Multirate Schemes and Multiuser Decoding in DS/CDMA Systems

ii iii Abstract i Contents iii Acknowledgements vii 1 INTRODUCTION 1 1-1 Background 1 1-2 Outline 3 1-3 Contributions 3 1-4 Notation 4 2 MULTIRATE SCHEMES FOR MULTIMEDIA APPLICATIONS 5 2-1 Introduction 5 2-2 System Models 6 Amplitude Modulated DS/CDMA Systems Quadrature Amplitude Modulated DS/CDMA Systems 2-3 Performance in AWGN Channels 9 Multi-Modulation Systems Multi Processing-Gain Systems Multi-Channel Systems Multi Chip-Rate Systems Miscellaneous Multirate Schemes CONTENTS iv 2-4 Performance in Multipath Rayleigh Fading Channels 15 Channel Model Performance Without Diversity Reception Performance of Diversity Receivers using Maximum Ratio Combining Performance of Diversity Receivers using Selection Combining 2-5 Numerical Results 19 2-6 Conclusions 25 2-7 Future Work 26 APPENDIX 2A: The Gaussian Approximations 26 APPENDIX 2B: Linearity Measure for the Multi-Channel Scheme 31 APPENDIX 2C: The Accuracy of the Gaussian Approximation 33 3 MULTIUSER DETECTION 39 3..