Intelligent Reflecting Surface Aided Multi-Antenna Secure Transmission

• Published in: IEEE wireless communications letters Vol. 9; no. 1; pp. 108 - 112
• Main Authors: Chu, Zheng, Hao, Wanming, Xiao, Pei, Shi, Jia
• Format: Journal Article
• Language: English
• Published: Piscataway IEEE 01.01.2020; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Algorithms; Antennas; Closed-form solutions; Computer simulation; Eigenvalues and eigenfunctions; Intelligent reflecting surface; Optimization; phase shift; Physical layer security; physical-layer secrecy; Power management; Programming; Reconfigurable intelligent surfaces; Resource management; secure beamforming; Semidefinite programming; Signal processing algorithms
• ISSN: 2162-2337; 2162-2345
• DOI: 10.1109/LWC.2019.2943559

In this letter, we propose intelligent reflecting surface (IRS) aided multi-antenna physical layer security. We present a power efficient scheme to design the secure transmit power allocation and the surface reflecting phase shift. It aims to minimize the transmit power subject to the secrecy rate constraint at the legitimate user. Due to the non-convex nature of the formulated problem, we propose an alternative optimization algorithm and the semidefinite programming (SDP) relaxation to deal with this issue. Also, the closed-form expression of the optimal secure beamformer is derived. Finally, simulation results are presented to validate the proposed algorithm, which highlights the performance gains of the IRS to improve the secure transmission.