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Researchers Beam 230Mb/sec Wireless Internet WIth LEDs

Posted by timothy on from the binded-by-the-light dept.

MikeChino writes "A group of scientists from Germany's Fraunhofer Institute have devised a way to encode a visible-frequency wireless signal in light emitted by plain old desklamps and other light fixtures. The team was able to achieve a record-setting data download rate of 230 megabits per second, and they expect to be able to double that speed in the near future. While the regular radio-frequency Wi-Fi most of us use currently is perfectly fine, it does have its flaws — it has a limited bandwidth that confines it to a certain spectrum and if you've ever had someone leech off of your connection, you know that it also leaks through walls. LED wireless signals would theoretically have none of these downsides."

10 of 218 comments (clear)

  1. No upsides either by IICV · · Score: 4, Informative

    "Leaking through walls" isn't a bug, it's a feature; I don't want to wire my whole house for Ethernet just to have wireless in every room, as that defeats the purpose.

    1. Re:No upsides either by NoMaster · · Score: 2, Informative

      I don't see why the response time of a fluorescent lamp has to be slow. You're dealing with a plasma in a partially evacuated tube controlled by an electrical current.

      You're forgetting that what you see is not the plasma (it emits mainly short-wavelength UV), but the phosphor coating (which is excited by the UV & emits visible light). The phosphor coating is specifically chosen to be (relatively) slow, in order to filter out the 50/60Hz flicker.

      In theory, you could use a faster phosphor and modulate the light output - but then you run into an issue with the half-life of the excited electron state. Basically, the electrons take a finite amount of time to drop from their excited state to their non-excited state (in the process releasing their energy as UV). This limits the maximum modulation frequency to somewhere ~5KHz. Again, this could probably be increased somewhat by the choice of plasma donor material, but there is a limit (e.g. I'd expect x-rays would be hard to contain ;-). And, since multi-bit encoding schemes like phase modulation are likely prove be tricky as best (aka 'improbable, if not impossible'), you're basically stuck with a maximum data transmission rate of half the modulation frequency - around 2.5Kbps.

      May as well stick to Bluetooth...

      --
      What part of "a well regulated militia" do you not understand?
  2. Fraunhofer juggernaut by Anonymous Coward · · Score: 2, Informative

    http://en.wikipedia.org/wiki/Fraunhofer_Society

    (anon, copied from wiki, I just thought people should be more aware that Fraunhofer is an amazingly huge beast.

    It employs over 12,500, mainly scientists and engineers, with an annual research budget of about €1.2 billion

    The Fraunhofer Society currently operates 59 institutes. These are Fraunhofer Institutes for:

    * Algorithms and Scientific Computing - SCAI
    * Applied Information Technology - FIT
    * Applied Optics and Precision Engineering - IOF
    * Applied Polymer Research - IAP
    * Applied Solid State Physics - IAF
    * Biomedical Engineering - IBMT
    * Building Physics - IBP
    * Center for Molecular Biotechnology- CMB
    * Ceramic Technologies and Systems - IKTS
    * Chemical Technology - ICT
    * Communication Systems - ESK
    * Computer Architecture and Software Technology - FIRST
    * Computer Graphics Research - IGD
    * Digital Media Technology - IDMT
    * Electron and Plasma Technology - FEP
    * e-Government - Fraunhofer eGovernment Center
    * Environmental, Safety and Energy Technology - UMSICHT
    * Experimental Software Engineering - IESE
    * Factory Operation and Automation - IFF
    * High-Speed Dynamics, Ernst-Mach-Institut - EMI
    * Industrial Engineering - IAO
    * Industrial Mathematics - ITWM
    * Information and Dataprocessing - IITB
    * Information Center for Regional Planning and Building Construction - IRB
    * Integrated Circuits - IIS
    * Integrated Systems and Device Technology - IISB
    * Integrated Publication and Information Systems - IPSI
    * Intelligent Analysis and Information Systems - IAIS
    * Interfacial Engineering and Biotechnology - IGB
    * Laser Technology - ILT
    * Machine Tools and Forming Technology - IWU
    * Manufacturing Engineering and Applied Materials Research - IFAM
    * Manufacturing Engineering and Automation - IPA
    * Material and Beam Technology - IWS
    * Material Flow and Logistics - IML
    * Mechanics of Materials - IWM
    * Medical Image Computing - MEVIS
    * Microelectronic Circuits and Systems - IMS
    * Molecular Biology and Applied Ecology - IME
    * Telecommunications, Heinrich-Hertz-Institut - HHI
    * Non-Destructive Testing - IZFP
    * Open Communication Systems - FOKUS
    * Patent Center for German Research - PST
    * Photonic Microsystems - IPMS
    * Physical Measurement Techniques - IPM
    * Process Engineering and Packaging - IVV
    * Production Systems and Design Technology - IPK
    * Production Technology - IPT
    * Reliability and Microintegration - IZM

  3. FhG owns MP3 by tepples · · Score: 2, Informative

    Fraunhofer Society (FhG) is the organization that owns the MP3 patents and licenses them through RCA.

  4. Oh, and ... by dtmos · · Score: 3, Informative

    Those interested in this LED-based technology can check out the IEEE 802.15.7 Visible Light Communication Task Group. Members of the Fraunhofer Institute are regular contributors to the standard.

    1. Re:Oh, and ... by xigxag · · Score: 2, Informative

      Members of the Fraunhofer Institute are regular contributors to the standard.

      In that case, it's bound to be cool. And by cool, I mean patent encumbered.

      BTW, {nitpick} it's not "the" Fraunhofer Institute, it's "Fraunhofer Society," within which are various institutes. Probably the most famous is on the internet is the Fraunhofer Institute for Integrated Circuits (Fraunhofer IIS) in Erlangen, whence came the mp3 standard. But the one responsible for Visible Light Communication is Fraunhofer HHI in Berlin. {/nitpick}

      --
      There are two kinds of people: 1) those who start arrays with one and 1) those who start them with zero.
  5. Re:Just different ones by twidarkling · · Score: 2, Informative

    With many modern remotes, you don't have to aim the remote at the device, but you can bounce it off walls and furniture and have it work great.

    Tell that to my fucking Blu-Ray player. The remote for my parents' 15 year old TV worked better at wider angles.

    Besides, the article mentioned Visible Spectrum. Good luck reflecting that and maintaining usefulness.

    --
    Canada: The US's more awesome sibling.
  6. No problem by Anonymous Coward · · Score: 1, Informative

    The modulation frequency is much too high to be perceptible. If an encoding is used which has a constant light/dark ratio, the light will look perfectly steady. (LEDs are often driven with an unfiltered pulse width modulation signal in the kHz range and that doesn't cause problems with epileptics. This technique uses hundreds of MHz.)

  7. I remember a DIY LED netsystem.... by Ogi_UnixNut · · Score: 4, Informative

    ...called Ronja, only 10-mbits/sec, but ~1.4km range, and it could all be built by yourself. Quite cool IMO. You can find out more info (on the now bit dated) site here: http://ronja.twibright.com/

  8. Re:Oh Great by noidentity · · Score: 2, Informative

    Now everything I own, from my Star Wars light saber to my Krusty the Klown glow-in-the-dark alarm clock, could potentially with wireless signal. Oy carumba

    That's actually been a documented problem in some devices with status LEDs, which inadvertently leaked information due to being tied directly to the (serial) data line, rather than a low-pass filtered version of it.