A few weeks ago I posted this It's beginning to look like the spectrum may be much more plentiful than we think, if we manage it well.. which suggests that smarter receivers and transmitters may be able to get more bandwidth out of available spectrum. The argument was clear (radio waves add non-destructively; interference is in-principle something that can be factored out) but the application was not (how do you factor out interference?).
Now this article Non-line-of-sight wireless systems promise strong signals for high-speed Internet access provides a good description of how this might work.
And indeed, that this article is referenced by etherlinx (thrust into the limelight by John Markoff's article in today's NYTimes) suggest that this is a good description of how it does work.
(In the old days, John Markoff once wrote an article about the Mosaic browser which forced the world wide web into popular consciousness. Today's New York Times article does not have that kind of mass appeal, but it just might be enough for the benevolent wireless militia to rally around. In which case, the popular wireless revolution may indeed begin today. Glenn Fleishman writes
I have a number of suppositions about what this company is doing, which I hope to confirm in a phone call in the next day or so. First, it's likely they're modifying PC cards, not access points. Second, Intersil chips are almost certainly at the center of their product. Third, the $100 price tag sounds like a "when we're in widescale production" target, but the current price might not be far off that. Fourth, they're writing their own microcode, or the instructions that direct the lowest-level radio layer. Fifth, while they're using Wi-Fi in one radio to handle the local network, the other radio is running a variant on 802.11 using frequency hopping.
More on the above as it's confirmed or explained.
I'll be keeping an eye on Glenn's http://80211b.weblogger.com/