Energy-Harvesting-Enabled UAV Relay-Assisted NOMA Network Under Finite Blocklength

Abstract

This work comprehensively investigates the complex dynamics and benefits that emerge from the incorporation of technologies, such as energy harvesting (EH), finite blocklength (FBL), non-orthogonal multiple access (NOMA), and unmanned aerial vehicles (UAVs) within the framework of a cellular network. To analyse such a network system, we use stochastic geometry (SG) where base stations (BSs), UAVs, and terrestrial devices are distributed as Poisson point processes (PPPs) across a large geographical area. A NOMA transmission scheme is employed, with UAVs acting as EH relays, to enable communication between edge users and BSs in situations where direct line of sight (LoS) is not possible. Moreover, we investigate the proposed system under finite blocklength, where a precise characterization of the distance distribution of randomly paired NOMA users for a given UAV is provided. The performance is evaluated in terms of outage probability for NOMA users, which are served through EH enabled UAVs, using linear and non-linear model. It is demonstrated that communication can be sustained, with reasonable reliability, solely through the harvested energy. Results show that two-phase transmission scheme with EH-enabled UAVs as relays performs better than the direct transmission from BS to users. Moreover, there exists an optimal height of UAV flight for which the probability of outage is minimum. The Theoretical results are validated through Monte Carlo simulations and the influence of various parameters on the network's outage performance is also assessed.