Opportunistic relaying in two-way networks

This paper is on opportunistic relaying for networks with two-way communications. For a network with two users that exchange information with each other through multiple amplify-and-forward relays, we propose a single-relay selection scheme. Since the communication is two-way, the proposed scheme aims at optimizing the worse performance of the two communication tasks between the pair of users. An approximation on the cumulative distribution function (CDF) of the effective worse signal-to-noise ratio (SNR) of the two users using the proposed scheme is obtained, based on which the block error rate (BLER) and the diversity order of the two-way network are derived. Then, the single-relay selection scheme is generalized to a multiple-relay selection scheme with the help of the relay ordering idea. Numerical and simulation results are provided to verify the analysis.