Secrecy performance analysis of amplify-and-forward relay cooperative networks with simultaneous wireless information and power transfer

Simultaneous wireless information and power transfer (SWIPT) is a promising technology to enhance the power constraint issue in the wireless networks. In this paper, we investigate the secrecy performance of a selective cooperative relaying network with an energy harvesting (EH) technique, in which a source terminal communicates with a legitimate user at the destination terminal through.. amplify-and-forward (AF) relays in the presence of multiple eavesdroppers. The relays deploy SWIPT with power splitting-based relaying (PSR) and time switching-based relaying (TSR) protocols to harvest energy. We present closed-form expressions for the secrecy performance metrics, consisting of the probability of non-zero secrecy capacity, the secrecy outage probability, and the average secrecy capacity to evaluate the physical layer security (PLS) of the system. Using the mathematical expressions, we obtain numerical results under the parameters of the system. These results demonstrate that using relay selection can significantly improve the secrecy performance of the system. Moreover, we compare the cooperative relay system without SWIPT and the system with SWIPT. It is observed that depending on the distance of eavesdroppers from the relays and the destination, the system based on SWIPT may achieve a better PLS than the system without SWIPT. Finally, we provide Monte-Carlo simulation results to confirm the validity of our analysis.