LTE SELF-ORGANISING NETWORKS (SON) LTE SELF-ORGANISING NETWORKS (SON) NETWORK MANAGEMENT AUTOMATION FOR OPERATIONAL EFFICIENCY Edited By Seppo Ha¨ma¨la¨inen, Henning Sanneck, Cinzia Sartori Nokia Siemens Networks Thiseditionfirstpublished2012 (cid:2)2012JohnWiley&Sons,Ltd Registeredoffice JohnWiley&SonsLtd,TheAtrium,SouthernGate,Chichester,WestSussex,PO198SQ,UnitedKingdom Fordetailsofourglobaleditorialoffices,forcustomerservicesandforinformationabouthowtoapplyfor permissiontoreusethecopyrightmaterialinthisbookpleaseseeourwebsiteatwww.wiley.com. TherightoftheauthortobeidentifiedastheauthorofthisworkhasbeenassertedinaccordancewiththeCopyright, DesignsandPatentsAct1988. Allrightsreserved.Nopartofthispublicationmaybereproduced,storedinaretrievalsystem,ortransmitted,in anyformorbyanymeans,electronic,mechanical,photocopying,recordingorotherwise,exceptaspermitted bytheUKCopyright,DesignsandPatentsAct1988,withoutthepriorpermissionofthepublisher. Wileyalsopublishesitsbooksinavarietyofelectronicformats. Somecontentthatappearsinprintmaynotbe availableinelectronicbooks. Designationsusedbycompaniestodistinguishtheirproductsareoftenclaimedastrademarks.Allbrandnames andproductnamesusedinthisbookaretradenames,servicemarks,trademarksorregisteredtrademarksof theirrespectiveowners.Thepublisherisnotassociatedwithanyproductorvendormentionedinthisbook. Thispublicationisdesignedtoprovideaccurateandauthoritativeinformationinregardtothesubjectmattercovered. Itissoldontheunderstandingthatthepublisherisnotengagedinrenderingprofessionalservices.Ifprofessional adviceorotherexpertassistanceisrequired,theservicesofacompetentprofessionalshouldbesought. LibraryofCongressCataloging-in-PublicationData LTEself-organisingnetworks(SON):networkmanagementautomationforoperationalefficiency/editedby SeppoH€am€al€ainen,HenningSanneck,CinziaSartori. p.cm. Includesbibliographicalreferencesandindex. ISBN978-1-119-97067-5(cloth) 1. Self-organisingnetworks. I. Ha¨ma¨la¨inen,Seppo,1969– II. Sanneck,Henning,1968– III. Sartori,Cinzia,1960– TK7872.D48L742012 6810.2–dc23 2011032030 AcataloguerecordforthisbookisavailablefromtheBritishLibrary. PrintISBN:9781119970675 Setin10/12ptTimesbyThomsonDigital,Noida,India PrintedandBoundinGreatBritainbyAntonyRoweLtd,Chippenham,Wiltshire. To Leevi, Lina-Maria and Terja In memory of Dr.-Ing. Hugo Sanneck (1932-2011) To Nikos and Marika 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 ConventionalNetworkOperation toSON 6 1.2.1 Automationof the Network Rollout 9 1.2.2 Automationof Network Optimisation andTroubleshooting 10 1.2.3 SON Characteristics and Challenges 11 References 12 2. LTE Overview 13 2.1 Introduction toLTE andSAE 13 2.1.1 3GPP Structure, Timeline and LTE Specifications 14 2.1.2 LTE Requirements 16 2.1.3 System ArchitectureOverview 16 2.1.4 Evolved UTRAN 18 2.1.5 E-UTRAN Functional Elements 19 2.1.6 Evolved Packet Core 21 2.1.7 Voice over LTE(VoLTE) 24 2.1.8 LTE-Advanced 24 2.1.9 Network Management 30 2.2 LTE Radio Access Network Scenariosand Their Evolution 33 2.2.1 LTE RadioCoverage 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 and3GPP SON Use Cases 42 viii Contents 3.2.1 Operational Use Cases 42 3.2.2 NGMN SON Use Casesand 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 ComputingandAutonomic Management 55 3.3.3 SON ResearchProjects 57 3.4 Architecture 60 3.4.1 Use-Case Related Criteria 62 3.4.2 System-Level Criteria 64 3.5 BusinessValue 65 3.5.1 The Economicsof eNB Sites 65 3.5.2 General Mode ofOperation ofSON 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 Transitionof OperationalProcessestoSON 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 GenerationofInitial Transmission Parameters 106 4.2.2 Physical Cell-IDAllocation 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 RobustnessOptimisation 136 5.1.1 Goals ofMRO 136 5.1.2 Cell Changes and Interference Challenges 137 5.1.3 MRO RelevantParameters 140 5.1.4 Causes for MobilityProblems 144 5.1.5 MRO Solutions 146 5.1.6 MROTime Scales 151 5.1.7 MRO Performance 152 Contents ix 5.2 MobilityLoad Balancingand TrafficSteering 157 5.2.1 Introduction toTrafficSteering 157 5.2.2 SON Policies for Mobility Load Balancing 159 5.2.3 ATheoretical ViewofLoadBalancing 160 5.2.4 Standardised Features and Procedures toDirect UEs tothe DesiredLayer 166 5.2.5 Exemplary Results ofMLB 182 5.2.6 UplinkLoadBalancing 189 5.2.7 Interactions Between TS/MLB and MRO 190 5.3 EnergySaving 193 5.3.1 Introduction 193 5.3.2 Requirements 195 5.3.3 Energy SavingManagement 195 5.3.4 eNB OverlaidScenario 196 5.3.5 Capacity-Limited Network 198 5.3.6 Equipment/Local ES 200 5.3.7 Example Scenarios andExpected Gains 201 5.3.8 Summary 204 5.4 Coverage andCapacity Optimisation 204 5.4.1 CCO with AdaptiveAntennas 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 RACHConfiguration 219 5.5.4 RACH/PRACH ConfigurationExample 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 6. Self-Healing 235 6.1 Introduction 236 6.1.1 3GPP Use Cases 236 6.1.2 3GPP Self-Healing Process andits Management 237 6.1.3 Cell DegradationManagement 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 x Contents 6.3.3 Case Based Reasoning 253 6.3.4 NeuralNetworks 255 6.3.5 Active Measurements 256 6.3.6 Prediction 257 6.4 Cell Outage Compensation 259 6.4.1 Activation ofCell Outage Compensation 260 6.4.2 MeansofCellOutageCompensation 260 6.4.3 Interaction between Cell Outage Compensation and Self-Configuration Functions 263 References 264 7. Supporting Function: Minimisation of Drive Tests (MDT) 267 7.1 Introduction 267 7.1.1 General 267 7.1.2 History and Background 269 7.2 Relationto SON 272 7.3 Requirements 273 7.4 Use Cases 275 7.4.1 Operator Scenarios 276 7.4.2 Coverage Optimisation 277 7.4.3 MobilityOptimisation 281 7.4.4 Capacity Optimisation 281 7.4.5 Parameterisation for Common Channels 282 7.4.6 QoS Verification 282 7.5 OverallArchitecture 283 7.6 Managing MDT 285 7.6.1 Subscriberand EquipmentTrace 285 7.6.2 MDT Configuration Parameters 285 7.6.3 Subscription Based MDT 287 7.6.4 Area Based MDT 292 7.6.5 Supporting Functionality inthe Management System 293 7.6.6 MDT Reporting 293 7.7 MDT RadioInterface Procedures 295 7.7.1 Immediate MDT 296 7.7.2 Logged MDT 298 7.7.3 RLF Reporting 303 7.7.4 Measurement Parameters 305 7.7.5 LocationInformation 308 7.8 Conclusion 309 References 310 8. SON for Core Networks 311 8.1 Introduction 311 8.2 SON for Packet Core Networks 311 8.2.1 PacketCore Element Auto-Configuration 311 8.2.2 Automatic Neighbour Relation 313 Contents xi 8.2.3 S1 Flex(MME Pooling) 314 8.2.4 Signalling Optimisation 315 8.2.5 LatencyOptimisation 317 8.2.6 Fast GatewayConvergencewith Bidirectional ForwardDetection 318 8.2.7 DynamicIP PoolAllocation 318 8.2.8 Energy Saving 319 8.3 SON for Voice Core Networks 319 8.3.1 Voice Over IPQuality Monitoring and Management 319 8.3.2 Resource OptimisationinVoice Core Network 320 References 321 9. SON Operation 322 9.1 SON FunctionInteractions 323 9.1.1 Spatial Characteristic 324 9.1.2 TemporalCharacteristic 324 9.1.3 CategoriesofSON Conflicts 326 9.1.4 Network ParametersRelated toSON Functions 329 9.1.5 Examples for Conflicts between SON Functions 330 9.2 Coordination of SON Functions 334 9.2.1 Basic Optionsfor SON Coordination 334 9.2.2 Goals ofSON Function Coordination 338 9.2.3 SON Coordination FunctionConcept 340 9.2.4 Coordination Schemes 346 9.2.5 Related Work 352 9.2.6 SON Function CoordinationExample 352 9.3 Conclusions 355 References 356 10. SON for Heterogeneous Networks (HetNet) 357 10.1 Introduction 357 10.2 Standardisationand Network Architecture 359 10.2.1 Network Architecture for HetNet 361 10.3 Self-Configuration 362 10.3.1 Auto-Connectivityand -Commissioning 363 10.3.2 AutomaticSite Identificationand Hardware-to-SiteMapping 364 10.3.3 AutomaticNeighbour Relations (ANR) 365 10.4 Self-Optimisation: Interference Management 365 10.4.1 Interference Characteristics inHetNet Scenarios 365 10.4.2 Basic Interference Management Techniques 366 10.4.3 Scenarios with Macro eNBs and Micro/PicoeNBs 369 10.4.4 Enhanced Time-DomainInterference Management: eICIC 370 10.4.5 Outlookon FurtherInterference Management Innovations 374 xii Contents 10.5 Self-Optimisation: Mobility Aspects; MROand TrafficSteering 375 10.5.1 MobilityRobustnessOptimisation 375 10.5.2 Multi-LayerTrafficSteeringandLoadBalancing 377 10.5.3 IEEE 802.11 (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 FutureOAMSystems 381 11.2 CognitiveRadio Networks (CRN) 381 11.2.1 FromSON to CRN 381 11.2.2 Definitions 382 11.2.3 Framework 383 11.2.4 ArtificialIntelligence 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