC

TCBTS

BTSTSC

BIE

BIE

BIE SM SM

TSC

BIE

OMCR

BIE : Base Station Interface Equipment

SM : Submultiplexer

TSC : Transcoder Submultiplexer Controller

TC : Transcoder

Figure 4: Transmission Components in the BSS

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1 Introduction

1.3.4 The Multi-BSS Fast Packet Server

The MFS is preferably located at the Transcoder/MSC site. It is internal to theBSS and provides the following functions:

PCU functions:

PAD function

Scheduling of packet data channels

Automatic Retransmission Request functions

Channel access control functions

Radio channel management functions.

The Gb interface protocol stack.

The MFS converts GPRS frames, carried on multiple 16 kb/s links from multipleBTSs, to one or more frame relay channels connected to the SGSN on the Gb

interface. See The Gb Interface (Section 2.3.1) for details of the Gb interface.The set-up of Packet Data Channels is controlled by the MFS. It also negotiatesresources with the BSC and routes GPRS packets. When an additional channelis required on a BTS, the MFS asks the BSC to allocate a channel and toconnect it to an Ater channel which the MFS controls.

The Alcatel solution also supplies two dedicated GPRS interfaces between theMFS and the BSS:

The BSCGP interface supplies routing of GPRS messages and resource

negotiation between the BSC and the MFS

The GCH interface routes user data traffic and signaling between the MFS

and the BTS transparently (to the BSC).

Hardware and software management of the MFS is provided using the IMT.

The MFS is divided in GPRS processing units (GPU) which are inter-connectedvia an Ethernet bus and controlled a control station. The GPU handles theO&M and telecom functions of several cells, but a cell cannot be sharedbetween several GPUs.

A GPU cannot be connected to more than one BSC, which means that eachGPU cannot manage simultaneously several BSSs. However, the use of severalGPUs per BSS is required for traffic capacity reasons. The MFS is in charge ofassociating each cell to a GPU. This later operation is called GPU cell mapping.

The GPU is in charge of:

O&M functions:

Initialization of the MFS

Software download

Software configuration

Performance monitoring.

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1 Introduction

Telecom functions:

Radio and transmission resources control

Radiolink control of packet connections

Common control channels management

MS radio resource controlLogical Link Control (LLC)

Protocol Data Unit (PDU) transfer

Multiframe management

Congestion control

Gb interface management

Signalling management on the GSL interface.

The GPU is split into two sub-units, the Packet Management Unit (PMU)and the Packet Traffic Unit (PTU).

The protocols handled by a GPU are split in the following manner:

Protocols handled by the PTU:

Radio interface protocols (RLC and MAC)

GCH interface protocols (L2-GCH and L1-GCH).

The PTU manages the corresponding GCH interface (see The GCHInterface(Section 2.3.3) for more information).

Protocols handled by the PMU:

Gb interface protocols (BSSGP, Network Service, and FR)

BSC interface protocols (BSCGP, L2-GSL, and L1-GSL)

RRM protocol.

The PMU manages the corresponding Gb and GSL interfaces.

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1.3.5 Multi-GPU per BSS

To increase the GPRS capacity of the BSS in terms of number of PDCH,several GPU boards can be connected to the BSC to support the PCU function.This feature is applied regardless of the BTS type. Four GPU boards canbe connected in each BSC.

Cell Mapping Mapping a cell means that a cell is associated to a GPU. Remapping a cellmeans that a cell, already linked to a GPU, is moved to another GPU. Themapping of cells onto GPUs is performed by the MFS, which actually definesthe mapping of cells onto LXPUs (logical GPU). An LXPU is either the primaryGPU, or the spare GPU in the case of switch-over. All the GPRS traffic of onecell is handled by only one GPU. The following figure shows an example ofcell mapping.

MFS

GPU1

GPU2

GPU3

GPU4

BSC

Cell 1

Cell 2Cell 4

Cell 3

Cell 8

Cell 9Cell 12

Cell 11

Cell 5

Cell 6

Cell 7

Cell 14

Cell 13

Cell 10

GPU : GPRS Processing Unit

Figure 5: Cell Mapping

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1.4 Extended GSM

Two 10 MHz extended bands for GSM 900 in the range 880-890 MHz/925-935MHz have been specified as an option on a national basis. The reason forthis is mainly due to the lack of primary band frequencies in countries outsideEurope. The term G1 is used for the extended band. The term P-GSM is

used for the primary band. The term E-GSM is used for the whole GSM-900frequency band, i.e. the primary band (890-915 MHz/935-960 MHz) plusthe extended band (880-890 MHz/925-935 MHz). This corresponds to 174addressable carrier frequencies and leads to an increase of 40% against the124 frequencies in the primary band.

All BCCH frequencies and SDCCH channels are entirely supported on theGSM primary band. This allows for the support of both primary and extendedband mobiles in the same network.

E-GSM Mobile StationRecognition

From messages sent by the mobile station, the BSS determines if a mobilesupports the E-GSM band.

The mobile station is determined to be E-GSM if:The FC bit of the Classmark 2 is set to 1 (regardless of the value of the

Band 2 bit of the Classmark 3) or

The FC bit of the Classmark 2 is set to 0, and the Band 2 bit of the

Classmark 3 is set to 1.

If the information is not available, the mobile station is considered as notsupporting the G1 band. The BSS never triggers a Classmark Interrogationprocedure to obtain the E-GSM ability of a mobile station.

E-GSM Management

After InitialDetermination

Once the E-GSM ability has been initially determined as described above, it

may happen that the mobile station radio characteristics change during atransaction. If the BSC receives a classmark change message, it takes thisinto account and updates the E-GSM ability according to the content of thereceived message.

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E-GSM Determinationat Handover

In the case of internal handover, the E-GSM ability of a mobile station isstored in the BSC memory. In the case of external incoming Handover, thehandover request message includes either Classmark 1 or Classmark 2 IE,and optionally Classmark 3 IE. If Classmark 1 is present and Classmark 3 isnot present or Classmark 3 is present but does not contain the Band 2 bit,the mobile station is not considered as E-GSM. If both Classmark 1 and

Classmark 3 are present, and Classmark 3 contains the Band 2 bit, the BSCgets the E-GSM ability of the mobile station from the Classmark 3. If Classmark2 is present and Classmark 3 is not present, or Classmark 3 is present butdoes not contain the Band 2 bit, the BSC gets the E-GSM ability of the mobilestation from the Classmark 2 ("FC" bit). If both Classmark 2 and Classmark 3are present, the mobile station is seen as E-GSM:

If the FC bit of the Classmark 2 is set to 1 (whatever the value of the band

2 bit of the Classmark 3)

If the FC bit of the Classmark 2 is set to 0 and the band 2 bit of the

Classmark 3 is set to 1.

After an incoming external handover, if a classmark change message hasbeen received from the mobile station, the BSC ignores any subsequentclassmark update message received from the MSC.

TCH Allocation The allocation of G1 band channels can be done for Normal Assignment(NASS), Internal Channel Change (ICC), or External Channel Change (ECC).Each TRE has the capability to support the P-GSM or the E-GSM band. EachTRX is configured as a P-GSM TRX or a G1 TRX. When a TCH is needed, if itis for an E-GSM mobile station then a TCH belonging to the G1 TRX subsetis preferably chosen. If no resource is available in the G1 TRX subset, themobile station is allocated to the P-GSM TRX subset.

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1.5 External Components

The BSS communicates with three external components:

The NSS on the A Interface

The mobile station on the Air Interface

The OMC-R on the BSS/OMC-R Interface.

The following figure shows the logical position of the External Components.

Base Station Subsystem

MobileStations

NetworkSubsystem

FixedNetwork

PLMN

OMCR

NMC

MFS

MSC

Transcoder

PSDN

HLR

AbisInterface

Ater Interface

Gb Interface

AInterface

BTS

BTS

BTS

BSC

PSTN

GGSNSGSN

GGSN : Gateway GRPS Support Node

HLR : Home Location Register



PSDN : Packet Switched Data Network

PSTN : Public Switched Telephone Network

SGSN : Serving GRPS Support Node

Figure 6: Logical Position of External Components Associated with BSS

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1.5.1 Network Subsystem

Managing communication within the PLMN and external networks is theprimary role of the NSS. The NSS manages the subscriber administrationdatabases. It contains the following components:

MSC

Home Location Register

Visitor Location Register

Authentication Center

Equipment Identity Register.

The Alcatel BSS shall support several own PLMN (up to four, at least one); anOMC-R may thus manage at least one (own) PLMN and up to eight PLMN(four own + four foreign). Both cell reselections and handovers shall be allowedbetween two cells belonging to different own PLMN.

MSC Performs and coordinates the outgoing and incoming Call Set Up function.The MSC is a large capacity switch used for passing mobile traffic to mobilesubscribers, or to subscribers of external networks. This part of the NSSinterfaces with the BSS.

Home Location Register The HLR is the central database within a given network for mobile subscriberspecific data. It contains static data such as access authorization, informationabout subscribers and supplementary services. It also controls the dynamicdata about the cell in which the mobile station is located.

Visitor Location Register The VLR temporarily stores information about mobile stations entering itscoverage area. Linked to one or more MSCs, the VLR transmits data to a new

VLR when a mobile station changes areas.

Authentication Center The AuC manages the security data used for subscriber authentication.

Equipment IdentityRegister

The EIR contains the lists of mobile station equipment identities.

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1.5.2 Mobile Stations

Mobile stations provide radio and processing functions which allow subscribersto access the mobile network via the Air Interface. Subscriber relatedinformation is stored on a specific device called a SIM.

The SIM is a removable smart-card that conforms to internationally recognizedstandards specified by the ISO. It contains the IMSI. This is used by theNetwork Operator to identify the subscriber in the network and to providesecurity and protection against misuse.

Each mobile station has its own IMEI. The IMEI is used by the NetworkOperator to prevent stolen, or non-type approved mobile stations, fromaccessing the network.

There are three types of mobile station in GSM:

Phase 1

Phase 1 extended

Phase 2.

For information on GPRS mobile stations, refer to GPRS Elements (Section2.1.2).

Mobile stations have different capabilities according to the class of mobilestation and the purpose for which the mobile station was designed. Thesedifferences include power output and ciphering.

Only phase 2 mobile stations can turn off ciphering, or change the cipheringmode, during a channel change procedure such as a handover. The cipheringcapability of a mobile station is signalled to the BSS in the mobile stationclassmark.

Ciphering is used to protect information transmitted on the Air Interface. Thisis performed between the BTS and the mobile station (i.e. Air Interface).Transmission ciphering does not depend on the type of data to be transmitted(i.e. speech, user data, signalling), but to normal transmission bursts. SeeCiphering (Section 3.8) for further information concerning mobile stationciphering capabilities.

Mobile Station Idle Mode A mobile station is in idle mode when it is switched on, but not communicatingwith the network on an SDCCH or a traffic channel. The BSS supports threeidle mode functions:

Cell selection and cell reselection

Location updating

Overload control.

Mobile StationCell Selection and

Reselection

A mobile station monitors the broadcast messages from the BTS. This includesmonitoring the FCCH and SCH.

The mobile station chooses the best cell on which to camp. If this cell is in alocation area other than that stored in the mobile station memory, then themobile station initiates a location update procedure. For a mobile station tocamp on a cell, it has to synchronize with the cell.

The BTS broadcasts an FCCH and an SCH at a defined time in the BCCHcycle. These channels are used as reference points for the mobile station to

synchronize with the BCCH. Once synchronized, the mobile station continuesto monitor these channels to stay synchronized.

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This type of synchronization, along with cell configuration and channelfrequency information, enables the mobile station to calculate where channelsoccur in the multiframe sequences.

Timing advance information is sent to the mobile station when an SDCCH isassigned. The mobile station uses the channel configuration informationto calculate which part of the CCCH contains its paging message, andtherefore which time slot to monitor for paging messages. When the mobilestation is camped on a cell, it continues to monitor the BCCH transmissionsfrom neighboring cells. The BCCH frequencies of the neighboring cells aretransmitted on the BCCH of the home cell (sys_info 2). It can decide to campon a new cell if it receives a better signal from an adjacent cell.

Reasons for moving to a new cell include:

A problem in the existing cell

The mobile station moving.If the mobile station moves to a new cell which is in the same location areaas the one currently in its memory, it does not initiate a location update. It

recalculates its paging group and monitors the new paging channel. Pagingmessages are broadcast from all cells in a particular location area.

GSM/GPRS to UMTSCell Reselection

The reselection of a UTRAN cell is triggered by a multi-RAT mobile stationin circuit-switched idle mode, packet-switched idle mode, or packet-switchedtransfer mode. In NC0 mode, a multi-RAT mobile station can reselect aUTRAN cell in any GMM state. In dedicated mode, the multi-RAT mobilestation follows the GSM handover procedures. The BSS then broadcasts theset of UTRAN cell parameters which allows the multi-RAT mobile station toreselect a UTRAN cell on its own.

Location Updating The location update procedure is always initiated by the mobile station.Location update is performed after the call has finished (cell reselection).

Reasons for location updates include:

A periodic updatePeriodic location update is performed by the mobile station after a lack ofsignalling activity for a specific time. If the timer expires, the mobile stationinitiates a location update, even if it has not changed Location Area. Theduration of the mobile station timer is defined by the network and sent to themobile station as system information messages on the BCCH. The time canbe between six minutes and 25 hours.

A handover to a cell in a new location area.When a mobile station is handed over to a cell in a new location area, thereis no automatic location update in the network. A new Location Area

Identity in the BCCH (sys_info 3 and sys_info 4) is detected by the mobilestation when the current call has finished, and initiates the location updateprocedure. This saves the system performing several location updates if themobile station is handed over several times during a call.

The mobile station camps on a cell with a different location area code to the onein the mobile station memory. The mobile station initiates the location updateprocedure by sending a channel_request message indicating that the call isfor a location update. The BSS assigns a dedicated signalling channel andestablishes a signalling path between the mobile station and MSC. See MobileOriginated Call (Section 3.2) for more information.

When a signalling path is established, the mobile station sends the Location

Area Identity of the old cell on which it was camped to the MSC. The new VLR

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interrogates the old VLR for authentication and subscriber information. Forfurther information see Location Updating with Classmark Procedure (Section3.6.3) and Authentication (Section 3.7).

The Location Area Identity is made up of:

Mobile Country Code

Mobile Network Code

Location Area Code.

The BSS adds the cell identity of the mobile station current location to themessage sent to the MSC. This information is sent in a Mobility Managementsub-layer message and is transparent to the BSS. The NSS stores thisinformation in either its HLR or its VLR. Following a location update procedure,the VLR can assign a new Temporary Mobile Subscriber Identity to the mobilestation. See Authentication (Section 3.7) for more information about the TMSI.The following figure shows a mobile station as it moves to a new location area.

MSC

MSCBSCBTS

BSC

Mobile Station connectingin a new location area

VLR

VLR

MobileStation

MobileStation

BTS

BSC

BSC

Protocol Messages

VLR : Visitor Location Register

Figure 7: Location Update

Overload Control To protect the system against overload, the system can bar access to mobilestations, by changing the RACH control information in the system informationmessages described in Table 1. For further information, see GPRS OverloadControl (Section 2.6.3) and Overload Control (Section 4.7).

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1.5.3 Phase 2 Mobile Support in a Phase 1 Infrastructure

When a phase 2 mobile station is used in a phase 1 infrastructure network,the BSS functions as phase 2 on the Air Interface and has the capability offunctioning as phase 1 or phase 2, depending on the MSC capabilities. Theinfrastructure (BSS and MSC) remains phase 1. This conforms to updated

GSM recommendations for phase 1.

The problems of using phase 2 mobile stations on a phase 1 network are:

The implementation rules for phase 1 are not strictly defined. Therefore

some implementations cannot function with phase 2 mobiles.For example, some of the spare bits in phase 1 are now used by the phase2 protocol. However, some phase 1 infrastructures reject the message asspare bits are used

Some protocol changes in phase 2 changed or replaced a phase 1 protocolFor example, power and quality measurements sent by phase 2 mobilestations have a finer range of power control, which the phase 1 infrastructure

must processPhase 2 mobile stations send some phase 2 messages even though they

are in a phase 1 environment.For example, phase 2 mobile stations send either new messages or newelements in messages, which the phase 1 infrastructure could reject. Thisblacklists the mobile station due to an invalid protocol message for phase1. Depending on what these messages are, the updates to the phase 1infrastructure would accept these messages/elements. The messagescan be either ignored or only partly treated. This is based on informationcontained within the messages or elements.

1.5.4 Operations and Maintenance Center-RadioThe OMC-R supervises one or more BSSs. It performs the following functions:

Manages the BSS software versions

Acts as the central repository for configurations

Manages fault and performance measurement reports

Handles supervision of alarms and events

Manages the MFS.

The reported data is available to the operator from the OMC-Rs centraldatabase. The OMC-R only performs O&M activities. It does not perform usertraffic processing or call establishment and control activities. Refer to theOperations & Maintenance Principles for more information.

Operator actions via the terminal interface trigger commands throughout theBSS. The OMC-R provides object-oriented management information, andsupports a Manager/Agent scheme to perform and control managementactivities. The terminal interface supports different user profiles with differentaccess rights.

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1.6 Network Management

Normally the OMC-R provides all the network management and controlfunctions required by the BSS. However, the management and controlfunctions are proprietary to the system supplier. In keeping with InternationalTelecommunications Union and European Telecommunication Standards

Institute recommendations, the Telecommunications Management Networkstructure has been developed to standardize the Network Managementfunction. Network Management is compatible with all equipment, even thatof different manufacturers. Network Management is controlled from one orseveral NMCs.

1.6.1 Telecommunications Management Network

The ability to transfer management information across the TelecommunicationsManagement Network environment is defined by a protocol suite, the QInterfaces. The following figure shows the hierarchical structure of theTelecommunications Management Network. It graphically defines the

respective management responsibilities in the three main levels of theManagement Information Tree.

Telecommunications Management Network is more fully discussed in theBSS/MFS and TMN Functions section of the Operations & MaintenancePrinciples document.

NMC

OMCR

BSC

BTSBTS

BTS

Q3

BSS

OSS

NMC Operator(Resource Management)

OMCR Operator(Resource and Equipment

Management)

Security Block (SBL)Management

Network Management

&

Network ElementManagement

Mediation Function

Network ElementMFS

OSS : Operation Support System



Figure 8: TMN System Hierarchy

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1.6.2 Q3 Interface

Communication between the NMC and the OMC-R takes place across the Q3Interface (see Figure 8). The Q3 protocols can be divided into the followingmain areas:

Association connection and disconnection mechanisms

Message format and structure

Command types.

For further information on Network Management and the Q3 Interface see theOperations & Maintenance Principles document.

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1.7 BSS Telecommunications Layers

The telecommunications functions of a GSM network are split into layers.These layers are split into two basic categories:

The Application layer is split into sub-layers, to control:

Call Management

Mobility Management

Radio Resource Management.

The transmission layers which provide transmission between the various

components.

Note: These transmission layers relate to the OSI layers, that is, the Physical Layer(i.e. Layer 1) and the Data Layer (i.e. Layer 2). The protocols used for theselayers are standard.

The following figure shows the general distribution of the telecommunicationfunctions within a GSM network.

MS BTS BSC NSS

CM

MM

RRM

GSMApplicationLayers

TRANSMISSION

CM : Call Management

MM : Mobility Management

MS : Mobile Station

RRM : Radio Resource Management

Figure 9: General Telecommunication Layers within GSM

1.7.1 Call Management

The Call Management sub-layer performs Call Control to establish, maintainand release calls. SMS within Call Management allows the mobile station tosend and receive messages of up to 160 characters. The SupplementaryService functions are also provided to the mobile stations as part of CallManagement.

1.7.2 Mobility Management

The Mobility Management sub-layer is used by the NSS to manage thesubscriber database, including information on subscriber location andauthentication. It is also used by the mobile stations to send location updateswhen they move to new location areas.

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1.7.3 Radio Resource Management

The Radio Resources Management sub-layer establishes, maintains andreleases stable connections between the mobile station and the MSC for theduration of a call. This includes functions such as managing the limited radioresources, to ensure high service availability. It also performs handovers

when a mobile station moves during a call, or the channel quality falls belowan acceptable level. RRM functions occur mainly between the mobile stationand the BSC.

The following figure shows the application layers, transmission layers andInterfaces of the BSS.

MS BTS BSC MSC

MM

RRM

GSMApplicationLayers

Layer 2

Air Interface Abis Interface A Interface

Layer 1 Layer 1

TC08.60

CM

LAPDm LAPD LAPDSCCP

SS7

SCCP

SS7

LAPDm

BSSAP BSSAP BSSAP

Layer 1Layer 1Layer 1Layer 1

BSSAP : BSS Application Part

CM : Call M

Alcatel BSS Description

Documents