Energy-efficient power allocation for secure communications in wireless powered massive MIMO relaying systems

In this paper, we address the problem of energy-efficient power allocation for secure communications in wireless powered relaying systems. The advantages of a massive multiple-input multiple-output (M-MIMO) relay are explored to improve the energy efficiency of both wireless information and power transfer. We first give a detailed performance analysis, and obtain a closed-form expression of the secrecy outage capacity. Then, by maximizing the secrecy energy efficiency (SEE), defined as the ratio of the secrecy outage capacity and the total power consumption, we derive an energy-efficient power allocation scheme. Finally, simulation results validate the effectiveness of the proposed scheme.