Full-duplex or half-duplex? Hybrid relay selection for physical layer secrecy

This paper studies the secrecy outage probability of hybrid relay selection scheme which switches between full-duplex and half-duplex mode. First, motivated by the fact that either the full-duplex or half duplex has its own disadvantages, i.e., the full- duplex suffers from inherently self-interference even after cancellation by advanced technology while half-duplex cannot receive and transmit data simultaneously, we study the hybrid relay scheme. Then, inspired by the superiority of relay selection scheme, we propose the optimal full-duplex relay selection scheme and optimal hybrid relay selection scheme where the eavesdropper adopts joint decoding. Finally, the simulation results are presented, which show proposed scheme significantly outperform the traditional half-duplex relay selection scheme.