LTE SELF-ORGANISING NETWORKS (SON) NETWORK MANAGEMENT AUTOMATION FOR OPERATIONAL EFFICIENCY

Edited By

Seppo Hämäläinen, Henning Sanneck, Cinzia Sartori

Nokia Siemens Networks

WILEY A John Wiley & Sons, Ltd., Publication

Contents

Foreword xiii

Preface xv

List of Contributors xix

Acknowledgements xxi

List of Abbreviations xxiii

1. Introduction 1 1.1 Self-Organising Networks (SON) 3 1.2 The Transition from Conventional Network Operation to SON 6

7.2.7 Automation of the Network Rollout 9 7.2.2 Automation of Network Optimisation and Troubleshooting 10 1.2.3 SON Characteristics and Challenges 11

References 12

2. LTE Overview 13 2.1 Introduction to LTE and SAE 13

2.7.7 3GPP Structure, Timeline and LTE Specifications 14 2.7.2 LTE Requirements 16 2.1.3 System Architecture Overview 16 2.7.4 Evolved UTRAN 18 2.7.5 E-UTRAN Functional Elements 19 2.1.6 Evolved Packet Core 21 2.7.7 Voice over LTE (VoLTE) 24 2.1.8 LTE-Advanced 24 2.7.9 Network Management 30

2.2 LTE Radio Access Network Scenarios and Their Evolution 33 2.2.7 LTE Radio Coverage Scenario 33 2.2.2 LTE for Capacity Enhancement in Existing GERAN/UTRAN 34 2.2.3 Enhancing LTE Capacity, the Multi-Layer LTE 34 2.2.4 Data Offloading, LIPA-SIPTO 35 2.2.5 Multi-Radio Access Network Scenarios or non-GPP 36

References 37

3. Self-Organising Networks (SON) 39 3.1 Vision 39 3.2 NGMN Operator Use Cases and 3GPP SON Use Cases 42

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3.2.1 Operational Use Cases 42 3.2.2 NGMN SON Use Cases and Requirements 47 3.2.3 SON Use Cases in 3GPP 50

3.3 Foundations for SON 52 3.3.1 Control Engineering: Feedback Loops 53 3.3.2 Autonomic Computing and Autonomic Management 55 3.3.3 SON Research Projects 57

3.4 Architecture 60 3.4.1 Use-Case Related Criteria 62 3.4.2 System-Level Criteria 64

3.5 Business Value 65 3.5.1 The Economics of eNB Sites 65 3.5.2 General Mode of Operation of SON 68 3.5.3 Installation and Planning 71 3.5.4 Network Optimisation 72 3.5.5 Fault Management 73 3.5.6 Conclusions 74

3.6 SON Operational and Technical Challenges 75 3.6.1 Transition of Operational Processes to SON 75 3.6.2 Technical (Engineering) Challenges 78

References 80

4. Self-Configuration ('Plug-and-Play') 81 4.1 Auto-Connectivity and -Commissioning 82

4.1.1 Preparation 85 4.1.2 Connectivity Setup, Site-Identification and

Auto-Commissioning 87 4.1.3 LTE-A Relay Auto-Connectivity 93 4.1.4 Conclusions 100

4.2 Dynamic Radio Configuration 100 4.2.1 Generation of Initial Transmission Parameters 106 4.2.2 Physical Cell-ID Allocation 111 4.2.3 Automatic Neighbour Relationship Setup (ANR) 118 4.2.4 DRC Architecture 130 4.2.5 Conclusions 132

References 133

5. Self-Optimisation 135 5.1 Mobility Robustness Optimisation 136

5.1.1 Goals ofMRO 136 5.7.2 Cell Changes and Interference Challenges 137 5.1.3 MRO Relevant Parameters 140 5.1.4 Causes for Mobility Problems 144 5.7.5 MRO Solutions 146 5.7.6 MRO Time Scales 151 5.7.7 MRO Performance 152

Contents ix

5.2 Mobility Load Balancing and Traffic Steering 157 5.2.1 Introduction to Traffic Steering 157 5.2.2 SON Policies for Mobility Load Balancing 159 5.2.3 A Theoretical View of Load Balancing 160 5.2.4 Standardised Features and Procedures to Direct UEs

to the Desired Layer 166 5.2.5 Exemplary Results of MLB 182 5.2.6 Uplink Load Balancing 189 5.2.7 Interactions Between TS/MLB and MRO 190

5.3 Energy Saving 193 5.3.1 Introduction 193 5.3.2 Requirements 195 5-3.3 Energy Saving Management 195 5.3.4 eNB Overlaid Scenario 196 5.3.5 Capacity-Limited Network 198 5.3.6 Equipment/Local ES 200 5.3.7 Example Scenarios and Expected Gains 201 5.3.8 Summary 204

5.4 Coverage and Capacity Optimisation 204 5.4.1 CCO with Adaptive Antennas 205 5.4.2 Performance Analysis for Antenna Parameter Optimisation

Based CCO 208 5.4.3 CCO with TX Power 216

5.5 RACH Optimisation 217 5.5.1 General 217 5.5.2 PRACH Configuration 218 5.5.3 RACH Configuration 219 5.5.4 RACH/PRACH Configuration Example 221 5.5.5 RA Performance 222 5.5.6 Self-Optimisation Framework 223 5.5.7 UE Reporting 223 5.5.8 Inter-eNB Communication 225

5.6 RRM and SON (Interference Coordination, P0 Optimisation) 226 5.6.1 Interference Coordination 226 5.6.2 P0 Optimisation 230

References 232

Self-Healing 235 6.1 Introduction 236

6.1.1 3GPP Use Cases 236 6.1.2 3GPP Self-Healing Process and its Management 237 6.1.3 Cell Degradation Management 238

6.2 Cell Degradation Detection 242 6.3 Cell Degradation Diagnosis and Prediction 248

6.3.1 Rule Based Systems 250 6.3.2 Bayesian Networks 251

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6.4

6.3.3 Case Based Reasoning 6.3.4 Neural Networks 6.3.5 Active Measurements 6.3.6 Prediction

Cell Outage Compensation 6.4.1 Activation of Cell Outage Compensation 6.4.2 Means of Cell Outage Compensation 6.4.3 Interaction between Cell Outage Compensation

and Self-Configuration Functions References

7. Supporting Function: Minimisation of Drive Tests (MDT) 7.1

7.2 7.3 7.4

7.5 7.6

7.7

7.8

Introduction 7.1.1 General 7.1.2 History and Background

Relation to SON Requirements Use Cases

7.4.1 Operator Scenarios 7.4.2 Coverage Optimisation 7.4.3 Mobility Optimisation 7.4.4 Capacity Optimisation 7.4.5 Parameterisation for Common Channels 7.4.6 QoS verification

Overall Architecture Managing MDT

7.6.1 Subscriber and Equipment Trace 7.6.2 MDT Configuration Parameters 7.6.3 Subscription Based MDT 7.6.4 Area Based MDT 7.6.5 Supporting Functionality in the Management System 7.6.6 MDT Reporting

MDT Radio Interface Procedures 7.7.1 Immediate MDT 7.7.2 Logged MDT 7.7.3 RLF Reporting 7.7.4 Measurement Parameters 7.7.5 Location Information

Conclusion References

8. SON for Core Networks 8.1 8.2

Introduction SON for Packet Core Networks 8.2.1 Packet Core Element Auto-Configuration 8.2.2 Automatic Neighbour Relation

253 255 256 257 259 260 260

263 264

267 267 267 269 272 273 275 276 277 281 281 282 282 283 285 285 285 287 292 293 293 295 296 298 303 305 308 309 310

311 311 311 311 313

Contents xi

8.2.3 SI Flex (MME Pooling) 314 8.2.4 Signalling Optimisation 315 8.2.5 Latency Optimisation 317 8.2.6 Fast Gateway Convergence with Bidirectional

Forward Detection 318 8.2.7 Dynamic IP Pool Allocation 318 8.2.8 Energy Saving 319

8.3 SON for Voice Core Networks 319 8.3.1 Voice Over IP Quality Monitoring

and Management 319 8.3.2 Resource Optimisation in Voice Core Network 320

References 321

9. SON Operation 322 9.1 SON Function Interactions 323

9.1.1 Spatial Characteristic 324 9.1.2 Temporal Characteristic 324 9.1.3 Categories of SON Conflicts 326 9.1.4 Network Parameters Related to SON Functions 329 9.1.5 Examples for Conflicts between SON Functions 330

9.2 Coordination of SON Functions 334 9.2.1 Basic Options for SON Coordination 334 9.2.2 Goals of SON Function Coordination 338 9.2.3 SON Coordination Function Concept 340 9.2.4 Coordination Schemes 346 9.2.5 Related Work 352 9.2.6 SON Function Coordination Example 352

9.3 Conclusions 355 References 356

10. SON for Heterogeneous Networks (HetNet) 357 10.1 Introduction 357 10.2 Standardisation and Network Architecture 359

10.2.1 Network Architecture for HetNet 361 10.3 Self-Configuration 362

10.3.1 Auto-Connectivity and-Commissioning 363 10.3.2 Automatic Site Identification and Hardware-to-Site Mapping 364 10.3.3 Automatic Neighbour Relations (ANR) 365

10.4 Self-Optimisation: Interference Management 365 10.4.1 Interference Characteristics in HetNet Scenarios 365 10.4.2 Basic Interference Management Techniques 366 10.4.3 Scenarios with Macro eNBs and Micro/Pico eNBs 369 10.4.4 Enhanced Time-Domain Interference

Management: elCIC 370 10.4.5 Outlook on Further Interference Management Innovations 374

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10.5 Self-Optimisation: Mobility Aspects; MRO and Traffic Steering 375 10.5.1 Mobility Robustness Optimisation 375 10.5.2 Multi-Layer Traffic Steering and Load Balancing 311 10.5.3 IEEE802.il (WiFi) Integration 378

References 378

11. Future Research Topics 379 11.1 Future Mobile Network Scenarios 379

11.1.1 Heterogeneous Networks 379 11.1.2 Cloud RAN 380 11.1.3 Requirements for Future OAM Systems 381

11.2 Cognitive Radio Networks (CRN) 381 11.2.1 From SON to CRN 381 11.2.2 Definitions 382 11.2.3 Framework 383 11.2.4 Artificial Intelligence 385

11.3 Applications 387 11.3.1 Self-Configuration 387 11.3.2 Self-Optimisation 387 11.3.3 Self-Healing 388 11.3.4 Operation 388

11.4 Conclusion 389 References 389

Index 391