A comprehensive summary of theoretical and practical developments in LTE Heterogeneous NetworksThe last decade has witnessed the proliferation of mobile broadband data and the trend is likely to increase in the coming years. Current cellular networks are ill equipped to deal with this surge in demand. To satisfy user demand and maximize profits, a new paradigm to operate networks is needed. Heterogeneous networks, that deploy an overlay of small cells with limited coverage and transmit power, over a macro coverage area is the solution by providing capacity and coverage where it is needed.This book presents a comprehensive overview of small cell based heterogeneous networks within the framework of 3GPP LTE-Advanced which is the major enabler of current and future heterogeneous networks. The book first establishes the basics of LTE standards 8 -10. Wherever relevant, the underlying theory of wireless communications is explained and the signaling and protocol aspects of LTE Releases 8-10 are presented. Next the book presents a systematic study of the inter cell interference (eICIC and FeICIC) mechanisms that have been standardized in LTE releases 10 and 11 to mitigate the interference arising in heterogeneous networks. From simple blank subframe design and implementation, the book discusses more advanced transceiver signal processing and carrier aggregation (CA) based mechanisms to improve performance. Besides data, control channel enhancements such as enhanced PDCCH (ePDCCH) are also discussed.Subsequently the book discusses the possibility of base stations being allowed to coordinate to manage interference. This technique, called CoMP, has the potential of vastly improving network performance. However several practical challenges first have to be overcome before this potential can be realized. The book presents the different CoMP categories introduced in LTE release 11, the required signal processing and the changes that were introduced in Release-11 for supporting CoMP. The book then presents the state of the art developments in heterogeneous networks that are currently taking place in 3GPP with the initiation of Release 12. A whole array of new technologies have been introduced such as dynamic switching of small cells, new carrier types with reduced control signaling, dynamic reconfiguration of TDD-LTE, joint configuration of TDD and FDD via carrier aggregation and lastly advanced MIMO signal processing with three dimensional beamforming. All these technologies will work in unison leading to efficient operations of small cells.The authors thus comprehensively summarize the advances in heterogeneous networks over the last couple of years as reflected in various LTE releases and then look ahead at what to expect in the future. Fully illustrated throughout and with an accompanying website including Matlab code for simulating heterogeneous networks, LTE channel models, and References to 3GPP specifications, contributions, and updates on recent standardization activities. The authors, being involved in LTE standardization, are well placed to give an excellent view on this topic, including valuable background and design rationale.* A comprehensive summary of wireless communications theory and practical developments in LTE heterogeneous networks.* Authors are experts in this field and are active members in standardization proceedings, enabling up-to-date coverage of current developments* Multiple case studies explain network design optimization of various heterogeneous network deployments.* Accompanying website includes Matlab code for simulating heterogeneous networks, LTE channel models, and References to 3GPP specifications, contributions, and updates on recent standardization activitiesEssential reading for Engineers and practitioners in wireless industry.

About the Authors xiForeword xiiiPreface xvAcknowledgements xviiList of Acronyms xix1 An Introduction to Heterogeneous Networks 11.1 Introduction 11.2 Heterogeneous Network Deployments 31.2.1 Distributed Antenna Systems 31.2.2 Public Access Picocells/Metrocells 41.2.3 Consumer-Grade Femtocells 41.2.4 WiFi Systems 51.3 Features of Heterogeneous Networks 51.3.1 Association and Load Balancing 51.3.2 Interference Management 61.3.3 Self-Organizing Networks 61.3.4 Mobility Management 71.4 Evolution of Cellular Technology and Standards 71.4.1 3GPP Standardization Process 9References 10Part I OVERVIEW2 Fundamentals of LTE 152.1 Introduction 152.2 LTE Core Network 172.2.1 Control Plane 182.2.2 User Plane 192.2.3 Practical Implementations of the Core Network 192.3 LTE Radio Access Network 202.3.1 Control Plane 202.3.2 User Plane 232.4 Connectivity Among eNodeBs: The X2 Interface 242.4.1 Load- and Interference-Related Information 262.4.2 Handover-Related Information 262.5 Technologies in LTE 272.5.1 Orthogonal Frequency Division Multiplexing 272.5.2 Multiple Antenna Communications 36References 423 LTE Signal Structure and Physical Channels 453.1 Introduction 453.2 LTE Signal Structure 453.3 Introduction to LTE Physical Channels and Reference Signals 483.4 Resource Block Assignment 513.5 Downlink Physical Channels 543.5.1 Physical Broadcast Channel (PBCH) 553.5.2 Physical Downlink Shared Channel (PDSCH) 573.5.3 Physical Multicast Channel (PMCH) 583.5.4 Physical Control Format Indicator Channel (PCFICH) 583.5.5 Physical Hybrid ARQ Indicator Channel (PHICH) 593.5.6 Physical Downlink Control Channel (PDCCH) 603.6 Uplink Physical Channels 673.6.1 Physical Uplink Shared Channel (PUSCH) 673.6.2 Physical Uplink Control Channel (PUCCH) 683.6.3 Physical Random Access Channel (PRACH) 70References 714 Physical Layer Signal Processing in LTE 734.1 Introduction 734.2 Downlink Synchronization Signals 734.2.1 Primary Synchronization Signal 744.2.2 Secondary Synchronization Signal 764.3 Reference Signals 774.3.1 Downlink Reference Signals 774.3.2 Uplink Reference Signals 844.4 Channel Estimation and Feedback 854.4.1 Basics of Link Adaptation 854.4.2 Feedback for MIMO OFDM Channels 884.4.3 New Features in LTE-Advanced 924.5 Design Paradigm of LTE Signaling 944.6 Scheduling and Resource Allocation 944.6.1 Scheduling Algorithms 964.6.2 Inter-eNodeB Coordination for Resource Allocation in LTE 98References 100Part II INTER-CELL INTERFERENCE COORDINATION5 Release 10 Enhanced ICIC 1035.1 Introduction 1035.2 Typical Deployment Scenarios 1035.2.1 Macro-Pico Deployment Scenario 1045.2.2 Macro-Femto Deployment Scenario 1075.3 Time Domain Techniques 1105.3.1 Almost Blank Subframe 1105.3.2 ABS Use Cases 1135.3.3 UE Measurement and Reporting 1165.3.4 Backhaul Support 1185.3.5 Simulation Results 1195.4 Power Control Techniques 1235.4.1 Target Scenario 1235.4.2 Power Control Schemes 1245.4.3 Results from Realistic Deployments 1255.5 Carrier Aggregation-Based eICIC 127References 1306 Release 11 Further Enhanced ICIC: Transceiver Processing 1336.1 Introduction 1336.2 Typical Deployment Scenarios 1336.3 Techniques for Mitigating CRS Interference 1366.3.1 Receiver-Based Techniques 1366.3.2 Transmitter-Based Techniques 1406.4 Weak Cell Detection 1426.5 Non-Zero-Power ABS 144References 1477 Release 11 Further Enhanced ICIC: Remaining Topics 1497.1 Carrier-Based Interference Coordination 1497.1.1 Operational Carrier Selection 1507.1.2 Primary and Secondary Cell Selection 1537.2 Enhanced PDCCH for Interference Coordination 154References 159Part III COORDINATED MULTI-POINT TRANSMISSION RECEPTION8 Downlink CoMP: Signal Processing 1638.1 Introduction 1638.2 CoMP Scenarios in 3GPP 1648.2.1 Homogeneous Networks with Intra-Site CoMP 1648.2.2 Homogeneous Networks with High-Power RRHs 1658.2.3 Heterogeneous Networks with Low-Power RRHs with Cell IDs Different from the Macro 1658.2.4 Heterogeneous Networks with Low-Power RRHs with Cell IDs the Same as the Macro 1668.3 CoMP Sets 1678.3.1 RRM Measurement Set/CoMP Resource Management Set 1678.3.2 CoMP Measurement Set 1688.3.3 CoMP Cooperating Set 1698.4 CoMP Transmission in 3GPP 1698.4.1 Coordinated Scheduling/Beamforming 1698.4.2 Dynamic Point Selection 1728.4.3 Joint Transmission 1778.5 Comparison of Different CoMP Categories 180References 1829 Downlink CoMP: Standardization Impact 1859.1 Introduction 1859.2 Modification of Reference Signals 1859.2.1 Modifications in CSI-RS 1859.2.2 Modifications in DMRS 1869.3 CSI Processes 1899.3.1 UE Processing Complexity and CSI Reference Resources 1919.3.2 Inheritance and Reference Processes 1929.4 PDSCH Rate Matching 1939.5 Quasi-Co-Location of Antenna Ports 1959.5.1 Quasi-Co-Location Between the Same Antenna Ports 1979.5.2 Quasi-Co-Location Between Different Antenna Ports 1989.6 New Transmission Mode and DCI Format 2009.7 Backhaul Support for CoMP 2019.8 Summary 203References 203Part IV UPCOMING TECHNOLOGIES10 Dense Small Cell Deployments 20710.1 Introduction 20710.2 Evolution of Small Cells 20710.2.1 Deployment Scenarios 20910.3 Efficient Operation of Small Cells 21210.3.1 Dual Connectivity 21410.3.2 ICIC Mechanism 21610.3.3 Small Cell Discovery 22010.4 Control Signaling Enhancement 22310.4.1 Multi-Subframe Scheduling 22310.4.2 Cross-Subframe Scheduling 22410.5 Reference Signal Overhead Reduction 22510.5.1 Downlink DMRS 22510.5.2 Uplink DMRS 227References 22811 TD-LTE Enhancements for Small Cells 23111.1 Enhancements for Dynamic TDD 23111.1.1 TDD UL/DL Reconfiguration Scenarios in 3GPP 23211.1.2 Interference Mitigation Schemes 23411.2 FDD-TDD Joint Operation 23911.2.1 Deployment Scenarios 24011.2.2 Issues and Potential Solutions 241References 24312 Full Dimension MIMO 24512.1 Introduction 24512.2 Antenna Systems Architecture: Passive and Active 24512.3 Antenna Patterns 24812.3.1 Passive Antenna Element Pattern 24812.3.2 Active Antenna Systems 25012.3.3 AAS with Additional Mechanical Tilt 25312.3.4 Effect of Multipath Fading Channels 25312.4 FD-MIMO Deployment Scenarios 25412.4.1 UE-Specific FD-MIMO 25412.4.2 Cell-Specific FD-MIMO 25512.4.3 System-Specific FD-MIMO 25512.5 Conclusion 256References 25613 Future Trends in Heterogeneous Networks 25713.1 Summary 25713.2 Small Cells and Cloud RAN 25813.3 Small Cells, Millimeter Wave Communications and Massive MIMO 25913.4 Small Cells and Big Data 26013.5 Concluding Remarks 260References 260Index 263