Secrecy outage analysis with Kth best relay selection in dual-hop inter-vehicle communication systems

In this paper, we investigate the secrecy outage performance of a dual-hop inter-vehicle communication system, in which all nodes are in motion and all fading channels are assumed to undergo cascaded Rayleigh distributions. In particular, a mobile node (source) with a single antenna transmits confidential information to another mobile node (destination) equipped with M(M⩾1) antennas through N(N>1) single-antenna road-side relays in the presence of an eavesdropper with L(L⩾1) antennas. Assuming decode-and-forward relaying, the Kth best relay is selected to assist source-destination transmission based on two classical relay selection schemes: (i) the optimal source-relay link scheme; and (ii) the optimal source-relay-destination link scheme. Closed-form analytical expressions for secrecy outage probability of those two schemes are derived, and verified with Monte Carlo simulation results.