Secure Beamforming for Multiple Intelligent Reflecting Surfaces Aided mmWave Systems

In this letter, secure beamforming in a multiple intelligent reflecting surfaces (IRSs)-aided millimeter-wave (mmWave) system is investigated. system, the secrecy rate maximized by controlling on-off status of each IRS as well optimizing phase shift matrix IRSs. This problem posed joint optimization transmit and control, whose goal to maximize under total transmission power unit-modulus constraints. The difficult solve optimally due nonconvexity constraint conditions coupled variables. To deal with problem, we propose an alternating (AO)-based algorithm based on successive convex approximation (SCA) manifold (MO) technologies. Numerical simulations show that proposed AO-based can effectively improve outperforms traditional single IRS-aided scheme.