Secure Beamforming and Artificial Noise Design in Full-Duplex Wireless-Powered Relay Networks

This thesis studies secure beamforming for simultaneous wireless information and power transfer (SWIPT) in full-duplex (FD) wireless-powered relay networks, in which the relay operates based on harvested energy from radio-frequency signals. We propose a joint AF beamforming and artificial noise (AB-AN) covariance matrix design with PS strategy to maximize the secrecy rate under harvesting energy constraints at the relay We assume that there is a PS device which splits the received signal power at relay for harvesting energy and receiving information. Since such a problem is nonconvex and hard to tackle, we propose a two-level optimization approach via the one-Dimension search and the semidefinite relaxation (SDR) technique. The proposed scheme is compared with AB scheme. Simulation results show that the proposed scheme outperforms the AB scheme.