Energy Efficient Antenna Selection Scheme for Downlink Massive MIMO Systems

With the rapid development of green wireless communication, the research on the energy efficiency characteristics of the downlink (broadcast channels, BC) is significant for a single-cell massive MIMO system. Based on the definition of energy efficiency (in bits/Joule), an optimized energy efficiency scheme is proposed in this paper. Before that, we derive the closed form lower capacity bounds of the achievable downlink sum-rate with the maximum-ratio transmission precoding. Also, we establish a power consumption model by taking into account the circuit power consumption, signal processing power consumption, cooling loss, in the practical situation. Under above scene, the optimization problem that maximizes energy efficiency is formulated and analyzed. We further give the global optimal closed form solution of the number of transmit antennas, for a given transmit power. The simulation results evaluate the performance of the energy efficiency as the number of transmit antennas increases, and reveal that the optimal number of transmit antennas can improve energy efficiency.