UMTS Network Planning, Optimization, and Inter-Operation with GSM

Preface xv

Acknowledgments xix

1 Introduction 1

1.1 Overview of 3G Standards and WCDMA Releases 1

1.2 3G Challenges 3

1.3 Future Trends 5

2 UMTS System and Air Interface Architecture 7

2.1 Network Architecture 8

2.1.1 The Access Stratum 8

2.1.2 The Non-Access Stratum and Core Network 9

2.1.3 UTRAN Architecture 9

2.1.4 Synchronization in the UTRAN 10

2.1.5 UE Power Classes 11

2.2 The Air Interface Modes of Operation 11

2.3 Spectrum Allocations 12

2.4 WCDMA and the Spreading Concept 12

2.4.1 Processing Gain and Impact on C/I Requirement 13

2.4.2 Resistivity to Narrowband Interference 14

2.4.3 Rake Reception of Multipath Signals and the Efficiency 15

2.4.4 Variable Spreading and Multi-Code Operation 16

2.5 Cell Isolation Mechanism and Scrambling Codes 17

2.6 Power Control Necessity 17

2.7 Soft/Softer Handovers and the Benefits 18

2.8 Framing and Modulation 19

2.9 Channel Definitions 19

2.9.1 Physical Channels 20

2.9.2 Frame Timing Relationships 28

2.9.3 Transport Channels 29

2.9.4 Channel Mappings 30

2.9.5 Logical Channels 30

2.10 The Radio Interface Protocol Architecture 31

2.10.1 The RLC Sub-layer 33

2.10.2 The MAC Protocol Functions 34

2.10.3 RRC and Channel State Transitions 34

2.10.4 Packet Data Convergence Sub-layer (PDCP) 36

2.10.5 The Broadcast Multicast Control (BMC) Protocol 37

2.11 The Important Physical Layer Measurements 37

2.11.1 UE Link Performance Related Measurements 37

2.11.2 UTRAN Link Performance Related Measurements 38

References 40

3 Multipath and Path Loss Modeling 41

3.1 Multipath Reception 42

3.1.1 Delay Spread 42

3.1.2 Coherence Bandwidth 43

3.1.3 Doppler Effect 45

3.1.4 Small-scale Multipath Effects 45

3.1.5 Channel Coherence Time 46

3.2 3GPP Multipath Channel Models 48

3.3 ITU Multipath Channel Models 49

3.4 Large-Scale Distance Effects 51

3.4.1 Lognormal Fading 51

3.4.2 Path Loss Models 52

3.4.3 Model Tuning and Generalized Propagation Models 59

3.5 Far-Reach Propagation Through Ducting 62

References 63

4 Formulation and Analysis of the Coverage-capacity and Multi-user Interference Parameters in UMTS 65

4.1 The Multi-user Interference 65

4.2 Interference Representation 67

4.2.1 Noise Rise 67

4.2.2 Load Factor 67

4.2.3 Geometric Factor 68

4.2.4 The f Factor 68

4.3 Dynamics of the Uplink Capacity 68

4.4 Downlink Power-capacity Interaction 71

4.4.1 The General Power-capacity Formula on Downlink 71

4.4.2 Downlink Effective Load Factor and Pole Capacity 73

4.4.3 Single Service Case and Generalization to Multi-service Classes 74

4.4.4 Implications of Downlink Power-capacity Analysis 75

4.5 Capacity Improvement Techniques 76

4.6 Remarks in Conclusion 77

References 78

5 Radio Site Planning, Dimensioning, and Optimization 81

5.1 Radio Site Locating 82

5.2 Site Engineering 83

5.2.1 Pilot and Common Channel Power Settings 83

5.2.2 Pilot Coverage Verification 85

5.2.3 RACH Coverage Planning 86

5.2.4 Site Sectorisation 87

5.2.5 Controlling Site Overlap and Interference 87

5.3 Link Budgeting for Dimensioning 89

5.3.1 Uplink Link Budgeting and Static Analysis 90

5.3.2 Downlink Load and Transmit Power Checking 99

5.3.3 Downlink Link Budgeting for the Pilot Channel (P-CPICH) 100

5.3.4 HS-PDSCH Link Budget Analysis 101

5.3.5 Setting Interference Parameters 102

5.4 Simulation-based Detailed Planning 104

5.4.1 Uplink Simulation Iterations 105

5.4.2 Downlink Simulation Iterations 106

5.4.3 Area Coverage Probabilities 110

5.5 Primary CPICH Coverage Analysis 111

5.6 Primary and Secondary CCPCH Coverage Analysis 111

5.7 Uplink DCH Coverage Analysis 112

5.8 Pre-launch Optimization 113

5.9 Defining the Service Strategy 113

5.10 Defining Service Requirements and Traffic Modeling 113

5.11 Scrambling Codes and Planning Requirements 115

5.12 Inter-operator Interference Protection Measures 116

5.12.1 The Characterizing Parameters 116

5.12.2 Effects on Downlink and Uplink 118

5.12.3 The Avoidance Measures 118

References 119

6 The Layered and Multi-carrier Radio Access Design 121

6.1 Introduction 121

6.2 Service Interaction Analysis 122

6.3 Layered Cell Architectures 126

6.3.1 Carrier Sharing 126

6.3.2 Multi-carrier Design 127

References 128

7 Utilization of GSM Measurements for UMTS Site Overlay 129

7.1 Introductory Considerations 129

7.2 Using GSM Measurements to Characterize Path Losses in UMTS 130

7.2.1 Local Cumulative Path Loss Distribution 132

7.2.2 Model Tuning 132

7.3 Neighbor-Cell Overlap and Soft Handover Overhead Measurement 132

7.4 Interference and Pilot Pollution Detection 134

References 135

8 Power Control and Handover Procedures and Optimization 137

8.1 Power Control 137

8.1.1 Open Loop Power Control 138

8.1.2 Fast Closed Loop Power Control (Inner-loop PC) 139

8.1.3 Outer-Loop Power Control 142

8.1.4 Power Control Optimization 145

8.2 Handover Procedures and Control 145

8.2.1 Neighbor Cell Search and Measurement Reporting 146

8.2.2 Hard Handover 148

8.2.3 Soft (and Softer) Handovers 149

References 157

9 Radio Resource and Performance Management 159

9.1 Admission Control 160

9.1.1 Processing Admission Control 160

9.1.2 Radio Admission Control 160

9.2 Congestion/Load Control 164

9.2.1 Congestion Detection Mechanisms 165

9.2.2 Congestion Resolving Actions 165

9.3 Channel Switching and Bearer Reconfiguration 166

9.4 Code Resource Allocation 168

9.4.1 Code Allocation on the Uplink 169

9.4.2 Code Allocation on the Downlink 169

9.5 Packet Scheduling 170

9.5.1 Time Scheduling 170

9.5.2 Code Division Scheduling 171

9.5.3 Scheduling on the HS-DSCH Channel 171

9.5.4 Integration with Load Control 173

References 173

10 Means to Enhance Radio Coverage and Capacity 175

10.1 Coverage Improvement and the Impact 176

10.2 Capacity Improvement and the Impact 176

10.3 HSDPA Deployment 177

10.4 Transmitter Diversity 177

10.4.1 Transmit Diversity Benefits and Gains 178

10.4.2 Mobile Terminal Requirements 178

10.5 Mast Head Amplifiers 179

10.5.1 MHA Benefit on System Coverage 180

10.5.2 MHA Impact on System Capacity 181

10.6 Remote Radio Heads (RRH) 181

10.6.1 RRH Benefits 181

10.7 Higher Order Receiver Diversity 182

10.7.1 Operation and Observed Benefits 182

10.7.2 Impact to Downlink Capacity 183

10.7.3 Diversity Reception at Mobile Terminal 184

10.8 Fixed Beam and Adaptive Beam Forming 184

10.8.1 Implementation Considerations and Issues 184

10.8.2 Gains of Beam Forming 185

10.9 Repeaters 185

10.9.1 Operating Characteristics 186

10.9.2 Repeater Isolation Requirements 187

10.9.3 Repeater Coverage and Capacity Evaluation 187

10.9.4 Impact on System Capacity 187

10.10 Additional Scrambling Codes 188

10.11 Self-Organizing Networks 188

References 189

11 Co-planning and Inter-operation with GSM 191

11.1 GSM Co-location Guidelines 191

11.1.1 The Isolation Requirements 191

11.1.2 Isolation Mechanisms 192

11.1.3 Inter-modulation Problems and Counter-measures 193

11.1.4 Antenna Configuration Scenarios 195

11.2 Ambient Noise Considerations 201

11.3 Inter-operation with GSM 201

11.3.1 Handover between the Operator’s GSM and UMTS Networks 202

11.3.2 Handover with other UMTS Operators 203

References 203

12 AMR Speech Codecs: Operation and Performance 205

12.1 AMR Speech Codec Characteristics and Modes 205

12.2 AMR Implementation Strategies 207

12.2.1 AMR Network Based Adaptation 207

12.2.2 AMR Source Controlled Rate Adaptation 208

12.3 Tradeoffs between AMR Source Rate and System Capacity in WCDMA 209

12.4 AMR Performance under Clean Speech Conditions 210

12.5 AMR Performance under Background Noise and Error Conditions 210

12.6 Codec Mode Parameters 211

12.6.1 Compression Handover Threshold 211

12.6.2 AMR Adaptation Parameters 211

12.7 The AMR-Wideband (WB) 212

12.8 AMR Bearer QoS Requirements 212

References 213

13 The Terrestrial Radio Access Network Design 215

13.1 RNC Planning and Dimensioning 215

13.2 Node Interconnect Transmission 216

13.2.1 Node B to RNC 216

13.2.2 RNC to Core Network Nodes 221

13.3 Link Dimensioning 223

13.3.1 Protocol Overhead 223

13.3.2 Dimensioning of Node B–RNC Link (Iub) 224

13.3.3 RNC–MSC Link Dimensioning 226

13.3.4 RNC to SGSN Link Dimensioning 227

13.3.5 SGSN to RNC Link Dimensioning 227

References 230

14 The Core Network Technologies, Design, and Dimensioning 231

14.1 The Core Network Function 231

14.2 The IP Core Network Architecture 232

14.2.1 The Serving GPRS Support Node (SGSN) 233

14.2.2 Gateway GPRS Support Node (GGSN) 234


14.2.3 The HLR 235

14.2.4 The Core Network Protocol Architecture in GPRS 235

14.2.5 SS7 Over IP Transport Option (SS7oIP) 237

14.3 Mobility Management in GPRS 237

14.3.1 Location and Routing Area Concepts 238

14.3.2 User States in Mobility Management 238

14.3.3 MS Modes of Operation 239

14.4 IP Address Allocation 239

14.5 Core Network in WCDMA 240

14.6 IP Multimedia Subsystem (IMS) 240

14.7 Roaming in Mobile Networks 241

14.7.1 Mobility Handling Mechanisms in Roaming 242

14.8 Soft Switching 242

14.8.1 Benefits of Soft Switching 243

14.8.2 Transition to Soft Switching 244

14.9 Core Network Design and Dimensioning 245

14.9.1 Traffic Model 245

14.9.2 The No Traffic Information Scenario 246

14.9.3 Dimensioning of SGSN, GGSN, and the Interfaces 247

14.9.4 Active PDP Contexts and Impact of Call Mix on Dimensioning 247

14.9.5 Signaling Traffic and Link Dimensioning Guidelines 248

14.9.6 Protocol Overheads 250

14.10 Core Network Transport Technologies 250

14.10.1 Dedicated Private Lines 251

14.10.2 ATM Virtual Circuits 252

14.10.3 Frame Relay 253

14.10.4 IP Transport 254

14.10.5 Transport Technology Selection for Core Network 255

References 256

15 UMTS QoS Classes, Parameters, and Inter-workings 257

15.1 The QoS Concept and its Importance 257

15.2 QoS Fundamental Concepts 258

15.3 QoS Monitoring Process 259

15.4 QoS Categories in UMTS 260

15.4.1 Conversational Traffic 261

15.4.2 Streaming Traffic 261

15.4.3 Interactive Traffic 262

15.4.4 Background Traffic 262

15.5 Instant Messaging 262

15.6 UMTS Bearer Service Attributes 262

15.6.1 Ranges of UMTS Bearer Service Attributes 263

15.6.2 Ranges of Radio Access Bearer Service Attributes 264

15.7 UMTS QoS Mechanisms 264

15.8 UMTS QoS Signaling 265

15.9 UMTS–Internet QoS Inter-working/Mapping 267

15.10 End-to-End QoS Delay Analysis 267

15.11 ATM QoS Classes 268

15.12 More on QoS Mechanisms in IP Networks 269

15.13 IP Precedence to ATM Class of Service Mapping 270

15.14 Web Traffic Classification for QoS 271

15.15 QoS Levels of Agreement 271

References 271

16 The TCP Protocols, Issues, and Performance Tuning over Wireless Links 273

16.1 The TCP Fundamentals 274

16.1.1 TCP Connection Set Up and Termination 275

16.1.2 Congestion and Flow Control 275

16.1.3 TCP RTO Estimation 277

16.1.4 Bandwidth-Delay Product 278

16.2 TCP Enhanced Lost Recovery Options 279

16.2.1 Fast Retransmit 279

16.2.2 Fast Recovery 279

16.2.3 Selective Acknowledgement (SACK) 280

16.2.4 The Timestamp Option 280

16.3 TCP Variations as used on Fixed Networks 280

16.3.1 TCP Tahoe 280

16.3.2 TCP Reno 280

16.3.3 TCP New Reno 281

16.3.4 TCP SACK 281

16.4 Characteristics of Wireless Networks and Particularly 3G 281

16.4.1 BLER, Delays, and Delay Variations 281

16.4.2 Delay Spikes 282

16.4.3 Dynamic Variable Bit Rate 282

16.4.4 Asymmetry 283

16.5 TCP Solutions Proposed for Wireless Networks 283

16.5.1 Link Layer Solutions 283

16.5.2 TCP Parameter Tuning 288

16.5.3 Selecting the Proper TCP Options 290

16.5.4 Conventional TCP Implementation Options 292

16.5.5 Split TCP Solutions 292

16.5.6 Indirect TCP (I-TCP) 293

16.5.7 Mobile TCP Protocol 293

16.5.8 Mobile-End Transport Protocol 293

16.5.9 The Proxy Solutions 293

16.5.10 TCP End-to-End Solutions 294

16.6 Application Level Optimization 295

References 296

17 RAN Performance Root Cause Analysis and Trending Techniques for Effective Troubleshooting and Optimization 299

17.1 RAN KPIs 299

17.2 Measurement Guidelines 300

17.2.1 Live Network Traffic 300

17.2.2 Drive Testing 301

17.3 Correlation Based Root Cause Analysis 303

17.3.1 Correlative Analysis Based on a priori Knowledge 303

17.3.2 Correlation Analysis Based on Data Clustering 306

17.4 Applications to Network Troubleshooting and Performance Optimization 309

17.4.1 Formation of Vector PIs 309

17.4.2 Data Scaling 310

17.4.3 Clustering of Performance Data (Building Performance Spectrum) 310

17.4.4 Clustering Cells into Behavioral Classes 311

Appendix 312

References 313

Abbreviations 315

Index 323