AT&T’s extreme-weather drone provides new LTE coverage option in difficult environments

AT&T recently announced a tethered drone that is designed to operate as a cell on wings (COW) that can provide broadband coverage in extreme weather conditions—a capability that promises to be valuable to AT&T, enterprise customers and first responders, according to an AT&T official.

Art Pregler, AT&T’s unmanned aircraft systems (UAS) program director, said that AT&T previously has used drones to provide surveillance video of cell tower and deliver LTE coverage to remote areas, but the new drone has been designed to operate in rain, snow and winds up to 50 miles per hour.

“With most drones, the manufacturer designs the drone and then—kind of as an afterthought—they figure out how it can fly in various weather conditions,” Pregler said during an interview with IWCE’s Urgent Communications. “Whereas, with this drone, from its initial concept, it was designed for harsh weather.

“For example, the motors are pointed down instead of up. The arms are hollow tubes that channels air through the tubes to cool the engines while it’s running. We put a cybersecurity system on our drone, as well, so that if anyone tries to hack it, jam it or spoof it, the drone autonomously detects what’s going on and will switch frequencies, and it will mitigate the threat. We’ve done quite a few things to it to ensure that it’s robust, so it can operate not only in harsh environments but in threatening environments, as well.”

AT&T’s all-weather drone has a 550-tether that provides power and two strands of fiber-optic connectivity—one to support data transmission and one for drone telemetry—from the LTE equipment on the drone to a ground station, where myriad backhaul options can be employed, Pregler said.

“If there’s no backhaul at all, then we’ll default to satellite,” he said. “But, if there’s Ethernet available, we’ll tap into that. If there’s microwave, we’ll go with that. We can also go with free-space optical, we can tie into aerostats, and we can even tie into AirGig, which is an AT&T technology using power lines. So, there are a lot of options for backhaul.”

From a power standpoint, the AT&T all-weather drone can use power from the commercial grid, generators, batteries or even a solar-panel array, Pregler said. As long as power is available, the new drone can remain in flight “theoretically forever,” but AT&T is still conducting tests to determine limits. Currently, AT&T is not using a drone for more than 24 hours at a time without maintenance, although manufacturers have stated that they believe the drone can remain operational for several weeks at a time.

Such power versatility and the 550-foot tether let the new AT&T drone provide LTE coverage for a significant area—potentially much more range that AT&T realized via LTE coverage during disaster-recovery efforts in Puerto Rico during the aftermath of Hurricane Maria, Pregler said.

“The value of the drone with LTE technology is that LTE is line of sight, so the higher you go in altitude, the wider the coverage area,” Pregler said. “If you fly the drone at 550 feet, that’s taller than any tower in our network, so we’re able to put out a very large coverage area.

“In Puerto Rico, we only flew it at 200 feet, and even there, we had a 14-square-mile coverage area for each drone. And the real value there is that we’re able to get over trees, ridges and rough terrain, over buildings and over other structures, so it has a lot of value in the coverage capability.”

Pregler said AT&T’s experience in Puerto Rico using drone technology to provide temporary LTE coverage was valuable.

“We took our program from something that we believed could be done to putting it into practice and proved that is something that is viable, it does provide value, and it works,” he said. “It validated a lot of assumptions for us. We feel much more confident. Not that we weren’t confident to begin with, but having proven it in the field, we know our solution works.”