Jamming or Forwarding? Full-Duplex Relaying for Physical Layer Security

This paper studies the secrecy outage probability of full-duplex (FD) relay networks in the presence of external eavesdropper and residual self-interference, where the FD relay can forward message or transmit jamming signal. Different with the existing researches which consider the full-duplex relay employs decode-and-forward (DF) protocol, we study the situation that the FD relay uses amplify-and-forward (AF) protocol, and propose a destination aided jamming scheme to further improve the secrecy performance when the FD relay transmits jamming. Furthermore, we compare the secrecy outage probability of four different schemes (i.e., AF forwarding scheme, AF destination- aided jamming scheme, DF forwarding scheme and DF jamming scheme), and give the answer that which mode the FD relay should employ with different system parameters.