A Unified Performance Optimization for Secrecy Wireless Information and Power Transfer over Interference Channels

In this paper, we give a unified performance optimization for secrecy wireless information and power transfer (SWIPT) over interference channels, where an external eavesdropper is also interested in the confidential message. We propose to perform cooperative energy beamforming between two sources to confuse the eavesdropper while satisfying the requirements on the minimum amounts of individual harvested energy, and the minimum signal-to-interference-plus-noise ratio (SINR) at the wiretap-free node, even under an adverse conditions that there exist channel uncertainties at the transmitters. Considering the maximization of secrecy rate subject to a power constraint and the minimization of power consumption with a minimum secrecy rate requirement are two commonly used design objectives for secure communications, we give a unified performance optimization from the both perspectives. Especially, since there exists channel uncertainty, we propose to optimize the worst performance, so as to satisfy the performance requirements under all channel conditions. To achieve a balance between system performance and implementation complexity, we present a robust cooperative beamforming and power splitting scheme for each secrecy problem while confining the information signal in the null space of the interference channel. Finally, simulation results validate the effectiveness of the proposed schemes.