Interference-Asymmetric UAV Remote Control Links: Measurements and Performance Evaluation

TL;DR

This paper investigates how interference asymmetry affects UAV remote control links, demonstrating through measurements and simulations that uplink interference significantly degrades throughput due to loss of feedback.

Contribution

It provides the first physical measurement evidence and performance evaluation of interference asymmetry effects on UAV control links using real-world data and LTE/5G simulations.

Findings

Uplink interference asymmetry degrades UAV link throughput.

Loss of HARQ feedback impacts downlink performance.

Measurements confirm interference effects in real-world scenarios.

Abstract

Reliable and secure connectivity is crucial for remote control (RC) and uncrewed aerial vehicles (UAVs) links. A major problem for UAV RC links is that interference sources within the coverage may degrade the link quality. Such interference problems are a higher concern for the UAV than the RC unit on the ground due to the UAV being in line of sight (LoS) with a larger number of interference sources. As a result, lost hybrid automatic repeat request (HARQ) indicators (ACK/NACK) feedback in the uplink (UL, RC to UAV) may degrade the downlink (DL, UAV to RC) throughput. To get physical evidence for our interference asymmetry argument, we first conducted a measurement campaign using a helikite platform at the Main Campus area of NC State University during the 2024 Packapalooza festival. Subsequently, we evaluated the throughput impact of the loss of HARQ indicator feedback caused by UL asymmetry using MATLAB long-term-evolution (LTE) and fifth-generation (5G) toolboxes. Our numerical results confirm that UL interference asymmetry substantially degrades the throughput performance due to the loss of HARQ indicator feedback.