Non-Orthogonal Multiple Access for mmWave Drones with Multi-Antenna Transmission

TL;DR

This paper explores the use of non-orthogonal multiple access (NOMA) with multi-antenna mmWave drone base stations to improve spectral efficiency and coverage for large-scale events, introducing beam scanning and analyzing power optimization.

Contribution

It introduces NOMA transmission for mmWave UAV base stations with multi-antenna beamforming and beam scanning, enhancing spectral efficiency and coverage in large user areas.

Findings

NOMA significantly outperforms OMA in spectral efficiency.

Beam scanning improves outage sum rates when coverage is limited.

An optimal transmit power exists beyond which performance gains plateau.

Abstract

Unmanned aerial vehicles (UAVs) can be deployed as aerial base stations (BSs) for rapid establishment of communication networks during temporary events and after disasters. Since UAV-BSs are low power nodes, achieving high spectral and energy efficiency are of paramount importance. In this paper, we introduce non-orthogonal multiple access (NOMA) transmission for millimeter-wave (mmWave) drones serving as flying BSs at a large stadium potentially with several hundreds or thousands of mobile users. In particular, we make use of multi-antenna techniques specifically taking into consideration the physical constraints of the antenna array, to generate directional beams. Multiple users are then served within the same beam employing NOMA transmission. If the UAV beam can not cover entire region where users are distributed, we introduce beam scanning to maximize outage sum rates. The simulation results reveal that, with NOMA transmission the spectral efficiency of the UAV based communication can be greatly enhanced compared to orthogonal multiple access (OMA) transmission. Further, the analysis shows that there is an optimum transmit power value for NOMA beyond which outage sum rates do not improve further.