Kazi Mohammed Saidul Huq, Senior Research Engineer, Instituto de Telecomunicações, Aveiro, Portugal. Kazi Mohammed Saidul Huq received the Ph.D. degree in electrical engineering from the University of Aveiro, Aveiro, Portugal, in 2014.  His research activities include fifth-generation (5G), energy-efficient wireless communication, Backhaul/Fronthaul, radio resource management. He has been involved in several EC R&D Projects in the field of green communication and next generation wireless systems. He has been also involved in one Portuguese funded projects (BENEFIC) in the area of networking coding and development of system level simulator for 5G wireless system.Jonathan Rodriguez Gonzalez, Senior Research Engineer & Group Leader, Instituto de Telecomunicações, Aveiro, Portugal. Jonathan Rodriguez received the Ph.D. degree from the University of Surrey, Surrey, U.K., in 2004. He was the Project Coordinator and the Technical Manager of, respectively, the FP7 C2POWER and the FP7 COGEU projects and currently acts as a coordinator of several national and international projects. He is the author of more than 300 scientific publications and has carried out consultancy for major manufacturers participating in DVB-T/H and HS-UPA standardization. His research interests include green communications, network coding, cognitive radio, cooperative networking, radio resource management, and cross-layer design. Dr. Rodriguez is a Chartered Engineer (Institution of Engineering and Technology) and has served as a General Chair for several prestigious conferences and workshops.

• List of Contributors ixPreface xiAcknowledgements xiii1 Introduction: The Communication Haul Challenge 1Kazi Mohammed Saidul Huq and Jonathan Rodriguez1.1 Introduction 1References 72 A C‐RAN Approach for 5G Applications 9Kazi Mohammed Saidul Huq, Shahid Mumtaz and Jonathan Rodriguez2.1 Introduction 92.2 From Wired to Wireless Backhaul/Fronthaul Technologies 112.3 Architecture for Coordinated Systems Accordingto Baseline 3GPP 122.4 Reference Architecture for C‐RAN 152.4.1 System Architecture for Fronthaul‐based C‐RAN 152.4.2 Cloud Resource Optimizer 162.5 Potential Applications for C‐RAN‐based Mobile Systems 202.5.1 Virtualization of D2D Services 202.5.2 Numerical Analysis 212.6 Conclusion 24References 273 Backhauling 5G Small Cells with Massive‐MIMO‐Enabled mmWave Communication 29Ummy Habiba, Hina Tabassum and Ekram Hossain3.1 Introduction 293.2 Existing Wireless Backhauling Solutions for 5G Small Cells 313.3 Fundamentals of mmWave and Massive MIMO Technologies 323.3.1 MmWave Communication 323.3.2 MU‐MIMO with Large Antenna Arrays 333.4 MmWave Backhauling: State of the Art and Research Issues 343.4.1 LOS mmWave Backhauling 353.4.2 NLOS mmWave Backhauling 363.4.3 Research Challenges for Backhauling in 5G Networks 373.5 Case Study: Massive‐MIMO‐based mmWave Backhauling System 403.5.1 System Model 413.5.2 Maximizing User Rate 443.5.3 Matching Theory for User Association 453.5.4 Numerical Results 483.6 Conclusion 51Acknowledgement 51References 514 Fronthaul for a Flexible Centralization in Cloud Radio Access Networks 55Jens Bartelt, Dirk Wübben, Peter Rost, Johannes Lessmann and Gerhard Fettweis4.1 Introduction 554.2 Radio Access Network Architecture 574.3 Functional Split Options 584.4 Requirements of Flexible Functional Splits 604.4.1 Split A 614.4.2 Split B 624.4.3 Split C 634.4.4 Split D 644.4.5 Summary and Examples 644.5 Statistical Multiplexing in a Flexibly Centralized Network 674.5.1 Distribution of FH Data Rate per Base Station 674.5.2 Outage Rate 684.5.3 Statistical Multiplexing on Aggregation Links 694.6 Convergence of Fronthaul and Backhaul Technologies 734.6.1 Physical Layer Technologies 734.6.2 Data/MAC Layer Technologies 754.6.3 Network Layer Technologies 774.6.4 Control and Management Plane 784.7 Enablers of a Flexible Functional Split 784.8 Summary 80Acknowledgement 82References 825 Analysis and Optimization for Heterogeneous Backhaul Technologies 85Gongzheng Zhang, Tony Q. S. Quek, Marios Kountouris, Aiping Huang and Hangguan Shan5.1 Introduction 855.2 Backhaul Model 885.2.1 Network Model 885.2.2 Delay Model 895.2.3 Cost Model 925.3 Backhaul Packet Delay Analysis 935.3.1 Mean Backhaul Packet Delay 935.3.2 Delay‐limited Success Probability 955.3.3 Performance Evaluation 975.4 Backhaul Deployment Cost Analysis 1015.5 Backhaul‐aware BS Association Policy 1035.5.1 Mean Network Packet Delay 1035.5.2 BS Association Policy 1075.5.3 Numerical Results 1095.6 Conclusions 115References 1156 Dynamic Enhanced Inter‐cell Interference Coordination Strategy with Quality of Service Guarantees for Heterogeneous Networks 119Wei‐Sheng Lai, Tsung‐Hui Chang, Kuan‐Hsuan Yeh and Ta‐Sung Lee6.1 Introduction 1196.2 System Model and Problem Statement 1216.2.1 Network Environments 1216.2.2 QoS Constraint 1246.2.3 Problem Statements 1256.3 Dynamic Interference Coordination Strategy 1266.3.1 SMDP Analysis 1266.3.2 Admission Control with a QoS Constraint 1286.3.3 Joint Dynamic eICIC and Admission Control for Sum Rate Maximization 1296.3.4 Joint Dynamic eICIC and Admission Control for Proportional Fairness Maximization 1306.4 Numerical Results 1326.5 Conclusion 140References 1407 Cell Selection for Joint Optimization of the Radio Access and Backhaul in Heterogeneous Cellular Networks 143Antonio De Domenico, Valentin Savin and Dimitri Ktenas7.1 Introduction 1437.2 System Model and Problem Statement 1457.2.1 Joint RAN/BH Capacity 1467.2.2 Problem Statement 1517.3 Proposed Solutions 1517.3.1 Evolve 1517.3.2 Relax 1547.3.3 Practical Implementation of the Proposed Algorithms 1567.4 Simulation Results 1577.5 Conclusion 165References 1658 Multiband and Multichannel Aggregation for High‐speed Wireless Backhaul: Challenges and Solutions 167Xiaojing Huang8.1 Introduction 1678.2 Spectrum for Wireless Backhaul 1708.2.1 Microwave Band and Channel Allocation 1708.2.2 Millimetre‐wave Band and Usage Trend 1718.3 Multiband and Multichannel Aggregation 1728.3.1 Band and Channel Aggregation Overview 1728.3.2 System Architecture 1748.3.3 Subband Aggregation and Implementations 1778.3.4 Full SDR Approach for Band and Channel Aggregation 1838.4 Spectrally Efficient Channel Aggregation 1858.4.1 System Overview 1858.4.2 Frequency‐domain Multiplexing Without a Guard Band 1868.4.3 Digital IF Signal Generation and Reception 1888.4.4 High-performance OFDM Transmission 1888.5 Practical System Examples 1898.5.1 CSIRO Ngara Backhaul 1908.5.2 CSIRO High‐speed E‐band Systems 1918.6 Conclusions 194References 1949 Security Challenges for Cloud Radio Access Networks 195Victor Sucasas, Georgios Mantas and Jonathan Rodriguez9.1 Introduction 1959.2 Overview of C‐RAN Architecture 1969.3 Intrusion Attacks in the C‐RAN Environment 1979.3.1 Entry Points for Intrusion Attacks 1989.3.2 Technical Challenges for Intrusion Detection Counter‐mechanisms 2019.3.3 Insider Attacks 2039.4 Distributed Denial of Service (DDoS) Attacks Against C‐RAN 2059.4.1 DDoS Attacks Using Signalling Amplification 2069.4.2 DDoS Attacks Against External Entities Over the Mobile Network 2079.4.3 DDoS Attacks from External Compromised IP Networks Over the Mobile Network 2089.5 Conclusions 209References 209Index 213

Kazi Mohammed Saidul Huq, Senior Research Engineer, Instituto de Telecomunicações, Aveiro, Portugal. Kazi Mohammed Saidul Huq received the Ph.D. degree in electrical engineering from the University of Aveiro, Aveiro, Portugal, in 2014.  His research activities include fifth-generation (5G), energy-efficient wireless communication, Backhaul/Fronthaul, radio resource management. He has been involved in several EC R&D Projects in the field of green communication and next generation wireless systems. He has been also involved in one Portuguese funded projects (BENEFIC) in the area of networking coding and development of system level simulator for 5G wireless system.Jonathan Rodriguez Gonzalez, Senior Research Engineer & Group Leader, Instituto de Telecomunicações, Aveiro, Portugal. Jonathan Rodriguez received the Ph.D. degree from the University of Surrey, Surrey, U.K., in 2004. He was the Project Coordinator and the Technical Manager of, respectively, the FP7 C2POWER and the FP7 COGEU projects and currently acts as a coordinator of several national and international projects. He is the author of more than 300 scientific publications and has carried out consultancy for major manufacturers participating in DVB-T/H and HS-UPA standardization. His research interests include green communications, network coding, cognitive radio, cooperative networking, radio resource management, and cross-layer design. Dr. Rodriguez is a Chartered Engineer (Institution of Engineering and Technology) and has served as a General Chair for several prestigious conferences and workshops.

• List of Contributors ixPreface xiAcknowledgements xiii1 Introduction: The Communication Haul Challenge 1Kazi Mohammed Saidul Huq and Jonathan Rodriguez1.1 Introduction 1References 72 A C‐RAN Approach for 5G Applications 9Kazi Mohammed Saidul Huq, Shahid Mumtaz and Jonathan Rodriguez2.1 Introduction 92.2 From Wired to Wireless Backhaul/Fronthaul Technologies 112.3 Architecture for Coordinated Systems Accordingto Baseline 3GPP 122.4 Reference Architecture for C‐RAN 152.4.1 System Architecture for Fronthaul‐based C‐RAN 152.4.2 Cloud Resource Optimizer 162.5 Potential Applications for C‐RAN‐based Mobile Systems 202.5.1 Virtualization of D2D Services 202.5.2 Numerical Analysis 212.6 Conclusion 24References 273 Backhauling 5G Small Cells with Massive‐MIMO‐Enabled mmWave Communication 29Ummy Habiba, Hina Tabassum and Ekram Hossain3.1 Introduction 293.2 Existing Wireless Backhauling Solutions for 5G Small Cells 313.3 Fundamentals of mmWave and Massive MIMO Technologies 323.3.1 MmWave Communication 323.3.2 MU‐MIMO with Large Antenna Arrays 333.4 MmWave Backhauling: State of the Art and Research Issues 343.4.1 LOS mmWave Backhauling 353.4.2 NLOS mmWave Backhauling 363.4.3 Research Challenges for Backhauling in 5G Networks 373.5 Case Study: Massive‐MIMO‐based mmWave Backhauling System 403.5.1 System Model 413.5.2 Maximizing User Rate 443.5.3 Matching Theory for User Association 453.5.4 Numerical Results 483.6 Conclusion 51Acknowledgement 51References 514 Fronthaul for a Flexible Centralization in Cloud Radio Access Networks 55Jens Bartelt, Dirk Wübben, Peter Rost, Johannes Lessmann and Gerhard Fettweis4.1 Introduction 554.2 Radio Access Network Architecture 574.3 Functional Split Options 584.4 Requirements of Flexible Functional Splits 604.4.1 Split A 614.4.2 Split B 624.4.3 Split C 634.4.4 Split D 644.4.5 Summary and Examples 644.5 Statistical Multiplexing in a Flexibly Centralized Network 674.5.1 Distribution of FH Data Rate per Base Station 674.5.2 Outage Rate 684.5.3 Statistical Multiplexing on Aggregation Links 694.6 Convergence of Fronthaul and Backhaul Technologies 734.6.1 Physical Layer Technologies 734.6.2 Data/MAC Layer Technologies 754.6.3 Network Layer Technologies 774.6.4 Control and Management Plane 784.7 Enablers of a Flexible Functional Split 784.8 Summary 80Acknowledgement 82References 825 Analysis and Optimization for Heterogeneous Backhaul Technologies 85Gongzheng Zhang, Tony Q. S. Quek, Marios Kountouris, Aiping Huang and Hangguan Shan5.1 Introduction 855.2 Backhaul Model 885.2.1 Network Model 885.2.2 Delay Model 895.2.3 Cost Model 925.3 Backhaul Packet Delay Analysis 935.3.1 Mean Backhaul Packet Delay 935.3.2 Delay‐limited Success Probability 955.3.3 Performance Evaluation 975.4 Backhaul Deployment Cost Analysis 1015.5 Backhaul‐aware BS Association Policy 1035.5.1 Mean Network Packet Delay 1035.5.2 BS Association Policy 1075.5.3 Numerical Results 1095.6 Conclusions 115References 1156 Dynamic Enhanced Inter‐cell Interference Coordination Strategy with Quality of Service Guarantees for Heterogeneous Networks 119Wei‐Sheng Lai, Tsung‐Hui Chang, Kuan‐Hsuan Yeh and Ta‐Sung Lee6.1 Introduction 1196.2 System Model and Problem Statement 1216.2.1 Network Environments 1216.2.2 QoS Constraint 1246.2.3 Problem Statements 1256.3 Dynamic Interference Coordination Strategy 1266.3.1 SMDP Analysis 1266.3.2 Admission Control with a QoS Constraint 1286.3.3 Joint Dynamic eICIC and Admission Control for Sum Rate Maximization 1296.3.4 Joint Dynamic eICIC and Admission Control for Proportional Fairness Maximization 1306.4 Numerical Results 1326.5 Conclusion 140References 1407 Cell Selection for Joint Optimization of the Radio Access and Backhaul in Heterogeneous Cellular Networks 143Antonio De Domenico, Valentin Savin and Dimitri Ktenas7.1 Introduction 1437.2 System Model and Problem Statement 1457.2.1 Joint RAN/BH Capacity 1467.2.2 Problem Statement 1517.3 Proposed Solutions 1517.3.1 Evolve 1517.3.2 Relax 1547.3.3 Practical Implementation of the Proposed Algorithms 1567.4 Simulation Results 1577.5 Conclusion 165References 1658 Multiband and Multichannel Aggregation for High‐speed Wireless Backhaul: Challenges and Solutions 167Xiaojing Huang8.1 Introduction 1678.2 Spectrum for Wireless Backhaul 1708.2.1 Microwave Band and Channel Allocation 1708.2.2 Millimetre‐wave Band and Usage Trend 1718.3 Multiband and Multichannel Aggregation 1728.3.1 Band and Channel Aggregation Overview 1728.3.2 System Architecture 1748.3.3 Subband Aggregation and Implementations 1778.3.4 Full SDR Approach for Band and Channel Aggregation 1838.4 Spectrally Efficient Channel Aggregation 1858.4.1 System Overview 1858.4.2 Frequency‐domain Multiplexing Without a Guard Band 1868.4.3 Digital IF Signal Generation and Reception 1888.4.4 High-performance OFDM Transmission 1888.5 Practical System Examples 1898.5.1 CSIRO Ngara Backhaul 1908.5.2 CSIRO High‐speed E‐band Systems 1918.6 Conclusions 194References 1949 Security Challenges for Cloud Radio Access Networks 195Victor Sucasas, Georgios Mantas and Jonathan Rodriguez9.1 Introduction 1959.2 Overview of C‐RAN Architecture 1969.3 Intrusion Attacks in the C‐RAN Environment 1979.3.1 Entry Points for Intrusion Attacks 1989.3.2 Technical Challenges for Intrusion Detection Counter‐mechanisms 2019.3.3 Insider Attacks 2039.4 Distributed Denial of Service (DDoS) Attacks Against C‐RAN 2059.4.1 DDoS Attacks Using Signalling Amplification 2069.4.2 DDoS Attacks Against External Entities Over the Mobile Network 2079.4.3 DDoS Attacks from External Compromised IP Networks Over the Mobile Network 2089.5 Conclusions 209References 209Index 213

Kazi Mohammed Saidul Huq, Senior Research Engineer, Instituto de Telecomunicações, Aveiro, Portugal. Kazi Mohammed Saidul Huq received the Ph.D. degree in electrical engineering from the University of Aveiro, Aveiro, Portugal, in 2014.  His research activities include fifth-generation (5G), energy-efficient wireless communication, Backhaul/Fronthaul, radio resource management. He has been involved in several EC R&D Projects in the field of green communication and next generation wireless systems. He has been also involved in one Portuguese funded projects (BENEFIC) in the area of networking coding and development of system level simulator for 5G wireless system.Jonathan Rodriguez Gonzalez, Senior Research Engineer & Group Leader, Instituto de Telecomunicações, Aveiro, Portugal. Jonathan Rodriguez received the Ph.D. degree from the University of Surrey, Surrey, U.K., in 2004. He was the Project Coordinator and the Technical Manager of, respectively, the FP7 C2POWER and the FP7 COGEU projects and currently acts as a coordinator of several national and international projects. He is the author of more than 300 scientific publications and has carried out consultancy for major manufacturers participating in DVB-T/H and HS-UPA standardization. His research interests include green communications, network coding, cognitive radio, cooperative networking, radio resource management, and cross-layer design. Dr. Rodriguez is a Chartered Engineer (Institution of Engineering and Technology) and has served as a General Chair for several prestigious conferences and workshops.

• List of Contributors ixPreface xiAcknowledgements xiii1 Introduction: The Communication Haul Challenge 1Kazi Mohammed Saidul Huq and Jonathan Rodriguez1.1 Introduction 1References 72 A C‐RAN Approach for 5G Applications 9Kazi Mohammed Saidul Huq, Shahid Mumtaz and Jonathan Rodriguez2.1 Introduction 92.2 From Wired to Wireless Backhaul/Fronthaul Technologies 112.3 Architecture for Coordinated Systems Accordingto Baseline 3GPP 122.4 Reference Architecture for C‐RAN 152.4.1 System Architecture for Fronthaul‐based C‐RAN 152.4.2 Cloud Resource Optimizer 162.5 Potential Applications for C‐RAN‐based Mobile Systems 202.5.1 Virtualization of D2D Services 202.5.2 Numerical Analysis 212.6 Conclusion 24References 273 Backhauling 5G Small Cells with Massive‐MIMO‐Enabled mmWave Communication 29Ummy Habiba, Hina Tabassum and Ekram Hossain3.1 Introduction 293.2 Existing Wireless Backhauling Solutions for 5G Small Cells 313.3 Fundamentals of mmWave and Massive MIMO Technologies 323.3.1 MmWave Communication 323.3.2 MU‐MIMO with Large Antenna Arrays 333.4 MmWave Backhauling: State of the Art and Research Issues 343.4.1 LOS mmWave Backhauling 353.4.2 NLOS mmWave Backhauling 363.4.3 Research Challenges for Backhauling in 5G Networks 373.5 Case Study: Massive‐MIMO‐based mmWave Backhauling System 403.5.1 System Model 413.5.2 Maximizing User Rate 443.5.3 Matching Theory for User Association 453.5.4 Numerical Results 483.6 Conclusion 51Acknowledgement 51References 514 Fronthaul for a Flexible Centralization in Cloud Radio Access Networks 55Jens Bartelt, Dirk Wübben, Peter Rost, Johannes Lessmann and Gerhard Fettweis4.1 Introduction 554.2 Radio Access Network Architecture 574.3 Functional Split Options 584.4 Requirements of Flexible Functional Splits 604.4.1 Split A 614.4.2 Split B 624.4.3 Split C 634.4.4 Split D 644.4.5 Summary and Examples 644.5 Statistical Multiplexing in a Flexibly Centralized Network 674.5.1 Distribution of FH Data Rate per Base Station 674.5.2 Outage Rate 684.5.3 Statistical Multiplexing on Aggregation Links 694.6 Convergence of Fronthaul and Backhaul Technologies 734.6.1 Physical Layer Technologies 734.6.2 Data/MAC Layer Technologies 754.6.3 Network Layer Technologies 774.6.4 Control and Management Plane 784.7 Enablers of a Flexible Functional Split 784.8 Summary 80Acknowledgement 82References 825 Analysis and Optimization for Heterogeneous Backhaul Technologies 85Gongzheng Zhang, Tony Q. S. Quek, Marios Kountouris, Aiping Huang and Hangguan Shan5.1 Introduction 855.2 Backhaul Model 885.2.1 Network Model 885.2.2 Delay Model 895.2.3 Cost Model 925.3 Backhaul Packet Delay Analysis 935.3.1 Mean Backhaul Packet Delay 935.3.2 Delay‐limited Success Probability 955.3.3 Performance Evaluation 975.4 Backhaul Deployment Cost Analysis 1015.5 Backhaul‐aware BS Association Policy 1035.5.1 Mean Network Packet Delay 1035.5.2 BS Association Policy 1075.5.3 Numerical Results 1095.6 Conclusions 115References 1156 Dynamic Enhanced Inter‐cell Interference Coordination Strategy with Quality of Service Guarantees for Heterogeneous Networks 119Wei‐Sheng Lai, Tsung‐Hui Chang, Kuan‐Hsuan Yeh and Ta‐Sung Lee6.1 Introduction 1196.2 System Model and Problem Statement 1216.2.1 Network Environments 1216.2.2 QoS Constraint 1246.2.3 Problem Statements 1256.3 Dynamic Interference Coordination Strategy 1266.3.1 SMDP Analysis 1266.3.2 Admission Control with a QoS Constraint 1286.3.3 Joint Dynamic eICIC and Admission Control for Sum Rate Maximization 1296.3.4 Joint Dynamic eICIC and Admission Control for Proportional Fairness Maximization 1306.4 Numerical Results 1326.5 Conclusion 140References 1407 Cell Selection for Joint Optimization of the Radio Access and Backhaul in Heterogeneous Cellular Networks 143Antonio De Domenico, Valentin Savin and Dimitri Ktenas7.1 Introduction 1437.2 System Model and Problem Statement 1457.2.1 Joint RAN/BH Capacity 1467.2.2 Problem Statement 1517.3 Proposed Solutions 1517.3.1 Evolve 1517.3.2 Relax 1547.3.3 Practical Implementation of the Proposed Algorithms 1567.4 Simulation Results 1577.5 Conclusion 165References 1658 Multiband and Multichannel Aggregation for High‐speed Wireless Backhaul: Challenges and Solutions 167Xiaojing Huang8.1 Introduction 1678.2 Spectrum for Wireless Backhaul 1708.2.1 Microwave Band and Channel Allocation 1708.2.2 Millimetre‐wave Band and Usage Trend 1718.3 Multiband and Multichannel Aggregation 1728.3.1 Band and Channel Aggregation Overview 1728.3.2 System Architecture 1748.3.3 Subband Aggregation and Implementations 1778.3.4 Full SDR Approach for Band and Channel Aggregation 1838.4 Spectrally Efficient Channel Aggregation 1858.4.1 System Overview 1858.4.2 Frequency‐domain Multiplexing Without a Guard Band 1868.4.3 Digital IF Signal Generation and Reception 1888.4.4 High-performance OFDM Transmission 1888.5 Practical System Examples 1898.5.1 CSIRO Ngara Backhaul 1908.5.2 CSIRO High‐speed E‐band Systems 1918.6 Conclusions 194References 1949 Security Challenges for Cloud Radio Access Networks 195Victor Sucasas, Georgios Mantas and Jonathan Rodriguez9.1 Introduction 1959.2 Overview of C‐RAN Architecture 1969.3 Intrusion Attacks in the C‐RAN Environment 1979.3.1 Entry Points for Intrusion Attacks 1989.3.2 Technical Challenges for Intrusion Detection Counter‐mechanisms 2019.3.3 Insider Attacks 2039.4 Distributed Denial of Service (DDoS) Attacks Against C‐RAN 2059.4.1 DDoS Attacks Using Signalling Amplification 2069.4.2 DDoS Attacks Against External Entities Over the Mobile Network 2079.4.3 DDoS Attacks from External Compromised IP Networks Over the Mobile Network 2089.5 Conclusions 209References 209Index 213