GSM Networks - Protocols, Terminology, and Implementation

This practical book provides an extremely comprehensive, up-to-date, and easy-to-understand treatment of the entire GSM network and the signaling methods of its terrestrial interfaces. You learn how to analyze network problems, what measurements you have to take to solve them, and where in a scenario you will find the desired information or parameter. The book introduces you to all the interfaces between the GSM subsystems, starting with the Abis- and Air- Interface and continuing on to VLR?s, HLR?s and MSC?s within the Network Switching Subsystem (NSS). You learn about the various signaling standards or methods used in GSM, including TCAP and MAP and how to apply this knowledge when working with GSM networks.

A special feature of the book is its extensive glossary that explains abbreviations, terms, parameters, counters, and messages frequently encountered when working with GSM. In addition, it features numerous figures, tables, lists, statistical formulas, real-life examples, and everyday comparisons to give you a detailed reference that?s quick to use and easy to understand. You get A-to-Z coverage of dozens of topics, including:

• Signaling standards like LAPD, LAPDm, SS7, SCCP, TCAP -- GSM applications such as RR, MM, CC, MAP -- and all the protocols used in GSM such as LAPD, ISUP, MAP, TCAP, SS7, SCCP, BSSAP, and more
• The Subscriber Identity Module (SIM) and Home Location Register (HLR)
• The OSI reference model and its applicability to GSM
• Failure resolution both in the lab and on site
• Measurements required to analyze network problems -- and the dependencies of failure messages
• Increase your knowledge of the ANSI-41 standard and how the network elements interact to help you better understand how the entire Digital PCS system works
• Examine industry activities currently underway to help make ANSI-136 a truly global, third-generation cellular system

This detailed book is a practical handbook for engineers involved with all aspects of the GSM infrastructure ? from research and development ? to installation, operation, and on-site management ? to technical support, maintenance, and testing. It is also a comprehensive self-study guide for engineers, other technical professionals, and university-level students with a basic knowledge of telecommunications who want to learn about the complex signaling architectures employed in GSM networks.

Table of contents

1 Introduction

1.1 About This Book

1.2 Global System for Mobile Communication (GSM)

1.2.1 The System Architecture of GSM: A Network of Cells

1.2.2 An Overview on the GSM Subsystems

1.3 The Focus of This Book

1.4 Signaling

1.4.1 What is Signaling?

1.4.2 How is Signaling Performed?

1.4.3 What is Signaling Used For?

1.5 Representation of Messages

2 The Mobile Station and the Subscriber Identity Module

2.1 Subscriber Identity Module

2.1.1 The SIM as a Database

2.1.2 Advantage for the Subscriber

2.2 Mobile Station

2.2.1 Types of Mobile Stations

2.2.2 Functionality

2.2.3 Mobile Stations as Test Equipment

3 The Base Station Subsystem

3.1 Base Transceiver Station

3.1.1 Architecture and Functionality of a Base Transceiver Station

3.1.2 Base Transceiver Station Configurations

3.2 Base Station Controller

3.2.1 Architecture and Tasks of the Base Station Controller

3.3 Transcoding Rate and Adaptation Unit

3.3.1 Function of the Transcoding Rate and Adaptation Unit

3.3.2 Site Selection for Transcoding Rate and Adaptation Unit

3.3.3 Relationship Between the Transcoding Rate, Adaptation Unit, and Base Station Subsystem

4 The Network Switching Subsystem

4.1 Home Location Register and Authentication Center

4.2 Visitor Location Register

4.3 The Mobile-Services Switching Center

4.3.1 Gateway MSC

4.3.2 The Relationship Between MSC and VLR

4.4 Equipment Identity Register

5 The OSI Reference Model

5.1 Reasons for Standardization

5.2 Layering in the OSI Reference Model

5.3 Data Types of the OSI Reference Model

5.4 Information Processing in the OSI Reference Model

5.5 Advantages of the OSI Reference Model

5.6 The Seven Layers of the OSI Reference Model

5.6.1 Layer 1: The Physical Layer

5.6.2 Layer 2: The Data Link Layer

5.6.3 Layer 3: The Network Layer

5.6.4 Layer 4: The Transport Layer

5.6.5 Layer 5: The Session Layer

5.6.6 Layer 6: The Presentation Layer

5.6.7 Layer 7: The Application Layer

5.7 Comprehension Issues

5.7.1 An Analogy: The Move to Europe

6 The Abis-Interface

6.1 Channel Configurations

6.2 Alternatives for Connecting the BTS to the BSC

6.2.1 BTS Connection in a Serial Configuration

6.2.2 Connection of BTSs in Star Configuration

6.3 Signaling on the Abis-Interface

6.3.1 OSI Protocol Stack on the Abis-Interface

6.3.2 Layer 2

6.3.3 Layer 3

6.4 Bringing an Abis-Interface Into Service

6.4.1 Layer 1

6.4.2 Layer 2

7 The Air-interface of GSM

7.1 The Structure of the Air-Interface in GSM

7.1.1 The FDMA/TDMA Scheme

7.1.2 Frame Hierarchy and Frame Numbers

7.1.3 Synchronization Between Uplink and Downlink

7.2 Physical Versus Logical Channels

7.3 Logical-Channel Configuration

7.3.1 Mapping of Logical Channels Onto Physical Channels

7.3.2 Possible Combinations

7.4 Interleaving

7.5 Signaling on the Air Interface

7.5.1 Layer 2 LAPDm Signaling

7.5.2 Layer 3

8 Signaling System Number 7

8.1 The SS7 Network

8.2 Message Transfer Part

8.3 Message Types in SS7

8.3.1 Fill-In Signal Unit

8.3.2 Link Status Signal Unit

8.3.3 Message Signal Unit

8.4 Addressing and Routing of Messages

8.4.1 Example: Determination of DPC, OPC, and SLS in a Hexadecimal Trace

8.4.2 Example: Commissioning of an SS7 Connection

8.5 Error Detection and Error Correction

8.5.1 Send Sequence Numbers and Receive Sequence Numbers (FSN, BSN, BIB, FIB)

8.5.2 BSN/BIB and FSN/FIB for Message Transfer

8.6 SS7 Network Management and Network Test

8.6.1 SS7 Network Test

8.6.2 Possible Error Cases

8.6.3 Format of SS7 Management Messages and Test Messages

8.6.4 Messages in SS7 Network Management and Network Test

9 Signaling Connection Control Part

9.1 Tasks of the SCCP

9.1.1 Services of the SCCP: Connection-Oriented Versus Connectionless

9.1.2 Connection-Oriented Versus Connectionless Service

9.2 The SCCP Message Format

9.3 The SCCP Messages

9.3.1 Tasks of the SCCP Messages

9.3.2 Parameters of SCCP Messages

9.3.3 Decoding a SCCP Message

9.4 The Principle of a SCCP Connection

10 The A-interface

10.1 Dimensioning

10.2 Signaling Over the A-Interface

10.2.1 The Base Station Subsystem Application Part

10.2.2 The Message Structure of the BSSAP.

10.2.3 Message Types of the Base Station Subsystem Management Application Part

10.2.4 Decoding of a BSSMAP Message

11 Transaction Capabilities and Mobile Application Part

11.1 Transaction Capabilities Application Part

11.1.1 Addressing in TCP/IP

11.1.2 The Internal Structure of TCP/IP

11.1.3 Coding of Parameters and Data in TCP/IP

11.1.4 TCP/IP Messages Used in GSM

11.2 Mobile Application Part

11.2.1 Communication Between MAP and its Users

11.2.2 MAP Services

11.2.3 Local Operation Codes of the Mobile Application Part

11.2.4 Communication Between Application, MAP, and TCP/IP

12 Scenarios

12.1 Location. Update

12.1.1 Location Update in the BSS

12.1.2 Location Update in the NSS

12.2 Equipment Check

12.3 Mobile Originating Call

12.3.1 Mobile Originating Call in the BSS

12.3.2 Mobile Originating Call in the NSS

12.4 Mobile Terminating Call

12.4.1 Mobile Terminating Call in the BSS

12.4.2 Mobile Terminating Call in the NSS

12.5 Handover

12.5.1 Measurement Results of BTS and MS

12.5.2 Analysis of a MEAS_RES/MEAS_REP

12.5.3 Handover Scenarios

13 Quality of Service

13.1 Tools for Protocol Measurements

13.1.1 OMC Versus Protocol Analyzers

13.1.2 Protocol Analyzer

13.2 Signaling Analysis in GSM

13.2.1 Automatic Analysis of Protocol Traces

13.2.2 Manual Analysis of Protocol Traces

13.3 Tips and Tricks

13.3.1 Identification of a Single Connection

13.4 Where in the Trace File to Find What Parameter?

13.5 Detailed Analysis of Errors on Abis Interface and A-Interface

13.5.1 Most Important Error Messages

13.5.2 Error Analysis in the BBS

Glossary

About the Author

Index