— This paper explores relay selection and selection diversity for coded cooperation in wireless sensor networks, with complexity constraints for the sensor nodes. In previous work, a relaying scheme based on repeat-accumulate (RA) codes was introduced, where the relay is assumed incapable of decoding the received signal’s error-correcting code, and simply uses demodulated bits to form codewords. However, in a network setting with multiple potential relays where relays do not decode the source transmission, it is not obvious how to select the best relay. The optimal choice involves the source-relay, relay-destination, and source-destination channels. In this paper, optimal relay selection is discussed, and is shown to be impractical for low-complexity sensor nodes. However, it is shown that the mutual information of the equivalent relay channel is a good selection heuristic. The importance of a good relay selection scheme is emphasized with the surprisingly poor performance when a n...
Josephine P. K. Chu, Raviraj S. Adve, Andrew W. Ec