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Communications Networking IT Technology

German Scientists' Visible Light Network Hits 3Gbps 79

Posted by timothy
from the let-there-be-network dept.
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."
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German Scientists' Visible Light Network Hits 3Gbps

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  • by Anonymous Coward

    "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.

    • 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.

    • by russotto (537200)

      I wonder whether they can also mudulate the phosphors at 1 Gbps, but I doubt so.

      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.

    • by Khyber (864651) <techkitsune@gmail.com> on Saturday April 06, 2013 @10:55AM (#43378977) Homepage Journal

      "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.

      • by JRIsidore (524392)

        ... 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]

        • by Khyber (864651)

          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

    • by Teun (17872)
      So?

      Where did you read they want to use the regular/primary room lights for this sort of communication?

      • So?

        Where did you read they want to use the regular/primary room lights for this sort of communication?

        It's in the story summary, and from the story's link to the Berlin Institute I found this...

        { Live-Demo: Optical Wireless High-Speed Data Communication

        Optical wireless data communication uses standard LED lights for transmission of broadband data. This transmission technology can equally be used for HD video streaming and two-way communication. Offering data rates of up to 1.25 Gbit/s, it can easily deal even with broadband video files in HD quality. All it takes are just a few add-on parts to turn an o

        • by Teun (17872)
          Using standard LED's is still a way off using a room's main lights.

          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 :)

  • Harold Haas - links (Score:5, Informative)

    by SternisheFan (2529412) on Saturday April 06, 2013 @10:34AM (#43378837)
    Harald Haas: Communications technology innovator: Harald Haas is the pioneer behind a new type of light bulb that can communicate as well as illuminate – access the Internet using light instead of radio waves.

    TedTalks - Why you should listen to him:

    Imagine using your car headlights to transmit data ... or surfing the web safely on a plane, tethered only by a line of sight. Harald Haas is working on it. A professor of engineering at Edinburgh University, Haas has long been studying ways to communicate electronic data signals, designing modulation techniques that pack more data onto existing networks. But his latest work leaps beyond wires and radio waves to transmit data via an LED bulb that glows and darkens faster than the human eye can see.

    The system, which he's calling D-Light, uses a mathematical trick called OFDM (orthogonal frequency division multiplexing), which allows it to vary the intensity of the LED's output at a very fast rate, invisible to the human eye (for the eye, the bulb would simply be on and providing light). The signal can be picked up by simple receivers. As of now, Haas is reporting data rates of up to 10 MBit/s per second (faster than a typical broadband connection), and 100 MBit/s by the end of this year and possibly up to 1 GB in the future.

    He says: "It should be so cheap that it’s everywhere. Using the visible light spectrum, which comes for free, you can piggy-back existing wireless services on the back of lighting equipment."

    "As well as revolutionising internet reception, it would put an end to the potentially harmful electromagnetic pollution emitted by wireless internet routers and has raised the prospect of ubiquitous wireless access, transmitted through streetlights." Herald Scotland

    http://www.ted.com/speakers/harald_haas.html [ted.com]

    Here is the TED talk video:

    http://www.ted.com/talks/harald_haas_wireless_data_from_every_light_bulb.html [ted.com]

    • by sanman2 (928866)

      Is this a secure mode of communication? Or are you going to need some kind of Lighting Encryption Protocol?

      • by CastrTroy (595695) on Saturday April 06, 2013 @11:18AM (#43379125) Homepage
        Any wireless network is going to need encryption. This is the reason why we have WPA for our radio frequency wireless networks. You could probably use the exact same security protocols as I'm pretty sure they don't depend on the medium you are transferring over.
        • by Teun (17872)
          Ah!

          I've just put in my patent application for * to include 'via light'.

          Next week you can find me on my personal tropical island.

    • by ceoyoyo (59147)

      "As well as revolutionising internet reception, it would put an end to the potentially harmful electromagnetic pollution emitted by wireless internet routers and has raised the prospect of ubiquitous wireless access, transmitted through streetlights." Herald Scotland

      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!"

      • by sanman2 (928866)

        Well, he said "electromagnetic pollution" and not "radiation" - so I think he means that just lighting is better than lighting+wireless.

        • by Ol Olsoc (1175323)

          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

  • by Anonymous Coward on Saturday April 06, 2013 @10:44AM (#43378899)

    Epileptic seizures sure make the download time breeze by.

    • 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)

    by Vario (120611) on Saturday April 06, 2013 @10:57AM (#43378995)

    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]

  • Fast download rates, okay. But what about the return/upload path?

    • by ceoyoyo (59147)

      Most computers have some LEDs in them. iPads would need a dongle or hardware revision.

      • But detecting that light from the flood of all the other light is a problem.

        • by ceoyoyo (59147)

          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.

      • LOL. He said dongle.
  • by mark_reh (2015546) on Saturday April 06, 2013 @11:07AM (#43379047) Journal

    Maybe engineer is a better term...

    • by Anonymous Coward

      Maybe engineer is a better term...

      This distinction is lost to the Germans.
      Here you can study something called engineering-sciences...

  • by SternisheFan (2529412) on Saturday April 06, 2013 @11:48AM (#43379337)
    I've been using a pair of Infra-Red Wireless headphones ($40 from Radio Shack) for some time now and the IR tech is impressive. While inside the room where the transmitter is there's really no interruption of the signal at all (it helps the transmission a lot when your walls/ ceiling are painted white to bounce the light off of). This sounds like a re-application of this pre-existing technology, and I'm not sure why it hasn't become mainstream for transmitting computer data already.
  • by Anonymous Coward

    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

  • Seriously, I can't see a practical application for this in combination with room lighting. And in the typical multipath light environment of a room that people live and work in, your speeds are going to be a lot less than what they measured under optimal conditions. One advantage though: only adding a conventional telescope, you could establish point to point links through open air over miles without breaking any FCC (or agency in your-country-of-choice) emission rules.
    • by Dthief (1700318) on Saturday April 06, 2013 @01:09PM (#43379841)
      FTA: The cheap LEDs, which could for example be placed on the ceiling or in room lights and tend to have coverage of around 10 meters, essentially blink on and off extremely fast to transmit the data (not visible to your naked eye). This would make it extremely useful for short range and high-speed networks that may also require something more secure than wifi (i.e. light doesn’t travel so well through solid walls etc.). So it IS the room lighting, and yes, it is not meant for long range wireless. But you could link everything in a room to it.
    • by brunes69 (86786)

      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)

    by stenvar (2789879) on Saturday April 06, 2013 @01:41PM (#43380001)

    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.

    • by tlhIngan (30335)

      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.

      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.

  • 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!?)

  • ...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

  • That's a lot of German porn.
  • At the library I want to see a list of all the titles in print from my favorite authors, I just use the local WiFi to get the data. For larger downloads I ask on the WiFi, but get the data over the visible light network. So I can see the text of all those books, DRM allowing. Or watch a lecture on the Great Bustard. At airports, my PDA/phone gets all the flight updates on an endless loop, via the visible light network. At Home Depot I'm offered product information and How To videos. I'd love to see

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