Asymptotic Analysis of Multiuser Diversity and Selection Diversity in Multiple-Relay Networks

Selection cooperation has been proposed as a promising way of realizing cooperative diversity for its simplicity and good performance. In this paper, a framework to analyze the multiuser diversity and selection diversity in multiple-relay networks is presented. Based on this framework, we derive closed-form asymptotic expressions of outage probability and symbol error rate (SER) for both amplify-and-forward (AF) and decode-and-forward (DF) based multiple-relay networks. Both the theoretical analysis and simulations show that a multiuser diversity order of K and a selection diversity order of M + 1 can be achieved simultaneously for both AF and DF protocols (where K is the number of accessing users and M is the number of available relays). These show that the multiuser diversity can be readily combined with the selection diversity in multiple-relay networks.