Joint source-relay selection and transmission mode selection in two-way relay networks

A joint source-relay selection and transmission mode selection scheme is proposed for two-way relay networks. The proposed scheme adaptively switches from one-way and two-way transmission mode according to the channel state information (CSI) of the selected relay and source. The proposed joint scheme utilizes the direct link channels and the time-varying character of the channels, therefore, it is more reliable than the existing schemes. A tight closed-form lower bound and an asymptotic expression in high SNR regime for the outage probability of the proposed scheme are derived. From these theoretical results, our scheme is shown to achieve the maximal diversity order of M + N, where M and N are the number of source nodes and relay nodes, respectively. Finally, simulation results validate the theoretical analysis.