Christopher Cox / Кристофер Кох - An Introduction to 5G, 2nd Edition / Введение в сети 5G, 2-е издание [2025, PDF, ENG]

Contents
Preface xxiii
Acknowledgements xxv
List of Abbreviations xxvii
1 Introduction 1
1.1 Architecture of a Mobile Telecommunication System 1
1.1.1 High-level Architecture 1
1.1.2 Internal Architecture of the Mobile 2
1.1.3 Architecture of the Radio Access Network 2
1.1.4 Coverage and Capacity 3
1.1.5 Architecture of the Core Network 4
1.1.6 Communication Protocols 4
1.2 History of Mobile Telecommunications 5
1.2.1 Introduction 5
1.2.2 Global System for Mobile Communications (GSM) 6
1.2.3 Universal Mobile Telecommunication System (UMTS) 6
1.2.4 Long-term Evolution (LTE) 7
1.2.5 LTE-Advanced 7
1.2.6 LTE-Advanced Pro 8
1.2.7 Other Mobile Communication Systems 8
1.2.8 Early Research into 5G 9
1.3 Technologies for 5G 9
1.3.1 Network Function Virtualization 9
1.3.2 Software-defined Networking 10
1.3.3 Network Slicing 10
1.3.4 Technologies for the Radio Access Network 11
1.3.5 Technologies for the Air Interface 12
1.3.6 Artificial Intelligence and Machine Learning 13
1.4 The 3GPP 5G System 13
1.4.1 The 3GPP Specifications for 5G 13
1.4.2 Technical Performance Capabilities 15
1.4.3 High-level Architecture 17
1.4.4 Architectural Options 17
1.5 Enhanced Mobile Broadband 19
1.5.1 eMBB Applications 19
vii
1.5.2 The Market for eMBB 19
1.6 Massive Machine-type Communications 21
1.6.1 mMTC Applications 21
1.6.2 The Market for MTC 22
1.7 Ultra-reliable Low-latency Communication 23
1.7.1 URLLC Applications 23
1.7.2 The Industrial Internet of Things 23
1.7.3 Vehicle-to-everything Communication 24
1.7.4 Extended Reality and Media 24
References 24
2 Architecture of the Core Network 29
2.1 The Evolved Packet Core 29
2.1.1 Release 8 Architecture 29
2.1.2 Control and User Plane Separation 30
2.2 The 5G Core Network 31
2.2.1 Representation Using Reference Points 31
2.2.2 Representation Using Service-based Interfaces 32
2.2.3 Data Transport 33
2.2.4 Roaming Architectures 34
2.2.5 Data Storage Architectures 36
2.3 Network Areas and Identities 36
2.3.1 Network Identities 36
2.3.2 AMF Areas and Identities 37
2.3.3 UE Identities 37
2.3.4 UE Registration Areas 38
2.4 State Diagrams 38
2.4.1 Registration Management 38
2.4.2 Connection Management 39
2.5 Network Slicing 39
2.5.1 Architecture 39
2.5.2 Identification 40
2.5.3 Slice-specific Attributes 41
2.6 Non-3GPP Access to the 5G Core 42
2.6.1 Untrusted Non-3GPP Access 42
2.6.2 Non-3GPP Access Enhancements 43
2.7 Signalling Protocols 43
2.7.1 Signalling Protocol Architecture 43
2.7.2 Example Signalling Procedures 44
2.8 The Hypertext Transfer Protocol 45
2.8.1 HTTP/1.1 and HTTP/2 45
2.8.2 Representational State Transfer 45
2.8.3 The HTTP/2 Data Layer 46
2.8.4 JavaScript Object Notation (JSON) 47
2.9 Example Network Function Services 48
2.9.1 Network Function Service Registration 48
2.9.2 Network Function Service Discovery 49
viii Contents
2.9.3 Network Function Service Subscription and Notification 50
2.9.4 Use of a Service Communication Proxy 51
References 52
3 Architecture of the Radio Access Network 57
3.1 The Evolved UMTS Terrestrial Radio Access Network 57
3.1.1 Release 8 Architecture 57
3.1.2 Carrier Aggregation 58
3.1.3 Dual Connectivity 59
3.2 The Next-generation Node B 60
3.2.1 High-level Architecture 60
3.2.2 Internal Architecture 60
3.2.3 Deployment Options 61
3.3 Architectural Options 62
3.3.1 Multi-radio Dual Connectivity 62
3.3.2 Options 1 and 3: EPC, E-UTRAN and MeNB 63
3.3.3 Options 5 and 7: 5GC, NG-RAN and MeNB 63
3.3.4 Options 2 and 4: 5GC, NG-RAN and MgNB 64
3.3.5 Dual Connectivity and Disaggregation 65
3.3.6 Data Transport 65
3.4 Network Areas and Identities 66
3.4.1 Tracking Areas 66
3.4.2 RAN Areas 67
3.4.3 Cell Identities 67
3.5 RRC State Diagram 67
3.5.1 5G State Diagram 67
3.5.2 Interworking with 4G 68
3.6 Signalling Protocols 69
3.6.1 Signalling Protocol Architecture 69
3.6.2 Signalling Radio Bearers 70
3.7 Open Radio Access Networks 71
3.7.1 O-RAN Architecture 71
3.7.2 O-RAN Use Cases 73
References 73
4 Spectrum, Antennas and Propagation 77
4.1 Radio Spectrum 77
4.1.1 Radio Waves 77
4.1.2 Use of Radio Spectrum 78
4.1.3 Spectrum Allocations for 5G 79
4.2 Antennas and Propagation 79
4.2.1 Antenna Gain 79
4.2.2 Radio Propagation in Free Space 80
4.2.3 Antenna Arrays for 5G 81
4.3 Radio Propagation Issues for Millimetre Waves 82
4.3.1 Diffraction and Reflection 82
4.3.2 Penetration Losses 83
Contents ix
4.3.3 Foliage Losses 84
4.3.4 Atmospheric Losses 85
4.4 Multipath, Fading and Coherence 86
4.4.1 Introduction 86
4.4.2 Angular Spread and Coherence Distance 87
4.4.3 Doppler Spread and Coherence Time 88
4.4.4 Delay Spread and Coherence Bandwidth 89
4.4.5 Channel Reciprocity 90
References 90
5 Digital Signal Processing 93
5.1 Modulation and Demodulation 93
5.1.1 Carrier Signal 93
5.1.2 Modulation 94
5.1.3 The Modulation Process 96
5.1.4 The Demodulation Process 97
5.1.5 Channel Estimation 98
5.1.6 Adaptive Modulation 98
5.2 Radio Transmission in a Mobile Cellular Network 99
5.2.1 Multiplexing and Multiple Access 99
5.2.2 FDD and TDD Modes 99
5.3 Orthogonal Frequency Division Multiple Access 100
5.3.1 Subcarriers 100
5.3.2 The OFDM Transmitter 101
5.3.3 The OFDM Receiver 101
5.3.4 The Fast Fourier Transform 104
5.3.5 Block Diagram of the OFDMA Downlink 104
5.3.6 Block Diagram of the OFDMA Uplink 105
5.4 Other Features of OFDMA 107
5.4.1 Frequency-specific Scheduling 107
5.4.2 Subcarrier Orthogonality 108
5.4.3 Inter-symbol Interference and the Cyclic Prefix 109
5.5 Signal-processing Issues for 5G 111
5.5.1 Power Consumption 111
5.5.2 Timing Jitter and Phase Noise 111
5.5.3 Choice of Symbol Duration and Subcarrier Spacing 112
5.6 Error Management 112
5.6.1 Forward Error Correction 112
5.6.2 Automatic Repeat Request 113
5.6.3 Hybrid ARQ 113
5.6.4 Hybrid ARQ Processes 114
5.6.5 Higher-layer Retransmissions 115
References 116
6 Multiple-antenna Techniques 117
6.1 Beamforming 117
6.1.1 Antenna Arrays 117
x Contents
6.1.2 Array Gain 118
6.1.3 Beam Steering 119
6.2 Beamforming at the gNB 120
6.2.1 Analogue Beam Selection 120
6.2.2 Digital Beamforming 121
6.2.3 Hybrid Beamforming 122
6.2.4 Deployment Scenarios 124
6.3 Beamforming at the Mobile 126
6.4 Beam Management 127
6.4.1 Reference Signals 127
6.4.2 Cell Acquisition 128
6.4.3 Analogue Beam Selection 128
6.4.4 Analogue Beam Pair Selection 129
6.4.5 Digital Beam Management 129
6.5 Spatial Multiplexing 130
6.5.1 Principles of Spatial Multiplexing 130
6.5.2 Coherence Issues 131
6.5.3 Matrix Representation 132
6.6 Multiple-user MIMO 133
6.6.1 Uplink Multiple-user MIMO 133
6.6.2 Downlink Multiple-user MIMO 135
6.6.3 Management of Multiple-user MIMO 135
6.6.4 Mathematical Details 136
6.7 Massive MIMO 137
6.7.1 Architecture 137
6.7.2 Benefits 138
6.8 Single-user MIMO 139
6.8.1 Principles of Single-user MIMO 139
6.8.2 Single-user MIMO in a Sparse Multipath Environment 140
6.8.3 Management of Single-user MIMO 141
6.8.4 Mathematical Details 141
6.9 Multipoint Transmission and Reception 143
References 144
7 Architecture of the 5G New Radio 145
7.1 Air Interface Protocol Stack 145
7.1.1 5G Protocol Stack 145
7.1.2 Midhaul Split Point 147
7.1.3 Dual Connectivity 147
7.1.4 Channels and Signals 148
7.1.5 Information Flows 148
7.2 Frequency Bands and Combinations 152
7.2.1 Frequency Bands 152
7.2.2 Band Combinations 155
7.2.3 Bandwidth Classes 156
7.3 Frequency Domain Structure 156
7.3.1 Numerologies 156
Contents xi
7.3.2 Transmission Bandwidth Configuration 157
7.3.3 Global and Channel Frequency Rasters 158
7.3.4 Common Resource Blocks 159
7.3.5 Bandwidth Parts 160
7.3.6 Virtual and Physical Resource Blocks 160
7.4 Time Domain Structure 161
7.4.1 Frame Structure 161
7.4.2 Timing Advance 163
7.4.3 TDD Configurations 163
7.4.4 Slot Format Combinations 164
7.4.5 Resource Grid 165
7.4.6 Dynamic Spectrum Sharing 165
7.5 Multiple Antennas 166
7.5.1 Antenna Ports 166
7.5.2 Relationships between Antenna Ports 167
7.6 Data Transmission 167
7.6.1 Transport Channel Processing 167
7.6.2 Physical Channel Processing 168
7.6.3 Analogue Processing 170
7.6.4 Fronthaul Split Point 170
References 171
8 Cell Acquisition 175
8.1 Acquisition Procedure 175
8.1.1 Introduction 175
8.1.2 Non-standalone Operation 176
8.1.3 Standalone Operation 177
8.2 Resource Mapping 177
8.2.1 SS/PBCH Blocks 177
8.2.2 Transmission Frequency 178
8.2.3 Transmission Timing 178
8.3 Acquisition of the SS/PBCH Block 180
8.3.1 Primary Synchronization Signal 180
8.3.2 Secondary Synchronization Signal 180
8.3.3 Demodulation Reference Signal for the PBCH 181
8.3.4 Physical Broadcast Channel 181
8.4 System Information 181
8.4.1 Master Information Block 181
8.4.2 System Information Block 1 182
8.4.3 Other System Information Blocks 182
8.4.4 Transmission and Reception of the System Information 182
References 184
9 Random Access 187
9.1 Physical Random Access Channel 187
9.1.1 PRACH Formats 187
9.1.2 Generation of the PRACH Preamble 189
xii Contents
9.1.3 Resource Mapping 190
9.2 Random Access Procedure 190
9.2.1 Random Access Preamble 190
9.2.2 Random Access Response 191
9.2.3 Message 3 192
9.2.4 Contention Resolution 192
9.3 Variations on the Random Access Procedure 193
9.3.1 Contention-free Procedure 193
9.3.2 Two-step Procedure 193
References 194
10 Link Adaptation 197
10.1 CSI Reference Signals 197
10.1.1 Transmission and Reception 197
10.1.2 Resource Mapping 198
10.1.3 CSI-RS Resources 199
10.1.4 CSI-RS Resource Sets 199
10.2 Channel State Information 201
10.2.1 Introduction 201
10.2.2 CSI-RS and SS/PBCH Block Resource Indicators 201
10.2.3 Layer 1 RSRP and SINR 201
10.2.4 Rank Indication 201
10.2.5 Precoding Matrix Indicator 201
10.2.6 Channel Quality Indicator 203
10.2.7 Layer Indicator 204
10.2.8 Time Domain Channel Property 204
10.2.9 CSI Reporting 205
10.3 Physical Uplink Control Channel 205
10.3.1 Introduction 205
10.3.2 PUCCH Formats 206
10.3.3 PUCCH Resources 207
10.4 Sounding 208
10.4.1 Transmission and Reception 208
10.4.2 Resource Mapping 208
10.4.3 SRS Resources 209
References 210
11 Data Transmission and Reception 213
11.1 Introduction 213
11.1.1 Data Transmission Procedure 213
11.1.2 Downlink Control Information 214
11.1.3 Radio Network Temporary Identifiers 214
11.2 Transmission and Reception of the PDCCH 216
11.2.1 Transmission of the PDCCH 216
11.2.2 Control Resource Sets 217
11.2.3 Search Spaces 218
11.2.4 Reception of the PDCCH 218
Contents xiii
11.3 Scheduling Messages 219
11.3.1 DCI Formats 0_0 and 1_0 219
11.3.2 Time Domain Resource Assignment 219
11.3.3 Frequency Domain Resource Assignment 221
11.3.4 Modulation and Coding Scheme 222
11.3.5 Other Fields 222
11.3.6 Other Scheduling Formats 223
11.4 Transmission and Reception of the PUSCH and PDSCH 223
11.4.1 Transport Channel Processing 223
11.4.2 Physical Channel Processing 224
11.4.3 Downlink MIMO 225
11.4.4 Uplink Codebook-based MIMO 226
11.4.5 Uplink Non-codebook-based MIMO 226
11.5 Reference Signals 226
11.5.1 Demodulation Reference Signals 226
11.5.2 Phase-tracking Reference Signals 228
11.6 Hybrid ARQ Acknowledgements 228
11.6.1 Downlink Acknowledgements of Uplink Data 228
11.6.2 Uplink Acknowledgements of Downlink Data 229
11.6.3 Timing of Uplink Acknowledgements 229
11.7 Related Procedures 230
11.7.1 Scheduling Requests 230
11.7.2 Semi-persistent and Configured Scheduling 230
11.7.3 Slot Format Indications 231
11.7.4 Pre-emption Indications 231
11.7.5 Transmit Power Control Commands 232
11.7.6 Discontinuous Reception in RRC_IDLE and RRC_INACTIVE 232
11.7.7 Discontinuous Reception in RRC_CONNECTED 233
11.7.8 Dynamic Spectrum Sharing 233
11.8 Performance of 5G 234
11.8.1 Peak Data Rate 234
11.8.2 Typical Cell Capacity 236
References 238
12 Air Interface Layer 2 241
12.1 Medium Access Control 241
12.1.1 Protocol Architecture 241
12.1.2 Scheduling 241
12.1.3 Logical Channel Prioritization 242
12.1.4 Multiplexing and De-multiplexing 243
12.1.5 MAC Control Elements 243
12.2 Radio Link Control 245
12.2.1 Protocol Architecture 245
12.2.2 Transparent Mode 245
12.2.3 Unacknowledged Mode 246
12.2.4 Acknowledged Mode 247
xiv Contents
12.3 Packet Data Convergence Protocol 249
12.3.1 Protocol Architecture 249
12.3.2 Transmission and Reception 249
12.3.3 PDCP Duplication 250
12.3.4 Prevention of Packet Loss during a Change of Node 250
12.3.5 Header and Data Compression 251
12.4 Service Data Adaptation Protocol 251
References 252
13 Registration Procedures 253
13.1 Power-on Sequence 253
13.2 Network and Cell Selection 254
13.2.1 Network Selection 254
13.2.2 Cell Selection 255
13.3 RRC Connection Establishment 256
13.3.1 RRC Connection Establishment with a gNB 256
13.3.2 Initial UE Message 257
13.3.3 RRC Connection Establishment with an eNB 258
13.4 Registration Procedure 258
13.4.1 Registration Without AMF Change 258
13.4.2 Registration with a New AMF 260
13.4.3 Registration with AMF Re-allocation 262
13.5 Deregistration Procedure 263
References 264
14 Security 267
14.1 Security Principles 267
14.2 Network Access Security 268
14.2.1 Network Access Security Architecture 268
14.2.2 Key Hierarchy 269
14.3 Network Access Security Procedures 270
14.3.1 Subscription Concealed Identifier 270
14.3.2 Authentication and Key Agreement 270
14.3.3 Activation of Non-access Stratum Security 273
14.3.4 Activation of Access Stratum Security 273
14.3.5 Key Handling during Mobility 274
14.3.6 Key Handling during State Transitions 274
14.3.7 Ciphering 275
14.3.8 Integrity Protection 275
14.4 Network Domain Security 276
14.4.1 Network Domain Security Architecture 276
14.4.2 Network Domain Security Protocols 276
14.5 Service-based Architecture Domain Security 278
14.5.1 Security Architecture 278
14.5.2 Initial Handshake Procedures over N32-c 279
14.5.3 Forwarding of JOSE Protected Messages over N32-f 279
References 280
Contents xv
15 Session Management, Policy and Charging 283
15.1 Types of PDU Session 283
15.1.1 IP PDU Sessions 283
15.1.2 Ethernet PDU Sessions 284
15.1.3 Unstructured PDU Sessions 284
15.2 Quality of Service 285
15.2.1 Packet Flows, Service Data Flows and QoS Flows 285
15.2.2 QoS Parameters 286
15.2.3 QoS Parameters for PDU Sets 290
15.2.4 Charging Parameters 290
15.3 Implementation of PDU Sessions 290
15.3.1 Bearers and Tunnels 290
15.3.2 User Plane Protocols 291
15.3.3 End-to-end Protocol Stack 292
15.3.4 Multiple PDU Session Anchors 293
15.3.5 PDU Session Anchor Relocation 294
15.4 Policy and Charging Control Architecture 295
15.4.1 High-level Architecture 295
15.4.2 Northbound API 297
15.4.3 Charging and Billing System 297
15.5 PDU Session Management Procedures 298
15.5.1 PDU Session Establishment 298
15.5.2 Interactions with the Policy and Charging Control System 300
15.5.3 Quality of Service Request 302
15.5.4 Addition of a PDU Session Anchor 303
15.5.5 PDU Session Release 305
References 305
16 Mobility Management in RRC_CONNECTED 309
16.1 Introduction to RRC_CONNECTED 309
16.1.1 Principles 309
16.1.2 Dual Connectivity 310
16.1.3 PDU Sessions 310
16.2 Measurement Configuration and Reporting 310
16.2.1 Measurement Configuration and Reporting Procedure 310
16.2.2 Measurement Objects 312
16.2.3 Reporting Configurations 312
16.2.4 Measurement Gaps 314
16.2.5 Measurement Reporting 315
16.3 Handover Procedures 315
16.3.1 Xn-based Handover Procedure 315
16.3.2 Path Switch Procedure 317
16.3.3 NG-based Handover Procedure 318
16.3.4 Handovers between a gNB and an ng-eNB 319
16.3.5 Handovers with no Change of Central Unit 319
16.3.6 Handover Optimizations 319
16.4 Dual Connectivity Procedures 320
xvi Contents
16.4.1 Secondary Node Addition 320
16.4.2 QoS Flow Mobility Procedure 322
16.4.3 Other Dual Connectivity Procedures 323
16.5 State Transitions out of RRC_CONNECTED 323
16.5.1 Core Network Assistance Information 323
16.5.2 Transition to RRC_IDLE 324
16.5.3 Transition to RRC_INACTIVE 325
References 326
17 Mobility Management in RRC_IDLE 329
17.1 Introduction to RRC_IDLE 329
17.1.1 Principles 329
17.1.2 Inactive PDU Sessions 330
17.2 Cell Reselection Procedures 330
17.2.1 Introduction 330
17.2.2 Intra-frequency Measurement Triggering 331
17.2.3 Intra-frequency Cell Reselection 331
17.2.4 Inter-frequency Measurement Triggering 332
17.2.5 Inter-frequency Cell Reselection 332
17.2.6 Fast-moving Mobiles 333
17.3 Registration Updating 333
17.3.1 Registration Update Procedure 333
17.3.2 Network Reselection 334
17.4 State Transitions out of RRC_IDLE 335
17.4.1 Mobile-triggered Service Request 335
17.4.2 Network-triggered Service Request 336
References 338
18 Mobility Management in RRC_INACTIVE 339
18.1 Introduction to RRC_INACTIVE 339
18.1.1 Principles 339
18.1.2 Suspended PDU Sessions 340
18.2 Mobility Management 341
18.2.1 RAN-based Notification Area Update 341
18.2.2 Registration Update 342
18.2.3 Mobility between a gNB and an ng-eNB 343
18.3 State Transitions 343
18.3.1 Transition to RRC_IDLE 343
18.3.2 Mobile-triggered Resumption of the RRC Connection 343
18.3.3 Network-triggered Resumption of the RRC Connection 345
18.4 Small Data Transmission in RRC_INACTIVE 347
References 347
19 Inter-operation with the Evolved Packet Core 349
19.1 Inter-operation Architectures 349
19.1.1 Migration Architecture 349
19.1.2 Interworking Architecture 350
Contents xvii
19.1.3 Signalling Protocols 351
19.1.4 State Diagrams 352
19.1.5 UDM-HSS Interworking 352
19.2 Registration Modes 353
19.2.1 Single Registration Mode 353
19.2.2 Dual Registration Mode 353
19.2.3 Temporary Identities 353
19.3 Use of the Migration Architecture 353
19.3.1 Configuration Procedures 353
19.3.2 Mobility in RRC_IDLE 354
19.3.3 RRC Release with Redirection from RRC_CONNECTED 355
19.4 Interworking Without N26 356
19.4.1 Configuration Procedures 356
19.4.2 Mobility in Single Registration Mode 356
19.4.3 Mobility in Dual Registration Mode 357
19.5 Interworking with N26 357
19.5.1 Configuration Procedures 357
19.5.2 Mobility in RRC_IDLE 357
19.5.3 Handovers in RRC_CONNECTED 359
References 361
20 Foundations of 5G-Advanced 363
20.1 Location Services 363
20.1.1 Introduction 363
20.1.2 System Architecture 364
20.1.3 Positioning Reference Signal 365
20.1.4 NR Position Estimation 365
20.2 Integrated Access and Backhaul 366
20.2.1 Introduction 366
20.2.2 Underlying Architecture 367
20.2.3 Architectural Refinements 367
20.2.4 Communication Protocols 368
20.2.5 Mobility 369
20.2.6 Air Interface 369
20.2.7 Repeaters and Relays 370
20.2.8 Wireless Access Backhaul 371
20.3 Use of Unlicensed Spectrum 371
20.3.1 Introduction 371
20.3.2 Spectrum 372
20.3.3 Dynamic Channel Access 373
20.3.4 Shared Channel Occupancy 375
20.3.5 Semi-Static Channel Access 375
20.3.6 Additional Procedures 375
20.4 Multicast and Broadcast Services 376
20.4.1 Introduction 376
20.4.2 MBS Service 376
20.4.3 MBS Architecture 378
xviii Contents
20.4.4 MBS User Service 378
20.4.5 Enhancements to the 5G New Radio 379
20.5 Non-terrestrial Networks 380
20.5.1 Introduction 380
20.5.2 Non-terrestrial Platforms 380
20.5.3 Radio Access Architecture 380
20.5.4 Enhancements to the 5G New Radio 382
20.5.5 Mobility Management 383
20.5.6 Satellite Backhaul 384
20.6 Network Automation, Artificial Intelligence and Machine Learning 385
20.6.1 TDD Interference Management 385
20.6.2 Self-Optimizing Networks 385
20.6.3 AI/ML in the Radio Access Network 386
20.6.4 Network Data Analytics 387
20.7 Service Enabler Architecture Layer 388
References 389
21 The Internet of Things 395
21.1 Time-sensitive Communications 395
21.1.1 Cyber-physical Control Applications 395
21.1.2 Example Applications 396
21.1.3 Time Synchronization 397
21.1.4 Time Synchronization Architecture for 5G 397
21.1.5 Architecture for Network Exposure 398
21.1.6 Signalling Procedures 399
21.2 Non-public Networks 400
21.2.1 The Market for NPNs 400
21.2.2 5G Support for NPNs 400
21.3 5G Virtual Networks 402
21.3.1 Capabilities 402
21.3.2 Virtual Network Groups 402
21.3.3 Data Transport 403
21.4 Edge Computing 404
21.4.1 Requirements and Applications 404
21.4.2 Architecture 404
21.4.3 EAS Deployment Information 405
21.4.4 EAS Discovery Procedure 406
21.4.5 Edge Relocation Procedure 407
21.4.6 Edge Enabler Layer 408
21.5 Massive Machine-type Communications 410
21.5.1 Air Interfaces for mMTC 410
21.5.2 Reduced Capability NR Devices 411
21.5.3 Enhancements to the 5G Core Network 412
21.6 Messaging Services 412
21.6.1 Short Message Service 412
21.6.2 5G Messaging Service 413
References 414
Contents xix
22 Vehicle Communications and the Sidelink 417
22.1 Vehicle-to-Everything (V2X) Communications 417
22.1.1 V2X Services 417
22.1.2 V2X Architecture 418
22.1.3 V2X Identities 419
22.1.4 Sidelink Quality of Service 419
22.1.5 V2X Policy 420
22.1.6 Sidelink Security 422
22.1.7 V2X Layer 422
22.1.8 V2X Application Enabler Layer 423
22.2 Uncrewed Aerial Vehicles 423
22.2.1 UAV Support in 5G 423
22.2.2 UAV Architecture 424
22.3 Proximity-based Services 425
22.3.1 Applications 425
22.3.2 ProSe Architecture 426
22.3.3 ProSe Relays 428
22.3.4 ProSe Identities 429
22.3.5 ProSe Policy 430
22.3.6 Additional Security Procedures 430
22.4 Architecture of the Sidelink 430
22.4.1 Protocol Stack 430
22.4.2 Channels, Signals and Information Flows 430
22.4.3 Physical Layer 434
22.4.4 Resource Pools 434
22.5 Sidelink Timing Synchronization 435
22.5.1 Acquisition of Timing Synchronization 435
22.5.2 Transmission of Sidelink Synchronization Blocks 436
22.6 Sidelink Transmission and Reception 437
22.6.1 Signalling Procedure 437
22.6.2 First-stage SCI 438
22.6.3 Second-stage SCI 439
22.6.4 Resource Mapping 440
22.6.5 Hybrid ARQ Acknowledgements 441
22.7 Access Stratum Procedures for the Sidelink 442
22.7.1 Resource Allocation by the NG-RAN 442
22.7.2 Autonomous Resource Selection 442
22.7.3 Conflict Resolution 443
22.7.4 Channel State Information 443
22.7.5 Sidelink Operation in Unlicensed Spectrum 443
22.7.6 Ranging-based Services and Sidelink Positioning 444
22.8 Operation of Sidelink Communication 444
22.8.1 Broadcast and Groupcast Vehicle Communication 444
22.8.2 Unicast Vehicle Communication 445
22.8.3 Aircraft and ProSe Direct Communication 446
22.9 Operation of ProSe Direct Discovery 447
22.9.1 Model A Procedure for Open Direct Discovery 447
xx Contents
22.9.2 ProSe Direct Discovery Variations 448
References 448
23 From 5G-Advanced to 6G 453
23.1 Release 19 453
23.1.1 AI/ML for the Air Interface 453
23.1.2 Integrated Sensing and Communication 454
23.1.3 Ambient Internet of Things 454
23.1.4 Low-power Wake-up Signal and Receiver 455
23.1.5 Sub-band Non-overlapping Full Duplex Transmission 455
23.1.6 Other Topics for Release 19 455
23.2 6G 456
23.2.1 Specification Process 456
23.2.2 Usage Scenarios 457
23.2.3 Applications 457
23.2.4 Spectrum Allocations 458
23.2.5 Technologies 459
23.2.6 Performance Targets for 6G 461
References 461
Further Reading 465
Index 469