Secrecy performance of RIS-assisted wireless-powered systems with artificial-jamming generation

Abstract

This paper proposes a reconfigurable intelligent surface (RIS)-aided communication systems, where energy harvesting (EH) and artificial jamming techniques are used. In the proposed system, a source harvests energy from a base station, and uses the harvested energy to send data to a destination via the RIS, under presence of an eavesdropper. A jammer is employed to generate noises on the eavesdropper. For performance evaluation, we derive expressions of outage probability (OP), intercept probability (IP), average secrecy capacity (ASC) and secrecy outage probability (SOP) for the proposed system under Rayleigh fading environment. Simulation results are provided to confirm the accuracy of the analytical expressions. We also evaluate the performance of a corresponding system without using the jammer. The results show that the proposed system obtains much better performance than the non-jammer one. Moreover, the performance of the proposed system can be enhanced by increasing the number of reflecting elements at the RIS, increasing the transmit power of the source and jammer nodes, and optimizing the fraction of time allocated for the EH phase. On the contrary, IP of the non-jammer system is very high, and its ASC and SOP performance converge to saturation points at high signal-to-noise ratio (SNR) levels.