Flying cell towers could power communications in disaster areas
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The quickly deployable communications network could deliver cell service to first responders and disaster victims.
Right in the middle of his two-year, National Science Foundation-funded project to improve communications during disasters, Kamesh Namuduri, a professor of electrical engineering at the University of North Texas, got a first-hand look at the problem when Hurricane Harvey slammed into the state on Aug. 25.
In Aransas County, the hurricane wiped out 18 of the 19 cell towers. In two other counties more than 80 percent of cell towers were put out of service. “There were lives lost just because of lack of communication,” Namuduri said.
Namuduri said he expected that big communications companies like AT&T and Verizon would fly in equipment to bridge the communications gaps. “But it didn’t happen,” he said.
With his NSF funding of $200,000, Namuduri is taking two tracks to improve communications during disasters. First, he’s experimenting with attaching portable cellular base stations to drones so that they can be flown to where cell service -- needed by both disaster victims and first responders -- is lacking.
Early in the process, Namuduri realized getting base stations aloft wouldn’t be easy. “One year ago the lightest base station was 20 pounds,” which was too heavy for available drones to carry, he said.
Over the next year, however, Namuduri found a manufacturer -- Virtual Network Communications -- that had developed a two-kilogram LTE base station called GreenCell.
“That,” he said, “we are able to lift.”
Last May, Namuduri and his team successfully flew a GreenCell base station at a test range in Waxahachie, Texas, aboard an AirRobot drone. The test showed that with 250 milliwatts of transmission power and from an altitude of 120 meters, the system could provide cell service within two kilometers, significantly farther than a conventional cell tower with the same transmission power.
Two major limitations of the system remain, Namuduri said. First, drones that can carry the base stations are very expensive, as are the base stations themselves. “The drone that we used in this demonstration was like $125,000,” he said. “Nobody can afford it.” The GreenCell base station, as well as similar portable base stations, can cost tens of thousands of dollars.
The other limitation is the maximum flight time of the drones, which is generally around 45 minutes.
He expects prices to go down and flight times to go up in the near future. “But we don't have to [use] drones all the time,” he said. “They are just to bridge the gaps in communications. Sometimes you can fly a manned flight.”
Namuduri is also focusing on is how to coordinate various media networks during the critical hours and days after a disaster.
He invited a social scientist onto the team to help understand how people on the ground actually communicate through social media and other avenues. “What we are trying to understand is what goes on on the ground,” he said. “How do people communicate? With the social networks there are many avenues for communication. And how do you feed that back into the first responder network?”
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