Facebook's quest for Internet is coming back to Earth with two wireless projects

At the company’s F8 conference on Wednesday, Facebook networking chief Jay Parikh introduced a super-high-frequency wireless backbone called Terragraph and a 96-antenna cellular base station named Aries. Facebook won’t sell these systems but wants to make the technologies available to others.

The world’s biggest social networking company has as much motivation as anyone does to make Internet access available to everyone. That’s the mission of its Connectivity Labs, which has so far made headlines with projects like satellites and a giant solar-powered airplane that would beam wireless signals down to users on the ground.

With its latest effort, the labs are taking it to the streets.

The Terragraph system is a collection of small radios designed to be installed around a city at close intervals (about 250 meters apart) as a cheaper alternative to laying fiber.

It’s based on WiGig, an extension of Wi-Fi that uses unlicensed spectrum in the 60GHz band to deliver gigabit speeds within a room. Using beam-forming and steering techniques, Facebook is using the same technology to shoot multigigabit signals between light poles or other nodes, forming a distribution network as a backbone for other services. 

Terragraph can steer around buildings and other urban sources of interference, Parikh said. A software-defined networking controller, derived from work Facebook has done on its own data-center networks, helps Terragraph find the best routes and recover when a node goes down.

Like Facebook, mobile operators are looking beyond even relatively high frequencies like 5GHz in search of bands where there’s more spectrum available for future growth. These millimeter-wave frequencies don’t go far on their own, and beaming and steering are two techniques to overcome the short range. In addition to the U.S., the U.K., Germany, Japan, South Korea and other countries have unlicensed spectrum at 60GHz.

By using WiGig, a consumer technology that runs on spectrum carriers don’t have to pay for, Facebook aims to make Terragraph a large-scale, low-cost form of high-frequency wireless. The company is testing the technology at its Menlo Park, California, campus and late this year plans a bigger trial in nearby downtown San Jose.

Aries is a wireless base station that can serve 24 client devices on the same spectrum at the same time. At F8, Parikh showed it sending 24 separate video streams simultaneously. It’s a proof-of-concept project to show how wireless networks could use scarce spectrum and energy more efficiently. Facebook sees Aries as a faster and cheaper way to bring Internet access to rural communities.

The array of 96 antennas in the Aries base station uses a technology called massive MIMO (multiple in, multiple out) that’s expected to play a big role in future 5G networks. Facebook thinks what it’s developed here could become part of the standard.

MIMO, using multiple antennas to form more than one stream of data through the air, has been used to boost the performance of Wi-Fi and cellular for a few years now.

Massive MIMO involves even more antennas and streams. Among other things, it could help networks overcome the limitations of millimeter-wave frequencies so they can use new, wide bands of spectrum. With Aries, Facebook believes it’s set a record for number of antennas and efficient use of spectrum in massive MIMO.

Facebook doesn’t plan to build Terragraph or Aries networks itself but will make these technologies available through the Telecom Infra Project, formed in February and modeled after the company’s Open Compute Project. It now has more than 300 members, including Nokia, Intel and SK Telecom.