Cognitive Radio Access to TV White Spaces: Spectrum Opportunities, Commercial Applications and Remaining Technology Challenges

Cognitive radio is being intensively researched as the enabling technology for secondary access to the so-called TV White Spaces (TVWS), large portions of spectrum in the UHF/VHF bands which become available on a geographical basis after digital switchover. Both in the US, and more recently, in the UK the regulators have given conditional endorsement to this new mode of access. This paper reviews the state-of-the-art in technology, regulation and standardization of cognitive access to TVWS. It examines the spectrum opportunity and commercial use cases associated with this form of secondary access.