If telecom industry executives think about drones at all, they are most likely pondering Facebook's massive solar-powered craft aimed at bringing the web to the unconnected.

But the commercial drone market, predicted to be worth $127 billion by 2020, is also a tempting prospect for telcos.

The most obvious problem is connectivity. A customer survey by German drone manufacturer Aibotix found that 83% of commercial operators used SD cards in flight because of the lack of a good connection to the cloud. Just 30% used the cloud and 97% of them said they needed a data uplink.

"In Europe there is no real way to work with cloud," says Benjamin Federmann, the director of project management at Aibotix. "In most countries it is difficult to have direct uplink in the field."

Drone companies also need big data, he says. "Data is nothing without analysis and archiving. Our customers don't have the money to run big computing systems. They need the support of telcos and other cloud firms."

Ralph Schepp, a vice president in Deutsche Telekom AG (NYSE: DT)'s group technology division, says the German operator has been trialing drone services with German aviation authorities.

In-air connectivity during tests has been "pretty good," he reports, while acknowledging the terrestrial network is not designed for supporting vehicles in flight.

But the biggest opportunity could be to build and operate an unmanned aerial vehicle (UAV) traffic management system, or UTM, that would handle the large volumes of vehicles and allow them to fly beyond line-of-sight restrictions.

German air traffic control today manages about 20,000 objects a year in a mostly manual operation. "If something is critical, they pick up a phone and call the pilot," says Schepp. But with UAV numbers in lower air space eventually expected to reach as much as 400,000, "you can't handle them in the same way."

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It might be possible to build an overlay infrastructure for UTM, but that would be costly, Schepp told an industry forum at Mobile World Congress last month. "The idea is to take what we have -- the mobile network -- and try to connect those drones with the mobile network. You don't need 5G."

Jane Rygaard, the head of marketing at Nokia Corp. (NYSE: NOK)'s advanced mobile solutions business, says a combination of UAVs and mobile networks will be used both for UTM and in-air connectivity.

These networks would have to manage complex interference challenges because the number of visible sites would vary with the altitude of the craft. Designing and optimizing networks for UAVs would also require different network models.

The other capability that mobile wants to sell to the UAV industry is identification through a SIM. Commercial drones don't carry any electronic identification, and the industry is under pressure from regulators and security agencies to come up with a solution. Mobile execs point to the SIM's low cost, availability and support from an established supply chain.

However, the drone industry is still weighing its options on all of these.

Michael Drobac, the executive director of the US Small UAV Coalition, says a number of "SIM-like technologies" are under consideration. DJI, the world's biggest private drone maker, has just announced its own radio-based electronic ID system.

Drobac says that, when it comes connectivity, a number of his members are using unlicensed spectrum, which they believe works as well as licensed services from operators.

"But I don't think we are looking at this being one size, one technology or one [form of] communications that will necessarily be the answer," he says.

— Robert Clark, contributing editor, special to Light Reading