Space-Time Multiuser Detection For Wireless CDMA Communication Systems

Multiple access interference (MAI) and multipath fading are two major factors limiting performances of CDMA communication systems. In this dissertation, multiuser detection and space-time processing are combined to suppress multiple access interferences and inter-symbol interferences (ISI) jointly in multipah fading channels with large delay spread. This dissertation is outlined as follows.In Chapter One, the present studies on multiuser detection and space-time processing in wireless CDMA communications are reviewed.In Chapter Two, a structured space-time multiuser CDMA signal model is built as the basis of the whole research, combing space-time channel models and multirate /multichannel CDMA signal models.In Chapter Three, the optimal space-time multiuser CDMA system and its implementation are studied based on the structured space-time multiuser CDMA signal model.In Chapter Four, sufficient conditions for existence of FIR space-time decorrelating receivers are analyzed and the optimal designs are studied with different optimal criteria.In Chapter Five, the minimum variance blind space-time multiuser detection is studied in multipath channels. The generalized canonical presentation is proposed, with which space-time channel estimation and interference suppression can be implemented jointly. Furthermore, residual interference is analyzed.In Chapter Six, Principal Component, Cross-Spectral Metric, Auxiliary-Vector Filtering and Multistage Wiener Filtering are applied to study low-rank blind space-time multiuser detection with the generalized canonical representation in multipath channels.In Chapter Seven, all the studies in this dissertation are summarized and the future directions are discussed.