NOMA Based UAV Relay Communication Protocol in Cellular Network

Abstract

Introducing unmanned aerial vehicles (UAVs) into wireless communication systems has recently gained a lot of attention. UAV provides many advantages such as shorter communication distance and a higher probability of having line-of-sight (LoS) condition due to its dynamic positioning. In this paper, UAV is deployed as a relay station because it can give superior performance due to the high probability of having LoS channel compared to a fixed ground relay station. However, the achievable throughput is decreased as relay communication requires twice of time resources in direct communication. To tackle this problem, non-orthogonal multiple access (NOMA) based communication protocol is proposed in this paper. Furthermore, as a specific problem for UAV, interference from neighbouring base stations (BSs) is large due to LoS channel between UAV and neighbouring BSs. In order to eliminate the interference from neighbouring BSs, UAV relay is equipped with array antenna. The simulation results elucidate that the throughput improvement of the proposed protocol over the conventional protocol.