Tethered Drones To Offer Flexible Wireless Hotspot Solution

Hovering drones could enhance wireless connectivity in temporary high-usage hotspots.
Chris Young
KAUST University's tethered drone conceptKAUST University/Xavier Pita

Data providers face a seemingly endless task to keep up with wireless demand, with temporary high-usage hotspots providing a particular strain on fixed-base station networks.

A group of students at KAUST University in Saudi Arabia believe they might have a solution in the form of tethered drones. The tethered machines would, ironically, provide a flexible, low-cost solution for dealing with sudden upsurges in data demand.

"Transient hotspots of heavy data traffic can occur at events such as sporting matches, concerts, conferences, and exhibitions," Osama Bushnaq, a former Ph.D. student at KAUST, explains in a statement.

"However, the high cost of deploying fixed terrestrial base stations to serve such occasional or periodic events may not be warranted. In such circumstances, drones could hover over the hotspot to provide ground users with better connectivity. The question for us was whether tethered or untethered drones would be better."

As well as providing a clear line-of-sight, drones could be programmed to fly above usage hotspots as they emerge. On their own, however, they have limited battery duration and would rely on a good wireless link to a fixed ground station to provide the necessary bandwidth.

"To overcome these challenges, the drone can be connected to a cable or tether that provides an unlimited power supply and a high-capacity link to the core network," says Bushnaq. "The tethered drone’s mobility is, however, restricted by the tether length and the ground station’s location. Given these advantages and shortcomings of tethered and untethered drones, we conducted a comparative analysis using a statistical coverage method and optimization of drone location."

Will tethered drones provide competition for other data providers?

In their study, published in IEE Xplore, the researchers present mathematical proof for the optimal drone location that provides maximum coverage for users within the hotspot. They also detail extensive simulations that, they say, showed the tethered drone system outperforms untethered drones in practical situations.  

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"In practice, the drone might fly to the nearest ground tether station to a hotspot, connect itself to the tether, and hover at the optimal position for as long as needed,” says Bushnaq. "The drone would then detach itself and fly to another ground tether station to serve another hotspot."

Al-Naffouri’s team are also exploring other useful application for the tethered drones: for example, highly connected drones could be used to pinpoint hostile drones in the area for security.

The advent of satellite-provided high-speed internet for rural areas — such as the service provided by SpaceX's Starlink satellites — might prove too strong a competition for tethered internet-providing drones to ever truly take off.

However, the tethered drone concept is one that has been tinkered with by Facebook and by climate scientists. Maybe it will eventually find its place in the crowded UAV solutions market.