Secure Beamforming for Intelligent Reflecting Surface Assisted MISO Wireless Communications

Abstract

This paper provides a method to provide physical layer security (PLS) between the source and the authorised user in the event that a direct line-of-sight (LoS) path is not feasible by using an intelligent reflecting surface (IRS). A new beamforming solution is proposed that can offer maximum gain at the intended user without any information leakage to eavesdropper when multiple-antenna base station (BS) with single antenna at legitimate user and eavesdropper (i.e., multiple-input-single-output, or MISO) is taken into consideration. In the absence of LoS, the proposed IRS-assisted approach can establish a communication link between the BS and the authorised user by combining maximum ratio transmission (MRT) with traditional zero-forcing (ZF) beamforming. The suggested approach is compared to other beamforming methods like MRT and traditional ZF in terms of performance metrics like channel capacity and secrecy capacity for the Rayleigh dispersed channel. The proposed approach outperforms the other techniques, it is concluded. In the end, the performance of secrecy is also examined in relation to many parameters, such as IRS elements or transmit antennas, and it is concluded that the provided method exhibits the most suitable performance.