iii Table of Contents Acknowledgements ii Summary .vi List of Tables viii List of Figures .ix Acronyms xi 1 Introduction 1 1.1 Brief History of Broadband Wireless Communications . . .1 1.2 Channel Impairments .3 1.2.1 Intentional Interferences . .3 1.2.2 Multipath Fading channels . . 4 1.2.3 Synchronization Errors . .5 1.3 Motivations and Scopes .6 1.4 Thesis Contributions . 8 1.5 Thesis Organization 10 2 Jamming Mitigation in Frequency Hopping Systems 11 2.1 Introduction 11 2.2 System Model .14 2.3 ML-Based Joint Jamming Rejection and Symbol Detection .18 2.4 Performance Analysis .21 2.5 Simulation Results and Discussions .24 2.6 Chapter Summary .31 iv 3 Channel Estimation and Synchronization in SISO-OFDM Systems 33 3.1 Introduction 33 3.2 System Model .36 3.3 ICI Reduction by TD CFO-SFO Compensation 39 3.4 Joint CIR, CFO and SFO Estimation .43 3.5 ML CFO and SFO Estimator 46 3.6 Simulation Results and Discussions .48 3.7 Chapter Summary .56 4 Joint Estimation of Multiantenna Channel Response and Frequency Offsets in MIMO-OFDM systems 58 4.1 Introduction 58 4.2 System Model .61 4.3 Joint Estimation of CIR, CFO and SFO .66 4.3.1 ICI Reduction at Multiple Receive Antennas 66 4.3.2 Brief Description of the Vector RLS Algorithm . 67 4.3.3 Vector RLS-Based Joint CIR, CFO and SFO Estimation .68 4.3.4 ML Coarse CFO and SFO Estimation at Multiantenna Receiver .72 4.4 Simulation Results and Discussions .75 4.5 Chapter Summary .79 5 Turbo Processing for Joint Channel Estimation, Synchronization and Decoding in MIMO-OFDM systems 81 5.1 Introduction 81 5.2 System Model .83 5.3 Turbo Processing 87 5.3.1 MIMO Demapper 89 5.3.2 Soft-input Soft-output Decoder .90 5.3.3 Soft Mapper .90 5.3.4 Semi-Blind Joint CIR, CFO and SFO Estimation .91 5.3.5 Coarse CFO and SFO estimation 93 5.4 Simulation Results and Discussions . 94 5.5 Chapter Summary .100 6 Summary and Future Work 101 6.1 Summary of Thesis Contributions .101 6.2 Suggestions of Future Work .103 References 105 Appendices 110