On the Reliability and Security Enhancements of Double-RIS Enabled WPC System with Jamming

This paper studies the physical layer security for a double reconfigurable intelligent surface (RIS) aided wireless powered communication system in the presence of an eaves-dropper, where a user acts as friendly jammer (J) to emit the artificial noise to improve the transmission security of another user. In particular, three RIS transmission schemes are proposed: 1) In scheme-I, both RISs are designed as optimal phase shift of wireless user (U); 2) In scheme-II, the first RIS is designed as optimal phase shift of U and the second RIS is designed as optimal phase shift of J, respectively; 3) In scheme-III, the first RIS is designed as optimal phase shift of J and the second RIS is designed as optimal phase shift of U, respectively. To reveal the achieved reliability and security performance of proposed three schemes, we analyze the connection outage probability (COP) and secrecy outage probability (SOP), respectively. The results show that scheme-II and scheme-III have the same COP performance and both of them are worse than scheme-I. The scheme-III achieves the best SOP performance, while scheme-I achieves the worst SOP performance that is slightly inferior to scheme-II.