Floating Antennas
By Jeff Goldman, Mon Sep 09 00:00:00 GMT 2002

Balloons and unmanned aircraft might seem like unlikely locations for cell sites, but they have the potential to solve some key issues facing wireless communications.

Along the southern border of the United States, a chain of tethered aerostats-helium-filled balloons which float at an altitude of 15,000 feet while connected to the ground by long
cables-monitor the traffic on the perimeter between the U.S. and Mexico. And every year, the U.S. National Weather Service releases a total of 75,000 radiosondes, or weather balloons, which track weather conditions in the upper atmosphere. Launched twice a day, the balloons reach an altitude of about 100,000 feet before they return safely to earth. Finally, NASA's Helios Project is developing an unmanned aircraft, powered by solar panels and fuel cells, which could fly at an altitude of approximately 70,000 feet for days or even months at a time.

What do these things have in common? They're all being tested as platforms for wireless communications.

A number of influential forces are behind the work on these airborne antennas, from the search for ubiquitous coverage to the drive to bridge the digital divide.

Familiar Territory

Tethered aerostats, which are being developed as communications platforms by Platforms Wireless International, are nothing new. According to Robert Harris, Platforms Wireless' Vice President and CTO, the aerostats at the U.S./Mexico border have been in operation since the early '80s. "We're adopting tried and proven technology," he said.

Weather balloons have an even longer history: they were first deployed by the National Weather Service in the 1930s. Gerald Knoblach is Chairman and CEO of Space Data Corporation, which is planning to deploy wireless equipment on NWS radiosondes: he says it just made sense to put wireless on a platform that's already being launched daily.

While the Helios aircraft doesn't have a long history, it has significant backing from NASA, which sees it as a potential research platform for high-altitude environments. SkyTower Telecommunications is developing the aircraft in cooperation with NASA, and successfully tested a 3G wireless system in flight over Hawaii in July.

With this kind of history and backing, these companies are hoping to release their products very soon. Platforms Wireless plans to have its first deployment by the first quarter of next year, and Space Data Corporation expects to follow shortly after. Pending further research on sustaining longer flight durations, SkyTower anticipates having its initial deployments within three years.

Permission to Fly

Still, there a number of challenges facing these technologies-enough of them that analysts like David Benson of SRI Consulting Business Intelligence are cynical about the prospects that they'll ever be deployed at all. From weather issues to safety and reliability concerns, there are a lot of reasons to be cautious.

In the US, the Federal Aviation Administration currently prohibits the use of unmanned aircraft, though SkyTower is working to find a compromise that would permit the deployment of its platform. And Platforms Wireless' ARC System, with an altitude of 15,000 feet, requires a no-fly zone in a three-mile radius around each of its aerostats-which makes deployment in the US problematic at best.

Space Data Corporation's Knoblach, of course, sees the restrictions as an advantage. By using lightweight weather balloons instead of aircraft, Space Data is able to bypass the FAA regulations and get an advantage over the competition. "Because we fly under the regulations that govern radiosondes, we basically have an early entry to market," he said.

For SkyTower's aircraft in particular, SRI's Benson points out, there are a number of challenges in terms of safety. "I really can't see the FAA saying it's okay to fly unmanned aircraft above a city," he said. "It runs counter to what the FAA demands of their airspace: airplanes tend to break, and I've never seen a 100 percent reliable airborne platform of any type."

Rough WeatherAhead

Weather, though, presents the biggest challenge. Not only can balloons and aircraft be buffeted by the elements as they take off and land, but rain and other particles between the platform and the ground can create interference-and inclement weather can make it impossible to fly a system like Platforms Wireless's tethered aerostats.

Platforms Wireless' Harris points out that his company's ARC System, which is deployed at 15,000 feet, flies low enough that interference isn't as much of an issue as it is for competitors. "For the real high-altitude HAPS, that can be a big problem," he said. "You get extremely high attenuation through water vapor, clouds, and rain, at the higher altitudes."

John del Frate, Solar Powered Aircraft Project Manager for NASA, says high altitudes present a temperature problem as well. "You're flying at nearly the coldest point in the atmosphere," he said. "At some of the places we've flown, it's -110 degree Fahrenheit. You have to make sure that the equipment can handle the cold, and that it can operate in a much thinner atmosphere."

Still, Platforms Wireless' Perry points out that, in truly inclement weather, a balloon can be a great asset. "If you get a storm that's ripping out cell towers, trees, and buildings, during that type of situation our system would be retrieved and bagged," he said. "But within 24 hours after the storm, we'd be back in business. We wouldn't have to go out and replace that cell tower that was ripped up."

A New World ofCoverage

With all these issues, though, why even try to make it work? The answer is simple: these solutions can help to bridge the digital divide, making coverage viable where it otherwise wouldn't be an option. Platforms Wireless, for example, has been working with the government of Indonesia, a country whose thousands of islands spread over a large geographic area present a unique challenge for communications.

As Space Data's Knoblach explains it, the value proposition comes down to this: fewer deployments, more coverage. "As you get the transceiver higher in the air, you address a larger footprint," he said. "So you can aggregate a bunch of sparsely populated people into a single piece of equipment and make economic sense-as opposed to a tower, which won't have a big enough footprint in sparsely populated areas."

With coverage footprints that start at a 70-mile radius, these solutions can help make it economically viable for carriers to serve ruralcustomers-and as Platforms Wireless' Perry points out, concernsabout possible downtime become less relevant in such areas. "If you're getting nothing now, and you're looking at getting nothing for a long time to come, some weather-related downtime is really not that significant," he said.

Platforms Wireless' Harris adds that these solutions can help a carrier to grow their customer base in a new location. "They can go ahead and establish a wide areas of subscribers, then move those subscribers off to terrestrial towers in the places where it makes the most economic sense-where they've got good high-density clusters," he said. "In the end, we can really work hand in glove with the terrestrial guys."

Advantages in theMarket

Stuart Hindle, Vice President of Strategy and Business Development for SkyTower, notes that speed to market is also a great selling point for these solutions. "You launch a single platform and you have instant market coverage on day one," he said. "Wireless carriers have paid billions for spectrum, and now they're trying to figure out how to cost-effectively meet the build-out requirements: this certainly is appealing."

And Space Data's Knoblach says these platforms can help carriers solve another key problem: keeping their customers happy. "If you look at churn rates, some surveys say that 30 to 50 percent of people say the reason they churn is because of poor coverage," he said. "One way to reduce churn is to provide ubiquitous coverage, yet towers just don't make economic sense. So people are searching for an alternative."

Still, SRI's Benson remains unconvinced. "To solve the problem of getting ubiquitous coverage, you really have to build a lot of cell towers, which is not going to happen in this country-and it's wildly unpopular in the UK and elsewhere-or you've got to use satellites, which are a lot more expensive," he said. "I just think ubiquitous coverage is always going to be one of our Achilles' heels."

But believers like SkyTower's Hindle contend that the potential of this solution is undeniable. "It has over 1,000 times the capacity of a satellite, it can be deployed at a fraction of the cost of cable and DSL, and it can be set up in a matter of days," he said. "It has such compelling attributes in terms of cost, capacity, coverage, and flexibility, that we believe it's going to have a tremendous impact on the telecom industry."

Jeff Goldman is a freelance writer covering a wide range of topics for a number of online journals. He currently writes regular articles for Internet.com's ISP-Planet. Brought up in Belgium, Jeff spent the last decade in New York, Chicago and London; he now lives in Los Angeles.