Hybrid One-Way Full-Duplex/Two-Way Half-Duplex Relaying Scheme

In this paper, we propose a hybrid one-way full-duplex (OWFD)/two-way half-duplex (TWHD) relaying scheme to improve the performance of the relay system with asymmetric channel gains and traffic requirements. In the proposed scheme, the transmit time interval is decomposed to three subintervals, and in each subinterval the relay operates in OWFD or TWHD mode. The duration of each subinterval is optimized to minimize the system outage probability. We show that the subinterval time optimization can be formulated as a linear programming problem. By exploiting the structure of the problem, the closed-form solution of the problem was derived. We also present a power control scheme to mitigate the effect of residual self-interference (RSI) when the relay is operated in the OWFD mode. Simulation results show that the hybrid scheme achieves better outage performance under the asymmetric environment when compared with the traditional schemes. Moreover, the scheme is robust to the RSI caused by the full-duplex operation.