are not many technical realms where Google engineers have not either entered or created. Wireless
connectivity is key to their continued dominance in the information domain, so they understandably have
a vested interest in the "white space
" spectrum debate. White space comprises portions of the
electromagnetic spectrum where bands are either unlicensed or where licensed bands are or will be up for
grabs. An example of the former is the 2.4 GHz Wi-Fi band, and an example of the latter is some parts of
the broadcast television band that is being vacated in areas.
Google is working with the Federal
Communications Commission (FCC
build a real-time database of what they term "dynamic spectrum" in order to provide useful information
about available white space
to both users and providers. A separate database is available for fixed and mobile spectrum. Enter your
location of interest and the map zooms into that region. For instance, in my town of Erie, Pennsylvania
(see marker on map below), there are 21 channels available as of January (the database is temporarily
locked for new entries), including three used for radio astronomy.
Interpreting the map is sort of
opposite of what you would expect. A more appropriate title would be "map of unavailable white spaces,"
since the more concentrated the color coded areas are, the less chance any spectrum is available. Not
surprisingly, regions in and around large cities have the least amount of white space for use. There is
a big push by smart phone manufacturers to enable users to access copious amount of data and at blazing
download speeds at reduced or no cost, so a major build-out of wireless hotspots is being undertaken. I
posted a headline story that addresses the effort: "Smartphone Party Ending for Wireless Carriers
and "Small Cells with Wi-Fi Set
to Reshape Wireless Communications Market
Per their website: "Google
is working to enable dynamic spectrum sharing while protecting licensed bands. Our database is designed
to allow the same spectrum to be shared, without interference, between multiple users, such as
government agencies, licensed commercial users and individuals. This means that if part of the spectrum
is being used in California, but available in Louisiana, those users will know. "
Hat tip to Bob Davis for letting me know about it.
Google Spectrum Map
Google Spectrum Table
Posted on 5/17/2013
These items are an archive of past Topical Smorgasbord items that have appeared on the RF Cafe homepage. In keeping with
the "cafe" genre, these tidbits of information are truly a smorgasbord of topics. They all pertain to topics
that are related to the general engineering and science theme of RF Cafe.
Please send me an e-mail
if you have
a good subject.