Protocol Design and Performance Analysis for X-Duplex Amplify-and-Forward Relay Networks

In this paper, a novel X-Duplex relay scheme with one source, one amplify-and-forward (AF) relay and one destination is proposed. The relay is equipped with a shared antenna and two radio frequency (RF) chains used for transmission or reception. The proposed scheme can be reduced to either full-duplex (FD) or half-duplex (HD) with different RF chain configurations. In the proposed scheme, relay adaptively configures the connection between its RF chains and the antenna to optimise the end-to-end system performance according to the instantaneous channel conditions. In this paper, we analyze the system overall performances based on the distribution of the signal to interference plus noise ratio (SINR) of the hybrid mode, including outage probability and average sum rate. Monte-Carlo simulations are used to validate the analytical expressions. Results show that the X-Duplex relay achieves a lower outage probability and a higher average sum rate compared to FD and HD schemes.