Microsoft researchers say they have a better way to utilize “white space” networks. Microsoft’s “SpecNet” would create a network of spectrum analyzers, allowing remote detection of frequencies that could be used for transmission, according to a paper that will be presented next week (pdf).
The SpecNet architecture, developed at Microsoft Research, contains three key components: users or clients, slave servers that comprise laptops/PCs connected to spectrum analyzers, and master servers that manage the slave servers.
Microsoft says a key requirement for enabling unused television frequencies for internet access is a way to measure the airwaves. But spectrum analyzers can cost $10,000 to $40,000 each. The researchers suggest that the network be set up by volunteers who have spectrum analyzers to commit to SpecNet for assigned time periods. [Apparently Microsoft believes there are alot of Spectrum Analyzers sitting around in basements].
Each analyzer would be connected to a server that would issue commands to it via XML remote procedure calls over HTTP, SpecNet fulfills this need by enabling geographically distributed spectrum analyzers to be networked. Furthermore, SpecNet has an API that allows users to build distributed sensing applications like SpectrumCop with relative ease.
Carlson Wireless says they have developed RuralConnect IP, a software-defined radio for white spaces service in rural and underserved areas.
The company worked with database provider Spectrum Bridge and KTS Wireless to develop the radio. The company hopes to receive Federal Communications Commission certification for the device — which is targeted primarily to the wireless Internet service providers — in May, said Jim Carlson, president of Carlson Wireless.
The company has received an experimental license from the FCC to test the radio on lands occupied by the Yurok Tribe in the Klamath River region of Northern California. The tribe is the state’s largest with about 5,000 members and its tribal lands cover roughly 63,000 acres of rugged terrain that render other broadband wireless technologies ineffective.
While use of white spaces has been approved in the U.S. by the FCC, no other country has given the OK. SpecNet, with its use of equipment that is lent to the project, could broaden the studies and push other countries to approve white space use, the researchers say.
White Spaces utilize unused 6 MHz-wide channels in the television band, compared to Wi-Fi, which uses 20 MHz channels. But multiple adjacent channels may be ganged together when spectrum is available and the signals generally penetrate walls and foliage better.
Software Defined Radio and Cognitive Radio are enablers for Dynamic Spectrum Access, says ABI Research. Spectrum Sensing Cognitive Radio has been developed for the TV bands.
Microsoft submitted comments highlighting reallocation of spectrum for licensed use, but also innovative technologies – such as dynamic spectrum access – that can make higher and better use of limited spectrum.
Microsoft submitted comments and sponsored a white paper (pdf) by Professor Dirk Grunwald of the University of Colorado, Boulder, as a part of their efforts to address the growing challenges of limited spectrum.
The FCC conditionally designated nine entities as TV band (“white space”) device database administrators (pdf). These databases tell TV band devices what channels they can transmit on without causing interference to TV broadcast stations, wireless microphones and other authorized broadcast auxiliary services.
White spaces aren’t likely to unset the balance of power anytime soon.
Mobile devices will be limited to 100 mW and fixed transceivers to 1 Watt (4 watts EIRP). Each Base Station is equipped with GPS and its location is sent back to centralized servers.
Frequencies in the 300-500MHz range are likely to penetrate walls and concrete much better than 1900/2100 Mhz cellular or WiFi signals, but the antennas are much bigger – the size of tv antennas. White spaces may also be used for Smart Meters and in-home communications.
Whether the FCC ruling will launch a new era in broadband remains to be seen.
TV white spaces availability can be found for any location in the US by using the free search tool at Spectrum Bridge’s ShowMyWhiteSpace.com website, or by downloading the company’s free iPhone application.
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