Hybrid Precoding Design for Security MU-MISO SWIPT Millimeter Wave Systems

Abstract

Hybrid precoding design for physical layer security multi-user multi-input single-output (MISO) simultaneous wireless information and power transfer (SWIPT) is investigated in a millimeter wave (mmWave) wireless system. Digital and analog precoding schemes are designed by minimizing the transmit power subject to the target secrecy rate, target harvested energy, total transmit power and analog precoding unit amplitude constraints. It is shown that the formulated problem is non-convex and the two sets of design variables are coupled. To deal with the complicated problem, an alternating optimization technique is employed to decompose the original problem into two subproblems. Specifically, to solve the subproblem of digital precoding design, a two-layer optimization approach is proposed. To reduce the computational complexity, a successive convex approximation approach is used. Then, for the subproblem of analog precoding design, a novel phase matching algorithm is proposed to tackle it. Digital precoding and analog precoding are iteratively calculated until convergence. Simulation results validates effectiveness of the proposed hybrid precoding technique.