UAV-Assisted Time Division Power Allocation Strategy Based on RF Energy Harvesting

Aiming at the difference in number of users in busy time and spare time for the femto base station (FBS), the power allocation problem of maximizing the total downlink information is investigated in this paper. By deploying a pico base station carried by unmanned aerial vehicle (PBS-UAV), it provides services for users of multiple FBSs in spare time. Both the FBS and PBS-UAV have energy harvesting function. During the busy time, the FBS and PBS-UAV simultaneously harvest energy from the macro base station, and FBSs transmit data to users. During the spare time, multiple FBSs are replaced by the PBS-UAV to communicate with users in downlink. The power allocation problem is modeled as an optimization problem. The objective is to maximize the amount of downlink information of FBSs and PBS-UAV while satisfying the constraints of FBS and PBS-UAV energy consumption and transmission power. The optimal solution is obtained by using an augmented Lagrange multiplier method. The simulation results show that compared with the equal power method and partial fixed power method with PBS-UAV, the proposed method has an increase in terms of total information to different degrees.