Scheduling of Energy Harvesting for MIMO Wireless Powered Communication Networks

Radio frequency (RF) energy harvesting has the potential to provide perpetual energy to the nodes in communication networks. In this letter, we study the optimization problem for the scheduling of the RF energy harvesting to satisfy the energy demands of the links in a wireless powered network containing a multi-antenna hybrid beamforming base station and multi-antenna users: The time is divided into multiple slots, where different beamforming weights are assigned to each slot. Upon formulation of the problem as a non-convex quadratically constrained linear program, we propose a solution method based on alternating minimization algorithm. We demonstrate via simulations that the additional degrees of freedom introduced by the scheduling algorithm can reduce the number of required RF chains in the hybrid beamforming structure for a certain delay performance, resulting in significant cost savings.