Secure wireless powered relaying networks: Energy harvesting policies and performance analysis

Abstract

In this paper, we investigate the problem of secure communication for a scenario, which consists of one pair of source-destination nodes and one untrusted relay.The source communicates with the destination via the help of energy harvesting-aware untrusted relay, which acts as the helper to forward the source information to the destination; however, the relay also acts as the unintended user to eavesdrop the source information. To keep the source information confidential from untrusted relay, the destination-assisted jamming technique is deployed.We evaluate the impact of energy harvesting protocols on such a secure communication scenario through the proposed energy transfer protocols, namely, source-based energy harvesting protocol and maximum energy harvesting protocol.To evaluate the secrecy performance of these proposed schemes, we derive analytical expressions for two important performance metrics including intercept probability and strictly positive secrecy capacity.The numerical analysis reveals the different trade-off between secure performance and relevant system parameters (i.e.,power splitting ratio, time switching ratio, energy conversion efficiency, transmit signal-to-noise ratio, and relay location).Simulation results are also provided to demonstrate the accuracy of the developed analytical expression.