Performance of channel coding in temporally and spatially correlated wireless channels

In mobile systems, channel coding is typically employed in conjunction with diversity techniques to combat the time-varying impairments over wireless channels. Diversity techniques typically provide greater performance gains when the signals on various diversity branches are uncorrelated. However, channel correlations may exist between diversity branches in many scenarios. In this thesis, we consider the performance of various channel coding schemes, such as Reed-Solomon codes, convolutional codes and turbo codes, in conjunction with diversity techniques in temporally and spatially correlated wireless channels.; For Reed-Solomon (RS) codes, we propose a new analytical method to evaluate their performance in Rayleigh fading channels with temporally correlated errors. Using the asymptotic results of level crossings of the faded envelope, we characterize the packet error probability of the Reed-Solomon code as a function of mean signal-to-noise ratio, Doppler frequency and interleaving depth. This approach allows us to directly evaluate the throughput of hybrid-ARQ schemes and also specify minimum interleaving depths for achieving optimum throughput on correlated Rayleigh channels.; Next, we present the performance analysis of convolutionally coded Direct Sequence-Code Division Multiple Access (DS-CDMA) systems. Considering both temporal and spatial channel correlations that may be encountered in space-time processing in such systems, we derive an upper bound for the average bit error probability in the case of ideal channel estimation. An analytical approximation for the average bit error probability is obtained in the case of erroneous channel estimates as well.; For turbo codes, we consider the third generation (3G) mobile systems, such as Wideband-CDMA (W-CDMA). We evaluate the performance of turbo coded W-CDMA systems employing Space-Time Transmit Diversity (STTD) techniques over temporally and spatially correlated multipath channels. It is found that the improvement by using turbo codes in conjunction with space-time transmit diversity is significant, especially in the case of slow fading when the temporal correlation is high. By considering the spatial correlation between the transmit antennas at a base station, we quantify the tolerable spatial correlation between transmit antennas for which the turbo coded W-CDMA systems with downlink transmit diversity will still achieve performance gains over single antenna systems.