Practical Guide to LTE-A, VoLTE and IoT

Practical Guide to LTE-A, VoLTE and IoT

Practical Guide to LTE-A, VoLTE and IoT

Paving the Way Towards 5G

Ayman Elnashar

Emirates Integrated Telecommunications Company (EITC)

Dubai Media City

Dubai

UAE

Mohamed El-saidny

MediaTek

Dubai Internet City

Dubai

UAE

This edition first published 2018

© 2018 John Wiley & Sons Ltd.

All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means,

electronic, mechanical, photocopying, recording or otherwise, except as permitted by law. Advice on how to obtain permission to reuse material

from this title is available at http://www.wiley.com/go/permissions.

The right of Ayman Elnashar and Mohamed El-saidny to be identified as the authors of this work has been asserted in accordance with law.

Registered Offices

John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030, USA

John Wiley & Sons Ltd, The Atrium, Southern Gate, Chichester, West Sussex, PO19 8SQ, UK

Editorial Office

The Atrium, Southern Gate, Chichester, West Sussex, PO19 8SQ, UK

For details of our global editorial offices, customer services, and more information about Wiley products visit us at www.wiley.com.

Wiley also publishes its books in a variety of electronic formats and by print-on-demand. Some content that appears in standard print versions of

this book may not be available in other formats.

Limit of Liability/Disclaimer of Warranty

While the publisher and authors have used their best efforts in preparing this work, they make no representations or warranties with respect to the

accuracy or completeness of the contents of this work and specifically disclaim all warranties, including without limitation any implied warranties

of merchantability or fitness for a particular purpose. No warranty may be created or extended by sales representatives, written sales materials or

promotional statements for this work. The fact that an organization, website, or product is referred to in this work as a citation and/or potential

source of further information does not mean that the publisher and authors endorse the information or services the organization, website, or

product may provide or recommendations it may make. This work is sold with the understanding that the publisher is not engaged in rendering

professional services. The advice and strategies contained herein may not be suitable for your situation. You should consult with a specialist where

appropriate. Further, readers should be aware that websites listed in this work may have changed or disappeared between when this work was

written and when it is read. Neither the publisher nor authors shall be liable for any loss of profit or any other commercial damages, including but

not limited to special, incidental, consequential, or other damages.

Library of Congress Cataloging-in-Publication Data applied for

Hardback ISBN: 9781119063308

Cover design by Wiley

Cover image: © jamesteohart/Shutterstock

Set in 10/12pt WarnockPro by SPi Global, Chennai, India

Printed in the UK by Bell & Bain Ltd, Glasgow

10 9 8 7 6 5 4 3 2 1

This book is dedicated to the memory of my parents (God bless their souls). They gave me the strong foundation and

unconditional love, which remains the source of motivation and is the guiding light of my life.

To my dearest wife, my pillar of strength, your encouragement and patience has strengthened me always.

To my beloved children Noursin, Amira, Yousef, and Yasmina. You are the inspiration!

I want to offer my sincerest appreciation to the innovation and vision of UAE. It has provided me with a fulfilling

career, an unmatched lifestyle and the inspiration to author this book.

– Ayman Elnashar, PhD

I would like to dedicate this book to my amazing family for their continuous support and encouragement. To my

beloved wife, you have guided and inspired me throughout the years. To my beautiful daughter, you always surprise me

with your motivational spirit and hard work.

“The scientific man does not aim at an immediate result. He does not expect that his advanced ideas will be readily

taken up. His work is like that of the planter—for the future. His duty is to lay the foundation for those who are to come,

and point the way”. – Nikola Tesla

Mohamed El-saidny

vii

Contents

About the Authors xvii

Preface xix

Acknowledgments xxi

1 LTE and LTE-A Overview 1

1.1 Introduction 1

1.2 Link Spectrum Efficiency 3

1.3 LTE-Advanced and Beyond 4

1.3.1 LTE and Wi-Fi 6

1.3.2 Wi-Fi Calling 7

1.3.2.1 QoS Challenges in VoWiFi 8

1.3.3 Internet of Things (IoT) 8

1.4 Evolved Packet System (EPS) Overview 9

1.5 Network Architecture Evolution 11

1.6 LTE UE Description 14

1.7 EPS Bearer Procedures 15

1.7.1 EPS Registration and Attach Procedures 16

1.7.2 EPS Security Basics 19

1.7.3 EPS QoS 20

1.8 Access and Non-access Stratum Procedures 20

1.8.1 EMM Procedures and Description 21

1.8.1.1 Definitions 21

1.8.1.2 ESM Procedures and Description 22

1.8.2 EPS Mobility Management (EMM) 23

1.8.3 Session Management (ESM) 23

1.8.3.1 Notification Procedure 23

1.8.3.2 ESM Status Procedure 23

1.8.4 EPS Idle and Active States 24

1.8.5 EPS Network Topology for Mobility Procedures 25

1.9 LTE Air Interface 26

1.9.1 Multiple Access in 3GPP Systems 26

1.9.2 Time–Frequency Domain Resources 28

1.10 OFDM Signal Generation 32

1.10.1 Main Definitions for MIMO 33

1.10.2 Scrambling 33

1.10.3 Higher-order Modulation 34

1.11 LTE Channels and Procedures 34

1.11.1 LTE Physical Layer Channels 36

1.11.2 Downlink Synchronization Channels 36

1.11.3 Downlink Reference Signals 36

1.11.4 Physical Broadcast Channel (PBCH) 38

1.11.5 Physical Hybrid ARQ Indicator Channel (PHICH) 38

1.11.6 Physical Control Format Indicator Channel (PCFICH) 40

viii Contents

1.11.7 Physical Downlink Control Channel (PDCCH) 41

1.11.8 Physical Downlink Shared Channel (PDSCH) 43

1.12 Uplink Physical Channels 43

1.12.1 Uplink Reference Signals 43

1.12.2 Physical Random Access Channel (PRACH) 44

1.12.3 Physical Uplink Control Channel (PUCCH) 44

1.12.4 Physical Uplink Shared Channel (PUSCH) 44

1.13 Physical Layer Procedures 45

1.13.1 CQI (Channel Quality Indicator) 46

1.13.2 DL Scheduling 47

1.13.3 UL Scheduling 47

1.13.4 Multiple Input, Multiple Output (MIMO) 48

1.13.5 Uplink Power Control 50

1.13.6 Techniques for Data Retransmission on the UL 51

1.14 RRC Layer and Mobility Procedures 51

1.14.1 Paging 56

1.14.2 Initial Security Activation 57

1.14.3 RRC Connection Reconfiguration 58

1.14.4 RRC Connection Release 58

1.14.5 DL Information Transfer 59

1.14.6 UL Information Transfer 59

1.14.7 UE Capability Transfer 59

1.14.8 UE Information 59

1.15 LTE Idle Mode Mobility Procedures 60

1.15.1 General Mobility Procedure 60

1.15.2 Public Land Mobile Network (PLMN) Selection 60

1.15.3 PLMN Selection Order 61

1.15.3.1 High Quality Criterion 62

1.15.4 Service Type and Cell Categories 62

1.15.4.1 Acceptable Cell, Exception 62

1.15.4.2 Suitable Cell, Exception 62

1.15.5 Cell Selection – S-criteria 62

1.15.6 Camping on a Suitable Cell 62

1.15.7 Cell Reselection in Idle Mode 63

1.15.8 Handling Reselection Priorities 64

1.15.9 Measurement Rules for Cell Reselection 64

1.15.10 Speed-dependent Scaling of Reselection Parameters 64

1.15.11 LTE Intra-frequency Cell Reselection 66

1.15.12 LTE Inter-frequency Cell Reselection Rules 66

1.15.13 LTE Inter-frequency Cell Reselection with Equal Priority 66

1.15.14 LTE Inter-frequency Cell Reselection with Low Priority 67

1.15.15 LTE Inter-frequency Cell Reselection with High Priority 68

1.16 LTE Connected Mode Mobility Procedures 68

1.16.1 Measurement Parameters 68

1.16.2 Measurement Procedure in RRC_Connected Mode 69

1.16.3 DRB Establishment During Initial Attach 70

1.16.4 DRB Establishment After Initial Attach 70

1.16.5 Connected Mode Mobility 70

1.16.6 LTE Intra-frequency Handover 71

1.16.7 Delay Assessment During Handover 71

1.16.8 Event A3 Measurement Report Triggering 71

1.16.9 Intra-frequency Handover Call Flow 72

1.16.10 Intra-frequency Parameter Tradeoffs 72

1.16.11 Radio Link Failures and Re-establishment 73

1.16.12 RLF Timers in Idle and Connected Modes 74

1.16.13 RLF Parameter Tradeoffs 75

Contents ix

1.16.13.1 Timers/Counters Definitions 75

1.17 Interworking with Other 3GPP Radio Access 76

1.17.1 E-UTRA States and Inter-RAT Mobility Procedures 76

1.17.2 Inter-RAT Cell Reselection 76

1.17.3 E-UTRAN to UTRAN Cell Reselection Flow 77

1.17.4 E-UTRAN to UTRAN Measurement Rules 77

1.17.5 E-UTRAN to UTRAN Measurement Stages 78

1.17.6 LTE Inter-RAT to UTRAN Cell Reselection with Low Priority 78

1.17.7 LTE Inter-RAT to UTRAN Cell Reselection with High Priority 79

1.17.8 UTRAN to E-UTRAN Cell Reselection Flow 79

1.17.9 UTRAN to E-UTRAN Measurement Rules 80

1.17.10 UTRAN to E-UTRAN Measurement Stages 81

1.17.11 LTE Inter-RAT to GERAN Cell Reselection with Low Priority 82

1.17.12 LTE Inter-RAT to GERAN Cell Reselection with High Priority 82

1.17.13 Inter-RAT Handover 83

1.17.14 Event B1 Measurement Report Triggering 83

1.17.15 Inter-RAT Handover Gap Measurements 84

1.17.16 Gap Measurement Example 84

1.17.17 Example of Inter-RAT Handover Parameters 86

1.17.18 Inter-RAT Handover to UTRAN Call Flow 86

References 86

2 Introduction to the IP Multimedia Subsystem (IMS) 87

2.1 Introduction 87

2.1.1 Voice over LTE Overview 87

2.1.2 SIP Protocol 88

2.1.3 SIP Basic Flow 88

2.1.4 SIP Session Flow in IMS 89

2.1.5 SDP Protocol 90

2.2 IMS Network Description 91

2.2.1 IMS Network Architecture 91

2.2.2 Call Session Control Function – CSCF 92

2.2.3 Interworking Nodes 95

2.2.4 Connection to Legacy Networks 96

2.2.5 Database Function 97

2.2.6 IMS Multimedia Resources Function 100

2.2.7 IMS Network Elements in Access and Bearer Layer 100

2.2.8 IMS Service Capability Layers 100

2.2.9 IMS Protocols and Reference Interfaces 102

2.2.10 Call Session Control Function (CSCF) 102

2.2.10.1 Proxy CSCF (P-CSCF) 103

2.2.10.2 Serving CSCF (S-CSCF) 106

2.2.10.3 Interrogating CSCF (I-CSCF) 106

2.2.10.4 CSCF Functions and Features 107

2.2.11 IMS Subscriber Registration 107

2.2.12 IMS Subscriber De-registration 110

2.2.13 IMS Discovery 112

2.2.14 CSCF Authentication 112

2.2.14.1 Service Profile 113

2.2.15 CSCF Roaming and Roaming Restriction 114

2.2.16 S-CSCF Service Trigger 114

2.2.17 S-CSCF Media Control 115

2.2.18 CSCF Emergency Call 115

2.2.19 Numbering Analysis 116

2.2.20 Route Selection Analysis 117

2.2.21 Topology Hiding 117

x Contents

2.2.22 Embedded DNS/ENUM 118

2.2.23 Functions of the DNS/ENUM in the CSCF 119

2.2.24 CSCF Charging 120

2.2.25 PSI Service 121

2.2.26 SIP Forking 121

2.2.27 Session and Service Control 123

2.2.27.1 Session Control 123

2.2.27.2 Service Control 124

2.2.28 Session Timer 124

2.2.29 Number Portability Service 125

2.2.30 Network Disaster Tolerance 126

2.2.31 S-CSCF Assignment 126

2.2.32 Routing 126

2.2.33 Telephone Number Mapping 127

2.2.34 Domain Name Portability 128

2.2.35 NAT Keep Alive 128

2.2.36 Fast Re-registration 129

2.2.37 Media Bypass 129

2.2.38 Media Resource Function Controller 129

2.3 IMS Identities and Subscription 131

2.3.1 Data Model of IMS 131

2.3.2 Initial Filter Criteria (iFC) 132

2.4 IMS Architecture and Interfaces 134

2.4.1 Session Border Control 134

2.4.2 Access Session Border Control (A-SBC) 135

2.4.3 Interconnection Session Border Control (I-SBC) 135

2.4.4 Access Transfer Control Function (ATCF) 135

2.4.5 Media GW Functions 136

2.4.6 VoLTE–CS Interworking 136

2.4.7 Media Resource Function (MRF) for VoLTE 136

2.5 MMTel (Multimedia Telephony) Services 136

2.5.1 Ut XCAP 138

2.5.2 MMTel Modification from an XCAP Client 138

2.5.3 MMTel Data Synchronization Between XCAP Client and Server 139

2.5.4 Location Mapping 139

2.5.5 Location Parameters 139

2.5.6 ECGI–CGI Mapping 140

2.5.6.1 Location Information in a Visited Network 140

2.6 Service Centralization and Continuity AS (SCC AS) 141

2.6.1 SCC AS Homing 141

2.6.2 T-ADS/Domain Selection 141

2.6.3 SRVCC 141

2.6.4 Policy Control 142

2.6.4.1 Bearer Establishment 142

2.6.4.2 QoS 143

2.6.4.3 Rx Diameter Call Flow 144

2.7 Operator X IMS–VoLTE Architecture 145

2.7.1 Architecture Design Concepts and Principles 145

2.7.2 Interconnection Topology 146

2.7.3 Topology of Interworking with PSTN 146

2.7.4 Topology of Interworking with NGN 146

2.7.5 Location-based Routing 146

2.7.5.1 Routing Zone and Use of LTE Location 146

2.7.6 Ut/XCAP 151

2.7.7 Existing Network 151

Contents xi

2.7.7.1 Operator X’s Network MGCF 151

2.7.7.2 HSS 152

2.7.7.3 HLR 152

2.7.7.4 SMSC 152

2.7.7.5 IN 152

2.7.7.6 STP 152

2.7.7.7 MME 152

2.7.7.8 PCRF 152

2.7.7.9 IP-SM-GW 152

2.7.7.10 Messaging Profile 153

2.7.7.11 IP-SM-GW and User Types 153

2.7.7.12 IP-SM-GW Interworking with Multi-SIM/ONS 153

2.7.7.13 HLR Support for IP-SM-GW 153

2.7.7.14 IP-SM-GW Address Registration to the HLR 153

2.7.7.15 IP-SM-GW Homing 153

2.7.8 External Network Connections 154

2.7.8.1 PSTN and IMS Subscription 154

2.7.9 Supported Explicit and Implicit Registration 155

References 156

3 VoLTE/CSFB Call Setup Delay and Handover Analysis 158

3.1 Overview 158

3.2 Introduction 158

3.3 CSFB Call Flow and Relevant KPIs 160

3.4 VoLTE Call Flow and Relevant KPIs 162

3.5 VoLTE Handover and Data Interruption Time 166

3.5.1 Recommendations on Call Re-establishment 166

3.6 Single Radio Voice Call Continuity (SRVCC) 169

3.7 Performance Analysis 171

3.7.1 CSFB Performance Analysis 173

3.7.2 VoLTE Call Setup Performance Analysis 175

3.7.3 VoLTE Handover Performance Analysis 177

3.7.4 eSRVCC Performance Analysis 180

3.8 Latency Reduction During Handover 182

3.8.1 Components of Handover Latency 184

3.8.2 Synchronous Handovers 184

3.8.3 Synchronized Handover with Early Handover Command (EHC) 186

3.9 Practical Use Cases and Recommendations 187

3.9.1 State Transition at Call Setup 187

3.9.2 SIP Timeout at Call Setup 188

3.9.3 UE Loses VoLTE due to an IMS Registration Issue 188

3.9.4 bSRVCC Collision Leading to Subsequent Setup Failure 190

3.9.5 Call Failure due to bSRVCC, Even if Supported 190

3.9.6 Network Planning Challenges 190

3.9.7 IRAT Redirection During VoLTE 190

3.9.8 No Response to SIP Message, Leading to Call Drop 190

3.10 Conclusions 190

References 195

4 Comprehensive Performance Evaluation of VoLTE 197

4.1 Overview 197

4.2 Introduction 197

4.3 VoLTE Principles 198

4.4 Main VoLTE Features 200

4.4.1 Robust Header Compression 200

xii Contents

4.4.2 Transmission Time Interval Bundling 201

4.4.3 Semi-persistent Scheduling (SPS) 202

4.5 Testing Environment and Main VoLTE KPIs 203

4.6 VoLTE Performance Evaluation 204

4.6.1 RoHC Efficiency and Performance Evaluation 204

4.6.2 TTI Bundling 205

4.6.3 RTP and Jitter Evaluation in Different VoLTE Call Scenarios 206

4.6.4 Scheduler Evaluation for VoLTE 206

4.6.5 RTP and Jitter Evaluation vs. Radio Conditions 209

4.6.6 Handover Impact on VoLTE Call Performance 210

4.6.7 VoLTE Voice Quality Evaluation 212

4.7 EVS Coding and Voice Evolution 214

4.8 TTI Bundling Performance Evaluation 219

4.9 BLER Impact on Voice Quality 220

4.10 Scheduler Performance 220

4.11 VoLTE KPI Evaluation 221

4.12 Use Cases and Recommendations 223

4.12.1 Traffic vs. User vs. Throughput Distribution in Busy Hours 225

4.12.2 Daily Per-band Share of Average RRC Connected Users – All Hours 225

4.12.3 Main KPIs for Different LTE Bands in Busy Hours 225

4.12.4 CQI vs. MIMO KPI Correlation – Busy Hours 226

4.12.5 Per-band DL Throughput vs. CQI and MIMO – Busy Hours 226

4.13 Conclusions 226

References 228

5 Evaluation of LTE-Advanced Features 230

5.1 Introduction to LTE-Advanced Features 230

5.2 Carrier Aggregation in LTE-A and LTE-A Pro 231

5.2.1 LTE TDD+TDD or FDD+FDD Carrier Aggregation 232

5.2.2 FDD–TDD Joint Operation 233

5.2.2.1 FDD–TDD Joint Operation Throughput Analysis 236

5.2.2.2 FDD–TDD Joint Operation Coverage Analysis 236

5.2.2.3 Additional Considerations 237

5.2.3 LTE Licensed Assisted Access (LAA) 239

5.2.4 LTE and Wi-Fi Aggregation (LWA) 241

5.3 Higher-order Modulation (HOM) for Uplink and Downlink 242

5.3.1 Downlink 256QAM 243

5.3.2 Uplink 64QAM 244

5.4 LTE-A Feature Dependencies 247

5.4.1 UE Category and Feature Combinations Towards Giga LTE 247

5.4.2 Interference Cancellation and Coordination Techniques 249

5.5 Other Enhancements Towards Advanced LTE Deployments 252

5.5.1 High Power/Performance User Equipment (HPUE) 254

5.5.2 Uplink Data Compression (UDC) 254

5.5.2.1 Compression Methods in 3GPP Now 254

5.5.2.2 Possible Applicable LTE Mode of Data Compression 257

5.5.2.3 Uplink Data Compression Performance Analysis Using RoHC 259

5.5.2.4 Performance Aspects of Uplink Data RoHC 259

5.5.2.5 Highlights of UDC Development and Challenges 260

5.5.3 Enhanced VoLTE (eVoLTE) 261

References 263

6 LTE Network Capacity Analysis 264

6.1 Overview 264

6.2 Introduction 264

Contents xiii

6.3 Users and Traffic Utilization 266

6.3.1 RRC Connected User Distribution 266

6.3.2 Active User Distribution 266

6.3.3 DL to UL Traffic Ratio 268

6.3.4 TTI Utilization (Time Domain Utilization) 269

6.4 Downlink Analysis 270

6.4.1 DL Cell Throughput Performance 270

6.4.2 Downlink Bit Rate per Resource Block 271

6.4.3 DL User Throughput 271

6.4.4 Scheduling Rate vs. DL Throughput 273

6.4.5 DL Carrier Aggregation Gains 273

6.5 DL KPI Analysis 274

6.5.1 DL CQI Analysis and Modulation Performance 274

6.5.2 DL Modulation Distribution 276

6.5.3 DL MCS Distribution 278

6.5.4 DL BLER per Modulation Distribution 278

6.5.5 DL Resource Block Utilization 280

6.5.6 Introduction to MIMO 280

6.5.6.1 MIMO Techniques: Open-loop MIMO and Closed-loop MIMO 280

6.5.6.2 MIMO Techniques: Single-user MIMO and Multi-user MIMO 281

6.5.7 MIMO Utilization 282

6.5.8 CL MIMO (TM4) Trial 283

6.5.9 PDCCH Performance 284

6.5.10 DL Summary of Observations 286

6.5.11 Downlink Analysis Conclusion and Recommendations 287

6.6 UL KPI Analysis 289

6.6.1 UL Cell Throughput Performance 289

6.6.2 UL Bit Rate per Resource Block 290

6.6.3 UL MCS Distribution 291

6.6.4 UL User Throughput 292

6.6.5 UL Modulation Distribution 293

6.6.6 UL BLER per Modulation Distribution 294

6.6.7 UL Resource Block (RB) Utilization 295

6.6.8 RACH Performance 296

6.6.8.1 RACH Contention-free Performance 299

6.6.8.2 RACH Contention-based Performance 299

6.6.9 UL Interference Performance 300

6.6.10 Uplink Analysis Conclusion and Recommendations 301

6.7 Data Connection Performance 302

6.7.1 RRC Connection Performance 303

6.7.2 E-RAB Performance 303

6.7.3 CSFB Performance (LTE Only) 303

6.7.4 Summary of Observations 304

6.8 Link Reliability Analysis 305

6.8.1 QCI = 9 PDCP Performance 305

6.8.1.1 QCI = 8 versus QCI = 9 307

6.9 Main KPI Comparison for Different Operators 307

6.9.1 DL Cell Throughput Comparison 308

6.9.2 DL Resource Block (RB) Utilization 308

6.9.3 Mean CQI Comparison 308

References 309

7 IoT Evolution Towards a Super-connected World 310

7.1 Overview 310

7.2 Introduction to the IoT 310