Exploiting full Duplex techniques for secure communication in SWIPT system

This work investigates the secure transmission in the wireless information and power transfer system where a source node communicates with a wireless-powered full-duplex destination node in the presence of a passive eavesdropper. In particular, we propose such a two-phase time-sharing (TS) secure communication protocol: in the first phase, energy harvesting is conducted from the source node to the destination node, while in the second phase, the source node transmits information-bearing signal under the protection of artificial noise sent from the destination node. It is worth to mention that the energy of this artificial noise at the destination node is converted from the harvested energy in the first phase and self-interference exists at the destination in the second phase. We derive the closed-form expressions for the connection outage probability (COP), the secrecy outage probability (SOP) and the transmission outage probability (TOP), based on which the secrecy throughput is formulated. Further, we determine the optimal time allocation factor and the optimal codeword transmission rate to maximize the secrecy throughput with dual outage constraints. Finally, numerical results verifies our results and exams the effect of the time allocation factor and the codeword transmission rate on the performance.