Energy-Efficient Resource Allocation for Wireless Powered Massive MIMO System With Imperfect CSI

In this paper, we propose an energy-efficient resource allocation scheme for a wireless power transfer (WPT) enabled multi-user massive multiple-input multiple-output system with imperfect channel estimation. In the considered system, the users who have data to transmit in the uplink only can be empowered by the WPT in the downlink from a base station (BS) with large scale multiple antennas. The problem of optimizing the energy efficiency of the considered system is formulated with consideration of beamforming design, antenna selection, power allocation, and time division protocol based on the practical consideration, i.e., imperfect channel state information at the BS. In particular, the proposed antenna selection scheme is intended to find the optimal number of antennas and then employ the energy beamforming. Moreover, In order to find the optimal power and time allocation, a scheme based on nonlinear fractional programming is utilized. Extensive simulation studies are conducted to demonstrate the effectiveness of the proposed schemes and their superior performance over other existing schemes.