Joint Energy Harvesting and Jamming Design in Secure Communication of Relay Network

This paper investigates the secrecy performance of amplified-and-forward (AF) relay wiretap model by using energy harvesting (EH) and signal alignment technique. All nodes equipped with multi antennas play different roles in terms of source, destination, relay, eavesdropper and jamming node. The jamming node designs artificial noise based on signal alignment principle, and then transmits it to the eavesdropper with harvested energy. Due to different power limitations, we propose power allocation schemes called Local Power Constraints scheme (LPCS) and Global Power Constraints scheme (GPCS), which maximize the secrecy rate of the system and obtain better secrecy performance when compared with the non-EH scheme and the partial nodes power allocation EH scheme. Furthermore, we also analyze the effect of the energy harvesting on the secure degrees of freedom (SDOF) in the high signal-to-noise (SNR) region, and simulate the secrecy performance with convex optimization method by proving the convexity of the optimization problem. Results show that the proposed schemes outperform the compared schemes on the secrecy performance, and achieve more secrecy rate when the destination and the relay have more antennas.