On the Secrecy Design of STAR-RIS Assisted Uplink NOMA Networks

• Published in: IEEE transactions on wireless communications Vol. 21; no. 12; pp. 11207 - 11221
• Main Authors: Zhang, Zheng, Chen, Jian, Liu, Yuanwei, Wu, Qingqing, He, Bingtao, Yang, Long
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.12.2022; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Algorithms; Array signal processing; Beamforming; Communication system security; Decoding; Eavesdropping; Electronic surveillance; NOMA; Non-orthogonal multiple access; Nonorthogonal multiple access; Optimization; physical layer security; secrecy beamforming design; STAR-RIS; Statistical analysis; Uplink; Uplinking; User requirements; Wireless communication; Wiretapping
• ISSN: 1536-1276; 1558-2248
• DOI: 10.1109/TWC.2022.3190563

This paper investigates the secure transmission in a simultaneously transmitting and reflecting reconfigurable intelligent surface (STAR-RIS) assisted uplink non-orthogonal multiple access system, where the legitimate users send confidential signals to the base station by exploiting STAR-RIS to reconfigure the electromagnetic propagation environment proactively. Depending on the availability of the eavesdropping channel state information (CSI), both the full CSI and statistical CSI of the eavesdropper are considered. For the full eavesdropping CSI scenario, we adopt the adaptive-rate wiretap code scheme with the aim of maximizing minimum secrecy capacity subject to the successive interference cancellation decoding order constraints. To proceed, we propose an alternating hybrid beamforming (AHB) algorithm to jointly optimize the receive beamforming, transmit power, and reflection/transmission coefficients. While for the statistical eavesdropping CSI scenario, the constant-rate wiretap code scheme is employed to minimize the maximum secrecy outage probability (SOP) subject to the quality-of-service requirements of legitimate users. Then, we derive the exact SOP expression under the constant-rate coding strategy and develop an extended AHB algorithm for the joint secrecy beamforming design. Simulation results demonstrate the effectiveness of the proposed scheme. Moreover, some useful guidance about the quantification of phase shift/amplitude and the deployment of STAR-RIS is provided.