Lightweight UAV-based Measurement System for Air-to-Ground Channels at 28 GHz

TL;DR

This paper introduces a lightweight UAV-based measurement system at 28 GHz for air-to-ground channels, overcoming payload limitations to enable high-frequency channel assessment in real flight conditions.

Contribution

A novel lightweight measurement system for 28 GHz UAV communications is developed and validated through real flight tests, addressing payload constraints and antenna pattern effects.

Findings

Measurement system is approximately 1.3 kg and suitable for UAVs.

Calibration procedure effectively corrects antenna gain variations.

System successfully validated at distances over 300 meters.

Abstract

Wireless communication at millimeter wave frequencies has attracted considerable attention for the delivery of high-bit-rate connectivity to unmanned aerial vehicles (UAVs). However, conducting the channel measurements necessary to assess communication at these frequencies has been challenging due to the severe payload and power restrictions in commercial UAVs. This work presents a novel lightweight (approximately 1.3 kg) channel measurement system at 28 GHz installed on a commercially available UAV. A ground transmitter equipped with a horn antenna conveys sounding signals to a UAV equipped with a lightweight spectrum analyzer. We demonstrate that the measurements can be highly influenced by the antenna pattern as shaped by the UAV's frame. A calibration procedure is presented to correct for the resulting angular variations in antenna gain. The measurement setup is then validated on real flights from an airstrip at distances in excess of 300 m.