SSCSMA-based random relay selection scheme for large-scale relay networks

Effective relay selection is a way to achieve considerable performance gains in cooperative communication. However, in practice, the best relay may not always be selected due to the difficulty in collecting accurate network information when the network scale is very large or when the channel information is time-varying. In this paper, we propose a suboptimal relay selection scheme where the only information available to the source is the destination location. The proposed scheme consists of three phases. During the first phase, the area of relay selection is narrowed down based on the outage probability and target transmission rate. In the second phase, a node within this region is selected using the Successive Slotted Carrier Sense Multiple Access (SSCSMA) protocol. In the third and last phase, data is transmitted from the source via the relay to the destination. We present a detailed analysis of the transmission rate and the outage probability. Simulation results have shown that our method using SSCSMA outperforms Random Access based Blind Relay Selection (RABRS) in terms of transmission rate. The results have also indicated that both the outage probability constraint and the source-destination distance affect the transmission rate.