Secrecy Throughput Analysis for Passive Reconfigurable Intelligent Surface Aided Communication System

In this paper, we study the secrecy performance of RIS (Reconfigurable Intelligent Surface)-aided wireless communication system. We assume a wireless system with a source, legitimate user, RIS and a eavesdropper. Specifically, the communication system equipped with a passive RIS transmit signals from the base station to legitimate user while being eavesdropped. In this scenario, we analyze the positive effect of passive RIS reflecting link on channel fading. We obtain the maximum/minimum signal-to-noise ratio (SNR) of the legitimate user/eavesdropper according to the corresponding channel coefficient. We also analysis the system secrecy outage probability (SOP), secrecy connectivity probability (SCP) and the secrecy throughput of the communication system. Our analytical results demonstrate that RIS has a positive effect on all users of communication system. And for legitimate users without RIS reflection link, with the increase of reflection elements, it has a greater positive impact on eavesdropper. And this paper can serve as a theoretical basis for RIS-aided secure communication in the future.