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HIGH RATE SPACE-FREQUENCY CODES FOR MIMO-OFDM SYSTEMS

In the recent years, multiple-input multiple-out (MIMO) technology has attracted lots of attention because it significantly increases the data throughput (multiplexing gain) and link reliability (diversity gain) without additional bandwidth or transmission power. Orthogonal frequency division multiplexing (OFDM) technology has been developed into a popular scheme for wideband digital communications since it is an efficient and effective techniques to deal with frequency-selective fading as well as achieving high speed data transmissions. The combination of the MIMO and OFDM, i.e. MIMO-OFDM system, has been widely recognized as the next generation broadband wireless system. In order to achieve both spatial and frequency diversities in MIMO-OFDM system, space-frequency (SF) codes have been proposed in the literature. In this thesis, we first look into the development of SF codes and various methods to achieve full diversity. Then we briefly describe the full-diversity layered space-time codes and propose an idea of high-rate full diversity space-frequency codes for a multiuser MIMO-OFDM system.