General and efficient relay selection for two‐way opportunistic amplify‐and‐forward relaying

Abstract

Considering the most general case that each node transmits with unequal powers, an efficient relay selection scheme is proposed for the two‐way amplify‐and‐forward (AF) relaying system, which bypasses the need for channel estimation and can be implemented by comparing the product of each relay's local transmit power and its received pilot signalling powers from the two sources. A tight closed‐form lower bound for the system outage probability is derived in Nakagami‐ m fading, followed by the analysis of diversity and coding gains. Simulation results are presented to corroborate analysis.