Inside Facebook’s First Efforts to Rain Internet from the Sky

January 12 13:15 2017 Print This Article

(WIRED) – STANDING ON THE roof of the Facebook lab in Woodland Hills, California, I can’t see the airplane I’m looking for. It’s too small and too far away. So I duck under a white tent beside me where a bunch of engineers are watching a live video feed from a nearby camera on a massive flat-panel display. Even at heavy magnification, the aircraft is a tiny spec against the blue sky.  By Cade Metz

Beside the tent, a ten-foot-tall dish antenna is trying to establish a connection with the plane. On the flat-panel, a small red circle shows the precise point in the sky where the rooftop antenna is aiming. The red circle flits around the tiny spec, without quite reaching it. At times, one will zoom away from the other. But after several minutes, they come together. “We got lock!” yells Abhishek Tiwari, a lead engineer at Facebook, as the two connect.

And then, just as quickly, the connection breaks.

This is one of the first airborne tests of a new wireless technology Facebook is building for use with Aquila, the company’s Boeing-737-sized, solar-powered, long-range drone that’s designed to deliver internet access. Facebook engineers hope this wireless system will one day transport enormous amounts of data from ground stations to dozens of drones in the stratosphere, miles away. The drones will then beam the signal down to ground stations that can serve a city or rural area using more traditional communications—or even send the signal straight to smartphones down below, like a flying cellular antenna.

Either way, Facebook’s plan aims to bring the internet (and, of course, a certain social network) to new areas without the need to dig holes, install towers, and stretch expensive wire lines across the planet.

But the company has a long way to go before reaching that goal. That plane circling the San Fernando Valley in the distance? It’s not the actual drone but a stand-in, a Cessna that Tiwari and his team have outfitted with an extra bulge of equipment on its belly.

The key to the whole idea is an old but suddenly resurgent signaling paradigm called millimeter wave technology. Millimeter waves are smaller than the radio waves that transmit cell phone and Wi-Fi signals, and since this portion of the airwaves is not as widely used as others, Facebook can use it to send much larger about of data. Others have used millimeter wave systems to send data between two distant points, like ground stations and satellites. But it’s always been a bulky, power-hungry setup. Facebook is pushing toward the kind of lightweight, energy efficient applications that have only been contemplated in scientific journals and maybe some secret government labs. “There are a lot of theoretical papers on this,” says Robert Heath, an electrical engineer at the University of Austin. “But there aren’t a lot of people who are actually making it work.” Heath says that Facebook’s millimeter wave team rivals any in the world.

The team has already proven that its millimeter wave system can trade data between two fixed points eight miles away from each other at a rate of nearly 20 Gigabits per second. That’s roughly 400 times the speed of your home Internet connection. Facebook believes this is a world record for equipment that’s so light and consumes so little power.

But achieving that rate in connection with a moving target—and pushing that data rate even faster—are enormously difficult. First the team has to calibrate the precise orientation of the ground antenna using the position of the Sun. Then the flying antenna must lock in on that ground antenna—while hurtling through the sky at more than a hundred miles an hour, eight miles away, connecting with nothing a millimeter wave beam. It’s is like trying to thread a moving needle from the other side of a room.

During the test flight, hours go by: red circle zooming past tiny spec, locking briefly, falling away, the team anxiously waiting for a consistent lock.

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