| In this dissertation two diversity combining issues related to the transmission of digital information over fading channels are considered. In the first problem, decisions based on individual branches are made and the decisions are combined to arrive at a final decision on the symbol under consideration. For binary FSK detection in a Rayleigh fading channel, the probabilities of bit error of linear weighted decisions, optimal decision rule, which is a likelihood ratio test, majority logic, and decision fusion with amplitude information are evaluated. In wireless sensor networks, reduced data rates between sensors become important and a study of decision fusion schemes that show good performance is of interest. In the second problem, we apply the antenna selection to noncoherent Alamouti space-time coding for transmission over a Rayleigh fading channel. We investigated the effect of antenna selection on average bit error probability of noncoherent detection of Alamouti space-time coded orthogonal modulation. The performance is evaluated, through a simulation study, for the cases of a single receive antenna and a dual receive antenna. Results establish the degree of diversity gain that could be achieved with antenna selection. |
