Diversity techniques in wireless communication systems: Performance analysis and iterative receiver design

Diversity techniques are promising means to combat the fading effect in wireless communication systems. This dissertation contributes to new understandings of different forms of diversity techniques (namely the time, frequency, spatial and net working diversity) and their impacts on performance improvement of wireless communication systems. We show that: (1) For a general space-time coded (STC) orthogonal frequency-division multiplexing (OFDM) system with multiple transmitter and receiver antennas over correlated frequency- and time-selective fading channels, the product of time-selectivity order and frequency-selectivity order is a key parameter to characterize the outage capacity of correlated fading channels. (2) In order to achieve full diversity in the above STC-OFDM systems, effective length of STC is necessary to be larger than the product of number of transmitter antennas and the overall-selectivity order of fading channels. (3) In both fixed-access and random-access CDMA packet data networks, a significant gain of network throughput is obtained by employing multiuser detection and packet combining of automatic retransmission request (ARQ) protocols.; Moreover, this dissertation also contributes to novel designs of signal processing and error-control coding schemes for different wireless communication applications, which significantly improve system performance over previously proposed schemes and further narrow the distance to theoretical performance limits. In particular, from signal processing perspective: (1) For both space-time block-coded (STBC) and space-time trellis-coded (STTC) multiuser systems, an iterative receiver based on Turbo principle and linear minimum mean-square-error (MMSE) soft interference cancellation technique is proposed. (2) For a STBC-OFDM system in unknown dispersive fading channels, an iterative receiver based on Turbo principle and expectation-maximization (EM) algorithm is derived. (3) For a coded OFDM system with both unknown dispersive fading and frequency offset, an iterative receiver based on Turbo principle and Markov chain Monte Carlo (MCMC) techniques is developed. Furthermore from error-control coding perspective: (1) A low-density parity-check (LDPC) based STC is proposed for OFDM systems, with low decoding complexity and excellent performance. (2) By drawing connection to traditional trellis coded modulation (TCM) codes, a novel STTC design method as well as a new class of STTC's are designed for OFDM systems.