Bit error rate analysis in hybrid full duplex/half duplex relay cooperative networks

The development of the self-interference cancellation techniques enables wireless nodes to work with the full duplex (FD) mode. In cooperative relay networks, however, FD relay (FDR) may not always outperform the half-duplex relay (HDR) due to the residual self-interference (RSI). On the other hand, the hybrid HD/FD relay strategy can adaptively facilitate the network performance. This paper investigates the bit error rate (BER) performance of such a hybrid relay network in which the decode-and-forward (DF) protocol is employed. Instead of treating the received signal from the source to the destination as the interference, we implement successive interference cancellation (SIC) to separate the concurrently received signals at the destination. Further, the closed-form expressions of the overall end-to-end BER for both the FDR and HDR are derived. By proposing optimal power allocation scheme for the source and relay, the throughput gain with respect to the corresponding BER can be maximized. Based on the simulation results, we characterize the conditions of switching the duplex mode in terms of the maximum throughput gain.