On Tue, Aug 19, 2014 at 10:50 AM, Troy Benjegerdes <hozer@hozed.org> wrote:

On Tue, Aug 19, 2014 at 02:37:35PM +0200, Eugen Leitl wrote:

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In unrelated vein, I've recently read that it was the spooks that killed the digital pulse radio star, by limiting licensend power to toy levels. Apparently they were very unhappy with a radio that's hard to look for. http://www.cringely.com/2014/05/15/nsa-help-kill-uwb/

" Rather than using specific frequencies UWB transmitted on all frequencies at the same time. The key was knowing when and where in the frequency band to expect a bit to appear. Two parties with synchronized clocks and codebooks could agree that at 10 nanoseconds after the hour at a certain frequency or range of frequencies a bit would appear if one was intended. The presence of that signal at that time and place was a 1 and the absence was a 0. But if you didn’t know when to listen where — if you weren’t a part of the conversation — it all looked just like noise."

UWB is a great idea in theory, until you build an antenna, or you avoid the antenna and the UWB noise floor ends up as a DDOS attack on all your existing communications channels.

I'm interested in further links to papers regarding this ultra wide band UWB, pulse position modulation PPM, time domain TD scheme as it applies to radio spectrum. Especially any links to hack work being done under software defined radio SDR.