Sprint evaluated the potential of small cells mounted on drones as a means of rapidly deploying temporary coverage for large events or disaster response situations.

Gunther Ottendorfer, Sprint’s COO of Technology, said in a blog post trials in the US state of Texas assessed the potential to use the operator’s Magic Box small cell to deliver “more coverage and capacity to support temporary spikes in network traffic”.

Equipment vendor Airspan designed a new aerial-friendly small cell which employs a base station chipset from Qualcomm and backhaul chipset from GCT Semiconductor. The latter reportedly includes 4Rx antenna technology and 2Tx diversity capabilities to help improve coverage across an area of 10 square miles to 20 square miles. The drone portion of the rig was supplied by CyPhy Works, a provider of tethered drones.

Though the Magic Box first made its debut in May as a plug-and-play coverage enhancer for consumers and businesses, Ottendorfer said the flying cell represents the “next extension of our toolbox”.

Like its ground-based counterpart, the airborne Magic Box provides wireless backhaul using a technology called LTE User Equipment (UE) Relay to connect to a donor cell cite, cell on wheels or a satellite cell on a light truck over Sprint’s 1.9GHz and 2.5GHz airwaves. The small cell is powered by a local commercial service or generator through a tether line.

“LTE UE Relay makes Sprint Magic Box highly portable – great for quick deployments when there’s going to be a sudden temporary increase in data traffic”, Ottendorfer wrote.

“The ability to fly obviously also makes Sprint Magic Box super portable, enabling it to zoom out over a flood zone or across an impassable bridge or obstructed roadway, bringing data coverage to previously unreachable locations.

Flying high
While the tests may have been Sprint’s first venture into the air, the trials aren’t the first of their kind among US operators. AT&T and Verizon have previously tested aerial LTE solutions.

AT&T began kicking the concept around in 2016 and in February announced the results of tests using a small cell mounted on the underside of a drone. The prototype was flown at an altitude of more than 300 feet and was able to provide coverage to an area of around 40 square miles. The model used a tether to provide both power and secure fibre connection to the ground.

Verizon began testing LTE coverage in the sky earlier this year after reportedly starting work on the idea back in 2014. Unlike AT&T and Sprint, the operator chose an aeroplane-like drone design featuring fixed wings and a forward propeller. Photos from Verizon’s tests did not show any ground tether.