User scheduling for non-orthogonal transmission in UAV-assisted relay network

An unmanned aerial vehicle (UAV) can be used as a relay node to provide a communication service to an isolated user equipment (iUE), which does not have a direct communication link from/to a near base station (BS). UAV-aided relay network (UARN) has been considered to provide a reliable communication service to iUE, and a non-orthogonal transmission scheme is utilized at BS to avoid performance degradation of user equipments inside a cell (cUEs). UE scheduling schemes, which are used for conventional relay networks, cannot maximize the longterm average throughput of cUEs in UARN, where UAV moves from BS to iUE or stays close to iUE. In this paper, a novel UE scheduling scheme is proposed to achieve higher long-term average throughput and fairness simultaneously in UARN, while providing a seamless relay transmission to iUE. Simulation results demonstrate that the proposed UE scheduling scheme outperforms the conventional UE scheduling schemes in UARNs.