Simultaneous information and power transfer in MISO interference systems

This paper considers simultaneous wireless information and power transfer (SWIPT) in multiple-input single-output (MISO) interference systems in presence of energy harvesting nodes. We investigate the interference temperature minimization problem while satisfying signal-to-interference-and-noise ratio (SINR) and energy harvesting thresholds at the information and energy receivers, respectively. The objective is to improve the received SINR as well as to reduce cross-link information leakage in order to improve physical-layer security. The formulation leads to a non-convex problem which we solve using semidefinite relaxation (SDR) technique. A rank-constrained optimization algorithm is proposed and a rank reduction procedure is developed in order to achieve a lower rank solution. Interestingly, we show that the SDR is in fact tight and an optimal rank-one solution can be developed in certain scenarios. Numerical simulations are performed to demonstrate the effectiveness of the proposed algorithm.