Outage-optimal opportunistic relaying for two-way amplify and forward relay channel

Presented is a simple opportunistic amplify and forward (AF) relaying for the two-way relay channel, where two nodes want to exchange information with each other at the same transmission rate with the help of relay nodes. In particular, the opportunistic relay can be selected in a distributed manner requiring only local channel knowledge. It is shown that opportunistic AF relaying is outage-optimal among single relay selection schemes and significantly outperforms an AF strategy based on equal-power multiple-relay transmission with local channel knowledge. Numerical and simulation results verify the analysis.