Energy-Efficient Beamforming for Wireless Backhaul under Non-Uniform Traffic

Due to the dense base station deployment, the high energy consumption caused by backhaul traffic is becoming increasingly serious. In this paper, a beamforming scheme is proposed to support dynamic and non-uniform uplink backhaul traffic with mmWave multiple-input-multiple-output (MIMO) arrays at the hub in a more energy-efficient manner. Assuming that the correct data link has been established during the initial access stage of backhauling, we consider beamforming for lighter backhaul traffic by forming a wider beam. The differentiation in backhaul traffic allows deactivating some phase shifters (PS) to improve energy efficiency (EE). We first formulate the optimization problem of maximizing EE, then convert latency constraints into effective rate constraints and finally introduce PS contribution to determine the deactivation sequence. The simulation results show that the strategy can improve EE by nearly 40%, demonstrating the superiority of the proposed PS deactivation strategy.