Adaptive AF/DF Selection With FD/HD Switching in Two-Way Relay Networks

The full-duplex (FD) and two-way relay are promising techniques for their high spectrum efficiency. However, the incompletely self-interference cancellation may reduce the performance gain of two-way relay networks, which operates in FD mode. In this paper, we propose an adaptive amplify-and-forward (AF) and decode-and-forward (DF) selection scheme for FD two-way relay networks, where the relay is allowed to operate in half-duplex (HD) mode. We first derive closed-form formulas of the outage probabilities of the non-adaptive AF and DF schemes for two-way relay networks in both FD and HD modes. To improve the outage performance, an adaptive AF/DF scheme will be proposed for two-way relay networks. However, with the residual self-inference, adaptive FD scheme is not always the best choice for achieving the optimal outage performance. Therefore, we also design an optimal switch scheme between FD and HD modes. The closed form formulas of the outage probability are also derived. The simulation results will not only verify the theoretical derivations, but also illustrate the significant performance gains compared with existing non-adaptive schemes.