"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.
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