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DARPA Wants Extreme Wireless Interference Buster
coondoggie writes "This month the Defense Advanced Research Projects Agency will begin looking for technology that will let wireless communications work through the most extreme interference. From the article: 'The CommEx program will assess next generation and beyond jamming threats and then develop advanced interference suppression and avoidance technologies to successfully communicate in the presence of severe, traditional, and novel types of interference that are orders-of-magnitude more severe than what are currently addressed by the most advanced systems, DARPA stated.'"
LDPC, spread spectrum and more EIRP. Or are they hoping to overturn Shannon ?
Really, the state of the art is fractions of a dB away from theory. There are no further breakthroughs to be found. Unless you count social engineering the bad guys to block the wrong signals.
Nullius in verba
The conventional approach by NASA is to use Turbo Codes to handle burst errors and Reed-Solomon to handle randomly-distributed errors. You'd need to increase the error correction bits to handle really significant errors, but that seems like a good starting point. If you were to imagine the data as a cube, then produce the error-correction codes for each and every line you could draw through that cube, then each unit within that cube is represented by three sets of error-correction codes.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
I think they could use sandpaper instead of wooden pallets to smoothen out the hills.
You give a very good textbook solution to the problem.
Personally, I'd just switch to shielded cables though. :P
Geekism is your _only_ God!
They are looking at intentional jamming, not at white noise. Your solution would be almost perfect for white noise channels but not for channels with jamming.
E.g.: No jammer will be able to distribute its noise evenly in both time and space. You should be able add a nice bit of performance if you are able to predict the behaviour of the jammer to some extend. So spread spectrum with non-uniform frequency distribution of the signal energy could be a topic. Some jammers might not even send real noise but pseudo random noise. Then you could try to subtract the jammer from your received signal.
Jan
Not really sure what they can advance on besides frequency hopping routines that are quicker and cover a larger spectrum. SINCGARS, HAVE QUICK I/II and SATURN are pretty good at counter-jamming already, as long as the sequence can not be easily predicted and the fills are updated regularly (every 24 hours or so) then jammers will have to invest quite a bit into the infrastructure of their broadcasting equipment. It certainly wouldn't be portable, and it'd be loud and easy enough to find and take out by more traditional means.
The only thing, like I mentioned above, is moving to waveforms that are spread across larger frequency ranges (which can be problematic) and are faster so the jamming equipment can't keep up with the normal signal. Beyond that, digital data over RF can be reinforced by better packet correction and error handling.
Of course you could always just overpower every other signal on your band, but I do not think battery tech has reached that level yet for portable radios, and well... Most soldiers prefer not to be cooked alive if they have a choice.