German Scientists' Visible Light Network Hits 3Gbps 79
Mark.JUK writes "Scientists working at Berlin's Fraunhofer Heinrich Hertz Institute have developed new components that can turn standard 'off-the-shelf' LED room lights into an Optical Wireless Local Area Network (OWLAN) that delivers data transmission rates of up to 3Gbps. The new kit is an extension of HHI's earlier work, which in 2011 delivered the first 800Mbps capable network using ordinary flashing LED lights. Since then the kit has been improved to achieve a transmission rate of 1Gbps per single light frequency (basic LEDs usually use up to three light frequencies) and the operating bandwidth has been pushed to 180MHz from 30MHz."
sounds overly optimistic (Score:2, Interesting)
"basic LEDs usually use up to three light frequencies" is BS. Nobody uses RGB for room lighting - color reproduction is not good enough. You use blue LEDs + photoluminescent phosphors. I wonder whether they can also mudulate the phosphors at 1 Gbps, but I doubt so.
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Nobody uses RGB for room lighting - color reproduction is not good enough.
They probably wouldn't be the sole light source in the room - I imagine that this is just a bit of added value.
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You wouldn't need to; enough of the original LED color gets through the phosphors to detect.
This isn't exactly a new idea; it's been known for years that you can read the data from an old-style modem's Tx and Rx LEDs from across the room.
Re:sounds overly optimistic (Score:5, Informative)
"Nobody uses RGB for room lighting"
You're wrong. In fact, not only can an RGB diode produce great white light, we have diode packages that can essentially cover the entire visible spectrum and thus create any CCT known with greater efficiencies than a white diode, which, again, you're wrong - it's a UV diode with a phosphor on it, not a blue diode.
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... it's a UV diode with a phosphor on it, not a blue diode.
Nope. Just look at the spectrum of some white LEDs, they clearly peak around 450 nm plus what the phosphor delivers. UV is very problematic as it quickly degrades the plastic optics which are predominantly used with LEDs. Plus, you would only get the yellow light from the phosphor, not white light. It's the mixture of blue and yellow that's necessary where the ratio determines the correlated color temperature.
E.g.: http://www.cree.com/led-components-and-modules/products/xlamp/discrete-directional/~/media/ [cree.com]
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I do LED work for a living. I work very closely with Cree, Nichia, etc.
All good high-efficiency white diodes are UVB diodes with a triple-component or more phosphor layer, and possibly with a ceramic recombination package design. You start with UV, add a blue phosphor base on top of that, then add your amber and red phosphors on top of that, then try to use the packaging to redirect light that scatters back through the phosphors for maximum output.
"UV is very problematic as it quickly degrades the plastic o
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Where did you read they want to use the regular/primary room lights for this sort of communication?
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The way I understand it is they use off the shelf visible-light LED's in stead of the for communication more regular UV or IR version. :)
Cool and one day it might end up in a room's primary illumination, meaning there's no network during daylight hours
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Comment removed (Score:5, Informative)
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Is this a secure mode of communication? Or are you going to need some kind of Lighting Encryption Protocol?
Re:Harold Haas - links (Score:5, Insightful)
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I've just put in my patent application for * to include 'via light'.
Next week you can find me on my personal tropical island.
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It's too bad you had to throw that one in. It's pretty funny though: "let's use flashing lights instead of electromagnetic radiation!"
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Well, he said "electromagnetic pollution" and not "radiation" - so I think he means that just lighting is better than lighting+wireless.
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Well, he said "electromagnetic pollution" and not "radiation" - so I think he means that just lighting is better than lighting+wireless.
And still digital people seem to think that bandwidth is infinite.
Modulating a light beam is incredibly trivial. The only limitation for frequency or bandwidth is the amount of time it takes to turn the light off, then back on. I could have somethign running in about ten minutes at the workbench. A reciever is a little more intricate, but still this is something that middle school students with a little electronics aptitude could figure out. Heck, Infrared Television remote controls are doing this now.
T
Visible Light Wireless Network (Score:5, Funny)
Epileptic seizures sure make the download time breeze by.
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When you first heard one of the "a horse walks into a bar" jokes, did you reply by citing a law the bans horses from bars and then explain that the premise of the joke was simply untenable?
I hope that your grasp of sarcasm is better than your grasp of humor.
You see, this is a problem with kids these days. They didn't grow up with "Mr. Ed" or "Green Acres" (or "I Dream of Jeanie" for that matter, but I digress). The subtle twists of cross species humor are just lost on them.
And no, Dick Cheney doesn't count.
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Dick Cheney? Being undead isn't a different species.
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You see, this is a problem with kids these days. They didn't grow up with "Mr. Ed" or "Green Acres" (or "I Dream of Jeanie" for that matter, but I digress). The subtle twists of cross species humor are just lost on them.
And no, Dick Cheney doesn't count.
Anyone who did not grow up with "I dream of Jeanie" was terribly terribly impoverished.
I suppose the show is terribly un-PC these days, but did I did indeed dream of her.
Then again, I also believe that Green Acres was the height of Western Civilization.
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Any flicker at 100Hz or faster is imperceptible to humans [wikipedia.org] (and even that's pretty generous; the actual threshold is lower). This is 30-180MHz; a million times as fast.
Link to article (Score:5, Informative)
Unfortunately the press release is a little short on details. Here is the link to the actual article (paywalled):
"1.25 Gbit/s Visible Light WDM Link based on DMT Modulation of a Single RGB LED Luminary", opticsinfobase.org [opticsinfobase.org]
But this is only half the problem (Score:2)
Fast download rates, okay. But what about the return/upload path?
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Most computers have some LEDs in them. iPads would need a dongle or hardware revision.
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But detecting that light from the flood of all the other light is a problem.
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I can see the LEDs on my notebook perfectly well in a lit room. You probably wouldn't be able to coax 3 Gbps out of them, but most people don't use as much upstream bandwidth as down. Exceptions are mostly wired machines anyway - gamers and servers. You could also use IR LEDs for the upstream channel if you wanted to have a full duplex network.
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Re:Who gives a flying monkey's?? (Score:5, Funny)
All of that is Obama's fault.
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A couple of centuries ago this guy Mohammed wanted to see the mountain and when it didn't show up on his doorstep instead he went to the mountain.
And would your present smart phone have the same speed and options as the one of 10 years ago it would probably last a lot longer now.
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It has a much higher chance of reaching the market than any project from grad students working with large quantities of alcohol.
Someone should really go check on those guys...
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Someone should really go check on those guys...
I suspect they are on their private yachts. They didn't actually make anything but the IPO was a hoot.
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Scientist? (Score:3)
Maybe engineer is a better term...
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Maybe engineer is a better term...
This distinction is lost to the Germans.
Here you can study something called engineering-sciences...
Comment removed (Score:3)
Re:Pre-existing technology (Score:5, Interesting)
Maybe because he's pushing several orders of magnitude more data through the system than your 20 khz headphones?
Size matters.
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IIRC, IBM, also, published a white paper on a system similar to Fraunhofer's about 10 years ago [to head off broad patent claims] based on research they had done.
"Basicode" (Score:1)
Back in the 80s, a radio station used -as part of a show on computers- part of the air time to distribute software; you just recorded the show on a regular tape deck, then used a BasiCode-decoder software and cassette recorder on your computer to load it.
So all "we" now need to do is to hack in the LED-based street lights on highways, and we can pump the latest software to car-based systems.
But seriously, you might be able to distribute low-data-rate stuff like traffic information,etc. into the lights to on
How does it work through walls? (Score:2)
Re:How does it work through walls? (Score:4, Interesting)
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There are a lot of companies and organizations where this would be considered a benefit since they would no longer need to construct special buildings to block wireless from leaving high-security rooms / the building.
PARCTAB (Score:4, Informative)
The original PARCTAB, basically the first computer to roughly look and work like a modern touch screen device, used networking based on ceiling-mounted LEDs. A paper describing the system is here [psu.edu]. Many systems used IrDA communications after that. Of course, it's probably been a lot of engineering work increasing the speed of the system, but it's not a fundamentally new idea, just the evolution of old technology.
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802.11 also includes an infrared PHY layer in the standard - sure it was only 1-2Mbps, but it was there. This was the original 802.11 standard, but it was there as an alternative to IrDA.
Congratulations, Dear all at HHI! (Score:2)
HHI used to be the world championship in optical signal transmission beating their own records as early as the late 1970 and early 1980. I myself had the honour to work there, at that time, though not in optical transmission systems. The time spend there has always been a great and endearing reminiscence.
I am proud of you, guys and girls! Congratulations!
(I really wonder if anyone from those days is still there!?)
Cool, but... (Score:2)
...can anyone come up with a use for this that existing WiFi doesn't already cover? It isn't more range, and I'm not sure it is usefully less range. If you are worried about eavesdroppers on the network you need light tight rooms, but if you want to set up a whole house network you need to have repeaters for each room.
This seems more like an answer in search of a problem. Sometimes that means we will find a problem we didn't understand we had, and sometimes this turns out to be the technology equival
Woah. (Score:2)
Asymmectric networks would be very useful. (Score:1)