August 7th, 2014
802.22 standard, approved in 2011, promises low-cost broadband for remote areas
Google, Microsoft and Facebook are cranking up an emerging wireless technology known as Wi-FAR to help reduce the digital divide in remote and unconnected regions of the world.
Wi-FAR is a recently trademarked name from the nonprofit WhiteSpace Alliance (WSA) that refers to the 802.22 wireless standard first approved by the IEEE (Institute of Electrical and Electronics Engineers) in 2011.
The standard shares the underused TV band of spectrum called whitespace to send wireless signals, typically over distances of six to 18 miles in rural and remote areas. It has a theoretical download speed of more than 22 Mbps per TV channel that serves up to 512 devices, according to the WSA. That could result in speeds of about 1.5 Mbps on a downlink to a single device.
While such speeds are far slower than for the gigabit fiber-optic cable services that Google and AT&T are building in some U.S. cities, the speeds could theoretically begin to compete with some 3G cellular speeds, although not 4G LTE speeds. For an impoverished or sparsely populated region where businesses and schoolchildren have little Internet access, Wi-FAR could be a godsend when used to link base stations (typically found at the ground level of cell towers) in a distributed network.
Students in South Africa
Students at the University of Limpopo in South Africa use laptops connected to the Internet using Wi-FAR wireless technology. (Photo: Microsoft)
About 28 million people in the U.S. don’t have access to broadband, while globally, about 5 billion people, nearly three-fourths of the world’s population — don’t have broadband Internet access, said Apurva Mody, chairman of both the WSA and of the 802.22 Working Group.
“This is cheap Internet access and there are dozens of trials underway, with Google in South Africa, Microsoft in Tanzania and other continents, and even Facebook’s interest,” Mody said in an interview. “You have 1.2 billion people in India who need cost-effective Internet access. There’s a lot of enthusiasm for Wi-FAR.”
Wi-FAR will be cheaper for access to the Internet than LTE and other wireless services. The lower cost is partly because Wi-FAR works over unlicensed spectrum, similar to Wi-Fi, which allows network providers, and even government entities, to avoid paying licensing fees or needing to build as many expensive cell towers, that can cost $50,000 apiece, Mody said. “The prices for Wi-FAR service will be very small, perhaps less than $10 per month per household.”
The 802.22 technology can be low cost because the whitespace spectrum is shared with conventional users, including TV stations on UHF and VHF bands. Thanks to sophisticated databases that track when a whitespace channel will be in use in a particular region, a cognitive (or smart) radio device can determine when to switch to another channel that’s not in use. Testing in various Wi-FAR pilots projects, many of them in Africa, is designed to prove that Wi-FAR devices won’t interfere with other existing users on the same channel.
“We have yet to have an interference problem,” said James Carlson, CEO of Carlson Wireless Technologies, a Sunnyvale, California-based company that is working with Google on two six-month trials of 802.22 in the UK, among other areas. The company completed a successful trial with Google serving students in South Africa in 2013. Carlson, in an email interview, said the company is working with five database providers, noting that the “prime purpose of the database is to protect the incumbent spectrum user.”
Whitespace spectrum sharing, coupled with the use of the databases, is generally called dynamic spectrum allocation technology. In January, the U.S. Federal Communications Commission approved Carlson’s RuralConnect TV whitespace radio system for use with a Spectrum Bridge TV whitespace database, effectively bringing the first dynamic spectrum sharing product to market.
In the U.S., RuralConnect is authorized for use in the UHF TV band, running from 470 MHz to 698 MHz. The FCC opened up the band in 2010.
At the time, Carlson said the FCC’s approval would give a boost to global efforts to use whitespace technology. “Providing connectivity to underserved populations worldwide is more than an interest to us,” he said in a statement. “It’s our corporate mission.”
RuralConnect will get competition from products in other companies, including Redline, Adaptrum and 6Harmonics, Carlson said. In addition to other providers, Google has built a whitespace database that Carlson is testing.
In all, Carlson Wireless has piloted dozens of whitespace projects, and expects to start its largest yet for 30 base stations and 5,000 users near New Delhi in the next six months, Carlson said.
“India is the next big boom for online needs, and the rural areas are not getting [Internet service] with [typical] mobile systems,” Carlson said. “So they are choosing to go with the TV whitespace because the UHF band is almost all vacant in rural areas and 600 MHz propagation is superb.”
While Carlson has been working with Google, Microsoft separately announced in June a whitespace pilot project at the University of Limpopo in South Africa. It is part of a Microsoft 4Afrika Initiative to help ignite economic development in Africa.
In May, Microsoft and Facebook joined with SpectraLink Wireless to announce a whitespace project for students and faculty at universities in Koforidua, Ghana. That project brought the number of nations where Microsoft has whitespace pilots to 10 countries on four continents.
In the Microsoft and SpectraLink partnership, Facebook’s Connectivity Lab team will lead efforts to better understand how TV whitespace spectrum can support wireless Internet users, according to a statement.
Microsoft and others believe that TV whitespace technology will best work in combination with Wi-Fi and other low-cost wireless technologies. While much of whitespace technology is focused on building specialized bridge hardware for use in base stations, Mody said some companies are developing fixed wireless 802.22 routers, similar in appearance to Wi-Fi routers, that will be placed inside of homes.
Microsoft also spearheaded the Dynamic Spectrum Alliance, which Google and Facebook joined last November. The alliance is exploring many uses for whitespace spectrum, including Internet of Things device connectivity.
Craig Mathias, an analyst and wireless consultant for The Farpoint Group, said 802.22 devices may compete against or complement a number of other technologies, including cellular and Wi-Fi.
“802.22 is not a pipe dream, but so far there’s not a lot of evidence of its success,” Mathias said in an interview. “It does make sense. The rate of innovation in wireless is so high that you hear something exciting every week. But not all wireless standards are successful in terms of having [successful] wireless products.”