A comprehensive resource to the latest developments of system enhancement techniques of Femtocells, power management, interference mitigation and antenna design
LTE Communications and Networks fills a gap in the literature to offer a comprehensive review of the most current developments of LTE Femtocells and antennas and explores their future growth. With contributions from a group of experts that represent the fields of wireless communications and mobile communications, signal processing and antenna design, this text identifies technical challenges and presents recent results related to the development, integration and enhancement of LTE systems in portable devices.
The authors examine topics such as application of cognitive radio with efficient sensing mechanisms, interference mitigation and power management schemes for the LTE systems. They also provide a comprehensive account of design challenges and approaches, performance enhancement techniques and effects of user’s presence on the LTE antennas. LTE Communications and Networks also highlights the promising technologies of multiband, multimode and reconfigurable antennas for efficient design of portable LTE devices. Designed to be a practical resource, this text:
- Explores the interference mitigation, power control and spectrum management in LTE Femtocells and related issues
- Contains information on the design challenges, different approaches, performance enhancement and application case scenarios for the LTE antennas
- Covers the most recent developments of system enhancement techniques in terms of Femtocells, power management, interference mitigation and antenna design
- Includes contributions from leading experts in the field
Written for industry professionals and researchers, LTE Communications and Networks is a groundbreaking book that presents a comprehensive treatment to the LTE systems in the context of Femtocells and antenna design and covers the wide range of issues related to the topic.
Table of Contents
List of Contributors xv
Preface xvi
1 Introduction 1
Ghazanfar Ali Safdar and Masood Ur Rehman
1.1 Evolution of Wireless and Cellular Communication 2
1.1.1 1 G 3
1.1.2 2 G 3
1.1.3 2.5 G 3
1.1.4 2.75 G 4
1.1.5 3 G 4
1.1.6 3.5 G 4
1.1.7 4 G/LTE 5
1.2 LTE Architecture 5
1.2.1 Communications Perspective Challenges in LTE Networks 8
1.2.1.1 Signalling System 8
1.2.1.2 Backward Compatibility 9
1.2.1.3 BS Efficiency 9
1.2.2 LTE Radio Frame 10
1.3 LTE Antennas 11
1.4 LTE Applications 11
1.4.1 Communications 11
1.4.2 Public Safety 12
1.4.3 DeviceÂ]toÂ]Device Communications 12
1.4.4 Video Streaming 12
1.4.5 Voice over LTE (VoLTE) 12
1.4.6 Internet of Things 13
1.4.7 Wearable Systems 13
1.4.8 Cloud Computing 13
1.5 Book Organization 14
References 16
Part I LTE Femtocells 19
2 LTE Femtocells 21
Ghazanfar Ali Safdar
2.1 Introduction 21
2.1.1 CrossÂ]Tier Interference 22
2.1.2 CoÂ]Tier Interference 24
2.1.3 Downlink Interference Modelling 24
2.1.4 Uplink Interference Modelling 25
2.2 Platform for Femtocell Deployment 26
2.3 LTE Architecture Overview 26
2.3.1 LTE Downlink Transmission 27
2.3.2 LTE Uplink Transmission 27
2.4 LTE Femtocell Interference Analysis 28
2.4.1 Scenario 1: CrossÂ]Tier Interference Analysis 28
2.4.2 Scenario 2: Effects of Femtocell Access Mode Deployment 28
2.4.3 Scenario 3: CoÂ]Tier Interference Analysis 29
2.4.4 Scenario 4: Effects of Varying FAP Transmit Power Levels on MUEs 29
2.5 Interference Mitigation: Current State of the Art 31
2.5.1 Spectrum Access/Frequency Assignment 31
2.5.2 Power Control 32
2.5.3 Antenna Schemes 33
2.6 Cognitive Femtocells: A Smart Solution to a Complex Problem 33
2.7 Summary 35
References 36
3 Interference Mitigation in Cognitive RadioÂ]Based LTE Femtocells 38
Ghazanfar Ali Safdar
3.1 Introduction 39
3.2 Femtocells 41
3.2.1 Femtocells – Interference versus Deployment 43
3.2.2 Femtocells – Typical Interference Mitigation Techniques 46
3.2.2.1 Spectrum Access/Frequency Assignment Schemes 46
3.2.2.2 Power Control (PC) Schemes 46
3.2.2.3 Antenna Schemes 48
3.3 Interference Mitigation in Femtocells using Cognitive Radio 49
3.3.1 Cognitive Interference Mitigation 51
3.3.1.1 Cognitive Interference Mitigation – PC 52
3.3.1.2 Cognitive Interference Mitigation – Spectrum Access 54
3.3.1.3 Cognitive Interference Mitigation – Antenna Schemes 64
3.3.1.4 Cognitive Interference Mitigation – Joint Schemes 66
3.3.2 Cognitive Interference Mitigation versus Conventional Interference Mitigation 70
3.4 Summary 74
References 75
4 Coverage AreaÂ]Based Power Control for Interference Management in LTE Femtocells 84
Ghazanfar Ali Safdar
4.1 Introduction 85
4.2 Coverage Radius Based Power Control Scheme (PS) 88
4.2.1 Radius Limit Setting 89
4.2.2 Initial Coverage Radius 89
4.2.3 SelfÂ]Update 89
4.2.4 Final Radius 89
4.3 System Model 90
4.4 Performance Analysis 92
4.4.1 Results and Discussion 93
4.4.1.1 SINR CrossÂ]Tier (Single Cell) 93
4.4.1.2 SINR CoÂ]Tier (Single Cell) 94
4.4.1.3 Downlink Throughput (Single Cell) 95
4.4.1.4 CoÂ] and CrossÂ]Tier SINR (Single Cell versus Multicell) 96
4.4.1.5 Droppage in SINR (Single Cell versus Multicell) 97
4.4.1.6 Coverage Area Bounds and Impact on SINR (Single Cell versus Multicell) 99
4.5 Summary 100
References 101
5 Energy Management in LTE Femtocells 104
Kapil Kanwal, Ghazanfar Ali Safdar, Masood Ur Rehman and Xiaodong Yang
5.1 Introduction 105
5.2 Architecture of LTE Networks 105
5.2.1 Communications Perspective Challenges in LTE Networks 106
5.2.1.1 Signalling System 106
5.2.1.2 Backward Compatibility 107
5.2.1.3 BS Efficiency 107
5.2.2 Importance of Energy Management in LTE Networks 108
5.3 Classification of ES Schemes 108
5.3.1 Static Power Consumption 109
5.3.2 Dynamic Power Consumption 109
5.4 Energy Efficient Resource Allocation 113
5.4.1 Hybrid FBS and MBS Based Schemes 113
5.4.2 Link Adaptation Schemes 114
5.4.3 Cross Layer Resource Allocation Schemes 115
5.4.4 MBSFN Resource Allocation Scheme 115
5.5 Bandwidth Expansion Schemes 117
5.5.1 CoMP Based Coverage Expansion 117
5.5.2 Time Compression (TCoM) Scheme 118
5.5.3 Bandwidth Expansion Mode (BEM) Scheme 119
5.5.4 Component Carrier Based Schemes 121
5.5.5 Scheduling Based Schemes 122
5.6 Load Balancing Schemes 123
5.6.1 Distance Aware Schemes 123
5.6.2 Coverage Expansion Based Schemes 125
5.6.3 Distributed Schemes 125
5.6.4 Shared Relay Based Schemes 127
5.6.5 CRN Adopted Switching Off of a BS 128
5.6.6 Reduced Early Handover (REHO) Scheme 129
5.7 Comparative Analysis 130
5.8 Open Research Issues 135
5.9 Summary 139
References 140
6 Spectrum Sensing Mechanisms in Cognitive Radio Based LTE Femtocells 150
Tazeen S. Syed and Ghazanfar Ali Safdar
6.1 Fundamentals of Signal Processing 151
6.1.1 Channel Model 151
6.1.1.1 Additive Gaussian Noise Channel 151
6.1.1.2 Linear Filter Channel 152
6.1.1.3 Band Limited Channel 153
6.1.2 Modulation Technique 153
6.1.3 Error Probability 154
6.2 Spectrum Sensing Techniques 155
6.2.1 Primary Transmitter Detection 155
6.2.1.1 Energy Detector 156
6.2.1.2 Matched Filter Detection 158
6.2.1.3 Cyclostationary Feature Detection 159
6.2.1.4 Waveform Detection 160
6.2.1.5 Wavelet Detection 161
6.2.1.6 Hybrid Sensing 162
6.2.1.7 MultiÂ]Taper Spectrum Sensing 163
6.2.2 Collaborative/Cooperative Detection 163
6.2.3 Interference Temperature Detection 166
6.2.4 Primary Receiver Detection 166
6.3 History Assisted Spectrum Sensing 166
6.4 ModelÂ]and StatisticsÂ]Based Spectrum Sensing Classification 167
6.5 Challenges and Issues 172
6.6 Summary 176
References 177
Part II Antennas for LTE Femtocells 185
7 Antenna Consideration for LTE Femtocells 187
Masood Ur Rehman
7.1 Antenna Fundamentals 187
7.1.1 Input Impedance and Matching 188
7.1.2 Bandwidth 189
7.1.3 Radiation Pattern 190
7.1.4 Directivity and Gain 191
7.1.5 Efficiency 193
7.1.6 Polarization 193
7.2 Antenna Requirements for LTE Femtocells 196
7.2.1 Frequency Bands 197
7.2.2 Form Factor and Size Limitation 201
7.2.3 Impedance Matching, Directivity, Gain and Efficiency 201
7.2.4 Directionality 202
7.2.5 Polarization 203
7.2.6 Human Body Effects and Specific Absorption Rate (SAR) 204
7.2.7 Multiple Input Multiple Output (MIMO) 205
References 206
8 Multiband Antennas for LTE Femtocells 209
Masood Ur Rehman and Xiaodong Yang
8.1 Fundamentals of Multiband Antennas 209
8.1.1 Multiband Techniques 210
8.1.1.1 Higher Order Resonances 210
8.1.1.2 Multiple Resonant Structures 211
8.2 Types of Multiband Antennas 211
8.3 Multiband Antenna Design: Case Studies 214
8.3.1 MultiÂ]Slot Antenna 215
8.3.1.1 Antenna Geometry 215
8.3.1.2 Antenna Performance Evaluation 215
8.3.2 PatchÂ]Loop Combination Antenna 220
8.3.2.1 Antenna Configuration 220
8.3.2.2 Antenna Performance 220
8.4 Open Research Issues 227
References 227
9 Reconfigurable Antennas for LTE Femtocells 230
Masood Ur Rehman and Waqas Farooq
9.1 Fundamentals of Reconfigurable Antennas 230
9.1.1 Types of Reconfigurable Antennas 231
9.1.1.1 Use of Switches 232
9.1.1.2 Structural and Mechanical Changes 232
9.1.1.3 Material Changes 234
9.2 Realization of Reconfigurable Antennas 234
9.3 Rectangular Patch Reconfigurable LTE Femtocell Antenna 237
9.3.1 Design Conception 237
9.3.2 Frequency Reconfiguration Mode 239
9.3.3 Antenna Performance Evaluation 240
9.4 Circular Patch Reconfigurable LTE Femtocell Antenna 246
9.4.1 Frequency Reconfiguration Mode 248
9.4.2 Antenna Performance Evaluation 248
9.5 Open Research Issues 253
References 254
10 Multimode Antennas for LTE Femtocells 259
Oluyemi Peter Falade, Xiaodong Chen and Masood Ur Rehman
10.1 Multimode Antennas: Fundamentals and Types 260
10.2 Design of a Compact Multimode LTE Femtocell Antenna for Handheld Devices 261
10.2.1 Numerical Analysis 263
10.2.2 Experimental Investigation 266
10.3 Design of a Multifunctional Compact Antenna for LTE Femtocells and GNSS Systems 268
10.3.1 Numerical Analysis 273
10.3.2 Experimental Investigation 279
10.4 Summary 284
10.5 Open Challenges and Issues 284
References 284
11 Human Body Effects on LTE Femtocell Antennas 289
Masood Ur Rehman and Qammer Hussain Abbasi
11.1 Interaction of the Human Body with Antennas 290
11.2 Numerical Modelling of the Human Body 291
11.2.1 Evaluation and Comparison of Numerical Models of Human Body 294
11.2.1.1 OnÂ]Body Transmission 294
11.2.1.2 Effects on Antenna Radiation Pattern 297
11.2.1.3 Electric Field Distribution 299
11.2.1.4 Specific Absorption Rate (SAR) 300
11.3 Evaluation of Human Body Effects on LTE Femtocell Antennas 305
11.3.1 OnÂ]Body Antenna Placement 308
11.3.2 AntennaÂ]Body Separation 310
11.3.3 OnÂ]Body LTE Channel Characterization 312
11.3.4 OnÂ]Off Body LTE Channel Characterization 313
11.3.5 BodyÂ]toÂ]Body LTE Channel Characterization 315
11.4 Open Research Issues 316
References 317
12 The Road Ahead for LTE Femtocells 322
Masood Ur Rehman and Ghazanfar Ali Safdar
12.1 Future Prospects and Challenges 323
12.1.1 Spectrum Sharing 324
12.1.2 Intelligent/Efficient Spectrum Sensing Schemes 324
12.1.3 Primary/Secondary User Issue 325
12.1.4 Energy Saving 325
12.1.5 Security 326
12.1.6 Pilot Power/Coverage Radius Issue 326
12.1.7 Signalling Overhead 326
12.1.8 Proximity Services 326
12.1.9 The InternetÂ]ofÂ]Things (IoT) 327
12.1.10 The Age of Big Data 328
12.1.11 5G and Femtocells 328
12.1.12 Antenna Design and Channel Modelling 328
References 330
Index 332
