UAV-Enabled Communication Using NOMA

TL;DR

This paper explores UAV-based communication systems employing NOMA, formulating a complex optimization problem and proposing algorithms that demonstrate NOMA's superior performance over OMA and DPC in multiuser scenarios.

Contribution

It introduces a joint optimization framework for UAV altitude, beamwidth, power, and bandwidth in NOMA systems, with algorithms solving the non-convex max-min rate problem.

Findings

NOMA outperforms OMA in rate performance.

Joint parameter optimization yields significant rate gains.

NOMA achieves rates comparable to DPC.

Abstract

Unmanned aerial vehicles (UAVs) can be deployed as flying base stations (BSs) to leverage the strength of line-of-sight connections and effectively support the coverage and throughput of wireless communication. This paper considers a multiuser communication system, in which a single-antenna UAV-BS serves a large number of ground users by employing non-orthogonal multiple access (NOMA). The max-min rate optimization problem is formulated under total power, total bandwidth, UAV altitude, and antenna beamwdith constraints. The objective of max-min rate optimization is non-convex in all optimization variables, i.e. UAV altitude, transmit antenna beamwidth, power allocation and bandwidth allocation for multiple users. A path-following algorithm is proposed to solve the formulated problem. Next, orthogonal multiple access (OMA) and dirty paper coding (DPC)-based max-min rate optimization problems are formulated and respective path-following algorithms are developed to solve them. Numerical results show that NOMA outperforms OMA and achieves rates similar to those attained by DPC. In addition, a clear rate gain is observed by jointly optimizing all the parameters rather than optimizing a subset of parameters, which confirms the desirability of their joint optimization.