Secure Multiple Amplify-and-Forward Relaying Over Correlated Fading Channels

Abstract

This paper quantifies the impact of correlated fading \non secure communication of multiple amplify-and-forward (AF) \nrelaying networks. In such a network, the base station (BS) is \nequipped with multiple antennas and communicates with the \ndestination through multiple AF relays, while the message from \nthe relays can be overheard by an eavesdropper. We focus \non the practical communication scenario, where the main and \neavesdropper’s channels are correlated. In order to enhance \nthe transmission security, transmit antenna selection (TAS) is \nperformed at the BS, and the best relay is chosen according to the \nfull or partial relay selection criterion, which relies on the dualhop \nrelay channels or the second-hop relay channels, respectively. \nFor these criteria, we study the impact of correlated fading \non the network secrecy performance, by deriving an analytical \napproximation for the secrecy outage probability (SOP) and an \nasymptotic expression for the high main-to-eavesdropper ratio \n(MER). From these results, it is concluded that the channel \ncorrelation is always beneficial to the secrecy performance of full \nrelay selection. However, it deteriorates the secrecy performance \nif partial relay selection is used, when the number of antennas \nat the BS is less than the number of relays.