Energy Efficiency of Massive MIMO Downlink WPT With Mixed-ADCs

This letter studies the energy efficiency of massive multi-input multi-output downlink wireless power transfer systems with mixed analog-to-digital converters (ADCs). Taking into account of imperfect channel state information estimation, the closed-form expression for the average amount of harvested energy of the users are derived. Then, considering a realistic energy consumption model, the end-to-end energy efficiency (EE) of the system is studied, and the optimal strategy maximizing the EE is analytically characterized. The findings of the letter suggest that the base station should adopt a binary policy by using either high-resolution ADCs or low-resolution ADCs. Simulation results are provided to corroborate the analytical results.