A simple distributed method for relay selection in cooperative diversity wireless networks, based on reciprocity and channel measurements

We propose a simple distributed method to find out the "best" end-to-end path between source and destination, among M possible relays. The method requires no explicit communication among the relays, assumes no prior knowledge of network geometry and is based on instantaneous wireless channel measurements and reciprocity. The success (or failure) to select the "best" available path, depends on the statistics of the wireless channel, and a methodology to evaluate performance for any kind of wireless channel statistics, is provided. Benefits of cooperative diversity are increased with increased number of cooperating relays, even though a single relay transmits. The method simplifies required space-time coding and coordination among the cooperating terminals.