Secure wireless communications in the multi-user MISO interference channel assisted by multiple reconfigurable intelligent surfaces

This paper exploits reconfigurable intelligent surfaces (RIS) to enhance physical layer security (PLS) in a challenging radio environment. By adjusting the reflecting coefficients, RIS can provide programmable wireless environment so that electromagnetic wave propagate desired way. Specifically, we consider scenario where multiple user pairs communicate simultaneously over same channel multiuser MISO interference and each pair of transceivers keeps their confidential information secret from other receivers. We investigate secrecy rate balance system aided by RISs exploit additional design degrees freedom provided coordinated increase capacity, achieving transmission. In particular, adopt cooperative beamforming among collaborative transmitters maximize all users' minimum rate, balance. Due non-convexity formulated optimization problem, propose alternating (AO) solve it iteratively optimize active transmit at passive phase shifts based on positive semi-definite relaxation (SDR) successive convex approximation (SCA). iteration, programming (SDP) problem finally get optimal local solution problem. Finally, simulation results validate proposed algorithm is effective introduced significantly performance compared conventional baseline schemes.