Secure Beamforming for SWIPT in Multiuser MISO Broadcast Channel With Confidential Messages

In this letter, we consider simultaneous wireless information and power transfer (SWIPT) in multiuser multiple-input single-output (MISO) broadcast channel with confidential messages, where each receiver adopts the power splitting (PS) approach to decode information and harvest energy simultaneously. Our goal is to minimize the total transmit power while guaranteeing the secrecy rate and harvested energy constraints at each receiver by jointly optimizing the transmit beamforming vectors, artificial noise vector, and PS ratios. To solve this non-convex problem, a two-stage optimization approach is proposed. In addition, we also propose a low-complexity suboptimal algorithm based on the genetic algorithm to solve the original problem. Simulation results are finally presented to illustrate the effectiveness of our proposed algorithm.