DARPA Wants Extreme Wireless Interference Buster 105
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.'"
distinct lack of content (Score:4, Interesting)
Do NOT open this link! (Score:1, Informative)
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You just have to employ some counter-measures for the signal jamming advertising technology. There's a little bit of content that makes it through.
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you need to deploy Adblock Plus AND Noscript!!!
What can they hope for (Score:5, Informative)
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.
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Just look at how long GPS has been around. For those not aware, it uses spread spectrum CDMA, with a signal is well below the noise level. I've speculated (in my mind) that you could easily combine the techniques to transmit and receive reasonable data at a level 'below the noise threshold' for some time. Just like GPS, you just need some reasonable clocks (hand held GPS quality), some decent processing (like an FPG
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Re:What can they hope for (Score:4, Informative)
No, it doesn't mean that at all. It does mean that your error-free bitrate will be limited to less than the bandwidth (how much less depends on how much more noise than signal you have). GPS uses 1.023MHz of bandwidth (for the civilian signal - 10.23MHz for the military one) and has a bitrate of 50 bits/sec. Typical noise levels are -110dBm and typical signal levels are -130dBm.
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jamming != white noise (Score:5, Interesting)
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.
Re:jamming != white noise (Score:4, Interesting)
And then let's not forget the spatial dimensions in addition to the frequency dimension - jamming signals originate from one or more sources at specific locations so this could also be used in eliminating interference from jammers.
I remebers from reading a bit of the GSM spec that mobile phones includes adaptative antenna and algorithms that allow retrieving a usefull signal not just from the direct line of sight transmission (from the mobile tower) but also from multiple reflections with different path lengths. Could not the same techniques be used to, instead of boosting a signal, offset that signal?
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If you know where exactly they are, it'll be much harder to jam, you can use all sorts of tricks to deal with the jamming.
It's just like someone trying to jam your eyes by shining a randomly flickering bright light in your general direction. Assuming what they are sending is not bright enough to destroy your receivers (in which case why bother jamming), you could just ha
Additional Nodes = Increased Adaptive Cognition (Score:1)
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Even a single carrier looks like white noise to a true spread spectrum receiver. Of course, a strong enough single carrier can look like strong enough white noise to obscure the information. Spreading wider reduces that effect. Smarter would be to have a system that detects such signals and applies active filtering, including modifying the transmission to not use frequencies around the interference (but maybe keep noise in there, anyway, to not let the interference operator know he was evaded). I'm sure
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I would be also interested on the distribution of the noise, more than its spectral characteristics. Many times it's easier to remove frequency shaped noise than distribution shaped noise.
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I think that's probably true for algorithms, but it might not be for deployed systems. Current communications devices can't use all the available theoretical techniques over all possible frequencies in all possible configurations, so there might be some significant gains on that front with new transmitters/receivers/etc. For example, most spread-spectrum systems operate over relatively narrow portions of the spectrum, at least compared to the whole electromagnetic spectrum--- nobody is spreading over everyt
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they could come up with some kind of missile designed to go after transmitters broadcasting interference, they'd be pretty loud and easy to spot.
of course this is probably for drone tech so if you armed a drones as such and programmed them to attack the transmitters if their command channel was blocked the first thing any amoral adversary would do would be to stick an interference transmitter in a preschool with a camera crew nearby.
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And then the taliban uses their favorite tactic : place the jammers in a kindergarten with journalists in the next building, camera's ready. Obviously the cameras won't flash when the journalists help the muslims kick a few more children directly into the weaponized zone, but they will flash after a rocket strikes.
So avoiding the issue altogether, if you can, is probably a better idea.
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Not if they EMP it!
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of course this is probably for drone tech so if you armed a drones as such and programmed them to attack the transmitters if their command channel was blocked the first thing any amoral adversary would do would be to stick an interference transmitter in a preschool with a camera crew nearby.
Not all bombs are munitions. You could kill the transmitter with an EMP burst. Nobody gets hurt except the electronics.
I think I need to start buying old vaccuum tubes -- EMP is ineffective against non-solid state gear.
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They already have a weapon similar to this. It's called a HARM (High Speed Anti Radiation Missile). They were developed/used to take out radar sites. Similarly, they can be used to take out radar jammers (at least theoretically, I don't know if they ever have) since they operate on the same frequencies. So if you could tune the antenna/software to the right frequencies, then you can now go after communications jammers (and assuming some sort of IFF).
But... (Score:1, Funny)
How long after they develop the extreme wireless interference buster that someone develops the supreme wireless interference generator?
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Sort of like VG-2 and Spectre speed radar. There's a huge list of technologies in a cat-and-mouse game between these radar guns and the detectors. Here's an idea of how it goes:
1. Police invent new speed radar
2. New detector comes out that can detect it
3. Police update technology to evade detection and detect detector (they detect some radiation the detector emits in operation from what I understand)
4. New detector comes out that can detect the updated radar gun and avoid detection
5. Steps 3-4 may repeat a
Ok, an interesting challenge. (Score:5, Interesting)
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.
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Any given point in a cube exists along three lines - one parallel to X, one parallel to Y and one parallel to Z. If you wish to find a fourth orthogonal axis, please do so. Your TARDIS awaits.
Regardless, three is plenty. If you want to improve reliability still further, then if turbo codes are mapped onto X, use LDPC (low-density parity-check code) alone -X.
Since Reed-Solomon is for random errors, you'd probably want to use a conventional ten-bit system - 8 bits of data, 2 bits of ECC. A layout used by a lo
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Faraday FTW! (Score:4, Funny)
This is so easy. All you need to do is roll out a point to point Faraday cage between the two parties that wish to communicate. To build the Faraday cage, go to your local hardware store and purchase all the rolls of chicken wire they have in stock. Now take the chicken wire and form a loop about 5 meters in diameter. Keep on doing this and stitch the loops together until you have a big enough tunnel to reach from your source to the destination. Remember! There must be line of sight for your wireless to properly function. I recommend getting wooden pallets to smooth out any hills and valleys so that you can see clear through.
Now the fun part. To make a proper Faraday cage you need to run current through the chicken wire. Experiment with the right voltage, but I find that running a chainsaw through a local wooden power pole will score you a big fat power cable capable of delivering the right amount of juice. Strip the power cable and attach the positive and negative wires to the chicken wire. CAREFUL!!! Make sure you're wearing latex gloves to protect your hands against the current. If you don't have latex gloves, fashion your own gloves out of banana peels.
Once the power is hooked up, you have now created an impenetrable electromagnetically shielded tunnel through which your wireless transmissions can propagate. Place the transmitter at one end and the receiver at the other and enjoy your interruption free communications!
Re:Faraday FTW! (Score:4, Funny)
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
Re:Faraday FTW! (Score:4, Funny)
BTW, IMHO, the outlined approach is a paradigm regards advanced technological solutions: if a given system does not work as demanded, create another layer and hope that the increase in complexity will automagically solve the problems.
CC.
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Is there some way we can get both XML and violence into this situation? They somehow seem appropriate...
Ok, here you go... "XML is the last refuge of the incompetent" -- Salvor Hardin [wikipedia.org]
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Let's call it 'Coaxial WiFi' :)
Darwin Alert! (Score:2)
Anyone want to bet that someone in this lunatic bin won't try this?
];)
Wireless Engineering (Score:3, Funny)
Suppression? (Score:2)
'The CommEx program will assess next generation and beyond jamming threats and then develop advanced interference suppression...
This is the only suppression I'm familiar with:
http://en.wikipedia.org/wiki/Wild_Weasel [wikipedia.org]
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For advanced interference, you might want this: http://en.wikipedia.org/wiki/Wicked_Weasel [wikipedia.org]
Busta busta (Score:1)
Sounds more like when you're trying to bust someone busting you.
Drones are the future. (Score:4, Insightful)
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This has drone research written all over it! Take out a signal to a drone and it's as good as shooting it down. It's probably easier to mess with a drone signal than shooting it down as well, but that's just pure speculation on my part.
I wouldn't be surprised if the drone has enough wherewithal to at least attempt to make it home when command-and-control and/or GPS signals fail. Even assuming whatever radio channels it uses are jammed, it still shouldn't have too much trouble using magnetic / visual orientation to return to base. Seems unlikely that there aren't quite a few layers of redundancy in there.
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True, but even so, whatever the drone's mission, it's no longer accomplishing it at that point.
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Neutrinos (Score:1)
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The author obviously wants a chunk of the military research budget. Are they going to make the output of their accelerator steerable? Or position one in space at the Lagrange 2 position so it can spray the whole Earth with muons. Sounds like a nice try.
I've got one for them!!! (Score:3, Interesting)
It's called cat5e.
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If it catches fire, that counts as "successfully blocked signal".
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its immune to EM interference using that computer
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The technology exists.... (Score:3, Funny)
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However, unlike EM waves, they are totally at the mercy of buckshot.
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> They would indeed be impervious to the jamming effects of EM interference.
Not if there is enough of it.
> However, unlike EM waves, they are totally at the mercy of buckshot.
I think you mean birdshot.
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I think you mean birdshot.
This is DARPA we're talking about, we need to spend millions on improving the state of the art pigeons until they're bandwidth is greatly increased and you'll need buckshot to down them.
Use a wired connection? (Score:1)
Seems like the best way to me...
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I think there's a practical problem with running wires to Predator or Global Hawk drones...
Frequency Hopping.... more? (Score:5, Interesting)
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.
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Don't we all (Score:1)
Flag semaphore and interference cancellation (Score:2, Informative)
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Might be safe against EM interference but interference from a sniper...
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Flag semaphore remains highly resistant to electromagnetic interference. http://en.wikipedia.org/wiki/Flag_semaphore [wikipedia.org].
You fail at both funny and informative: it's enough to block the electromagnetic spectrum from 390 to 750 nm to render those inoperative. It can happen with fog, or be done with smoke or any material placed in the line of sight. Guess why IR communications are hardly used for anything except TV remote controls even though they've been around for decades...
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You're forgetting, this is the U.S. dod. They're not the Boy Scouts. By the time the military-industrial complex gets done with this, the semaphore flags will be made of new cutting edge materials that reflect x-rays and can withstand anything short of a nuclear weapon. They'll be handled by an armor plated remotely operated computer controlled boy-scout mark 2. The reciever will use a combination of visible light, soft x-rays, and infrared.
About as impossible as a secure connection. (Score:1)
So.... (Score:2)
All I need to do to block those devices is to use a lot of those devices. The definition of "lot" depends on frequency spread, distance, power used, algorithmic magic etc, but...
Use Neutrinos (Score:1)
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A couple more options (Score:1)
1) spatial domain: beamforming: make sure that the receiver, the transmitter, and the interferer are not aligned in a line. 3D: assume the interferer is on the ground. as long as one of the transmitter or the receiver is in the air/space, there is a good chance to use beamforming to improve reception.
2) narrow band or long code: Effectively, this is slowing down the data rate. In this way, the SINR for a message can be good enough.
Active cancelation of interference with anti phase (Score:2, Funny)
Multiple antennas (Score:2)
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