An Introduction to LTE: LTE, LTE-Advanced, SAE, VoLTE and 4G Mobile Communications

Following on from the successful first edition (March 2012), this book gives a clear explanation of what LTE does and how it works. The content is expressed at a systems level, offering readers the opportunity to grasp the key factors that make LTE the hot topic amongst vendors and operators across the globe. The book assumes no more than a basic knowledge of mobile telecommunication systems, and the reader is not expected to have any previous knowledge of the complex mathematical operations that underpin LTE. This second edition introduces new material for the current state of the industry, such as the new features of LTE in Releases 11 and 12, notably coordinated multipoint transmission and proximity services; the main short- and long-term solutions for LTE voice calls, namely circuit switched fallback and the IP multimedia subsystem; and the evolution and current state of the LTE market. It also extends some of the material from the first edition, such as inter-operation with other technologies such as GSM, UMTS, wireless local area networks and cdma2000; additional features of LTE Advanced, notably heterogeneous networks and traffic offloading; data transport in the evolved packet core; coverage and capacity estimation for LTE; and a more rigorous treatment of modulation, demodulation and OFDMA. The author breaks down the system into logical blocks, by initially introducing the architecture of LTE, explaining the techniques used for radio transmission and reception and the overall operation of the system, and concluding with more specialized topics such as LTE voice calls and the later releases of the specifications. This methodical approach enables readers to move on to tackle the specifications and the more advanced texts with confidence.

Table of Contents:
Preface xxi Acknowledgements xxiii List of Abbreviations xxv 1 Introduction 1 1.1 Architectural Review of UMTS and GSM 1 1.1.1 High-Level Architecture 1 1.1.2 Architecture of the Radio Access Network 2 1.1.3 Architecture of the Core Network 4 1.1.4 Communication Protocols 5 1.2 History of Mobile Telecommunication Systems 6 1.2.1 From 1G to 3G 6 1.2.2 Third Generation Systems 7 1.3 The Need for LTE 8 1.3.1 The Growth of Mobile Data 8 1.3.2 Capacity of a Mobile Telecommunication System 9 1.3.3 Increasing the System Capacity 10 1.3.4 Additional Motivations 11 1.4 From UMTS to LTE 11 1.4.1 High-Level Architecture of LTE 11 1.4.2 Long-Term Evolution 12 1.4.3 System Architecture Evolution 13 1.4.4 LTE Voice Calls 14 1.4.5 The Growth of LTE 15 1.5 From LTE to LTE-Advanced 16 1.5.1 The ITU Requirements for 4G 16 1.5.2 Requirements of LTE-Advanced 16 1.5.3 4G Communication Systems 16 1.5.4 The Meaning of 4G 17 1.6 The 3GPP Specifications for LTE 17 References 19 2 System Architecture Evolution 21 2.1 High-Level Architecture of LTE 21 2.2 User Equipment 21 2.2.1 Architecture of the UE 21 2.2.2 UE Capabilities 22 2.3 Evolved UMTS Terrestrial Radio Access Network 23 2.3.1 Architecture of the E-UTRAN 23 2.3.2 Transport Network 24 2.3.3 Small Cells and the Home eNB 25 2.4 Evolved Packet Core 25 2.4.1 Architecture of the EPC 25 2.4.2 Roaming Architecture 27 2.4.3 Network Areas 28 2.4.4 Numbering, Addressing and Identification 28 2.5 Communication Protocols 30 2.5.1 Protocol Model 30 2.5.2 Air Interface Transport Protocols 31 2.5.3 Fixed Network Transport Protocols 31 2.5.4 User Plane Protocols 32 2.5.5 Signalling Protocols 33 2.6 Example Signalling Flows 34 2.6.1 Access Stratum Signalling 34 2.6.2 Non-Access Stratum Signalling 35 2.7 Bearer Management 36 2.7.1 The EPS Bearer 36 2.7.2 Default and Dedicated Bearers 37 2.7.3 Bearer Implementation Using GTP 38 2.7.4 Bearer Implementation Using GRE and PMIP 39 2.7.5 Signalling Radio Bearers 39 2.8 State Diagrams 40 2.8.1 EPS Mobility Management 40 2.8.2 EPS Connection Management 40 2.8.3 Radio Resource Control 41 2.9 Spectrum Allocation 43 References 45 3 Digital Wireless Communications 49 3.1 Radio Transmission and Reception 49 3.1.1 Carrier Signal 49 3.1.2 Modulation Techniques 50 3.1.3 The Modulation Process 51 3.1.4 The Demodulation Process 53 3.1.5 Channel Estimation 55 3.1.6 Bandwidth of the Modulated Signal 55 3.2 Radio Transmission in a Mobile Cellular Network 56 3.2.1 Multiple Access Techniques 56 3.2.2 FDD and TDD Modes 56 3.3 Impairments to the Received Signal 58 3.3.1 Propagation Loss 58 3.3.2 Noise and Interference 58 3.3.3 Multipath and Fading 58 3.3.4 Inter-symbol Interference 60 3.4 Error Management 61 3.4.1 Forward Error Correction 61 3.4.2 Automatic Repeat Request 62 3.4.3 Hybrid ARQ 63 References 65 4 Orthogonal Frequency Division Multiple Access 67 4.1 Principles of OFDMA 67 4.1.1 Sub-carriers 67 4.1.2 The OFDM Transmitter 68 4.1.3 The OFDM Receiver 70 4.1.4 The Fast Fourier Transform 72 4.1.5 Block Diagram of OFDMA 72 4.1.6 Details of the Fourier Transform 73 4.2 Benefits and Additional Features of OFDMA 75 4.2.1 Orthogonal Sub-carriers 75 4.2.2 Choice of Sub-carrier Spacing 75 4.2.3 Frequency-Specific Scheduling 77 4.2.4 Reduction of Inter-symbol Interference 78 4.2.5 Cyclic Prefix Insertion 79 4.2.6 Choice of Symbol Duration 80 4.2.7 Fractional Frequency Re-use 81 4.3 Single Carrier Frequency Division Multiple Access 82 4.3.1 Power Variations From OFDMA 82 4.3.2 Block Diagram of SC-FDMA 83 References 85 5 Multiple Antenna Techniques 87 5.1 Diversity Processing 87 5.1.1 Receive Diversity 87 5.1.2 Closed Loop Transmit Diversity 88 5.1.3 Open Loop Transmit Diversity 89 5.2 Spatial Multiplexing 90 5.2.1 Principles of Operation 90 5.2.2 Open Loop Spatial Multiplexing 92 5.2.3 Closed Loop Spatial Multiplexing 94 5.2.4 Matrix Representation 96 5.2.5 Implementation Issues 99 5.2.6 Multiple User MIMO 99 5.3 Beamforming 101 5.3.1 Principles of Operation 101 5.3.2 Beam Steering 102 5.3.3 Downlink Multiple User MIMO Revisited 103 References 104 6 Architecture of the LTE Air Interface 105 6.1 Air Interface Protocol Stack 105 6.2 Logical, Transport and Physical Channels 107 6.2.1 Logical Channels 107 6.2.2 Transport Channels 107 6.2.3 Physical Data Channels 108 6.2.4 Control Information 109 6.2.5 Physical Control Channels 110 6.2.6 Physical Signals 111 6.2.7 Information Flows 111 6.3 The Resource Grid 111 6.3.1 Slot Structure 111 6.3.2 Frame Structure 113 6.3.3 Uplink Timing Advance 115 6.3.4 Resource Grid Structure 116 6.3.5 Bandwidth Options 117 6.4 Multiple Antenna Transmission 118 6.4.1 Downlink Antenna Ports 118 6.4.2 Downlink Transmission Modes 119 6.5 Resource Element Mapping 119 6.5.1 Downlink Resource Element Mapping 119 6.5.2 Uplink Resource Element Mapping 121 References 123 7 Cell Acquisition 125 7.1 Acquisition Procedure 125 7.2 Synchronization Signals 126 7.2.1 Physical Cell Identity 126 7.2.2 Primary Synchronization Signal 127 7.2.3 Secondary Synchronization Signal 128 7.3 Downlink Reference Signals 128 7.4 Physical Broadcast Channel 129 7.5 Physical Control Format Indicator Channel 130 7.6 System Information 131 7.6.1 Organization of the System Information 131 7.6.2 Transmission and Reception of the System Information 133 7.7 Procedures after Acquisition 133 References 134 8 Data Transmission and Reception 135 8.1 Data Transmission Procedures 135 8.1.1 Downlink Transmission and Reception 135 8.1.2 Uplink Transmission and Reception 137 8.1.3 Semi Persistent Scheduling 139 8.2 Transmission of Scheduling Messages on the PDCCH 139 8.2.1 Downlink Control Information 139 8.2.2 Resource Allocation 140 8.2.3 Example: DCI Format 1 141 8.2.4 Radio Network Temporary Identifiers 142 8.2.5 Transmission and Reception of the PDCCH 143 8.3 Data Transmission on the PDSCH and PUSCH 144 8.3.1 Transport Channel Processing 144 8.3.2 Physical Channel Processing 146 8.4 Transmission of Hybrid ARQ Indicators on the PHICH 148 8.4.1 Introduction 148 8.4.2 Resource Element Mapping of the PHICH 148 8.4.3 Physical Channel Processing of the PHICH 149 8.5 Uplink Control Information 149 8.5.1 Hybrid ARQ Acknowledgements 149 8.5.2 Channel Quality Indicator 150 8.5.3 Rank Indication 151 8.5.4 Precoding Matrix Indicator 151 8.5.5 Channel State Reporting Mechanisms 151 8.5.6 Scheduling Requests 152 8.6 Transmission of Uplink Control Information on the PUCCH 153 8.6.1 PUCCH Formats 153 8.6.2 PUCCH Resources 154 8.6.3 Physical Channel Processing of the PUCCH 155 8.7 Uplink Reference Signals 155 8.7.1 Demodulation Reference Signal 155 8.7.2 Sounding Reference Signal 156 8.8 Power Control 157 8.8.1 Uplink Power Calculation 157 8.8.2 Uplink Power Control Commands 158 8.8.3 Downlink Power Control 159 8.9 Discontinuous Reception 159 8.9.1 Discontinuous Reception and Paging in RRC_IDLE 159 8.9.2 Discontinuous Reception in RRC_CONNECTED 159 References 161 9 Random Access 163 9.1 Transmission of Random Access Preambles on the PRACH 163 9.1.1 Resource Element Mapping 163 9.1.2 Preamble Sequence Generation 165 9.1.3 Signal Transmission 165 9.2 Non-Contention-Based Procedure 166 9.3 Contention-Based Procedure 167 References 169 10 Air Interface Layer 2 171 10.1 Medium Access Control Protocol 171 10.1.1 Protocol Architecture 171 10.1.2 Timing Advance Commands 173 10.1.3 Buffer Status Reporting 173 10.1.4 Power Headroom Reporting 173 10.1.5 Multiplexing and De-multiplexing 174 10.1.6 Logical Channel Prioritization 174 10.1.7 Scheduling of Transmissions on the Air Interface 175 10.2 Radio Link Control Protocol 176 10.2.1 Protocol Architecture 176 10.2.2 Transparent Mode 177 10.2.3 Unacknowledged Mode 177 10.2.4 Acknowledged Mode 178 10.3 Packet Data Convergence Protocol 180 10.3.1 Protocol Architecture 180 10.3.2 Header Compression 180 10.3.3 Prevention of Packet Loss during Handover 182 References 183 11 Power-On and Power-Off Procedures 185 11.1 Power-On Sequence 185 11.2 Network and Cell Selection 187 11.2.1 Network Selection 187 11.2.2 Closed Subscriber Group Selection 187 11.2.3 Cell Selection 188 11.3 RRC Connection Establishment 189 11.3.1 Basic Procedure 189 11.3.2 Relationship with Other Procedures 190 11.4 Attach Procedure 191 11.4.1 IP Address Allocation 191 11.4.2 Overview of the Attach Procedure 192 11.4.3 Attach Request 192 11.4.4 Identification and Security Procedures 194 11.4.5 Location Update 195 11.4.6 Default Bearer Creation 196 11.4.7 Attach Accept 197 11.4.8 Default Bearer Update 198 11.5 Detach Procedure 199 References 200 12 Security Procedures 203 12.1 Network Access Security 203 12.1.1 Security Architecture 203 12.1.2 Key Hierarchy 204 12.1.3 Authentication and Key Agreement 205 12.1.4 Security Activation 207 12.1.5 Ciphering 208 12.1.6 Integrity Protection 209 12.2 Network Domain Security 210 12.2.1 Security Protocols 210 12.2.2 Security in the Evolved Packet Core 210 12.2.3 Security in the Radio Access Network 211 References 212 13 Quality of Service, Policy and Charging 215 13.1 Policy and Charging Control 215 13.1.1 Quality of Service Parameters 215 13.1.2 Service Data Flows 217 13.1.3 Charging Parameters 218 13.1.4 Policy and Charging Control Rules 219 13.2 Policy and Charging Control Architecture 219 13.2.1 Basic PCC Architecture 219 13.2.2 Local Breakout Architecture 220 13.2.3 Architecture Using a PMIP Based S5/S8 220 13.2.4 Software Protocols 221 13.3 Session Management Procedures 222 13.3.1 IP-CAN Session Establishment 222 13.3.2 Mobile Originated SDF Establishment 223 13.3.3 Server Originated SDF Establishment 224 13.3.4 Dedicated Bearer Establishment 225 13.3.5 PDN Connectivity Establishment 226 13.3.6 Other Session Management Procedures 228 13.4 Data Transport in the Evolved Packet Core 228 13.4.1 Packet Handling at the PDN Gateway 228 13.4.2 Data Transport Using GTP 229 13.4.3 Differentiated Services 230 13.4.4 Multiprotocol Label Switching 231 13.4.5 Data Transport Using GRE and PMIP 231 13.5 Charging and Billing 231 13.5.1 High Level Architecture 231 13.5.2 Offline Charging 232 13.5.3 Online Charging 233 References 234 14 Mobility Management 237 14.1 Transitions between Mobility Management States 237 14.1.1 S1 Release Procedure 237 14.1.2 Paging Procedure 239 14.1.3 Service Request Procedure 239 14.2 Cell Reselection in RRC_IDLE 241 14.2.1 Objectives 241 14.2.2 Measurement Triggering on the Same LTE Frequency 241 14.2.3 Cell Reselection to the Same LTE Frequency 242 14.2.4 Measurement Triggering on a Different LTE Frequency 243 14.2.5 Cell Reselection to a Different LTE Frequency 244 14.2.6 Fast Moving Mobiles 244 14.2.7 Tracking Area Update Procedure 245 14.2.8 Network Reselection 246 14.3 Measurements in RRC_CONNECTED 247 14.3.1 Objectives 247 14.3.2 Measurement Procedure 247 14.3.3 Measurement Reporting 248 14.3.4 Measurement Gaps 249 14.4 Handover in RRC_CONNECTED 250 14.4.1 X2 Based Handover Procedure 250 14.4.2 Handover Variations 252 References 253 15 Inter-operation with UMTS and GSM 255 15.1 System Architecture 255 15.1.1 Architecture of the 2G/3G Packet Switched Domain 255 15.1.2 S3/S4-Based Inter-operation Architecture 257 15.1.3 Gn/Gp-Based Inter-operation Architecture 258 15.2 Power-On Procedures 259 15.3 Mobility Management in RRC_IDLE 259 15.3.1 Cell Reselection 259 15.3.2 Routing Area Update Procedure 260 15.3.3 Idle Mode Signalling Reduction 262 15.4 Mobility Management in RRC_CONNECTED 262 15.4.1 RRC Connection Release with Redirection 262 15.4.2 Measurement Procedures 264 15.4.3 Optimized Handover 265 References 268 16 Inter-operation with Non-3GPP Technologies 271 16.1 Generic System Architecture 271 16.1.1 Network-Based Mobility Architecture 271 16.1.2 Host-Based Mobility Architecture 273 16.1.3 Access Network Discovery and Selection Function 274 16.2 Generic Signalling Procedures 275 16.2.1 Overview of the Attach Procedure 275 16.2.2 Authentication and Key Agreement 276 16.2.3 PDN Connectivity Establishment 278 16.2.4 Radio Access Network Reselection 280 16.3 Inter-Operation with cdma2000 HRPD 280 16.3.1 System Architecture 280 16.3.2 Preregistration with cdma2000 281 16.3.3 Cell Reselection in RRC_IDLE 282 16.3.4 Measurements and Handover in RRC_CONNECTED 283 References 286 17 Self-Optimizing Networks 289 17.1 Self-Configuration of an eNB 289 17.1.1 Automatic Configuration of the Physical Cell Identity 289 17.1.2 Automatic Neighbour Relations 290 17.1.3 Random Access Channel Optimization 291 17.2 Inter-Cell Interference Coordination 292 17.3 Mobility Management 292 17.3.1 Mobility Load Balancing 292 17.3.2 Mobility Robustness Optimization 293 17.3.3 Energy Saving 295 17.4 Radio Access Network Information Management 295 17.4.1 Introduction 295 17.4.2 Transfer of System Information 296 17.4.3 Transfer of Self-Optimization Data 297 17.5 Drive Test Minimization 297 References 298 18 Enhancements in Release 9 301 18.1 Multimedia Broadcast/Multicast Service 301 18.1.1 Introduction 301 18.1.2 Multicast/Broadcast over a Single Frequency Network 302 18.1.3 Implementation of MBSFN in LTE 302 18.1.4 Architecture of MBMS 304 18.1.5 Operation of MBMS 305 18.2 Location Services 306 18.2.1 Introduction 306 18.2.2 Positioning Techniques 306 18.2.3 Location Service Architecture 307 18.2.4 Location Service Procedures 308 18.3 Other Enhancements in Release 9 309 18.3.1 Dual Layer Beamforming 309 18.3.2 Commercial Mobile Alert System 310 References 310 19 LTE-Advanced and Release 10 313 19.1 Carrier Aggregation 313 19.1.1 Principles of Operation 313 19.1.2 UE Capabilities 314 19.1.3 Scheduling 316 19.1.4 Data Transmission and Reception 316 19.1.5 Uplink and Downlink Feedback 317 19.1.6 Other Physical Layer and MAC Procedures 317 19.1.7 RRC Procedures 317 19.2 Enhanced Downlink MIMO 318 19.2.1 Objectives 318 19.2.2 Downlink Reference Signals 318 19.2.3 Downlink Transmission and Feedback 320 19.3 Enhanced Uplink MIMO 321 19.3.1 Objectives 321 19.3.2 Implementation 321 19.4 Relays 322 19.4.1 Principles of Operation 322 19.4.2 Relaying Architecture 323 19.4.3 Enhancements to the Air Interface 324 19.5 Heterogeneous Networks 324 19.5.1 Introduction 324 19.5.2 Enhanced Inter-Cell Interference Coordination 325 19.5.3 Enhancements to Self-Optimizing Networks 326 19.6 Traffic Offload Techniques 326 19.6.1 Local IP Access 326 19.6.2 Selective IP Traffic Offload 327 19.6.3 Multi-Access PDN Connectivity 327 19.6.4 IP Flow Mobility 329 19.7 Overload Control for Machine-Type Communications 330 References 331 20 Releases 11 and 12 333 20.1 Coordinated Multipoint Transmission and Reception 333 20.1.1 Objectives 333 20.1.2 Scenarios 334 20.1.3 CoMP Techniques 335 20.1.4 Standardization 336 20.1.5 Performance 337 20.2 Enhanced Physical Downlink Control Channel 337 20.3 Interference Avoidance for in Device Coexistence 338 20.4 Machine-Type Communications 339 20.4.1 Device Triggering 339 20.4.2 Numbering, Addressing and Identification 340 20.5 Mobile Data Applications 340 20.6 New Features in Release 12 341 20.6.1 Proximity Services and Device to Device Communications 341 20.6.2 Dynamic Adaptation of the TDD Configuration 342 20.6.3 Enhancements for Machine-Type Communications and Mobile Data 344 20.6.4 Traffic Offloading Enhancements 344 20.7 Release 12 Studies 345 20.7.1 Enhancements to Small Cells and Heterogeneous Networks 345 20.7.2 Elevation Beamforming and Full Dimension MIMO 346 References 346 21 Circuit Switched Fallback 349 21.1 Delivery of Voice and Text Messages over LTE 349 21.1.1 The Market for Voice and SMS 349 21.1.2 Third Party Voice over IP 350 21.1.3 The IP Multimedia Subsystem 351 21.1.4 VoLGA 351 21.1.5 Dual Radio Devices 352 21.1.6 Circuit Switched Fallback 353 21.2 System Architecture 353 21.2.1 Architecture of the 2G/3G Circuit Switched Domain 353 21.2.2 Circuit Switched Fallback Architecture 354 21.3 Attach Procedure 355 21.3.1 Combined EPS/IMSI Attach Procedure 355 21.3.2 Voice Domain Preference and UE Usage Setting 356 21.4 Mobility Management 357 21.4.1 Combined Tracking Area/Location Area Update Procedure 357 21.4.2 Alignment of Tracking Areas and Location Areas 357 21.4.3 Cell Reselection to UMTS or GSM 358 21.5 Call Setup 359 21.5.1 Mobile-Originated Call Setup using RRC Connection Release 359 21.5.2 Mobile Originated Call Setup using Handover 361 21.5.3 Signalling Messages in the Circuit Switched Domain 362 21.5.4 Mobile-Terminated Call Setup 363 21.5.5 Returning to LTE 364 21.6 SMS over SGs 365 21.6.1 System Architecture 365 21.6.2 SMS Delivery 365 21.7 Circuit Switched Fallback to cdma2000 1xRTT 366 21.8 Performance of Circuit Switched Fallback 367 References 368 22 VoLTE and the IP Multimedia Subsystem 371 22.1 Introduction 371 22.1.1 The IP Multimedia Subsystem 371 22.1.2 VoLTE 372 22.1.3 Rich Communication Services 372 22.2 Hardware Architecture of the IMS 373 22.2.1 High-Level Architecture 373 22.2.2 Call Session Control Functions 374 22.2.3 Application Servers 375 22.2.4 Home Subscriber Server 375 22.2.5 User Equipment 375 22.2.6 Relationship with LTE 376 22.2.7 Border Control Functions 377 22.2.8 Media Gateway Functions 378 22.2.9 Multimedia Resource Functions 379 22.2.10 Security Architecture 380 22.2.11 Charging Architecture 380 22.3 Signalling Protocols 381 22.3.1 Session Initiation Protocol 381 22.3.2 Session Description Protocol 382 22.3.3 Other Signalling Protocols 382 22.4 Service Provision in the IMS 382 22.4.1 Service Profiles 382 22.4.2 Media Feature Tags 383 22.4.3 The Multimedia Telephony Service for IMS 383 22.5 VoLTE Registration Procedure 384 22.5.1 Introduction 384 22.5.2 LTE Procedures 384 22.5.3 Contents of the REGISTER Request 385 22.5.4 IMS Registration Procedure 387 22.5.5 Routing of SIP Requests and Responses 388 22.5.6 Third-Party Registration with Application Servers 389 22.5.7 Subscription for Network-Initiated Deregistration 389 22.6 Call Setup and Release 390 22.6.1 Contents of the INVITE Request 390 22.6.2 Initial INVITE Request and Response 391 22.6.3 Acceptance of the Initial INVITE 393 22.6.4 Establishment of a Call to a Circuit Switched Network 396 22.6.5 Call Release 396 22.7 Access Domain Selection 397 22.7.1 Mobile-Originated Calls 397 22.7.2 Mobile-Terminated Calls 398 22.8 Single Radio Voice Call Continuity 398 22.8.1 Introduction 398 22.8.2 SRVCC Architecture 399 22.8.3 Attach, Registration and Call Setup Procedures 400 22.8.4 Handover Preparation 400 22.8.5 Updating the Remote Leg 401 22.8.6 Releasing the Source Leg 403 22.8.7 Handover Execution and Completion 403 22.8.8 Evolution of SRVCC 404 22.9 IMS Centralized Services 405 22.10 IMS Emergency Calls 406 22.10.1 Emergency Call Architecture 406 22.10.2 Emergency Call Setup Procedure 407 22.11 Delivery of SMS Messages over the IMS 408 22.11.1 SMS Architecture 408 22.11.2 Access Domain Selection 409 References 410 23 Performance of LTE and LTE-Advanced 413 23.1 Peak Data Rates of LTE and LTE-Advanced 413 23.1.1 Increase of the Peak Data Rate 413 23.1.2 Limitations on the Peak Data Rate 415 23.2 Coverage of an LTE Cell 416 23.2.1 Uplink Link Budget 416 23.2.2 Downlink Link Budget 418 23.2.3 Propagation Modelling 419 23.2.4 Coverage Estimation 420 23.3 Capacity of an LTE Cell 421 23.3.1 Capacity Estimation 421 23.3.2 Cell Capacity Simulations 422 23.4 Performance of Voice over IP 424 23.4.1 AMR Codec Modes 424 23.4.2 Transmission of AMR Frames on the Air Interface 425 23.4.3 Transmission of AMR Frames in the Fixed Network 426 References 427 Bibliography 429 Index 431

About the Author :
Christopher Cox is a professional technical trainer and consultant in mobile telecommunications. He is an expert in the technical and radio network planning aspects of LTE and UMTS, and regularly delivers training courses about them to audiences drawn from equipment manufacturers, network operators and consultancies worldwide. He has a degree in Physics and a PhD in Radio Astronomy from the University of Cambridge and 20 years’ experience in scientific and technical consultancy, telecommunications and training.