Space-time coding and decoding for MIMO wireless communication systems

It is well understood that multiple antennas can be used to effectively combat the fading in wireless links and increase the channel capacity by exploiting the spatial diversity. This dissertation addresses two main techniques to approach the increased capacity: space-time coding/modulation and iterative decoding.; For space-time coding we proposed a systematic and closed form construction of complex orthogonal space-time block codes of rates (k + 1)/(2k) for 2k or 2k - 1 transmit antennas, where k is any positive integer. The rates of our construction are the maximum rates for complex orthogonal designs without linear processing. Furthermore, another closed form construction is proposed when the number of transmit antennas is a multiple of 4, where the delay size is only half of the designs known previously. This dissertation also presented a new recursive space-time trellis codes design from differential encoding, which can be applied to serially concatenated system to achieve turbo gain through iterative decoding. We proposed a new design criterion to obtain the recursive trellis with larger error event length, which makes it possible to increase the performance by careful design of the STBC mapped to the states. By using the new criterion we developed a class of recursive space-time trellis with number of states M2 for any size of constellation M.; For the application of iterative decoding in MIMO system, we presented an iterative decoding/demodulation technique for an orthogonal space-time coded continuous-phase modulation system. By taking advantage of the orthogonal structure, the complexity of extrinsic information extraction can be significantly reduced at each iteration. We also investigated the concatenation of a low density generator matrix code as an outer encoder and a recursive space time trellis code as an inner coder to increase the system performance.