BSS System Description

Alcatel BSSBSS System Description

Descriptive Documentation BSS Concepts

3BK 20572 AAAA TQZZA Ed. 02

BLANK PAGE BREAK

Status Short title

RELEASED System DescriptionAll rights reserved. Passing on and copying of this document, use and communication of its contents not permitted without written authorization from Alcatel.

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3BK 20572 AAAA TQZZA Ed.02

Contents

ContentsPreface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2 BSS Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2.1 Call Set Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2.2 Call Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2.3 Call Release . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2.4 Operations & Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.3 BSS Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.3.1 Base Station Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.3.2 Base Transceiver Station . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.3.3 Transcoder And Transmission Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.3.4 The Multi-BSS Fast Packet Server . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.3.5 Multi-GPU per BSS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.4 Extended GSM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.5 External Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.5.1 Network Subsystem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.5.2 Mobile Stations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.5.3 Phase 2 Mobile Support in a Phase 1 Infrastructure . . . . . . . . . . . . . . . . . . . . . . . 1.5.4 Operations and Maintenance Center-Radio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.6 Network Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.6.1 Telecommunications Management Network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.6.2 Q3 Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.7 BSS Telecommunications Layers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.7.1 Call Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.7.2 Mobility Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.7.3 Radio Resource Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.7.4 The A Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.7.5 The Abis Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.7.6 Satellite Links . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.7.7 The Air Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . GPRS in the BSS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1.1 Packet Switching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1.2 GPRS Elements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2 GPRS Channels and System Information Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2.1 Master Channels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2.2 Static Allocation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2.3 Dynamic Allocation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2.4 Multiple PCCCH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2.5 Logical Channels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2.6 Virtual Channels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2.7 System Information Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3 GPRS Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3.1 The Gb Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3.2 The BSCGP Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3.3 The GCH Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4 GPRS Network Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4.1 Mobility Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4.2 Paging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4.3 Radio Power Control and Radio Link Measurement . . . . . . . . . . . . . . . . . . . . . . . . 2.5 Resource Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.5.1 Time Slot Allocation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 14 16 16 17 17 17 18 18 19 22 23 25 26 28 29 30 33 33 34 34 35 36 36 36 37 38 39 39 41 47 48 48 49 52 52 52 53 54 56 56 57 59 59 60 61 62 63 64 64 65 65

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2.5.2 Frequency Hopping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66 2.5.3 PCM Link Sharing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66 2.5.4 Resource Reallocation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 2.6 Traffic Load Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68 2.6.1 Congestion Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 2.6.2 Smooth PDCH Traffic Adaption to Cell Load Variation . . . . . . . . . . . . . . . . . . . . . . 70 2.6.3 GPRS Overload Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 2.6.4 Delayed Downlink TBF Release . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71 2.7 Data Transmission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72 2.7.1 GPRS Attach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72 2.7.2 Packet Data Protocol Context Activation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74 2.7.3 Data Transfer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76 2.7.4 Packet Data Protocol Context De-activation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 2.7.5 GPRS Suspend . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81 2.7.6 GPRS Resume . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82 2.7.7 GPRS Detach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84 Call Set Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87 3.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 3.2 Mobile Originated Call . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90 3.2.1 Radio and Link Establishment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90 3.2.2 Authentication and Ciphering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96 3.2.3 Normal Assignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96 3.3 Mobile Terminated Call . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102 3.3.1 Radio and Link Establishment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103 3.3.2 Authentication and Ciphering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103 3.3.3 Normal Assignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104 3.3.4 IMSI Attach-Detach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106 3.4 Paging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107 3.4.1 Paging Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109 3.4.2 Discontinuous Reception . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111 3.5 Congestion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112 3.5.1 Queueing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112 3.5.2 In-queue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113 3.5.3 Pre-emption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116 3.6 Classmark Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118 3.6.1 Classmark IE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118 3.6.2 Classmark Updating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120 3.6.3 Location Updating with Classmark Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121 3.7 Authentication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123 3.8 Ciphering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125 3.8.1 Ciphering Keys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127 3.8.2 Ciphering Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127 3.9 Tandem Free Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129 3.9.1 TFO Functional Architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131 3.9.2 TFO Optimization and Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132 Call Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133 4.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134 4.2 In-Call Modification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134 4.2.1 In-Call Modification Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135 4.2.2 Circuit-switched Group 3 Fax Data Rate Change . . . . . . . . . . . . . . . . . . . . . . . . . 136 4.2.3 Error Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136 4.3 Frequency Hopping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137 4.3.1 Baseband Frequency Hopping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138 4.3.2 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 . . . . . . . . . . . . . . . . . 4.4.3 Mobile Station Discontinuous Transmission Towards BSS . . . . . . . . . . . . . . . . . 4.5 Radio Power Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.5.1 BTS Radio Power Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.5.2 Mobile Station Radio Power Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.5.3 Radio Link Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.5.4 Power Control Decision and Handover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.5.5 Change Power Levels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.6 Handover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.6.1 Radio Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.6.2 Handover Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.6.3 Target Cell Evaluation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.6.4 Synchronous and Asynchronous Handover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.7 Overload Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.7.1 BTS Overload . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.7.2 BSC Overload . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.8 Call Re-establishment by the Mobile Station . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Call Release . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.2 Call Release Procedures in Normal Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.2.1 Normal Release . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.2.2 Calls Terminated Following a Channel Change . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.3 Call Release - Special Cases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.3.1 Call Release Following Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.3.2 BSC-Initiated Release . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.3.3 BSC-Initiated SCCP Release . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.3.4 BTS-Initiated Call Release . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.3.5 Mobile Station-Initiated Call Release . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.3.6 Remote Transcoder Alarms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Handling User Traffic Across the BSS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.2 Speech . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.2.1 Enhanced Full-Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.2.2 Half-Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.2.3 Adaptive Multiple Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.2.4 Channel Mode Adaption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.3 Circuit-Switched Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.3.1 Transparent Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.3.2 Non-Transparent Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.4 Short Message Service - Cell Broadcast . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.5 Support of Localized Service Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Cell Environments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.2 Concentric Cell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.3 Sectored Site . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.4 Extended Cell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.5 Umbrella Cell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.5.1 Mini Cell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.5.2 Microcell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.6 Cell Shared by Two BTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Operations & Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.2 O&M Architecture and Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.2.1 O&M Architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.2.2 O&M Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Contents

8.3

8.4

8.5

8.6

8.7 8.8

O&M Control - The OMC-R . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.3.1 Multiple Human-Machine Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.3.2 ACO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.3.3 Secured X.25 Connection From BSC to OMC-R . . . . . . . . . . . . . . . . . . . . . . . . . . 8.3.4 Electronic Documentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Configuration Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.4.1 Hardware Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.4.2 Logical Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.4.3 Software Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.4.4 Auto Identification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.4.5 OML Auto-detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.4.6 NE Provisioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Fault Management - Alarms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.5.1 Alarm Generation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.5.2 Alarm Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.5.3 BSC Alarms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.5.4 BTS Alarms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.5.5 Alarms Detected by the TSC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.5.6 MFS Alarms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.5.7 Recovery Example: Carrier Unit Failures with BCCH . . . . . . . . . . . . . . . . . . . . . . 8.5.8 Automatic Power-Down . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.5.9 BSC Alerter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Performance Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.6.1 Traces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.6.2 Performance Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.6.3 Radio Measurements Statistics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.6.4 Results Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Audits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Remote Inventory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

223 224 225 226 228 229 230 230 230 231 232 233 234 236 236 237 240 242 242 243 245 245 246 246 247 248 249 250 252

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Figures

FiguresFigure 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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 Figure 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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107 Figure 37: Four TDMA Frame Cycles Providing 24 Paging Sub-channels . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108 Figure 38: Paging Message Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110 Figure 39: Location Update with Classmark Update . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121


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Figures

Figure 40: Location Update with Mobile Station Sending Location Area Identity of Previous VLR . . . . . . . 123 Figure 41: Ciphering Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128 Figure 42: Example of TFO Establishment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130 Figure 43: Frequency Hopping within an FHS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138 Figure 44: Different Forms of Discontinuous Transmission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143 Figure 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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162 Figure 53: Asynchronous External Handover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165 Figure 54: Mobile Station Disconnecting a Call . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175 Figure 55: Normal Call Release . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176 Figure 56: Initiation of Normal Release by MSC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177 Figure 57: BSC/BTS/Mobile Station interactions in Normal Call Release . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178 Figure 58: Normal Release Final Steps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179 Figure 59: Call Release Following a Channel Change . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180 Figure 60: Call Release Following Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182 Figure 61: BSC-initiated Call Release toward the MSC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183 Figure 62: BTS-initiated Call Release following LAPD failure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187 Figure 63: Call Release due to Mobile Station initiated Radio Link Failure . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189 Figure 64: Call Release due to Communication Failure detected by Transcoder . . . . . . . . . . . . . . . . . . . . . . 190 Figure 65: Encoded Speech Transmission Across the BSS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192 Figure 66: Multiplexed Ater Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193 Figure 67: Data Transmission Across the BSS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199 Figure 68: Short Message Service - Cell Broadcast . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202 Figure 69: Example: Cell Configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207 Figure 70: Sectored site configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209 Figure 71: Example of Extended Cell Topology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210 Figure 72: Umbrella Cell with Mini Cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212 Figure 73: Example: Handovers due to Threshold Triggering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214 Figure 74: Indoor cell example network hierarchy with three layers and two bands . . . . . . . . . . . . . . . . . . . . 215 Figure 75: Multiple HMI Access to OMC-Rs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224 Figure 76: ACO Links . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225 Figure 77: X.25 Without Redundancy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226 Figure 78: X.25 With Redundancy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227 Figure 79: RSL Correlation on the Abis Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238

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Figures

Figure 80: Example: Alarm Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239 Figure 81: Example: Loss of Carrier Unit Holding BCCH. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244


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Tables

TablesTable 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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109 Table 12: Paging Request Message and Mobile Station Identification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110 Table 13: Classmark Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118 Table 14: Classmark Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120 Table 15: Mobile Station Ciphering Capabilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125 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 . . . . . . . . . . . . . . . . . . . . . . . . . . 200 Table 21: Configuration Management Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229 Table 22: Fault Management Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235 Table 23: BTS Alarm Hardware Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 240 Table 24: BTS Alarms Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 240 Table 25: Performance Management Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 246 Table 26: Audit Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250

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Preface

PrefacePurposeThis document provides detailed descriptions of the functions and features of the Alcatel BSS. Some functions and features may not be available on the system installed at your location. The technical information in this document covers: Mobile Communications Support These areas describe how the BSS handles communications between a mobile station and the NSS. It follows a call through the Alcatel BSS, and describes how each element in the system functions individually and with other elements. This shows how the BSS and its units react as a system. Operations and Maintenance These areas describe the O&M functions within the system. It describes both local and distributed O&M functions in a BSS.

Audience

This manual is for people requiring an in-depth understanding of the functions of 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 IntroductionThis chapter gives a brief overview of the Alcatel BSS, its functions and features. 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 OverviewThe BSS provides radio coverage for GSM subscribers in a defined area. Its principal role is to provide and support signalling and traffic channels between mobile stations and the NSS. The following figure shows the BSS within the PLMN, and its links to the PSTN and the PSDN in a fixed network.PLMNMobile Stations Network Subsystem MSC TC BTS BSC MFS SGSN PSDN Fixed Network PSTN

Base Station Subsystem

OMCR

NMC

GGSN HLR MFS NMC PSDN PSTN SGSN

: Gateway GRPS Support Node : Home Location Register : Multi-BSS Fast Packet Server : Network Management Center : Packet Switched Data Network : Public Switched Telephone Network : Serving GRPS Support Node

Figure 1: BSS in the PLMN

EVOLIUM Radio Solutions

To respond to the swiftly evolving needs in BSSs, Alcatel offers the EVOLIUM Radio 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 3GPP Standard in 1999 to allow operators to replace progressively the D-AMPS and CDMA technologies that were using these frequencies. Besides certain Asian countries, the GSM 850 MHz band concerns in particular the Latin American countries where many operators already use in their network the GSM system with 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 to 849 MHz band for the uplink direction and in the 869 MHz to 894 MHz band for the downlink direction. The GSM 850 band is defined by 124 absolute radio frequency channel numbers (ARFCN) among the 1024 ARFCNs available in the GSM standard. 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.

Frequency Band Configurations

GPRS

GPRS, the solution chosen by European Telecommunication Standards Institute to answer the demand for increased data transmission rates, is now available in the Alcatel BSS. This means there are now two parallel systems in the PLMN: circuit-switched transmission for voice, and packet-switched transmission 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 FunctionsFunctions are defined by the International Telecommunications Union and European 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 and functional units are indicated where applicable, but are not described. For more information, refer to the specific network element description manuals, such as the BTS Functional Description. The BSS provides signalling and traffic channels between the mobile station and the NSS. To ensure a high level of service to the subscribers, the BSS offers the following functions: Call Set Up Call Handling Call Release Operations & Maintenance.

1.2.1 Call Set UpThe Call Setup function is used for speech and data calls. The three basic types of call are: Mobility Management Supplementary service User traffic.

Mobility Management Calls Supplementary Service Calls User Traffic Calls

Mobility Management calls, such as location update, are used by the system to gather mobile station information. The exchanges are protocol messages only. Therefore, only a signalling channel is used. Supplementary service calls, such as SMS, allows the mobile station to send and receive messages to and from the BTS. These calls pass small amounts of information. Therefore, only a signalling channel is used. User traffic calls, such as speech or data calls to a correspondent, can pass large amounts of information. Therefore, they require greater bandwidth than a signalling 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 HandlingThe call handling function is used to supervise and maintain calls which are in 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 ReleaseThe call release function ensures that resources allocated to a call are free for reuse 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 & MaintenanceO&M provides the operator interface for the management and control of the BSS, and its interconnection to the NSS. O&M is divided into three principal areas: Configuration Management Fault Management Performance Management. See Operations & Maintenance (Chapter 8) for more information.


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1 Introduction

1.3 BSS ComponentsThere 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 centralize network management activities. The NMC has the authority to send directives to the OMC-R. For more information about the NMC, refer to documentation supplied with the NMC.

1.3.1 Base Station ControllerThe BSC provides control of the BTSs and manages radio resources and radio parameters. From a transmission point of view, the BSC also performs a concentration function if more radio traffic channels than terrestrial channels are connected to the MSC. A single BSC can control a large number of BTSs. The exact 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 Abis Interface (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/TC Overall Description document.

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1 Introduction

1.3.2 Base Transceiver StationThe BTS provides radio transmission, control and baseband functions for a cell. The BTS also supports the Air Interface with the mobile stations. Alcatel furnishes 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 functionally identical, (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 over the Abis interface. In the BTS A9100 and BTS A910, the BIE is integrated into the SUM. For a more detailed description of the BTS, refer to the BTS Functional Description or the EVOLIUM BTS A9100/A910 Functional Description documents.

1.3.2.1 Antenna DiversityAntenna Diversity is a BTS feature that protects against multipath fading. This is achieved by duplicating the receive antenna and receive path up to the Frame Unit 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 the low-power mobile station range, thereby allowing larger cells.


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1 Introduction

1.3.2.2 G1 and G2 BTS Antenna DiversityAntenna diversity on G1 and G2 BTSs duplicates the receive antenna and receive path up to the Frame Unit. The Frame Unit uses the data burst which has the fewest errors. This increases low-power mobile station range, thus allowing larger cells and lowering infrastructure investment. The following figure shows the antenna diversity path through the G1 and G2 BTS.OTHER ANTENNAS

TX C O U P L I N G a a ab best of a&b b b a U N I T RX

B I E

FU

F H U

CU

a

b

RX (option)

b

OMU CONTROLBIE CU FHU FU OMU RX TX

BASEBAND CONTROL

BASEBAND

RADIO

COUPLING

: Base Station Interface Equipment : Carrier Unit : Frequency Hopping Unit : Frame Unit : Operations and Maintenance Unit : Receiver : Transmitter

Figure 2: Antenna Diversity on G1 and G2 BTSs

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1 Introduction

1.3.2.3 BTS A9100/A910 Antenna DiversityAntenna diversity on the BTS A9100 or BTS A910 follows the same principle as in 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 in efficiency and low-power mobile station range. The following figure shows the antenna diversity path through the BTS A9100.

TRE 1ab best of a&b a b a ANT a Tx / Rx a a b b

TRE 2 S U Mab best of a&b

TRE 3ab ab best of a&b b a

TRE 4ab best of a&b b a

b a

b ANT b Tx / Rx

ANy

ANx

ANCBASEBAND CONTROLANT ANx ANy SUM TRE : Antenna : Antenna Network Type x : Antenna Network Type y : Station Unit Module : Transmitter/Receiver Equipment

BASEBAND

RADIO COMBINING

RADIO DUPLEXING

Figure 3: Antenna Diversity on the BTS A9100

Note:

The configuration shown above (1 Sector, 3X4 Transceivers) is one example only. Other combinations of Antennas and TREs are possible. There is no antenna 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 FunctionThe Transcoder is the key component for the transmission function, which provides 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 is located at each end of the link. The following figure shows how transmission components are distributed in the BSS.TSC OMCR

BTS

BIE

BIE

BSC

SM

SM

TC

MSC

BTS

BIE

BIE

BSC

TC

TSC BTS

BIE SM TSC TC

: Base Station Interface Equipment : Submultiplexer : Transcoder Submultiplexer Controller : Transcoder

Figure 4: Transmission Components in the BSS

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1 Introduction

1.3.4 The Multi-BSS Fast Packet ServerThe MFS is preferably located at the Transcoder/MSC site. It is internal to the BSS 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 multiple BTSs, 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 negotiates resources with the BSC and routes GPRS packets. When an additional channel is required on a BTS, the MFS asks the BSC to allocate a channel and to connect it to an Ater channel which the MFS controls. The Alcatel solution also supplies two dedicated GPRS interfaces between the MFS 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-connected via an Ethernet bus and controlled a control station. The GPU handles the O&M and telecom functions of several cells, but a cell cannot be shared between several GPUs. A GPU cannot be connected to more than one BSC, which means that each GPU cannot manage simultaneously several BSSs. However, the use of several GPUs per BSS is required for traffic capacity reasons. The MFS is in charge of associating 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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Telecom functions: Radio and transmission resources control Radiolink control of packet connections Common control channels management MS radio resource control Logical 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 GCH Interface (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 BSSTo 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 can be connected in each BSC.

Cell Mapping

Mapping a cell means that a cell is associated to a GPU. Remapping a cell means that a cell, already linked to a GPU, is moved to another GPU. The mapping of cells onto GPUs is performed by the MFS, which actually defines the mapping of cells onto LXPUs (logical GPU). An LXPU is either the primary GPU, or the spare GPU in the case of switch-over. All the GPRS traffic of one cell is handled by only one GPU. The following figure shows an example of cell mapping.MFSCell 1 Cell 4 Cell 3 Cell 5 Cell 6 Cell 7 Cell 8 Cell 12 Cell 11 Cell 10 Cell 14 Cell 13 Cell 9 Cell 2

GPU1

BSC

GPU2

GPU3

GPU4: GPRS Processing Unit

GPU

Figure 5: Cell Mapping


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1.4 Extended GSMTwo 10 MHz extended bands for GSM 900 in the range 880-890 MHz/925-935 MHz have been specified as an option on a national basis. The reason for this is mainly due to the lack of primary band frequencies in countries outside Europe. 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-900 frequency band, i.e. the primary band (890-915 MHz/935-960 MHz) plus the extended band (880-890 MHz/925-935 MHz). This corresponds to 174 addressable carrier frequencies and leads to an increase of 40% against the 124 frequencies in the primary band. All BCCH frequencies and SDCCH channels are entirely supported on the GSM primary band. This allows for the support of both primary and extended band mobiles in the same network.

E-GSM Mobile Station Recognition

From messages sent by the mobile station, the BSS determines if a mobile supports 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 not supporting the G1 band. The BSS never triggers a Classmark Interrogation procedure to obtain the E-GSM ability of a mobile station.

E-GSM Management After Initial Determination

Once the E-GSM ability has been initially determined as described above, it may happen that the mobile station radio characteristics change during a transaction. If the BSC receives a classmark change message, it takes this into account and updates the E-GSM ability according to the content of the received message. In the case of internal handover, the E-GSM ability of a mobile station is stored in the BSC memory. In the case of external incoming Handover, the handover request message includes either Classmark 1 or Classmark 2 IE, and optionally Classmark 3 IE. If Classmark 1 is present and Classmark 3 is not 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 BSC gets the E-GSM ability of the mobile station from the Classmark 3. If Classmark 2 is present and Classmark 3 is not present, or Classmark 3 is present but does not contain the Band 2 bit, the BSC gets the E-GSM ability of the mobile station from the Classmark 2 ("FC" bit). If both Classmark 2 and Classmark 3 are 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.

E-GSM Determination at Handover

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After an incoming external handover, if a classmark change message has been received from the mobile station, the BSC ignores any subsequent classmark 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. Each TRX is configured as a P-GSM TRX or a G1 TRX. When a TCH is needed, if it is for an E-GSM mobile station then a TCH belonging to the G1 TRX subset is preferably chosen. If no resource is available in the G1 TRX subset, the mobile station is allocated to the P-GSM TRX subset.


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1.5 External ComponentsThe 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.PLMNMobile Stations Network SubsystemA Interface

Base Station Subsystem BTS BTS BTSAbis Interface Ater Interface

Fixed Network PSTN

MSC

Transcoder BSC MFSGb Interface

SGSN

GGSN

PSDN

OMCR

HLR

NMC

GGSN HLR MFS NMC PSDN PSTN SGSN

: Gateway GRPS Support Node : Home Location Register : Multi-BSS Fast Packet Server : Network Management Center : Packet Switched Data Network : Public Switched Telephone Network : Serving GRPS Support Node

Figure 6: Logical Position of External Components Associated with BSS

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1.5.1 Network SubsystemManaging communication within the PLMN and external networks is the primary role of the NSS. The NSS manages the subscriber administration databases. It contains the following components: MSC Home Location Register Visitor Location Register Authentication Center Equipment Identity Register

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 mobile subscribers, or to subscribers of external networks. This part of the NSS interfaces with the BSS. The HLR is the central database within a given network for mobile subscriber specific data. It contains static data such as access authorization, information about subscribers and supplementary services. It also controls the dynamic data about the cell in which the mobile station is located. The VLR temporarily stores information about mobile stations entering its coverage area. Linked to one or more MSCs, the VLR transmits data to a new VLR when a mobile station changes areas. The AuC manages the security data used for subscriber authentication. The EIR contains the lists of mobile station equipment identities.

Home Location Register

Visitor Location Register

Authentication Center Equipment Identity Register


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1.5.2 Mobile StationsMobile stations provide radio and processing functions which allow subscribers to access the mobile network via the Air Interface. Subscriber related information is stored on a specific device called a SIM. The SIM is a removable smart-card that conforms to internationally recognized standards specified by the ISO. It contains the IMSI. This is used by the Network Operator to identify the subscriber in the network and to provide security and protection against misuse. Each mobile station has its own IMEI. The IMEI is used by the Network Operator to prevent stolen, or non-type approved mobile stations, from accessing 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 (Section 2.1.2). Mobile stations have different capabilities according to the class of mobile station and the purpose for which the mobile station was designed. These differences include power output and ciphering. Only phase 2 mobile stations can turn off ciphering, or change the ciphering mode, during a channel change procedure such as a handover. The ciphering capability of a mobile station is signalled to the BSS in the mobile station classmark. Ciphering is used to protect information transmitted on the Air Interface. This is 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. See Ciphering (Section 3.8) for further information concerning mobile station ciphering capabilities.

Mobile Station Idle Mode

A mobile station is in idle mode when it is switched on, but not communicating with the network on an SDCCH or a traffic channel. The BSS supports three idle mode functions: Cell selection and cell reselection Location updating Overload control.

Mobile Station Cell Selection and Reselection

A mobile station monitors the broadcast messages from the BTS. This includes monitoring the FCCH and SCH. The mobile station chooses the best cell on which to camp. If this cell is in a location area other than that stored in the mobile station memory, then the mobile station initiates a location update procedure. For a mobile station to camp on a cell, it has to synchronize with the cell. The BTS broadcasts an FCCH and an SCH at a defined time in the BCCH cycle. These channels are used as reference points for the mobile station to synchronize with the BCCH. Once synchronized, the mobile station continues to monitor these channels to stay synchronized.

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This type of synchronization, along with cell configuration and channel frequency information, enables the mobile station to calculate where channels occur in the multiframe sequences. Timing advance information is sent to the mobile station when an SDCCH is assigned. The mobile station uses the channel configuration information to calculate which part of the CCCH contains its paging message, and therefore which time slot to monitor for paging messages. When the mobile station is camped on a cell, it continues to monitor the BCCH transmissions from neighboring cells. The BCCH frequencies of the neighboring cells are transmitted on the BCCH of the home cell (sys_info 2). It can decide to camp on 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 area as the one currently in its memory, it does not initiate a location update. It recalculates its paging group and monitors the new paging channel. Paging messages are broadcast from all cells in a particular location area.

GSM/GPRS to UMTS Cell Reselection

The reselection of a UTRAN cell is triggered by a multi-RAT mobile station in circuit-switched idle mode, packet-switched idle mode, or packet-switched transfer mode. In NC0 mode, a multi-RAT mobile station can reselect a UTRAN cell in any GMM state. In dedicated mode, the multi-RAT mobile station follows the GSM handover procedures. The BSS then broadcasts the set of UTRAN cell parameters which allows the multi-RAT mobile station to reselect a UTRAN cell on its own. 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 update Periodic location update is performed by the mobile station after a lack of signalling activity for a specific time. If the timer expires, the mobile station initiates a location update, even if it has not changed Location Area. The duration of the mobile station timer is defined by the network and sent to the mobile station as system information messages on the BCCH. The time can be 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, there is 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 mobile station when the current call has finished, and initiates the location update procedure. This saves the system performing several location updates if the mobile station is handed over several times during a call. The mobile station camps on a cell with a different location area code to the one in the mobile station memory. The mobile station initiates the location update procedure by sending a channel_request message indicating that the call is for a location update. The BSS assigns a dedicated signalling channel and establishes a signalling path between the mobile station and MSC. See Mobile Originated 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

Location Updating


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interrogates the old VLR for authentication and subscriber information. For further information see Location Updating with Classmark Procedure (Section 3.6.3) 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 the message sent to the MSC. This information is sent in a Mobility Management sub-layer message and is transparent to the BSS. The NSS stores this information in either its HLR or its VLR. Following a location update procedure, the VLR can assign a new Temporary Mobile Subscriber Identity to the mobile station. 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.

Mobile Station

BTS

BSC BSC

MSC

VLR

Mobile Station connecting in a new location area

Mobile Station

Protocol Messages

BTS

BSC BSC

MSC

VLR

VLR

: Visitor Location Register

Figure 7: Location Update

Overload Control

To protect the system against overload, the system can bar access to mobile stations, by changing the RACH control information in the system information messages described in Table 1. For further information, see GPRS Overload Control (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 InfrastructureWhen 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 of functioning as phase 1 or phase 2, depending on the MSC capabilities. The infrastructure (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 phase 2 protocol. However, some phase 1 infrastructures reject the message as spare bits are used. Some protocol changes in phase 2 changed or replaced a phase 1 protocol. For example, power and quality measurements sent by phase 2 mobile stations have a finer range of power control, which the phase 1 infrastructure must process. Phase 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 new elements in messages, which the phase 1 infrastructure could reject. This blacklists the mobile station due to an invalid protocol message for phase 1. Depending on what these messages are, the updates to the phase 1 infrastructure would accept these messages/elements. The messages can be either ignored or only partly treated. This is based on information contained 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 central database. The OMC-R only performs O&M activities. It does not perform user traffic processing or call establishment and control activities. Refer to the Operations & Maintenance Principles for more information. Operator actions via the terminal interface trigger commands throughout the BSS. The OMC-R provides object-oriented management information, and supports a Manager/Agent scheme to perform and control management activities. The terminal interface supports different user profiles with different access rights.


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1.6 Network ManagementNormally the OMC-R provides all the network management and control functions required by the BSS. However, the management and control functions are proprietary to the system supplier. In keeping with International Telecommunications Union and European Telecommunication Standards Institute recommendations, the Telecommunications Management Network structure has been developed to standardize the Network Management function. Network Management is compatible with all equipment, even that of different manufacturers. Network Management is controlled from one or several NMCs.

1.6.1 Telecommunications Management NetworkThe ability to transfer management information across the Telecommunications Management Network environment is defined by a protocol suite, the Q Interfaces. The following figure shows the hierarchical structure of the Telecommunications Management Network. It graphically defines the respective management responsibilities in the three main levels of the Management Information Tree. Telecommunications Management Network is more fully discussed in the BSS/MFS and TMN Functions section of the Operations & Maintenance Principles document.NMC Operator (Resource Management) NMC Q3 OSS Network Management & Network Element Management

OMCR Operator (Resource and Equipment Management)

OMCR

Mediation Function

MFS

Network Element

Security Block (SBL) Management

BSC

BSS

BTS

BTS

BTS

OSS MFS NMC

: Operation Support System : Multi-BSS Fast Packet Server : Network Management Center

Figure 8: TMN System Hierarchy

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1.6.2 Q3 InterfaceCommunication between the NMC and the OMC-R takes place across the Q3 Interface (see Figure 8). The Q3 protocols can be divided into the following main areas: Association connection and disconnection mechanisms Message format and structure Command types. For further information on Network Management and the Q3 Interface see the Operations & Maintenance Principles document.


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1.7 BSS Telecommunications LayersThe 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 these layers are standard. The following figure shows the general distribution of the telecommunication functions within a GSM network.MS BTS BSC NSS CM MM RRM GSM Application Layers

TRANSMISSION

CM MM MS RRM

: Call Management : Mobility Management : Mobile Station : Radio Resource Management

Figure 9: General Telecommunication Layers within GSM

1.7.1 Call ManagementThe Call Management sub-layer performs Call Control to establish, maintain and release calls. SMS within Call Management allows the mobile station to send and receive messages of up to 160 characters. The Supplementary Service functions are also provided to the mobile stations as part of Call Management.

1.7.2 Mobility ManagementThe Mobility Management sub-layer is used by the NSS to manage the subscriber database, including information on subscriber location and authentication. It is also used by the mobile stations to send location updates when they move to new location areas.

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1.7.3 Radio Resource ManagementThe Radio Resources Management sub-layer establishes, maintains and releases stable connections between the mobile station and the MSC for the duration of a call. This includes functions such as managing the limited radio resources, to ensure high service availability. It also performs handovers when a mobile station moves during a call, or the channel quality falls below an acceptable level. RRM functions occur mainly between the mobile station and the BSC. The following figure shows the application layers, transmission layers and Interfaces of the BSS.MS BTS BSC MSC CM MM RRM BSSAP BSSAP BSSAP GSM Application Layers

LAPDm

LAPDm

LAPD

LAPD

SCCP SS7

SCCP SS7

Layer 2

Layer 1

Layer 1

Layer 1

Layer 1

Layer 1

Layer 1

08.60 Air InterfaceBSSAP CM LAPD LAPDm MM RRM SCCP SS7 TC : BSS Application Part : Call Management : Link Access Protocol on the D Channel : Link Access Protocol on the Dm Channel : Mobility Management : Radio Resource Management : Signal Connection Control Part : Signaling System No. 7 : Transcoder

TC A Interface

Abis Interface

Figure 10: BSS Application, Transmission Layers and Interfaces


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1.7.4 The A InterfaceThe A Interface is used for communication between the BSC and the MSC. The connection between the BSC and MSC can be via one of the following: Terrestrial lines Satellite link. The A Interface comprises the: Physical layer 1 Data Link layer 2 RRM sub-layer 3 of the application layer

Physical Layer 1

The physical layer provides a physical connection to transport the signals. It supports a 2 Mbit/s link divided into 32 x 64 kbit/s channels by Time Division Multiplex. The actual physical link used depends on Network Operator implementation. Layer 2 provides the frame handling functions for the interface. It is also used to pass signalling messages using the International Telecommunications Union signalling System No. 7 protocol. This comprises: Message Transfer Part, which provides the mechanism for reliable transfer of the signalling messages Signalling Connection Control Part, which provides the mechanism to identify transactions relating to a specific communication.

Data Link Layer 2

Application Sub-layer RRM

To transfer layer 3 messages relating to a transaction, the SCCP uses the BSS Application Part. This is divided into two parts: Direct Transfer Application Part, which transfers messages directly between the MSC and the mobile station. These messages are not interpreted by the BSS. The BSS must read and recognize the initial message as a DTAP message. BSS Management Application Part which supports procedures between the MSC and the BSC, such as resource management and handover control. On the A Interface, the process is terminated at the BSC. Messages for the BSS, passed by the BSSMAP, are interpreted by the BSC layer 3.

Ater Interface

The part of the A Interface between the Transcoder and BSC is known as the Ater Mux Interface. The Ater Mux Interface is the result of multiplexing four Ater Interfaces. Transcoding is a layer 1 process, therefore the difference between the two interfaces is at the physical level. This feature improves efficiency on the Ater Mux PCM connection between the G2 BSC and the G2 Transcoder. Four Ater Interfaces are submultiplexed onto the Ater Mux connection. This interconnects four Digital Trunk Controllers and four Transcoder Rate Adaption Units, achieving a 4:1 mapping. The 4:1 mapping of the G2 BSC and G2 Transcoder allows up to 116 traffic channels.

Optimized Ater Interface Mapping

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1.7.5 The Abis InterfaceThe Abis Interface is used for communication between the BSC and the BTS. The Abis Interface comprises: Physical layer 1 Data Link layer 2 BTS management sub-layer 3 of the application layer.

Physical Layer 1

The physical layer provides a physical connection to transport the signals. It supports a 2 Mbit/s link divided into 32 x 64 kbit/s channels by TDM. The physical link used depends on the Network Operator implementing the interface.

Data Link Layer 2

The data link layer provides frame handling and signalling functions using the LAPD. This layer supports three types of signalling links: The Radio Signalling Link for signalling to the mobile station (including SMS) The O&M Link for O&M information The OML Auto-detection feature (see OML Auto-detection (Section 8.4.5)) allows the time slot reserved for the O&M Link to be used for signalling (if there are no G1/G2 BTS on the Abis interface). This provides for an increase in the amount of telecom traffic on the Abis interface. The Layer 2 Management Link for the layer 2 management functions such as frame checking and error correction.

Application Sub-layer BTS

The BTS management layer is used for layer 3 messages between the BSC and the BTS. Some of these messages are transparent to the BTS. These are passed directly to the mobile station using the BTS RR management sub-layer 3 on the Air Interface. Non-transparent messages include messages for radio link layer control and channel management.

1.7.6 Satellite LinksThe Abis and Ater interfaces were designed to use terrestrial transmission links. However, in developing countries the terrestrial transmission infrastructure does not exist and in many cases is difficult and costly to provide. There is also a need in the developed world to provide temporary GSM coverage for transient mobile population density increases, for example at sporting events. Using geostationary earth orbiting satellites is a simple and relatively low cost solution to these problems. Unfortunately, there is one major drawback, transmission delay. The Geostationary orbit is located at an altitude of 35,786 km above the equator, therefore propagation delay of radio signals can vary between 119 ms at the equator to a maximum delay of 139 ms. The delay for one hop (the path from one point on earth to another point, via one satellite link) varies between 238 and 278 ms. This delay degrades speech quality, but although the degradation is worse than experienced in the PSTN, it is usable. The delay also

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