Robust Beamforming Design for IRS-Aided Secure SWIPT Terahertz Systems With Non-Linear EH Model

Abstract

In this letter, we study intelligent reflecting surface (IRS) aided simultaneous wireless information and power transfer (SWIPT) terahertz secure systems under a non-linear energy harvesting (EH) model. Assuming that the cascaded channel state information is imperfect, we propose a robust beamforming design to minimize the total transmit power by jointly optimizing the transmit beamforming and phase shifts of IRS subject to the outage rate probability constraints. We first transform the outage constraints into deterministic forms by using the Bernstein-type inequality. Then, we applying semidefinite programming to change the original non-convex problem into an equivalent convex problem, and develope an alternate iterative optimization algorithm to obtain a feasible solution of the original problem. Finally, simulation results validate the effectiveness of our proposed scheme.