DARPA Wants Wireless Devices That Can Blast Through the Noise 79
coondoggie writes "What if your wireless communications just absolutely, positively have to be heard above the din of other users or in the face of massive interference? That is the question at the heart of a new $150,000 challenge that will be thrown down in January by the scientists at DARPA as the agency detailed its Spectrum Challenge — a competition that aims to find developers who can create software-defined radio protocols that best use communication channels in the presence of other users and interfering signals."
Comment removed (Score:4, Interesting)
RTFM (Score:5, Interesting)
The goal is to "engineer software-based radios that transmit data faster than a competitor using identical hardware" [darpa.mil].
The goal isn't to develop fancy new hardware, or to use an overwhelming amount of power. The goal is to develop fancy new software.
With frequency-hopping and time-hopping [wikipedia.org] techniques, if you can intelligently adapt to the local interference, and transmit in the time and frequency gaps where the interference doesn't occur, then you can transmit more data for the same amount of power. That's the goal.
Finding a place to put data (Score:5, Interesting)
The rules aren't available on the site yet, but I assume they're interested in resistance to jamming. From a theoretical perspective, as long as the receiver isn't saturated, there should be some data rate at which transmission is possible. This follows from Shannon. Noise can be overcome with redundancy, at the cost of data rate.
You can usually do better than that by moving around the spectrum to quieter areas. That's what frequency-hopping systems do. Jammers can be agile too, but unless the jammer is in a direct line between sender and receiver, the jammer is always at a time disadvantage due to speed of light lag. Very fast frequency hopping can overcome agile jammers.
What DARPA wants, I suspect, are systems that package up all this into a system that takes care of any noise problems automatically and will get a message through if it is physically possible. DoD has had systems for that for decades, but the technology tended to assume that the opposition didn't know the details of how it worked. It may be possible to have jam-resistant systems that work even if the opposition knows the technology.