A STAR-RIS assisted MIMO secure communication optimization method and device

Abstract

The present invention provides a method and apparatus for STAR-RIS assisted MIMO secure communication optimization, comprising: establishing a STAR-RIS assisted MIMO secure communication optimization system model; Using coupled phase-shifting STAR-RIS, under the constraints of transmission power and coupling phase-shifting, the total confidentiality rate of legitimate users in the STAR-RIS assisted MIMO secure communication system is maximized by jointly optimizing the transmission beamforming of the base station (BS) and the transmission and reflection coefficients of STAR-RIS; In order to solve the optimization problem of complex variables in long time slots, a Soft Actor Critic (SAC) algorithm is used to approximate the Q function, soft state value function, and policy using function approximators. Random gradient descent is alternately used to optimize the neural network to maximize the future cumulative reward value and entropy, obtaining the optimal solution for the maximum total secrecy rate of legitimate users. STAR-RIS has higher secrecy rate and better performance improvement than traditional reconfigurable metasurfaces (RIS).

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