STAR-RIS Aided Secure MIMO Communication Systems

• Published in: IEEE transactions on vehicular technology Vol. 73; no. 10; pp. 15715 - 15720
• Main Authors: Dong, Xiequn, Fei, Zesong, Wang, Xinyi, Hua, Meng, Wu, Qingqing
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.10.2024; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Algorithms; Array signal processing; Beamforming; Communications systems; Eavesdropping; majorization-minimization; MIMO; MIMO communication; multiple-input multiple-output; Optimization; Reconfigurable intelligent surfaces; Secrecy aspects; secure communication; Security; Simultaneous transmission and reflection reconfigurable intelligent surface; Transforms; Wireless communication
• ISSN: 0018-9545; 1939-9359
• DOI: 10.1109/TVT.2024.3400277

This paper investigates simultaneous transmission and reflection reconfigurable intelligent surface (STAR-RIS) aided physical layer security (PLS) in multiple-input multiple-output (MIMO) systems, where the base station (BS) transmits secrecy information with the aid of STAR-RIS against multiple eavesdroppers equipped with multiple antennas. We aim to maximize the secrecy rate by jointly optimizing the active beamforming at the BS and passive beamforming at the STAR-RIS, subject to the hardware constraint for STAR-RIS. To handle the coupling variables, a minimum mean-square error (MMSE) based alternating optimization (AO) algorithm is applied. In particular, the amplitudes and phases of STAR-RIS are divided into two blocks to simplify the algorithm design. Besides, by applying the Majorization-Minimization (MM) method, we derive a closed-form expression of the STAR-RIS's phase shifts. Numerical results show that the proposed scheme significantly outperforms various benchmark schemes, especially as the number of STAR-RIS elements increases.