Wireless information and energy transfer in MIMO communication with interference channels

In this paper, we consider a wireless information and energy transfer (WIET) system, which consists of multiple information transmitter-receiver pairs, and multiple additional energy transmitters to improve the energy transfer. For such a new WIET system, we investigate the energy efficiency (EE) under two different setups, respectively: the information transmitters and energy transmitters use the same and different frequency bands. For each setup, we propose a novel centralized beamformer design method to solve the EE maximization problem, which can be transformed into a convex optimization problem using semidefinite relaxation (SDR) technique. Moreover, we develop a distributed optimization algorithm to solve the SDR approximation formulation for each setup. Simulation results show that the same frequency setup can achieve larger EE value and less computational complexity, however, suffering from lower sum rate. For each setup, the distributed scheme has slightly worse performance than the centralized one, while enjoys less computational complexity, especially when the number of the additional energy transmitters is large.