Airborne WiFi networks through directional antennae: An experimental study

In this paper, we study the design and development of airborne WiFi networks through directional antennae. Specifically, we conduct an experimental study to investigate the feasibility of transmitting WiFi signals over two unmanned aerial vehicles (UAVs). WiFi has become the de facto configuration for most communication devices, from personal smartphones to industrial instruments. The integration of WiFi signals with airborne networks will enable a fast deployment of WiFi infrastructures, which provide real-time communication for disaster scenarios where a communication infrastructure does not exist. One unique feature of this work is the use of directional antennae for long range WiFi signal transmission. Directional antennae are considered because they not only boost the signal strength, but also have the potential to reduce interference with other WiFi channels. However, the performance of communication using directional antennae depends highly on the alignment of facing directions, which requires online control in response to the movement of UAVs. In our experimental study, we develop two hexacopters that are equipped with NanoStations. They maintain correct facing and thus connectivity through an automatic mechanical heading control. Field tests are conducted to understand how distance impacts the WiFi signal throughput. The experimental study suggests the promising use of directional antennas for WiFi aerial communication, and also discloses challenges to enable robust WiFi airborne networks.