Advanced relay selection schemes for cooperative communications

It is widely considered that cooperative diversity, in idealized conditions, can provide dramatic performance improvements in capacity and error probability. But non-ideal phenomena, such as fast time variations of the channel, channel estimation errors (CEE), feedback delay (FD) and co-channel interference, degrade the performance of the cooperative communication networks. This thesis studies the impact of these phenomena on advanced relay selection techniques in cooperative communication networks. In particular, Chapters 2-4 treat inter-vehicular communication (IVC) networks with fast time variations in the channel. For different relaying protocols, the impact of CEE and FD on the performance of cooperative communication with relay selection is presented in terms of average capacity, average symbol error rate, outage probability, and the achievable diversity order. Chapters 5 and 6 discuss how interference deteriorates the performance of a cognitive secondary network using relay selection in the presence of a primary network which has priority access to the spectrum. The primary and secondary network signals are treated as mutually interfering noise. Transmission powers in the secondary network are constrained such that the primary user can still perform satisfactorily. Based on interference levels, new selection and power control techniques are presented for the secondary network, and the outage probability is determined. Finally Chapter 7 summarizes the research and proposes future works related.