Covert communications assisted by simultaneously transmitting and reflecting reconfigurable intelligent surface (STAR-RIS) in non-orthogonal multiple access (NOMA) systems have been explored in this paper. In particular, the access point (AP) transmitter adopts NOMA to serve a downlink covert user and a public user. The minimum detection error probability (DEP) at the warden is derived considering the uncertainty of its background noise, which is used as a covertness constraint. We aim at maximizing the covert rate of the system by jointly optimizing APs transmit power and passive beamforming of STAR-RIS, under the covertness and quality of service (QoS) constraints. An iterative algorithm is proposed to effectively solve the non-convex optimization problem. Simulation results show that the proposed scheme significantly outperforms the conventional RIS-based scheme in ensuring system covert performance.
@article{arxiv.2306.07105,
title = {STAR-RIS Assisted Covert Communications in NOMA Systems},
author = {Han Xiao and Xiaoyan Hu and Tong-Xing Zheng and Kai-Kit Wong},
journal= {arXiv preprint arXiv:2306.07105},
year = {2023}
}
Comments
arXiv admin note: text overlap with arXiv:2305.04930, arXiv:2305.03991