Optimal Relay-Destination Pair Selection Mechanism for Secure Communications in Wireless Cooperative Relay Networks

This paper investigates the optimal relay-destination pair selection problem in a wireless cooperative relay network comprising one source, multiple Decode-and-Forward (DF) relays, a cluster of destinations and one eavesdropper of available channel information overhearing both the source-relay link and relay-destination link. More specifically, we first propose a new relay-destination pair selection mechanism that maximizes the signal-to-noise ratio (SNR) of the relay-destination link by selecting the optimal relay-destination pair from the pairs formed by the cluster of destinations and a set of relays able to decode the source message with a high level of security. We then derive the closed-from expressions of the outage probability (OP) and the intercept probability (IP) to model the reliability and security performances of the proposed relay-destination pair selection mechanism. Finally, extensive numerical results are provided to illustrate the parameters of network on the OP and IP performances of the proposed mechanism and also to show the inherent trade-off between OP and IP.