The empty TV spectrum known as "white spaces" could be worth as much as $100 billion in 15 years, according to a report commissioned by Microsoft.

Perspective Associates performed the study, which said using white spaces in conjunction with Wi-Fi could generate between $3.9 and $7.3 billion in value per year over the next 15 years. White spaces are the unused spectrum in the 700-MHz band that sits between licensed blocks, and the Federal Communications Commission last year approved unlicensed usage after receiving support from companies like Google, Microsoft, Motorola, and Hewlett-Packard.

The report said the unlicensed usage of white spaces could lead to cheap wireless broadband access in rural communities because white spaces can essentially provide Wi-Fi-like connections over a much larger space. Additionally, the study said the spectrum will lead to a plethora of new devices and services because the unlicensed usage means there will be a lower barrier of entry.

"This innovation in unlicensed spectrum is built on competition between thousands of manufacturers, service providers, and system integrators of varying scale and scope competing to sell a wide range of products and services directly to end users," the report said. "In contrast, voice and data services in licensed spectrum are provided by a small number of network operators, selling largely similar bundles of services."

The white spaces standards are being hashed out by regulators and device manufacturers, but there is still opposition to using this spectrum in an unlicensed manner. The National Association of Broadcasters has sued the FCC over its white spaces decision because it said unlicensed usage will cause harmful interference with nearby spectrum. Multiple telecommunications companies and wireless microphone producers have also opposed public usage due to potential interference issues.

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