RIS-NOMA Assisted Covert Transmission for Integrated Sensing and Communication With Statistical CSI

This letter proposes a covert beamforming framework for a RIS-NOMA assisted integrated sensing and communication system under statistical CSI. Specifically, the dual functional base station transmits both public and covert signal to users in NOMA protocol and performs sensing function simultaneously while avoiding the detection of covert signal by an eavesdropper. The RIS is deployed to help both covert transmission and sensing performance. By jointly designing the transmit beamforming vectors and the reflection coefficients of the RIS, we aim to maximize the covert signal transmission rate. We propose an alternative algorithm to decouple the variables and split the problem into two subproblems. The penalty-based method is utilized to optimize the transmit beamforming and the majorization-minimization method is adopted to transform the quartic radar SNR constraint into a quadratic constraint. Simulation results show the effectiveness of our proposed covert transmission design.