Hybrid half-duplex/full-duplex multi-hop relaying schemes: Outage performance and power optimization

Full-duplex (FD) relays can transmit and receive simultaneously over the same frequency band, hence enable a significant improvement of spectral efficiency compared to half-duplex (HD) relays and have attracted much research interests. However, there exists severe interference for FD multi-hop relay networks in which all the relays operate in FD mode. To overcome this problem, we propose hybrid HD/FD multi-hop decode-and-forward (DF) relaying schemes, where in each time block two nodes communicate directly with each other in HD mode or communicate with the help of an FD relay. Assuming that all the channels including the residual self-interference (RSI) channel are subject to Rayleigh fading, we derive the outage probabilities of FD multi-hop relay networks and hybrid HD/FD multi-hop relaying schemes, respectively. Then we optimize the power allocation of the hybrid HD/FD relaying scheme under individual power constraint with the aim of minimizing the outage probability. Finally, we compare the performance of different transmission schemes and validate our analysis by simulation results.