| This thesis addresses a number of timely and important aspects of space-time coding and interference cancellation for multiple-input multiple-output wireless communication systems. The main theme of the thesis is to propose space-time encoding and decoding as well as interference cancellation techniques to reduce the system complexity and improve the performance so that the proposed techniques are applicable to real-world future applications.; First, we propose various linear quasi-maximum-likelihood decoders for orthogonal space-time block codes over time-selective fading channels, which offer close-to-optimal performances at no extra cost of decoding complexity. The proposed decoders are suitable for practical wireless applications because in practice the channels are often time-selective. Then, we propose a space-time coded multi-user communication system that relies on the notion of group signature and soft interference-cancellation and decoding to achieve robust performance and low complexities. Next, we construct a class of quasi-orthogonal space-time block codes that enjoys linear decoding complexity. The proposed codes offer greater flexibility than the existing codes. They have linear decoding complexities if no signal constellation rotation is applied. If the signal constellation rotation is applied, they also achieve full diversity advantage like the existing improved codes. Then, we propose various interference-cancellation-based receivers for single-carrier space-time block coded communication systems over frequency-selective fading channels with manageable complexities and robust performances. Finally, we derive the moment generating and probability density functions of a sum of arbitrarily correlated Gamma random variables with non-identical and non-integral parameters. The derived moment generating and probability density functions are used to analyze a number of performance measures of diversity combining wireless communication systems, including orthogonal space-tune block coded systems over Nakagami-m fading channels.; The proposed research on space-tune coding and interference cancellation offers the potential for enhanced performance, network capacity and high-speed delivery of information in future wireless communication systems. The ultimate goal is to have wireless services such as mobile computing, high-speed Internet access, and other personal communication services delivered with improved quality of service and be accessible to more users. |
