Thursday, September 23, 2010

White Spaces Passes FCC



White Spaces at a Glance:
"A" can use 400 MHz without interfering with anyone
Which means that it's now official, and any number of high speed wireless devices will be able to operate without a license in the spaces between TV channels:
The Federal Communications Commission today unanimously approved new rules for the use of unlicensed white space spectrum in a move that could pave the way for more unused wireless spectrum to be released in the future.

White space is unused spectrum that sits between TV channels. The 300MHz to 400MHz of unused spectrum is considered prime spectrum for offering wireless broadband services because it can travel long distances and penetrate through walls. The FCC unanimously agreed in November 2008 to open up this spectrum for unlicensed use. Even so, technical issues to allow device makers and service providers to use the spectrum still need to be worked out.
(emphasis mine)

The technical issues are a big deal, because, as the redoubtable Harold Feld notes, the devil is really in the details here, and the incumbent wireless providers want to require that devices ping themselves to death:
Right now, the rules require a Mode 2 (the ones that access the database directly) to ping the database every 24 hours. Mode 1 devices “listen” to Mode 2, according to the 2008 Order (which I understand means “get told when an actual change occurs). The broadcasters want the Mode 1 devices to ping the Mode 2s every 60 seconds and want Mode 2 to ping the database every 15 minutes, if not more frequently. Since television broadcast towers are big stationary things, not Ents marching on Isengard, one may ask why devices need to check more than once a day. In response, broadcasters explain that if some day some news team somewhere they might possibly be running down the street after some hot news lead if they ran into someone using a smart phone with white spaces capability it might, possibly, cause some sort of interference with the mobile news crew’s wireless microphone system.
At this time, it appears that they did not go with the ping of death regulations, nor did they require "Sense and Avoid" technology, which is purported to be both expensive and technically challenging.

One of the big things here is the geographical database: If the TV stations start making bogus claims of interference, we may end up with a situation where the coverage will be limited to remote rural areas.

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