Robust Secrecy Beamforming and Power-Splitting Design for Multiuser MISO Downlink with SWIPT

In this paper, we investigate the physical layer security design in multiuser multiple-input single-output downlink with simultaneous wireless information and power transfer. Specifically, by considering that legitimate receivers use power splitting to extract information and harvest energy simultaneously, we investigate the robust weighted sum secrecy rate maximization design, subject to multiple signal-to-interference-and-noise ratio and harvested energy constraints. To solve the formulated highly nonconvex problem and avoid high-rank solution obtained by the common semidefinite relaxation method, we utilize the constrained concave convex procedure and second-order cone programming to formulate a tractable problem and propose an iterative algorithm to obtain the solution. In addition, we discuss the feasibility condition and computational complexity of our algorithm. Furthermore, our algorithm can be extended to other optimization designs. Simulation results show the superiority of our proposed design.