Throughput Maximization in IRS-Aided Simultaneous Communication and Jamming System

Abstract

This paper proposes an IRS-assisted simultaneous communication and jamming (SCAJ) system, where legitimate and suspicious communication pairs coexist in the same spec-trum. Different from traditional IRS-aided communication or jamming systems, SCAJ system not only can enhance the communication effectiveness of legitimate user, but also can decrease the communication reliability of the suspicious user. Specifically, we aim to maximize the throughput of the legitimate communication by optimizing the phase shift of IRS and the precoding vector of legitimate transmitter, while restricting the SINR of the suspicious user below a certain threshold. The formulated problem can not be solved directly due to its non-convexity. Hence, it is firstly converted into two sub-problems. The former is solved by semi-definite relaxation (SDR) and Dinkelbach, while the latter is solved by SDR and Gaussian randomization. An alternate optimization algorithm is proposed to solve the joint phase shift and precoding optimization problem. Simulation results show that the proposed scheme can significant-ly increase the throughput of legitimate communication compared with traditional system without IRS.