Physical Layer Security of a Buffer-Aided Relay Selection for Underlay Cognitive Radio Network

This paper investigates the physical layer security in underlay cognitive radio networks with multiple buffer-aided decode-and-forward relays, where an eavesdropper can intercept the data transmission from the source and relay nodes. Different from existing works, we propose a new buffer-aided relay selection scheme in multi-relay scenario instead of a link selection scheme in one relay scenario. Moreover, finite data buffers are assumed to be available at every relay to avoid selecting the best source-to-relay and relay-to-destination links concurrently, and the secrecy outage probability is derived. The proposed scheme is evaluated using simulations and theoretical results, which show that proposed scheme has performance advantage over the conventional unbuffered relay selection scheme.