Efficient GBS Sleep Strategy of UAV Assisted Wireless Networks for Energy Saving

In 5G Radio Access Networks (RANs), the energy consumption of the ground base station (GBS) accounts for more than 80%. Therefore, reducing the energy consumption of GBSs has been an important research direction for building green and environment-friendly communication networks. In view of this, we formulate an unmanned aerial vehicle (UAV)-assisted GBS sleep strategy for energy saving, which utilizes the mobility of UAVs to fill the wireless coverage holes caused by the sleeping of GBSs. To further enhance the effect of the formulated strategy, we propose a joint GBS sleeping, UAV trajectory planning, and UAV transmission power allocation problem to minimize the energy consumption of the entire system. To address the intractable problem, we first devise an iterative algorithm to optimize the trajectory and power of the UAV based on the block coordinate descent (BCD), and then nest it into the branch and bound (BaB) to obtain the GBSs operation status. Simulations demonstrate that the formulated strategy efficiently reduces the energy consumption of the network compared with other schemes.