Wireless Powered ALOHA Networks with Fixed User Rates and UAV-mounted Base Stations

Abstract

In this paper, we study an unmanned aerial vehicles (UAVs) assisted wireless powered communication networks (WPCNs) were the base station (BS) is mounted on the UAV. The UAV flies along a circular trajectory and allows for a line of sight (LoS) link between the BS and each energy harvesting user (EHU). The WPCN employs a slotted ALOHA random access, where the EHUs transmit information at a fixed rate to the BS. The EHUs are assumed to have only statistical channel state information and thus outage can occur. For such WPCN, we obtain proportionally fair resource allocation by finding the optimal channel access probability, and the rate at which each EHU transmits. Using numerical results we determine the conditions where nonzero outage probability is optimal.