UAV Communications in Integrated Terrestrial and Non-terrestrial Networks

TL;DR

This paper investigates how integrating terrestrial and non-terrestrial networks, specifically LEO satellites and ground cellular systems, can significantly improve UAV connectivity and reduce outages in urban environments.

Contribution

It demonstrates that offloading UAV traffic to LEO satellite networks can drastically reduce outages and enhance communication quality, even with limited bandwidth.

Findings

UAV outage reduced from 70% to nearly zero with NTN offloading

UAV command and control rates met across large urban areas

Offloading benefits also improve ground user uplink reliability

Abstract

With growing interest in integrating terrestrial networks (TNs) and non-terrestrial networks (NTNs) to connect the unconnected, a key question is whether this new paradigm could also be opportunistically exploited to augment service in urban areas. We assess this possibility in the context of an integrated TN-NTN, comprising a ground cellular deployment paired with a Low Earth Orbit (LEO) satellite constellation, providing sub-6 GHz connectivity to an urban area populated by ground users (GUEs) and uncrewed aerial vehicles (UAVs). Our study reveals that offloading UAV traffic to the NTN segment drastically reduces the downlink outage of UAVs from 70% to nearly zero, also boosting their uplink signal quality as long as the LEO satellite constellation is sufficiently dense to guarantee a minimum elevation angle. Offloading UAVs to the NTN also benefits coexisting GUEs, preventing uplink outages of around 12% that GUEs would otherwise incur. Despite the limited bandwidth available below 6 GHz, NTN-offloaded UAVs meet command and control rate requirements even across an area the size of Barcelona with as many as one active UAV per cell. Smaller UAV populations yield proportionally higher rates, potentially enabling aerial broadband applications.