Microsoft, Dell, etc, etc looking at DTV overlay for consumer broadband access and networking

[Kevin Purcell]

The recent FCC filing from Microsoft isn't a Zune :-)

The actually FCC filing is for a more interesting device ... this  
link pulls down a 108kB PDF and cryptically explains it.

<http://gullfoss2.fcc.gov/prod/ecfs/retrieve.cgi? 
native_or_pdf=pdf&id_document=6518724937>

It looks like some sort of UHF TV band transceiver that uses a 2.4GHz  
802.11g translated down to a TV channel (nice and cheap). And the  
device will (cognitive radio style ... perhaps overselling it) will  
avoid DTV channels or shift channels when it senses the channel is  
occupied. Maximum bandwidth is 4.5MHz to fit in a TV channel which is  
rather narrower than the normal 802.11g 22MHz at -30dB so there might be  
some modifications (the symbol rate will be less than 54Msps).

It's not a product -- it's a test device to verify the underlay can  
work with the end purpose of "provide consumer broadband access and  
networking". And from the "uses a UHF discone" and "the antenna port  
will no be accessible in the final device" I suspect it will be roof  
mounted box with the antenna built in. A mesh network perhaps?

<http://werbach.com/blog/archives/2007/02/microsofts_misu.html>

> Microsoft and a coalition of other companies including Dell, HP,  
> Intel, and Google are pushing the FCC to allow low-power unlicensed  
> "underlay" usage of wireless frequencies currently occupied by TV  
> broadcasters. The broadcasters oppose this. One argument they make  
> is that it's not technically feasible for an unlicensed device to  
> operate that way, and not interfere with the licensed broadcast  
> signals. So, obviously, Microsoft and its allies have built a  
> prototype to show they are wrong.

FCC moves forward on unlicensed "white spaces"

<http://werbach.com/blog/archives/2006/10/fcc_moves_forwa.html>
<http://hraunfoss.fcc.gov/edocs_public/attachmatch/DOC-267867A1.pdf>

Interesting.
--
Kevin Purcell
kevinpurcell at pobox.com