UAV Relaying: Power Allocation and Trajectory Optimization Using Decode-and-Forward Protocol

In this paper, we consider an unmanned aerial vehicle (UAV) relay network where a UAV works as a decode-and-forward (DF) relay to extend the coverage of the base station. We first derive the outage probability for the communication link from the mobile device (MD) to the base station (BS). To minimize the outage probability, we jointly optimize both the trajectory of the UAV and the transmit power of the MD as well as the UAV. The simulation results show that the outage performance obtained from the proposed joint trajectory optimization and power allocation algorithm (JTO-PA) is better than that obtained from circle trajectory with power allocation scheme (CT-PA) and fixed position with equal transmit power scheme (FT-EP).