Energy Efficient Beamforming and Polarization Reception for Massive MIMO Enabled SWIPT Systems

In order to improve the energy efficiency (EE) of massive MIMO enabled simultaneous wireless information and power transfer (SWIPT) systems, a joint beamforming and polarization reception (JBPR) scheme is proposed in this paper. Considering that inter-user interference may degrade the performance of information decoding (ID) users, and can be beneficial for energy harvesting (EH) users at the same time, we design different beamforming and reception strategies for the ID users and the EH users, respectively. While zero-forcing beamforming and polarization filtering based reception are considered for the ID users to eliminate interference, polarization matching reception is adopted for the EH users to receive the resultant signal vectors and maximize the harvested power. The proposed JBPR scheme can be derived from a fractional optimization problem formulated by joint beamforming and polarization reception for the ID users and the EH users. The optimization problem can be solved iteratively by the Dinkelbach method based fractional programming. Simulation results demonstrate that, the JBPR scheme has better EE performance for massive MIMO enabled SWIPT system, comparing with the conventional zero-forcing beamforming scheme.