| Wireless communications are subject to a complex and harsh radio propagation environment, i.e., multipath and shadowing effects. Many of the current and emerging wireless communication systems make use in one form or another of diversity to overcome these deleterious effects. There are two kinds of diversity systems: transmitter and receiver diversity. Receiver diversity combining consists of receiving redundantly the same information-bearing signal over two or more fading channels, then combining these multiple replicas at the receiver to improve the overall performance. On the other hand, the transmitter diversity systems transmit the same data from multiple antennas or on different carriers and achieves the diversity gain at the receiver by combining the multiple replicas that propagated over different channels. The advantage of the transmitter diversity is that, even if the receiver has a single antenna, diversity gain can be achieved.; As far as the performance analysis of these systems is concerned, wireless communication engineers are interested in average output signal-to-noise ratio, outage probability, average probability of error, and average outage duration. In this dissertation, we address all these performance measures. First, we consider the receiver diversity systems. In this subject, we develop a numerical algorithm to calculate the outage probability and the average outage duration of the receiver diversity systems over generalized fading channels. We then consider the transmitter diversity systems. In this topic, an optimum power loading algorithm over general fading channels is developed and the required fading channel parameter estimators are proposed and applied to the optimal transmitter diversity systems. As a final subject of the dissertation, the estimators of fading parameters, signal strength and Doppler spread, over wireless fading channel are investigated and analyzed. We propose various new practical estimators over general fading channels and show that they provide significant performance improvement. |
