Outage performance of relay-assisted transmissions in cognitive full-duplex relay networks

Relay cooperation can enhance coverage, throughput, and reliability of wireless communication systems, thus attracting intense research interest in the past decade. However, most of them focused on half-duplex relay systems, which encounter loss of resource efficiency. With the progress of self-interference cancellation technologies, full-duplex relay systems come into sight. In this paper, outage performances of the primary system and the secondary system in a cognitive full-duplex relay network are analyzed, under the adverse effect of self-interference caused by the signals at the transmitting and receiving antennas of the relay. The full-duplex decode-and-forward relay assists the transmissions of the primary system and the secondary system where there is no direct link between the secondary transmitter and the secondary receiver. Simulation results show that better outage performance of the primary system is achieved compared with the cognitive relay network adopting half-duplex relaying. Moreover, communication of the secondary system is realized on the condition that the secondary transmission link is non-ideal.