Got bandwidth? Microsoft Research and university researchers team up to find white spaces

Joint research conducted by Microsoft Research and The Chinese University of Hong Kong reveals that in a typical city, more than 50 to 70 percent of spectrum in the TV band goes unused. These vacant frequencies are called TV white spaces.

Demand for radio frequency spectrum (the airwaves wireless devices use) continues to increase throughout the world. However, access to spectrum is still regulated by strict licensing systems. As a result, a large amount of the white space spectrum that could be meeting demand goes unused. Regulators have started to recognize the inefficiency of the status quo, and are beginning to open up access to unlicensed white spaces.

While this is good news, it poses a new problem: How will wireless devices find these frequencies?

Spectrum-sensing technology is currently available, but it can be expensive and difficult to implement, according to Ranveer Chandra, a senior researcher at Microsoft. Geo-location databases are another available technology, but they tend to not capture all of the white spaces that are truly available.

There is also the consideration of indoor versus outdoor use. Most trials and studies of white space technologies have focused on outdoor applications, even though 70 percent of demand for spectrum is in indoor environments, explains Chandra in a post on the Microsoft on the Issues blog.

Enter Microsoft Research and The Chinese University of Hong Kong, who have been studying white spaces in partnership and developed WISER (White-space Indoor Spectrum EnhanceR) – a new system for improving indoor use of wireless technologies in cities. Presented in this paper released on Sept. 29, WISER uses spectrum-sensing technology but, unlike previous approaches, it optimizes the position of a limited number of sensors.

“This allows us to control costs and maximize effectiveness, without losing out on accuracy,” says Chandra.

In testing, WISER was able to accurately identify 30 to 50 percent more indoor white spaces than other baseline approaches.

Between technical innovations such as WISER and the regulatory progress being made on dynamic spectrum access, Chandra says the future is bright for wireless technology.

Learn more about the research and this new technology in Chandra’s post on the Microsoft on the Issues blog.

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Deborah Pisano
Microsoft News Center Staff