Secrecy Rate Maximization for Intelligent Reflecting Surface Assisted Multi-Antenna Communications

• Published in: IEEE communications letters Vol. 23; no. 9; pp. 1488 - 1492
• Main Authors: Shen, Hong, Xu, Wei, Gong, Shulei, He, Zhenyao, Zhao, Chunming
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.09.2019; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Algorithms; Antennas; Closed form solutions; Computer simulation; Covariance; Covariance matrices; Design optimization; Exact solutions; Intelligent reflecting surface (IRS); Laboratories; Mathematical analysis; MISO communication; multi-antenna communications; Optimization; physical-layer security; Reconfigurable intelligent surfaces; Secrecy aspects; secrecy rate; Security; Signal to noise ratio; Wireless communication
• ISSN: 1089-7798; 1558-2558
• DOI: 10.1109/LCOMM.2019.2924214

We investigate transmission optimization for intelligent reflecting surface (IRS) assisted multi-antenna systems from the physical-layer security perspective. The design goal is to maximize the system secrecy rate subject to the source transmit power constraint and the unit modulus constraints imposed on phase shifts at the IRS. To solve this complicated non-convex problem, we develop an efficient alternating algorithm where the solutions to the transmit covariance of the source and the phase shift matrix of the IRS are achieved in closed form and semi-closed form, respectively. The convergence of the proposed algorithm is guaranteed theoretically. Simulation results validate the performance advantage of the proposed optimized design.