有源智能超表面赋能的隐蔽RSMA通信OA

In order to overcome the double-fading problem of signals in a Passive Reconfigurable Intelligent Surface(P-RIS)enabled multi-user covert communication system,a covert communication method based on Active Reconfigurable Intelligent Surface(A-RIS)enabled Rate Splitting Multiple Access(RSMA)technology is proposed.In this method,the base station splits the user message rate,divides it into the public part and private part,precodes them respectively,and uses the A-RIS to transform the A-RIS thermal noise that is originally unfavorable to the communication into a factor that is beneficial to improving the covertness,thus confusing the eavesdropper and weakening the interference to the normal user communication.In order to explore the covert communication performance limit of the proposed method,under the condition of ensuring the low detection probability of the eavesdropper,meeting the user's quality of service requirements and successive interference cancellation,the communication rate of the covert user is maximized by jointly optimizing the beamforming of the base station and A-RIS.In order to solve the above non-convex optimization problem with highly coupled variables,an alternating optimization algorithm is proposed to effectively decouple and iteratively solve the original optimization problem.Simulation results show that compared with the P-RIS,the proposed scheme can improve the covertness,and that the reasonable use of thermal noise can further improve the covert rate.Besides,the number of RSMA users and the A-RIS reflection unit can also improve the covert rate.