The Connectivity Lab, the engineering arm of Facebook, Inc.’s non-profit initiative, which aims to bring the world online, unveiled two new technologies yesterday during Facebook’s F8 conference that could make its ambitious goal easier: a low-cost, high-capacity wireless system for dense urban environments, and a wide-coverage platform expressly designed for sparsely populated areas.

The first, Terragraph, utilizes multi-device wireless coverage and Facebook’s considerable cloud-based data processing muscle to deliver low-cost, 60-GHz speeds to urban areas; while proof-of-concept research project ARIES (Antenna Radio Integration for Efficiency in Spectrum) uses radio waves to provide wide-ranging internet connections to areas with low population density.

“Facebook believes that people — no matter where they live — deserve a consistent, high-bandwidth internet experience,” developers Neeraj Choubey and Ali Yazdan Panah wrote in an April 13 blog post explaining the technologies after they were announced at F8.

The urban-centric Terragraph is based on WiGig, a Wi-Fi enhancement designed for consumer electronics that provides high-bandwidth communication within a limited space on the unlicensed 60 GHz band.

“Up to 7 GHz of bandwidth is available in the 60 GHz band, and forward-thinking countries like the United States are seeking input to expand this to a total of 14 GHz,” the developers write.

Because of WiGig’s consumer-focused design, the Terragraph system is less expensive to install than traditional telecom infrastructure – though given the 60 GHz signal’s limited range, each device must be placed across a city at 200-250 meter intervals.

This too is an advantage, the developers write: the 60 GHz band has such wide bandwidth and absorbs signals so well, interference is limited and networks are easier to plan, while its narrow area of focus makes it easy to steer around the sort of obstacles associated with cities such as tall buildings or high wireless traffic. Moreover, the 60 GHz band’s unlicensed status minimizes its traffic costs.

Terragraph network
Urban deployment of the Terragraph network.

The Terragraph system is also easy to build and deploy: utilizing a compact design and conventional materials, each device can be easily attached to the outside of a building and connected to an ethernet data network inside.

Terragraph distribution nodes
Terragraph four sector distribution node (left) and Terragraph prototype node (right).

Meanwhile, the current ARIES prototype uses a base station with 96 antennas to support 24 simultaneous radio streams over a single radio spectrum, with the large number of transmission antennas overcoming the potential data loss.

The prototype ARIES array
The prototype ARIES array.

At the moment, Terragraph is being tested at Facebook headquarters in Menlo Park, Calif., with the company preparing a broader trial with the nearby city of San Jose. Thus far, it’s been able to achieve connection speeds of up to 8.4 Gbps per installation point, and believes this number could be as high as 12.8 Gbps in the future.

Like all of Facebook’s efforts, the Connectivity Lab will also be making the results of its two latest projects available to wireless communications researchers and the academic community.

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