Secure Communication in Active RIS-Assisted MISO Systems With Hardware Impairments

In this letter, we address hardware impairments (HWIs) in security-focused communication systems using Active Reconfigurable intelligent surface (ARIS). A robust beamforming design is proposed to mitigate impairments at the base station (BS), legitimate users, and RIS. Using an alternating optimization (AO) approach, we optimize BS beamforming and ARIS reflection phase coefficients. Auxiliary variables are introduced to tackle non-convex constraints, while techniques such as successive convex approximation (SCA) and semidefinite relaxation (SDR) are employed to solve the subproblems. Numerical results illustrate that our scheme significantly improves security, achieving a higher secrecy rate, and enhancing the robustness of the method.