Secrecy Outage of an Energy Harvesting Multi-relay Network with Multiple-antenna

Secrecy performance of a cooperative communication network is analyzed in which source transmits information to a destination via multiple relays, assisted with multiple antennas, where an eavesdropper is able to eavesdrop the information signal from relay only. The direct link does not exist between source and destination due to deep fading and shadowing effect and transmission of a signal from source to destination is completed in two phases; first is the broadcasting phase and other is the relaying phase. Each relay follows decode and forward protocol and receives the information signal with multiple antennas. A selected relay harvests energy from received multiple signals through multiple antennas. Both information and jamming signals are transmitted by the selected antenna of a selected relay. It has been seen that a selected relay harvests energy 0.3706 joule with an array of 5 antennas when the source transmits the information signal with 5 dBW power. We have also observed that the performance increased by 99.24 % in case of an array four antennas system with respect to an array of two antennas system when secrecy threshold is 1 bit/s/Hz . Secrecy performance is measured in terms of secrecy outage probability (SOP). A closed-form expression of the SOP is derived to analyze the secrecy performance which is verified by the simulation results.