The recent widespread use of mobile Internet together with the advent of numerous smart applications has led to the explosive growth of the mobile data traffic in the last few years. This momentum of mobile traffic will continue due to the emerging needs of connecting people, machines, and applications through mobile infrastructure. As a result, the current and projected dramatic growth of mobile data traffic necessitates the development of fifth-generation (5G) mobile communications technology. As a result, there is significant interest in the development of innovative backhaul and fronthaul solutions for ultra-dense heterogeneous networks. This book brings together mobile stakeholders from academia and industry to identify and promote technical challenges and recent results related to smart backhaul/fronthaul research for future communication system such as 5G. Moreover, it presents a comprehensive analysis on different types of backhaul/fronthaul technology and topology. It considers already available topology for backhauling/fronthauling and explains all fundamental requirements for deploying future smart and efficient backhauling/fronthauling infrastructure from an architectural, technical and business point of view and presents real life applications and use cases. Expanding on standardization activities, this book consists of multiple channels on specific research topics. The chapters are logically organized as the authors approach the subject from overview to specifics and from a lower to higher layer direction.

Table of Contents:
List of Contributors ix Preface xi Acknowledgements xiii 1 Introduction: The Communication Haul Challenge 1 Kazi Mohammed Saidul Huq and Jonathan Rodriguez 1.1 Introduction 1 References 7 2 A C‐RAN Approach for 5G Applications 9 Kazi Mohammed Saidul Huq, Shahid Mumtaz and Jonathan Rodriguez 2.1 Introduction 9 2.2 From Wired to Wireless Backhaul/Fronthaul Technologies 11 2.3 Architecture for Coordinated Systems According to Baseline 3GPP 12 2.4 Reference Architecture for C‐RAN 15 2.4.1 System Architecture for Fronthaul‐based C‐RAN 15 2.4.2 Cloud Resource Optimizer 16 2.5 Potential Applications for C‐RAN‐based Mobile Systems 20 2.5.1 Virtualization of D2D Services 20 2.5.2 Numerical Analysis 21 2.6 Conclusion 24 References 27 3 Backhauling 5G Small Cells with Massive‐MIMO‐Enabled mmWave Communication 29 Ummy Habiba, Hina Tabassum and Ekram Hossain 3.1 Introduction 29 3.2 Existing Wireless Backhauling Solutions for 5G Small Cells 31 3.3 Fundamentals of mmWave and Massive MIMO Technologies 32 3.3.1 MmWave Communication 32 3.3.2 MU‐MIMO with Large Antenna Arrays 33 3.4 MmWave Backhauling: State of the Art and Research Issues 34 3.4.1 LOS mmWave Backhauling 35 3.4.2 NLOS mmWave Backhauling 36 3.4.3 Research Challenges for Backhauling in 5G Networks 37 3.5 Case Study: Massive‐MIMO‐based mmWave Backhauling System 40 3.5.1 System Model 41 3.5.2 Maximizing User Rate 44 3.5.3 Matching Theory for User Association 45 3.5.4 Numerical Results 48 3.6 Conclusion 51 Acknowledgement 51 References 51 4 Fronthaul for a Flexible Centralization in Cloud Radio Access Networks 55 Jens Bartelt, Dirk Wübben, Peter Rost, Johannes Lessmann and Gerhard Fettweis 4.1 Introduction 55 4.2 Radio Access Network Architecture 57 4.3 Functional Split Options 58 4.4 Requirements of Flexible Functional Splits 60 4.4.1 Split A 61 4.4.2 Split B 62 4.4.3 Split C 63 4.4.4 Split D 64 4.4.5 Summary and Examples 64 4.5 Statistical Multiplexing in a Flexibly Centralized Network 67 4.5.1 Distribution of FH Data Rate per Base Station 67 4.5.2 Outage Rate 68 4.5.3 Statistical Multiplexing on Aggregation Links 69 4.6 Convergence of Fronthaul and Backhaul Technologies 73 4.6.1 Physical Layer Technologies 73 4.6.2 Data/MAC Layer Technologies 75 4.6.3 Network Layer Technologies 77 4.6.4 Control and Management Plane 78 4.7 Enablers of a Flexible Functional Split 78 4.8 Summary 80 Acknowledgement 82 References 82 5 Analysis and Optimization for Heterogeneous Backhaul Technologies 85 Gongzheng Zhang, Tony Q. S. Quek, Marios Kountouris, Aiping Huang and Hangguan Shan 5.1 Introduction 85 5.2 Backhaul Model 88 5.2.1 Network Model 88 5.2.2 Delay Model 89 5.2.3 Cost Model 92 5.3 Backhaul Packet Delay Analysis 93 5.3.1 Mean Backhaul Packet Delay 93 5.3.2 Delay‐limited Success Probability 95 5.3.3 Performance Evaluation 97 5.4 Backhaul Deployment Cost Analysis 101 5.5 Backhaul‐aware BS Association Policy 103 5.5.1 Mean Network Packet Delay 103 5.5.2 BS Association Policy 107 5.5.3 Numerical Results 109 5.6 Conclusions 115 References 115 6 Dynamic Enhanced Inter‐cell Interference Coordination Strategy with Quality of Service Guarantees for Heterogeneous Networks 119 Wei‐Sheng Lai, Tsung‐Hui Chang, Kuan‐Hsuan Yeh and Ta‐Sung Lee 6.1 Introduction 119 6.2 System Model and Problem Statement 121 6.2.1 Network Environments 121 6.2.2 QoS Constraint 124 6.2.3 Problem Statements 125 6.3 Dynamic Interference Coordination Strategy 126 6.3.1 SMDP Analysis 126 6.3.2 Admission Control with a QoS Constraint 128 6.3.3 Joint Dynamic eICIC and Admission Control for Sum Rate Maximization 129 6.3.4 Joint Dynamic eICIC and Admission Control for Proportional Fairness Maximization 130 6.4 Numerical Results 132 6.5 Conclusion 140 References 140 7 Cell Selection for Joint Optimization of the Radio Access and Backhaul in Heterogeneous Cellular Networks 143 Antonio De Domenico, Valentin Savin and Dimitri Ktenas 7.1 Introduction 143 7.2 System Model and Problem Statement 145 7.2.1 Joint RAN/BH Capacity 146 7.2.2 Problem Statement 151 7.3 Proposed Solutions 151 7.3.1 Evolve 151 7.3.2 Relax 154 7.3.3 Practical Implementation of the Proposed Algorithms 156 7.4 Simulation Results 157 7.5 Conclusion 165 References 165 8 Multiband and Multichannel Aggregation for High‐speed Wireless Backhaul: Challenges and Solutions 167 Xiaojing Huang 8.1 Introduction 167 8.2 Spectrum for Wireless Backhaul 170 8.2.1 Microwave Band and Channel Allocation 170 8.2.2 Millimetre‐wave Band and Usage Trend 171 8.3 Multiband and Multichannel Aggregation 172 8.3.1 Band and Channel Aggregation Overview 172 8.3.2 System Architecture 174 8.3.3 Subband Aggregation and Implementations 177 8.3.4 Full SDR Approach for Band and Channel Aggregation 183 8.4 Spectrally Efficient Channel Aggregation 185 8.4.1 System Overview 185 8.4.2 Frequency‐domain Multiplexing Without a Guard Band 186 8.4.3 Digital IF Signal Generation and Reception 188 8.4.4 High-performance OFDM Transmission 188 8.5 Practical System Examples 189 8.5.1 CSIRO Ngara Backhaul 190 8.5.2 CSIRO High‐speed E‐band Systems 191 8.6 Conclusions 194 References 194 9 Security Challenges for Cloud Radio Access Networks 195 Victor Sucasas, Georgios Mantas and Jonathan Rodriguez 9.1 Introduction 195 9.2 Overview of C‐RAN Architecture 196 9.3 Intrusion Attacks in the C‐RAN Environment 197 9.3.1 Entry Points for Intrusion Attacks 198 9.3.2 Technical Challenges for Intrusion Detection Counter‐mechanisms 201 9.3.3 Insider Attacks 203 9.4 Distributed Denial of Service (DDoS) Attacks Against C‐RAN 205 9.4.1 DDoS Attacks Using Signalling Amplification 206 9.4.2 DDoS Attacks Against External Entities Over the Mobile Network 207 9.4.3 DDoS Attacks from External Compromised IP Networks Over the Mobile Network 208 9.5 Conclusions 209 References 209 Index 213