Facebook's Terragraph technology moves from testing to commercial use

A set of programs allows groups of small wireless base stations operating at 60 GHz to communicate with each other.

Wireless World: Mikebuda (Hungary) equipment installs small stations with Terragraph support for testing starting in May 2018

Over the years, Facebook has been developing technology that improves the organization of data and its transmission over wireless networks. Now this technology is being integrated into commercially available small base stations at 60 GHz. And if communication providers are connected to the project, he will soon be able to help connect to the Internet via wireless connection at home and businesses around the world.

Facebook technology called Terragraph allows you to combine base stations into groups that transmit at a frequency of 60 GHz and independently control and distribute traffic among themselves. If one base station stops working, the other immediately takes over its tasks - and they can work together to find the most efficient way to pass information.

Already, several equipment manufacturers, including Cambium Networks , Common Networks , Nokia and Qualcomm , have agreed to produce commercial devices that integrate Terragraph. His most recent presentation took place in February at the MWC trade fair in Barcelona. If the technology can work as it should, Terragraph will make Internet access faster and cheaper at deployment sites.
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Increasingly, broadband Internet, which used to be distributed over expensive fiber optic cables buried in the ground, comes to homes and businesses by air. To do this, telecom operators are looking at the high-frequency bands, the bandwidth of which is higher than that of the low frequencies that have been used for a long time in consumer electronics.

Facebook is interested in the V-band , which is usually called simply 60 GHz, although technically speaking, it stretches from 40 to 75 GHz. In many countries, it is not occupied by anyone, and therefore free for use.

Although equipment for indoor installation that supports 60 GHz as an alternative to WiFi has already appeared for a long time, street stations appear only now. Many Internet providers are thinking about using 60 GHz to close the gap between existing infrastructure and new places they would like to cover, or to increase the capacity of already covered places.

“This is definitely interesting,” says Svetank Kumar Saha , a researcher and PhD in computer science at the University of Buffalo (New York), who studies the performance of 60 GHz consumer equipment for indoor installation. - Many people faced the problems of 60 GHz commercialization. There was a lot of talk on this topic. ”

One of the problems is that millimeter-wave signals (from 30 to 300 GHz) do not propagate as far as lower-frequency signals, are easily absorbed by rain and foliage, and do not pass through walls and windows.

To get around these problems, providers typically use fixed wireless networks in which base stations transmit a signal to a fixed receiver located outside the building. And from there the data is already going over Ethernet cables.

Last year, Facebook cooperated with a division of Deutsche Telekom to test the Terragraph system in two Hungarian villages. In the first test, 100 houses were connected to the network. Terragraph allowed residents to use the Internet at an average speed of 500 Mbit / s, instead of 5-10 Mbit / s, received via DSL. Facebook is now completing tests conducted jointly with operators in Brazil, Greece, Hungary, Indonesia, Malaysia and the United States.

The technology consists of a set of software based on IEEE 802.11ay , and includes features such as multiple access with time division, which divides the channel into time segments, during which different bases can transmit signals, quickly replacing each other. In the seven - tier network model, OSI Terragraph operates at the third level, passing information between IP addresses.

In the Terragraph system, Facebook used its data transfer experience over its fiber channel and applied it to wireless networks, says Chetan Hebbala , senior director of Cambium. In 2017, the project completed a full cycle when Facebook made the routing software based on it free. This program, Open / R , was originally intended for Terragraph, but is now also used to transfer information between Facebook data centers.

The technology does have its limitations. Each base station can transmit a signal over a distance of up to 250 m, and all transmission must be carried out on a line of sight that is not blocked by foliage, walls or other obstacles. Anozhu Madan, a product manager for Facebook, said that the company was testing the Terragraph in the rain and snow, and that the weather “hasn't created any problems yet” for its speed. But Hebbala says that just in case many stations at 60 GHz are designed so that, with heavy losses, they can temporarily switch to standard for WiFi frequencies of 5 GHz or 2.4 GHz.

A Sprint spokesman said the company plans to test the Terragraph equipment and is studying issues related to the 60 GHz band for its network. A spokesman for AT & T said the company was conducting laboratory tests of 60 GHz frequencies, but so far it has no plans to incorporate this range into existing networks.

Sakha from the University of Buffalo is optimistic about the Terragraph's chances to go out into the world. “As a result, companies will look at the cost of technology, and if it is less than fiber, they will definitely use it,” he says.

Hebbala says that the first base station with Terragraph support from his company is now in the “design and development phase,” and is likely to appear later this year. The company's goal is to offer Terragraph as a software feature that is easy to enable or reconfigure remotely. “I hope that when we talk in six months, I can talk about the pilot launches and test deployment with the first customers,” he says.