Investigation into factors that allow performance enhancement using widely linear receivers for space-time block code transmission.

摘要

Transmit diversity has been proven to provide performance gains over conventional wireless communications systems, but the number of transmit antennas cannot be infinite. To further enhance performance, a detection technique called widely linear (WL) processing is proposed for space-time block coding and its effectiveness has been shown to be occasional under a limited number of test cases. The focus of this thesis is to define the system settings that would allow WL processing to benefit transmit diversity systems using space-time block codes (STBCs).; In this thesis, Alamouti's STBC and the Lindskog-Paulraj STBC are tested with receivers that are designed for different channel characteristics with known or unknown channel state information. For the latter scheme, three MLSE receivers are invented for testing with time-varying channels. Their performance is found to be comparable to the original MLSE receiver for quasi-static channels, and one of them does not require any increase in complexity. Simulation results under different system settings established the main factors that influenced the system's favourability for WL processing.