White Space is the term broadly applied by technologist's and the FCC to the vast spectrum spaces, especially in urban areas, which are wastelands. For now, we will concentrate on the frequencies currently allocated solely to television stations. Since there are only a few channels occupied in even the most populous cities, coupled with the fact that the primary propagation mode for these frequencies is line of sight, much of the spectrum for TV channels is completely unoccupied even in these cities.
We need spectrum to increase the amount available to wireless devices. The FCC realizes this and in November of 2008, issues rules allowing this. CTVR at Trinity College Dublin has been interested in this concept for a while. A prominent DARPA project manager, Preston Marshall, a leading person in DySpan has long been interested, personally and professionally in White Spaces (a Dynamic Spectrum hot spot issue, pun intended). Preston is getting his Ph. D. from CTVR.
Tom Rondeau, hired by my employer, with my being the primary instigator, finished his Ph.D. thesis for Charles Bostian at Virginia Tech while working at CTVR. He then did a short post-doc before joining us. While Tom was at CTVR, with Keith Nolan, also of CTVR did a cross country tour following the SDR Forum meeting in Denver Colorado in Oct. 2007 and did a survey of white space while doing their drive.
This will be of increasing interest in the coming years with a lot of support for this coming from a consortium including Microsoft and Google.