On the outage performance of selection amplify-and-forward relaying scheme

In this letter, we propose a selection amplify-and-forward (AF) relaying scheme which has the lower outage probability than that of a conventional AF relaying scheme in cooperative relay networks. In real wireless environments, as the channel of source-to-destination (SD) link varies with an increase in time, we can also obtain a diversity gain through the SD link by retransmission in common with a conventional AF relaying scheme. Thus, we can expect a performance enhancement by adaptively determining the transmitting node between the relaying and source nodes. We propose a method for adaptively determining between AF relaying and retransmission schemes, and show that the additional diversity gain can be obtained by the proposed scheme.