Optimization Algorithm for Physical Layer Security in Multiple Flying RISs-Based Systems

Recently, as data demand has increased due to the rapidly increasing demand for wireless devices and the influence of data traffic, various technologies are being developed to support it. Among them, in the case of millimeter wave (mmWave) frequencies with rich spectra and high data transmission rates, there is a problem of large path loss. As a result, there is a growing interest in unmanned aerial vehicle (UAV) and reconfigurable intelligent surfaces (RIS) that can be reconstructed advantageously to communicate wireless communication environments. Therefore, this paper introduces the penalty-based successive convex approximation (SCA) and minorization-maximization (MM) algorithms to optimize transmission beamforming vectors and RIS beamforming vectors in a large system consisting of multiple users, eavesdroppers, and a number of Flying RISs combining UAV and RIS.