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DARPA Wants Wireless Devices That Can Blast Through the Noise 79

Posted by timothy
from the don't-we-all? dept.
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."
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DARPA Wants Wireless Devices That Can Blast Through the Noise

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  • Re:Ideas? (Score:4, Interesting)

    by Gaygirlie (1657131) <gaygirlie@NOsPAM.hotmail.com> on Saturday December 22, 2012 @03:03PM (#42370703) Homepage

    1) Can you use out of band communications to trigger a special mode of the router (assuming you control it)? (e.g., A special listening mode that gives certain devices priority)

    This isn't about routing the data, this is about getting the data to reach the other end at all. Besides, routing priority has already been handled by QoS for years now.

    2) Rather than use typical QAM type of modulation, can you use a more limited constellation but BOOST the power so you can punch it through the noise? (which would also allow you to make very good use of forward error correction (FEC); again assumes that you are able to program both the sender and the router.

    Assuming you can't alter the Network Stack on either device than you have to look at the communications itself

    3) Other than that, it would seem you would need to use a programmable antenna/software antenna, Etc. turning your own Antenna into a high directional Antenna with as much gain as possible. Basically find the WIFI router you want (geo locate it, perhaps triangulation with the help of friendly nearby devices) and the push all your signal towards (a dynamic Yagi antenna that auto-magically maintains it's "aim" at the router even as the sender and/or the receiver move about.

    Just increasing the power until the signal is heard is one way of doing it, sure, but there is always a limit to how high you can go. Plus then you're contributing yourself to the noise and broadcasting your location on the battlefield to everyone around you.

  • RTFM (Score:5, Interesting)

    by interiot (50685) on Saturday December 22, 2012 @03:14PM (#42370775) Homepage

    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.

  • by Animats (122034) on Saturday December 22, 2012 @03:22PM (#42370827) Homepage

    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.

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