University of South Florida Scholar Commons Graduate Theses and Dissertations Graduate School 11-20-2015 Multidimensional Waveform Shaping in Multicarrier Systems Ertugrul Guvenkaya University of South Florida, [email protected] Follow this and additional works at: http://scholarcommons.usf.edu/etd Part of the Communication Commons, and the Electrical and Computer Engineering Commons Scholar Commons Citation Guvenkaya, Ertugrul, "Multidimensional Waveform Shaping in Multicarrier Systems" (2015). Graduate Theses and Dissertations. http://scholarcommons.usf.edu/etd/5958 This Dissertation is brought to you for free and open access by the Graduate School at Scholar Commons. It has been accepted for inclusion in Graduate Theses and Dissertations by an authorized administrator of Scholar Commons. For more information, please contact [email protected]. Multidimensional Waveform Shaping in Multicarrier Systems by Ertu˘grulG¨uvenkaya A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy Department of Electrical Engineering College of Engineering University of South Florida Major Professor: H¨useyinArslan, Ph.D. Richard D. Gitlin, Sc.D. Nasir Ghani, Ph.D. Yao Liu, Ph.D. Erdem Bala, Ph.D. Date of Approval: September 23, 2015 Keywords: Artificial noise, asymmetric pulse shaping, OFDM, PAPR reduction, sidelobe suppression Copyright c 2015, Ertu˘grulG¨uvenkaya DEDICATION To our martyrs. ACKNOWLEDGMENTS First, I would like to thank my advisor Dr. H¨useyin Arslan for his guidance, encouragement, and support throughout my study. I wish to thank Dr. Richard D. Gitlin, Dr. Nasir Ghani, Dr. Yao Liu, and Dr. Erdem Bala for serving in my committee and for offering valuable suggestions. I hope to be able to benefit from their profound knowledge and experience in the future, as well. It has been a privilege to have the opportunity to do research as a member of the Wireless Communications and Signal Processing (WCSP) group at USF. I would like to thank my friends Ali G¨or¸cin,Alphan S¸ahin, M. Bahadır C¸elebi, Anas Tom, M. Harun Yılmaz, Z. Esad Ankaralı, Ali Fatih Demir, Emre Seyyal and Emre Arslan for their support as friends and productive discussions as colleagues. Special thanks to Alphan S¸ahin for his vigorous support and fruitful discussions. I would like to appreciate Ali G¨or¸cin'sbrotherhood, which I believe is another benefit of my PhD years. Also, I owe much to Yılmaz and Arslan families for their great hospitality which minimized the longing to my family and Turkish food. Last, but by no means least, I would like to express my deepest gratitude to my parents Fatma G¨uvenkaya and Ya¸sarG¨uvenkaya and my dear sisters S¸¨uhedaand Asude B¨u¸srafor their unconditional support throughout these years. Especially, it is not possible to thank my beloved future wife, B¨u¸sra,enough for her unconditional love and her prayers. I am very grateful for having such a wonderful family. May Allah (swt) reward them all with blessings for ever. TABLE OF CONTENTS LIST OF TABLES iv LIST OF FIGURES v ABSTRACT viii CHAPTER 1: INTRODUCTION 1 1.1 Scope of the Dissertation 3 1.2 Contributions 3 1.2.1 Waveform Shaping in Time and Frequency Domains 3 1.2.2 Waveform Shaping in Time and Frequency Domains with Wireless Channel 4 1.2.3 Waveform Shaping in Frequency and Power Domains 5 1.2.4 Waveform Shaping in Frequency and Power Domains with PHY Security 6 1.2.5 Waveform Design for PHY Security Using Fade-Avoiding Artificial Noise 7 1.3 Dissertation Outline 8 CHAPTER 2: PHYSICAL-LAYER SECURITY CONCEPTS AND METRICS IN SIGNAL TRANSMISSION 9 2.1 Introduction 9 2.2 Reception Stages with Eavesdropper 11 2.2.1 Coverage 12 2.2.2 Detection 13 2.2.3 Interception 14 2.2.4 Exploitation 14 2.3 Performance Metrics 16 2.3.1 Information-Theoretic Measures 17 2.3.1.1 Equivocation and Secrecy Rate 17 2.3.1.2 Secrecy Outage Probability 18 2.3.2 Practical Measures 20 2.3.2.1 Security Gap 20 2.3.2.2 Bit Error Rate 21 2.3.2.3 Low Probability of Interception (LPI) / Detection (LPD) 21 2.4 PHY Techniques Against Eavesdropping 23 2.4.1 Time/Frequency-Based Techniques 23 i 2.4.1.1 Spread-Spectrum LPI/LPD Approaches 23 2.4.1.2 Coding Techniques 24 2.4.2 Directional Transmission 25 2.4.2.1 Array Beamforming 26 2.4.2.2 Directional Modulation 27 2.4.3 Randomized Space-Time Transmission 30 2.4.4 Artificial Noise 32 2.4.5 Channel-Driven Techniques 34 2.5 Conclusions 35 CHAPTER 3: A WINDOWING TECHNIQUE FOR OPTIMAL TIME- FREQUENCY CONCENTRATION AND ACI REJECTION IN OFDM-BASED SYSTEMS 36 3.1 Introduction 36 3.2 System Model 40 3.3 Optimally Concentrated Windowing Functions for OFDM Subcarriers 43 3.4 Transmitter Windowing for OOB Suppression 46 3.4.1 Fixed Windowing and Per-subcarrier Windowing 48 3.4.2 Design Under a Prescribed Spectral Mask 50 3.5 Receiver Windowing for ACI Rejection 51 3.6 Numerical Results 54 3.6.1 OOB Emission 55 3.6.2 The Effect of Concentration Band 55 3.6.3 Time-Frequency Concentration with Spectral Constraint 56 3.6.4 ACI Results 58 3.6.5 Computational Complexity 60 3.7 Conclusions 61 CHAPTER 4: TIME-ASYMMETRIC AND SUBCARRIER-SPECIFIC PULSE SHAPING IN OFDM-BASED WAVEFORMS 63 4.1 Introduction 63 4.2 System Model 66 4.3 Interference Analysis and Asymmetric Pulse-Shape 69 4.4 Per-Subcarrier Asymmetric Pulse Shaping 74 4.4.1 OOB Emission Constraint for Composite Signal 78 4.4.2 Optimization of Per Subcarrier Pulse Shapes 79 4.5 A Novel Solution to Asymmetric Pulse Design: Generalized Kaiser Window 80 4.6 Further Notes 84 4.6.1 Per Resource-Block (RB) Time-Asymmetric Pulse Shaping 84 4.6.2 Improvements for Non-Uniform Interference 85 4.6.3 Complexity 85 4.7 Results 86 4.8 Conclusions 93 ii CHAPTER 5: JOINT SIDELOBE SUPPRESSION AND PAPR REDUCTION IN OFDM USING PARTIAL TRANSMIT SEQUENCES 95 5.1 Introduction 95 5.2 System Model 98 5.3 Stage 1: Sidelobe Suppression with Frequency Domain Criterion 99 5.4 Stage 2: PAPR Reduction with PTS 101 5.5 Stage 3: Sidelobe Suppression with Time Domain Criterion 102 5.6 Simulation Results 105 5.7 Conclusions 108 CHAPTER 6: CP-ALIGNED OFDM WITH JOINT OOB AND PAPR REDUCTION WITH PHY SECURITY 109 6.1 Introduction 109 6.2 System Model 111 6.3 Generalized N-Continuous OFDM 114 6.4 CP-Alignment 117 6.5 PAPR Reduction 120 6.6 PHY Security Aspects 122 6.7 Numerical Results 123 6.7.1 Power Spectrum 123 6.7.2 PAPR Performance 124 6.7.3 Bit Error Rate 125 6.8 Conclusions 126 CHAPTER 7: SECURE COMMUNICATION IN FREQUENCY SELECTIVE CHANNELS WITH FADE-AVOIDING SUBCHANNEL USAGE 128 7.1 Introduction 128 7.2 System Model 130 7.3 Adaptive Subchannel Usage 133 7.3.1 Outage Probability 135 7.3.2 Discussion on Threshold Selection 139 7.4 Fade-Filler Artificial Noise 140 7.5 Results 140 7.6 Conclusions 143 CHAPTER 8: CONCLUSIONS 145 REFERENCES 147 APPENDICES 158 Appendix A: Derivation Steps 159 Appendix B: List of Acronyms 161 Appendix C: Copyright Notices 165 ABOUT THE AUTHOR End Page iii LIST OF TABLES Table 3.1 Symbol densities for different windowing schemes. 58 Table 3.2 Complexity comparison of the windowing schemes for N = 512, G = 64, and M = 32 61 Table 4.1 Procedure for finding GKW parameters. 82 Table 4.2 Normalized complexity of the pulse shaping schemes for N = 512, G = 32, and M = 96 86 Table 4.3 Parameters for three waveform cases complying the spectrum mask with same data rate 91 iv LIST OF FIGURES Figure 1.1 Outline of the dissertation that includes the domains and concepts that are studied. 5 Figure 2.1 Information transmission consists of mapping operations from message space to signal space at transmitter, channel effect with distortion via warping the signal space and addition of noise, and mapping back to message space at the receiver. 11 Figure 2.2 Stages of the overall reception mechanism at the eavesdropper. 12 Figure 2.3 (a) 2 × 1 MISO communication system where two dimensional trans- mitted signal x is mapped to one dimensional received signals yB and yE along the direction channels hB and hE, respectively. 15 Figure 2.4 Information-theoretic measures. 16 Figure 2.5 Security gap when both receivers are assumed to have identical BER performance. 19 Figure 2.6 Generalized security gap when the Bob and Eve have different BER performances. 19 Figure 2.7 While the information is spread along time (of frequency) in SS and de- spread by the receiver, the dimension where the information is spread in array transmission is space in which the de-spreading is inherently done by the channel itself. 25 Figure 2.8 Directional transmission vs directional modulation. 29 Figure 3.1 (a) The illustration of signal model and aggressors operating at the adjacent channels in time-frequency plane. 39 Figure 3.2 Power spectrum of individual windowing functions. 47 Figure 3.3 Block diagram for the considered scenario. 49 Figure 3.4 Illustration of Nyquist property when receiver windowing is applied. 51 Figure 3.5 OOB leakage for various optimization bands with proposed subcarrier- specific and RC windowing. 56 v Figure 3.6 Fixed windowing and asymmetric implementation of the per-subcarrier windowing with different left and right guard bands. 57 Figure 3.7 Spectral leakage performances for a given concentration band.