Physical Layer Security of Non Orthogonal Multiple Access Using Reconfigurable Intelligent Surfaces

In this paper, we propose to improve the physical layer security of non orthogonal multiple access (NOMA) using reconfigurable intelligent surfaces (RIS). RIS is decomposed in different sets of reflectors dedicated to NOMA users. As reflections reach the ith user with the same phase, the transmitter can reduce its power so that the eavesdropper cannot detect its signal. We derive the secrecy outage probability and the Strictly positive secrecy capacity (SPSC) for NOMA systems using RIS for Rayleigh fading channels.