Wireless Local Loops: Theory and Applications

List of Contributors xi

Preface xv

Acknowledgement xvii

Part I Theoretical aspects 1

1 Introduction to WLL: Digital Service Technologies 3

1.1 Background 3

1.2 Advantages of Wireless Systems 5

1.3 WLL Service Requirements 6

1.4 Generic WLL System Architecture 9

1.5 WLL System Technologies 14

1.6 Comparison of WLL Services 29

Appendix A Fixed versus Mobile Cellular Systems 30

Appendix B CDMA versus TDMA in WLL 31

References 33

2 Propagation Models for Wireless Local Loops 35

2.1 Introduction 35

2.2 WLL System Configuration 36

2.3 Delay Spread in WLL Environments 37

2.4 Components of Overall Path Loss 39

2.5 Path Loss Models 43

2.6 Comparison of Propagation Models 55

References 55

2 Propagation Models for Wireless Local Loops 35

2.1 Introduction 35

2.2 WLL System Configuration 36

2.3 Delay Spread in WLL Environments 37

2.4 Components of Overall Path Loss 39

2.5 Path Loss Models 43

2.6 Comparison of Propagation Models 55

References 55

3 Wireless Local Loop Networks Capacity Enhancement by Space Division Multiple Access 57

3.1 Introduction 57

3.2 Background 57

3.3 Technologies for the First Generation of Wireless Local Loop 63

3.4 Multiple Access Techniques 70

3.5 Simulation Description 75

3.6 Performance Results 76

References 77

4 Combined Trellis Coded Quantization/Modulation over a Wireless Local Loop Environment 81

4.1 Introduction 81

4.2 Fundamentals of Trellis Coded Modulation 81

4.3 General Aspects of Combined Trellis Coded Quantization Modulation Schemes 83

4.4 Basic Model 88

4.5 An Example: 4-State 8-Psk Combined Trellis Coded Quantization/Modulation 95

References 99

5 Low Sequency W-CDMA Codes Lead to More Economic WLL and Infostation Terminals 101

5.1 Introduction 101

5.2 Code Selection and Generation 104

5.3 Infostation Transmitter 106

5.4 Terminal Receiver 107

5.5 Simplified Signal Processing for a Low Data Terminal 108

5.6 Noise Analysis and Processing Gain 110

References 112

6 Wide-band Wireless Outdoor to Indoor Local Loop Channel Models for Urban and Suburban Environments at 2 GHz 115

6.1 Introduction 115

6.2 Experimental Procedure 116

6.3 Data Processing 120

6.4 Channel Parameters 123

6.5 Channel Model 131

References 139

7 Traffic Considerations in Comparing Access Techniques for WLL 141

7.1 Introduction 141

7.2 Fixed Wireless Access Networks 142

7.3 Multiple Access Technologies 144

7.4 CDMA Capacity Analysis 146

7.5 Comparison of TDMA and CDMA Results 159

List of Abbreviations 161

References 161

8 Traffic Based Dynamic Channel Allocation Schemes for WLL 163

8.1 Introduction 163

8.2 Access on Allocation Technologies 163

8.3 FWA Network Scenarios 168

8.4 Simulations Results of DCA in FWA Networks 178

List of Abbreviations 189

References 190

9 WLL as an Interferer 191

9.1 Introduction 191

9.2 System Overview of WLL as an Interferer 194

9.3 Architecture of WLL as an Interferer 201

9.4 Problem Definition 201

9.5 Description of the Systems 202

9.6 Spectral Characteristics of Signals 210

9.7 Interference Effects Analysis 214

9.8 Study Case 217

References 228

Part II Applications 231

10 Development of a Prototype of the Broadband Radio Access Integrated Network 233

10.1 Introduction 233

10.2 System Overview 234

10.3 MAC Protocol: RS-ISMA 236

10.4 BRAIN Indoor LAN Prototype 240

References 245

11 PBX based Mobility Manager for WLL 247

11.1 Introduction 247

11.2 A Computer-controlled PBX Architecture 247

11.3 Mobility Management for PBX 248

11.4 Registration Procedures 252

11.5 Call Termination 255

11.6 Performance Issues 258

References 260

12 Remote Management and Upgrade in a Wireless Local Loop System 261

12.1 Introduction 261

12.2 Wireless Local Loop Application Overview 262

12.3 Remote Upgrade of Fixed Subscriber Units 263

12.4 Event Logging for Remote Management 266

References 270

13 Current and Future Services Using Wireless Local Loop (WLL) Systems 271

13.1 Introduction 271

13.2 WLL System Architecture 272

13.3 WLL Service Requirements 274

13.4 Services with Currently Available Systems 276

13.5 Further Considerations for Multimedia Services 280

References 281

Index 283