Optical Wireless Communications (eBook)

Murat Uysal received the B.Sc. and the M.Sc. degree in electronics and communication engineering from Istanbul Technical University, Istanbul, Turkey, in 1995 and 1998, respectively, and the Ph.D. degree in electrical engineering from Texas A&M University, College Station, Texas, in 2001. Dr. Uysal is currently a Full Professor and Chair of the Department of Electrical and Electronics Engineering at Ozyegin University, Istanbul, Turkey. Prior to joining Ozyegin University, he was a tenured Associate Professor at the University of Waterloo (Canada) where he still holds an adjunct faculty position. Prof. Uysal’s research interests are in the broad areas of communication theory and signal processing with a particular emphasis on the physical layer aspects of wireless communication systems in radio and optical frequency bands. He has authored more than 220 journal and conference papers on these topics and received more than 3800 citations. Prof. Uysal currently serves on the editorial boards of IEEE Transactions on Communications, IEEE Transactions on Vehicular Technology, Wiley Wireless Communications and Mobile Computing (WCMC) Journal, and Wiley Transactions on Emerging Telecommunications Technologies (ETT). In the past, he served as an Editor for IEEE Transactions on Wireless Communications (2003-2011), IEEE Communications Letters (2004-2012), Guest Co-Editor for WCMC Special Issue on MIMO Communications (October 2004) and IEEE Journal on Selected Areas in Communications Special Issues on Optical Wireless Communications (December 2009 and June 2015). Prof. Uysal is the Chair of the EU COST Action OPTICWISE which is a high-profile consolidated European scientific network for interdisciplinary research activities in the area of optical wireless communications.Carlo Capsoni graduated in Electronic Engineering at the Politecnico di Milano, Milano, Italy, in 1970 and in the same year joined the “Centro di Studi per le Telecomunicazioni Spaziali” (CSTS), research centre of the Italian National Research Council (CNR), Politecnico di Milano, Milano, Italy. In this position, he was in charge of the installation of the meteorological radar of the CNR sited at Spino d’Adda, Italy, and since then, he has been the scientific responsible for radar activity. In 1979, he was actively involved in the satellite Sirio SHF propagation experiment (11–18 GHz) and later in the Olympus (12, 20, and 30 GHz) and Italsat (20, 40, and 50 GHz) satellite experiments. His scientific activity mainly focuses on theoretical and experimental aspects of electromagnetic-wave propagation at centimetre and millimetre wavelengths in the presence of atmospheric precipitation with a particular emphasis on attenuation, wave depolarization, incoherent radiation, interference due to hydrometeor scatter, precipitation-fade countermeasures, modelling of the radio channel, and the design of advanced satellite-communication systems. He is also active in free-space optics theoretical and experimental activities. Since 1975, he has been teaching a course on aviation electronics at the Politecnico di Milano, where he became Full Professor of Electromagnetics in 1986. Prof. Capsoni was a member of the ITU national group and was the Italian delegate in COST projects of the European Economic Community related to propagation aspects of telecommunications (COST 205, 210).He is a member of the Italian Society of Electromagnetics (SIEm) and editor of the SIEm Magazine. He is also a member of the Coritel governing body. Prof. Capsoni currently serves as the Chair of OPTICWISE Working Group on “Propagation Modelling and Channel Characterization”.Zabih Ghassemlooy received his BSc (Hons) from the Manchester Metropolitan University in 1981, and MSc and PhD from the University of Manchester Institute of Science and Technology (UMIST), in 1984 and 1987, respectively. During 1986-87, he worked in UMIST and from 1987 to 1988 he was a Post-doctoral Research Fellow at the City University, London. In 1988, he joined Sheffield Hallam University as a Lecturer, becoming a Professor in Optical Communications in 1997. During 2004-2012, he was an Associate Dean for Research in the School of Computing, Engineering and from 2012-2014 Associate Dean for Research and Innovation in the Faculty of Engineering and Environment, Northumbria University at Newcastle, UK. He currently heads the Northumbria Communications Research Laboratories within the Faculty. He has been a visiting professor at a number of institutions and currently is at University Tun Hussein Onn Malaysia. He is the Editor-in-Chief of the International Journal of Optics and Applications, and British Journal of Applied Science Technology. His researches interests are on optical wireless communications, visible light communications and radio over fibre/free-space optics. He has over 48 PhD students and published over 550 papers (195 in journals + 4 books) and presented over 65 keynote and invited talks. He is a co-author of a CRC book on “Optical Wireless Communications – Systems and Channel Modelling with MATLAB®(2012); a co-editor of an IET book on “Analogue Optical Fibre Communications”. From 2004-06 he was the IEEE UK/IR Communications Chapter Secretary, the Vice-Chairman (2004-2008), the Chairman (2008-2011), and Chairman of the IET Northumbria Network (Oct 2011-..) Prof. Ghassemlooy is the Vice Chair of the EU COST Action OPTICWISE and also serves as the Chair of OPTICWISE Working Group on “Physical Layer Algorithm Design and Verification”.Anthony C. Boucouvalas is a Professor in Communications Networks and Applications at the University of Peloponnese in Tripoli, Greece. Prof. Boucouvalas has been actively involved with research in various aspects of fibre optic communications, wireless communications and multimedia and has an accumulated 35 years experience in well known academic and industrial research centres. He graduated with a B.Sc. in Electrical and Electronic Engineering from Newcastle upon Tyne University in 1978. He received his MSc and D.I.C. degrees in Communications Engineering, in 1979, from Imperial College, where he also received his PhD degree in Fibre Optics in 1982. Subsequently he joined GEC Hirst Research Centre, and became Group Leader and Divisional Chief Scientist working on fibre optic components, measurements and sensors, until 1987, when he joined Hewlett Packard Laboratories as Project Manager. At HP he worked in the areas of optical communication systems, optical networks, and instrumentation, until 1994, when he joined Bournemouth University. In 1996, he became a Professor in Multimedia Communications and in 1999 the Director of the Microelectronics and Multimedia research Centre at Bournemouth University. In 2007, he joined the Department of Telecommunication Science at the University of Peloponnese where he served for 6 years as Head of Department. His current research interests lie in optical wireless communications, fibre optic communications, inverse fibre optic problems, network protocols, and human-computer interfaces and Internet Applications. He has published over 300 scientific papers. He is a Fellow of IET, a Fellow of IEEE, (FIEEE), and a Fellow of the Royal Society for the encouragement of Arts, Manufacturers and Commerce. Prof. Boucouvalas currently serves as the Chair of OPTICWISE Working Group on “Networking Protocols”.Eszter UdvaryReceived Ph.D. degree in electrical engineering from Budapest University of Technology and Economics (BME), Budapest, Hungary, in 2009. She is currently an associate professor at BME, Department of Broadband Infocommunications and Electromagnetic Theory, where she leads the Optical and Microwave Telecommunication Lab. She currently teaches courses on optical communication devices and networks. Dr. Udvary’s research interests are in the broad areas of optical communications, include optical and microwave communication systems, radio over fibre systems, optical and microwave interactions and applications of special electro-optical devices. Her special research focuses on multifunctional semiconductor optical amplifier application techniques. She is deeply involved in visible light communication, indoor optical wireless communication and microwave photonics techniques. Dr. Udvary has authored more than 80 journal and conference papers, and one book chapter. She currently serves as the Chair of OPTICWISE Working Group on “Advanced Photonic Components”.

Preface 6
Contents 9
1 An Overview of Optical Wireless Communications 21
Abstract 21
1.1 Introduction 22
1.2 Historical Overview and Current Status 25
1.3 Existing and Envisioned Application Areas 27
1.3.1 Ultra Short Range OWC Applications 29
1.3.2 Short Range OWC Applications 30
1.3.3 Medium Range OWC Applications 32
1.3.4 Long Range OWC Applications 34
1.3.5 Ultra Long Range OWC Applications 37
1.4 Conclusions 39
References 39
2 Optical Propagation in Unguided Media 44
Abstract 44
2.1 Introduction 44
2.2 Degrading Effects of Turbulence 45
2.3 Power Spectra of Turbulence in Free Space Optics (FSO), Slant Satellite and Underwater Links 46
2.4 Rytov Method 48
2.5 Extended Huygens–Fresnel Principle 51
2.6 Average Received Intensity 52
2.7 Intensity and Power Scintillation Index 52
2.8 Bit Error Rate 55
2.9 Beam Effects in Turbulent Medium 56
2.10 Mitigation Methods to Reduce Turbulence Effects 60
2.11 Sample Results 61
2.12 Conclusions and Future Directions 62
References 62
3 Effects of Adverse Weather on Free Space Optics 65
Abstract 65
3.1 Introduction 65
3.2 Gas Absorption 67
3.3 Propagation Through Atmospheric Particulates 67
3.3.1 Refractive Index of Water 69
3.3.2 Electromagnetic Computation: Mie Theory 69
3.3.3 Asymptotic Theories 70
3.4 Multiple Scattering Effects 71
3.5 Fog and Clouds 73
3.5.1 Fog Types 73
3.5.2 Cloud Types 74
3.5.3 Microphysical Characterization 75
3.5.4 Specific Attenuation 75
3.6 Rain 80
3.6.1 Microphysical Characterization 80
3.6.2 Specific Attenuation 81
3.7 Snow 82
3.7.1 Microphysical Characterization 82
3.7.2 Specific Attenuation 83
3.8 Conclusions and Recommendations 84
References 84
4 Experimental Validation of FSO Channel Models 87
Abstract 87
4.1 Introduction 87
4.2 Total Attenuation 90
4.3 Measurement of Fog Attenuation 91
4.4 Modeling of DSD in Fog and Clouds 94
4.4.1 Experimental Data 95
4.4.2 Analysis of LWC and PSA 97
4.5 Rain Attenuation 98
4.6 Impact of Atmospheric Turbulences 100
4.7 Conclusion 101
References 102
5 Channel Characterization and Modeling for LEO-Ground Links 105
Abstract 105
5.1 Introduction 105
5.2 Atmospheric Turbulence 108
5.2.1 Scintillation 109
5.2.2 Fading Statistics 112
5.3 Measurements 114
5.3.1 KIODO Campaign 114
5.3.2 Instrument 115
5.3.3 Results 117
5.3.3.1 Power Scintillation 117
5.3.3.2 Signal Fading 117
5.4 Modeling Approach of Power Scintillation 118
5.5 Conclusions and Future Directions 121
References 121
6 Channel Modeling for Visible Light Communications 124
Abstract 124
6.1 Introduction 124
6.2 Channel Modeling Approach 126
6.3 CIR for an Empty Room 128
6.4 Effect of Surface Materials, Objects, and Transmitter/Receiver Specifications on CIR 133
6.5 Conclusion 138
Acknowledgments 138
References 138
7 Diffraction Effects and Optical Beam Shaping in FSO Terminals 140
Abstract 140
7.1 Introduction 141
7.2 Wave Effects in OWC 141
7.3 Modeling of Diffraction Effects in Terrestrial FSO Links 142
7.4 Simulation, Assessment, and Discussion 146
7.5 Geometrical and Pointing Loss 148
7.6 Optical Beam Shaping 150
7.7 FG Beams and Transformation Techniques 151
7.8 FG Beam Propagation, Scintillation and Averaging Effect 152
7.9 Conclusions and Future Directions 158
References 158
8 Ultraviolet Scattering Communication Channels 161
Abstract 161
8.1 Introduction 162
8.2 Historical and Technological Perspectives 163
8.3 Ultraviolet Channel Propagation Effects 164
8.3.1 Non-Line-of-Sight Channel Geometry 164
8.3.2 Tropospheric Ultraviolet Absorption and Scattering 165
8.3.3 Tropospheric Turbulence and Ultraviolet Scintillation 170
8.4 Ultraviolet Scattering Channel Models 170
8.4.1 Radiative Transfer in Turbid Media 172
8.4.2 Single-Scattering Impulse Response and Path Loss Models 173
8.4.3 Multiple Scattering Numerical and Approximate Models 176
8.4.4 Turbulence Effects on Ultraviolet Propagation 179
8.5 Ultraviolet Experimental Results and System Analysis 180
8.5.1 NLOS-UV Measurements and Model Inter-comparisons 180
8.5.2 NLOS-UV System Performance Analysis 181
8.6 Conclusions and Future Directions 183
References 183
9 Information Theoretical Limits of Free-Space Optical Links 187
Abstract 187
9.1 Introduction 189
9.1.1 General Background 189
9.1.1.1 Free-Space Optics (FSO) 189
9.1.2 Motivation 191
9.1.3 Objectives and Contributions 192
9.1.4 Structure 193
9.2 System and Channel Models 193
9.2.1 Atmospheric Turbulences 193
9.2.1.1 Gamma (G) Turbulence Scenario 194
9.2.1.2 Lognormal (LN) Turbulence Scenario 195
9.2.1.3 Rician–Lognormal (RLN) Turbulence Scenario 195
9.2.1.4 Gamma–Gamma (/Gamma /Gamma) Turbulence Scenario 196
9.2.1.5 Málaga ({{/cal M}}) Turbulence Scenario 196
9.2.1.6 Double Generalized Gamma (DGG) Turbulence Scenario 197
9.2.2 Pointing Errors 198
9.2.2.1 General Beckmann Pointing Error Model 199
9.2.2.2 Special Cases 201
9.2.3 Closed-Form Statistical Probability Density Functions (PDF) 204
9.2.3.1 Gamma (G) Turbulence Scenario 204
9.2.3.2 Lognormal (LN) Turbulence Scenario 205
9.2.3.3 Rician–Lognormal (RLN) Turbulence Scenario 205
9.2.3.4 Málaga ({{/cal M}}) and Gamma–Gamma ({/Gamma /Gamma }) Turbulence Scenarios 206
9.2.3.5 Double Generalized Gamma (DGG) Turbulence Scenario 207
9.2.4 Important Outcomes and Further Motivations 207
9.3 Exact Analysis 208
9.3.1 Gamma (G) Atmospheric Turbulence 208
9.3.2 Málaga ({{/cal M}}) and Gamma–Gamma ({/Gamma /Gamma }) Atmospheric Turbulences 208
9.3.3 Double Generalized Gamma (DGG) Atmospheric Turbulence 209
9.3.4 Results and Discussion 210
9.3.4.1 Málaga ({{/cal M}}) Atmospheric Turbulence 210
9.3.4.2 Double Generalized Gamma (DGG) Atmospheric Turbulence 210
9.4 Asymptotic Analysis 211
9.4.1 Rician–Lognormal (RLN) Atmospheric Turbulence with Boresight Pointing Errors 213
9.4.1.1 Moments-Based Ergodic Capcity Analysis 213
9.4.1.2 Results and Discussion 215
9.4.2 Gamma–Gamma ({/Gamma /Gamma }) Atmospheric Turbulence with Beckmann Pointing Errors 217
9.4.2.1 Moments-Based Ergodic Capcity Analysis 217
9.4.2.2 Results and Discussion 218
9.5 Conclusions and Future Directions 220
References 220
10 Performance Analysis of FSO Communications Under Correlated Fading Conditions 225
Abstract 225
10.1 Introduction 226
10.2 Channel Modeling for FSO Communications 226
10.2.1 Turbulence Modeling for a SISO FSO System 226
10.2.2 Channel Modeling for Space-Diversity FSO Systems 227
10.3 Evaluating Fading Correlation in Space-Diversity FSO Channels 227
10.3.1 Study of Fading Correlation for SIMO Case 228
10.3.1.1 Effect of the Refractive Index Structure Parameter 229
10.3.1.2 Case of Fixed Aperture Diameter 230
10.3.1.3 Case of Fixed Link Distance 230
10.3.2 Fading Correlation in MISO and MIMO Cases 234
10.3.2.1 Fading Correlation in MISO Systems 234
10.3.2.2 General Model for MIMO Systems 234
10.4 Performance Evaluation Over Correlated /Gamma /Gamma Channels via Monte-Carlo Simulations 235
10.4.1 Generation of Correlated /Gamma /Gamma RVs 236
10.4.2 Study of BER Performance by Monte-Carlo Simulations 237
10.4.2.1 Signal Detection Formulation 237
10.4.2.2 Effect of Fading Correlation on BER 238
10.5 Analytical Performance Evaluation of FSO Over Correlated Channels 239
10.5.1 /alpha { - }/mu Approximation to the Sum of Multiple /Gamma /Gamma RVs 240
10.5.2 BER Analysis Based on /alpha { - }/mu Approximation 241
10.5.3 Numerical Results 241
10.6 Conclusions 243
References 243
11 MIMO Free-Space Optical Communication 246
Abstract 246
11.1 Introduction 246
11.2 Channel Modelling 248
11.2.1 Turbulence Statistics 251
11.2.2 FSO Links with Misalignment 252
11.3 MIMO FSO Diversity Techniques 253
11.3.1 Receive Diversity 253
11.3.2 Transmit Diversity 254
11.4 Performance of MIMO FSO Systems 256
11.4.1 Average Error Rate 257
11.4.2 Outage Probability 258
11.4.3 Diversity Gain 260
11.4.4 Aperture Averaging, Correlation, and Near-Field Effects 262
11.5 Distributed MIMO FSO 263
11.6 Conclusions and Future Directions 265
References 266
12 OFDM-Based Visible Light Communications 269
Abstract 269
12.1 Introduction 270
12.2 Unipolar OFDM (U-OFDM) 272
12.2.1 Concept 272
12.2.2 Theoretical Bit Error Rate Analysis 277
12.2.3 Results and Discussion 284
12.3 Enhanced Unipolar Orthogonal Frequency Division Multiplexing (U-OFDM) 287
12.3.1 Concept 287
12.3.2 Spectral Efficiency 289
12.3.3 Theoretical Bit Error Rate Analysis 290
12.3.3.1 Electrical Power 290
12.3.3.2 Optical Power 293
12.3.4 Results and Discussion 295
12.4 Superposition Modulation for Orthogonal Frequency Division Multiplexing (OFDM) 298
12.4.1 Generalised Enhanced Unipolar Orthogonal Frequency Division Multiplexing (U-OFDM) 299
12.4.1.1 Concept 299
12.4.1.2 Spectral Efficiency 299
12.4.1.3 Theoretical Bit Error Rate Analysis 300
12.4.2 Enhanced Asymmetrically-Clipped Optical OFDM (ACO-OFDM) 302
12.4.3 Enhanced Pulse-Amplitude-Modulated Discrete Multitone Modulation (PAM-DMT) 303
12.4.3.1 Concept 303
12.4.3.2 Spectral Efficiency 305
12.4.3.3 Theoretical Bit Error Rate Analysis 307
12.4.4 Results and Discussion 308
12.5 Conclusions and Future Directions 310
Acknowledgments 311
References 311
13 Block Transmission with Frequency Domain Equalization for VLC 313
Abstract 313
13.1 Introduction 313
13.2 Basic Modeling Aspects 315
13.2.1 Intensity Modulation and Direct Detection 315
13.2.2 NRZ-OOK Reference and Optical Power Penalty 316
13.2.3 Power Penalty of PAM in a Flat AWGN Channel 317
13.2.4 Discrete Time PAM Transmission Model 319
13.3 PAM Block Transmission with Cyclic Prefix 320
13.3.1 An Example Illustrating the Cyclic Convolution 320
13.3.2 A High Level Channel Model in Matrix-Vector Notation 321
13.3.3 Equalizer Coefficients 322
13.3.3.1 Symbol Spaced Zero Forcing Equalization 322
13.3.3.2 Fractionally Spaced Zero Forcing Equalization 323
13.3.3.3 Symbol Spaced MMSE Equalization 323
13.3.3.4 Fractionally Spaced MMSE Equalization 325
13.3.4 Impact of a Fixed Timing Error 325
13.4 How to Obtain DC-Balance 326
13.4.1 Line Coding 326
13.4.2 DC-Biased SSC-QAM and Similar Schemes 327
13.4.3 DC-Biased DMT 329
13.5 VLC Channel 330
13.6 Results 333
13.6.1 Performance in Gaussian Lowpass Channels 333
13.6.2 Performance in Multipath Channels 334
13.7 Conclusions 336
References 336
14 Satellite Downlink Coherent Laser Communications 338
Abstract 338
14.1 Introduction 338
14.2 Adaptive Coherent Receivers 340
14.3 Performance of Coherent Laser Downlinks 345
14.4 Outage Capacity of Laser Downlinks 350
14.5 Conclusions 353
Acknowledgments 354
References 354
15 Cooperative Visible Light Communications 357
Abstract 357
15.1 Introduction 357
15.2 Indoor Environment with Illumination Constraints 359
15.3 VLC Indoor Channel Model 361
15.4 System Model 363
15.4.1 Non-cooperative (Direct) Transmission 363
15.4.2 AF Cooperative Transmission 364
15.4.3 DF Cooperative Transmission 366
15.4.4 Cooperative Transmission with Imperfect CSI 368
15.5 Numerical Results 369
15.6 Conclusion and Future Directions 373
Acknowledgments 373
References 373
16 Coded Orbital Angular Momentum Modulation and Multiplexing Enabling Ultra-High-Speed Free-Space Optical Transmission 375
Abstract 375
16.1 Introduction 376
16.2 OAM Modulation and Multiplexing Principles 377
16.3 Signal Constellation Design for OAM Modulation and Multidimensional Signaling Based on OAM 380
16.4 Experimental Study of Coded OAM in the Presence of Atmospheric Turbulence 384
16.5 Adaptive Coding for FSO Communications and Corresponding FPGA Implementation 390
16.6 Conclusion and Future Work 394
Acknowledgments 394
References 394
17 Mixed RF/FSO Relaying Systems 398
Abstract 398
17.1 Introduction 398
17.2 System and Channel Model 401
17.2.1 RF Channel Model 403
17.2.2 FSO Channel Model 405
17.3 Outage Probability Analysis 406
17.3.1 Negligible Pointing Errors 409
17.3.2 System with a Single Relay 409
17.4 Numerical Results 410
17.5 Conclusions and Future Directions 414
References 415
18 Dimming and Modulation for VLC-Enabled Lighting 419
Abstract 419
18.1 Introduction 420
18.2 Digital Modulation with Dimming Concepts 421
18.3 Digital Techniques 422
18.3.1 Data/Dimming Control Modulator 424
18.4 Circuit Architecture 425
18.4.1 Buck Converter Design 426
18.4.2 Data-Dimming Multiplication Method 429
18.4.3 Measurement Results of Digital Modulation with Dimming 430
18.5 Analog Techniques 434
18.6 Conclusions and Future Directions 439
References 439
19 Diversity for Mitigating Channel Effects 441
Abstract 441
19.1 Introduction 442
19.2 Receiver Diversity in Log-Normal Atmospheric Channels 442
19.2.1 Maximum Ratio Combining (MRC) 444
19.2.2 Equal Gain Combining (EGC) 446
19.2.3 Selection Combining (SelC) 448
19.3 Transmitter Diversity in Log-Normal Atmospheric Channels 449
19.4 Transmitter-Receiver Diversity in a Log-Normal Atmospheric Channel 450
19.5 Results and Discussions of SIM-FSO with Spatial Diversity in a Log-Normal Atmospheric Channel 451
19.6 Experimental Set-up 454
19.7 Outdoor Measurements of Diversity Links 457
19.8 Conclusions 460
References 460
20 Multiple Access in Visible Light Communication Networks 461
Abstract 461
20.1 Introduction 462
20.2 Overview of PHY and MAC Layer Design for VLC 463
20.3 IEEE 802.15.7 Channel Access Mechanisms 465
20.4 Markov-Based Random Access Models for 802.15.7 466
20.5 Performance Evaluation for 802.15.7 MAC 468
20.6 Conclusion and Future Directions 470
Acknowledgments 470
References 470
21 Link Layer Protocols for Short-Range IR Communications 472
Abstract 472
21.1 Introduction 472
21.2 Irda Protocol Stack 474
21.2.1 Physical Layer (PHY) 474
21.2.2 Link Access Protocol (IrLAP) 477
21.2.3 Link Management Protocol (IrLMP) 480
21.2.4 Tiny Transport Protocol (TTP) 480
21.2.5 Object Exchange Protocol (OBEX) 481
21.3 IrLAP Functional Model Description 481
21.4 IrLAP MATHEMATICAL MODEL 484
21.5 IrLAP THROUGHPUT ANALYSIS 488
21.6 Conclusions 491
References 491
22 On the Resilient Network Design of Free-Space Optical Wireless Network for Cellular Backhauling 493
Abstract 493
22.1 Introduction 494
22.2 A Review of Related Works 496
22.3 Notations and Problem Definitions 497
22.4 Problem Formulation: A Two-Layer Model 499
22.5 A Path Generation-Based Heuristic Method 504
22.5.1 A New Formulation Based on Paths 504
22.5.2 Path Generation 505
22.5.3 Framework of the Solution Approach 508
22.6 Experimental Results 510
22.6.1 Channel Model 510
22.6.2 The Study of a Deployment Scenario 511
22.6.3 Algorithm Comparisons 513
22.7 Conclusions and Future Directions 516
Acknowledgments 516
References 516
23 FSO for High Capacity Optical Metro and Access Networks 519
23.1 Introduction 519
23.2 Terabit/s OWC for Next Generation Convergent Urban Infrastructures 520
23.3 Advanced Modulation Formats and Pulse Shaping 525
23.4 High Data Rate Links with FSO 527
23.5 Multi System Next Generation and Fully Bidirectional Optical Wireless Access 529
23.6 Concluding Remarks 531
References 531
24 Multiuser Diversity Scheduling: A New Perspective on the Future Development of FSO Communications 535
Abstract 535
24.1 Introduction 535
24.2 System Model and Assumptions 537
24.3 Multiuser Diversity in FSO Systems 540
24.3.1 Selective Multiuser Diversity Scheduling 542
24.3.2 Proportional Fair Scheduling 546
24.3.3 Proportional Fair Scheduling with Exponential Rule 547
24.3.4 SMDS/ER Policy 548
24.3.5 SMDS with Earlier Delay First Policy 549
24.4 Numerical Results 549
24.5 Conclusions and Future Directions 551
References 551
25 Optical Camera Communications 554
Abstract 554
25.1 Introduction 554
25.2 OCC Concept 556
25.2.1 Transmitters 557
25.2.2 Receivers 559
25.3 Imaging MIMO 561
25.4 Modulation Schemes 563
25.4.1 OOK 563
25.4.2 Undersampled-Based Modulation 564
25.4.3 Rolling Shutter Effect-Based Modulation 567
25.4.4 LCD-Based Modulation 568
25.5 Application of OCC 569
25.5.1 Indoor Positioning 569
25.5.2 Vehicle-to-Vehicle and Vehicle-to-Infrastructure Communication 571
25.5.3 Other Applications 572
25.6 Conclusions 572
References 572
26 Optical Wireless Body Area Networks for Healthcare Applications 576
Abstract 576
26.1 Introduction 576
26.2 Optical On-Body Channel Modeling 579
26.2.1 System Description 580
26.2.2 Channel Gain Distribution 581
26.3 Optical WBAN Performance 583
26.3.1 Optical CDMA-WBAN Error Probability 584
26.3.2 Validation 587
26.4 Typical Optical CDMA-WBAN Scenario Analysis 588
26.4.1 Optical WBAN Configuration 588
26.4.2 Channel and Performance Analysis 590
26.5 Conclusions 592
References 593
27 Free-Space Quantum Key Distribution 595
Abstract 595
27.1 Introduction 595
27.2 Quantum Key Distribution Protocols 596
27.2.1 BB84 Protocol 596
27.2.2 B92 Protocol 598
27.3 Free-Space as the ‘Quantum’ Channel 599
27.3.1 Transmission Through the Atmosphere 599
27.3.2 Scattering, Absorption, and Weather Dependence 600
27.3.2.1 Scattering 600
27.3.2.2 Absorption 601
27.3.2.3 Weather Dependence 602
27.3.3 Atmospheric Turbulence 603
27.4 Design of the Transmitter: Alice 604
27.4.1 Choice of Wavelength and Source for the Transmitter 605
27.4.2 Optical Configuration of the Transmitter 605
27.4.3 Temporal Synchronization 608
27.5 Design of the Receiver: Bob 608
27.5.1 Optical Setup of the Receiver 608
27.5.2 Single-Photon Detection 610
27.6 Results of the QKD System 611
27.6.1 300-m Link Experiment 611
References 612
28 VLC-Based Indoor Localization 614
Abstract 614
28.1 Introduction 614
28.2 Location Determining Methods 615
28.2.1 Proximity Detection 615
28.2.2 Triangulation 616
28.2.3 Trilateration 617
28.2.4 Location Patterning/Pattern Recognition 618
28.3 Accessing the Shared VLC Channel 619
28.3.1 Time Division Multiple Access (TDMA) 619
28.3.2 Frequency Division Multiple Access (FDMA) 619
28.3.3 Code Division Multiple Access (CDMA) 620
28.4 Experimental VLC Localization Systems 621
28.4.1 First VLC Positioning Systems Based on CoO Method 622
28.4.2 CoO Method Extended with RSSI Measurements 623
28.4.3 Radiation Model of the LED Light Source 623
28.4.4 VLC Positioning Based on Landmarks 624
28.4.5 VLC Positioning Systems with Advanced Transmitters and Receivers 625
28.5 Conclusions and Future Directions 625
28.5.1 Recent Research on VLC Localization Systems 625
28.5.2 Commercialization of VLC Localization Systems 626
References 626
Index 628