Downlink NOMA in Multi-UAV Networks over Bivariate Rician Shadowed Fading Channels

TL;DR

This paper investigates downlink NOMA in multi-UAV networks over bivariate Rician shadowed fading channels, deriving analytical expressions and demonstrating NOMA's advantages in outage probability and shadowing resilience.

Contribution

It introduces a novel analysis of downlink NOMA in multi-UAV networks using the bivariate Rician shadowed model, providing closed-form expressions and outage probability comparisons.

Findings

NOMA achieves lower outage probability than OMA.

NOMA is less affected by shadowing effects.

Analytical expressions for joint PDF and CDF are derived.

Abstract

Unmanned aerial vehicles (UAVs) are set to feature heavily in upcoming fifth generation (5G) networks. Yet, the adoption of multi-UAV networks means that spectrum scarcity in UAV communications is an issue in need of urgent solutions. Towards this end, downlink non-orthogonal multiple access (NOMA) is investigated in this paper for multi-UAV networks to improve spectrum utilization. Using the bivariate Rician shadowed fading model, closed-form expressions for the joint probability density function (PDF), marginal cumulative distribution functions (CDFs), and outage probability expressions are derived. Under a stochastic geometry framework for downlink NOMA at the UAVs, an outage probability analysis of the multi-UAV network is conducted, where it is shown that downlink NOMA attains lower outage probability than orthogonal multiple access (OMA). Furthermore, it is shown that NOMA is less susceptible to shadowing than OMA.