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Researchers Beam 230Mb/sec Wireless Internet WIth LEDs 218

Posted by timothy
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."
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Researchers Beam 230Mb/sec Wireless Internet WIth LEDs

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  • No upsides either (Score:5, Informative)

    by IICV (652597) on Thursday March 11, 2010 @06:40PM (#31445728)

    "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.

    • by maxume (22995) on Thursday March 11, 2010 @06:51PM (#31445892)

      That's a huge upside for linking up video devices though. No interference from the neighbors, no interference from the other room.

      • That's a huge upside for linking up video devices though. No interference from the neighbors, no interference from the other room.

        There is probably another use (ironically based off 'NCIS: LA') which I can think of: temporary connection to a visual display device without needing a physical connection. Imagine the following:

        You have a large display screen in the conference room with a line of sight receptor built in. You want to quickly show something to everyone in the room, but don't want to spend time lea

      • But what about interference from the LEDs on your monitor?

        I mean sure, I guess this would be great for the people who can use a Braille interface...

    • by martas (1439879)
      what if you could use the lighting that already exists in your house to do this? kinda like internet over power lines?
      • by Anonymous Coward on Thursday March 11, 2010 @07:12PM (#31446228)

        I tried that in my epilepsy classroom and everyone had a fit.

      • by icebike (68054)

        what if you could use the lighting that already exists in your house to do this? kinda like internet over power lines?

        Probably not. The summary mentions "plain old desk lamps", but TFA is specific in stating the lamps must be LED, which is still not common.

        Incandescent can't be modulated at the frequencies necessary for anything much beyond S O S signals.

        Of course once all your house lighting is converted to LED, your network might work provided you modulated at least one lamp in every room. This of course would leak out windows, which the Summary writer would be perfectly fine with, even tho he disparages leaking radio

        • Re: (Score:3, Insightful)

          by petermgreen (876956)

          More than that even if you use LED lights you have the issue of the power supplies to contend with. I bet most PSUs won't pass through high frequency modulations.

          So you are talking about either rewiring your lights with a low voltage distribution system of some sort (possible but the cables get very big) or replacing the LED PSUs with something that can carry a signal across (say homeplug one side LED modulation the other)

          There is also the question of what to do for the return link.

          All in all nice idea but

      • Re:No upsides either (Score:5, Interesting)

        by Nefarious Wheel (628136) on Thursday March 11, 2010 @08:14PM (#31446928) Journal

        what if you could use the lighting that already exists in your house to do this? kinda like internet over power lines?

        Retailers already use this technology to change the display tags on shelves. After hours, they send a series of codes to modulate the fluorescent lighting in such a way that it sends new data to smart shelf tags. The shelf tags display a product name and a price. Changing the prices on those shelf tags are a major operational cost of grocery retailers.

        Fujitsu is one of the firms offering this. Here's Fujitsu's system [fujitsu.com].

        • That's really neat application! The trouble is that incandescent and fluorescent lamps would both be unable to transmit at a high bandwidth because they have a slow response time to a change in the electrical current. LEDs, on the other hand, respond much faster and would be appropriate for high-bandwidth applications.

          • That's a really neat application!

            There. Fixed that for myself. Uhg.

          • 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 could theoretically run a much higher frequency through the globe than the limited 50-60Hz power cycling. And given the sensitivity of the receptors, light variation wouldn't have to travel the length of the tube - a variation in light at the ends should be enough to do it.

            What people haven't mentioned, however, is that this is essenti

            • Re: (Score:3, Informative)

              by NoMaster (142776)

              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 th

        • by IICV (652597) on Thursday March 11, 2010 @10:32PM (#31448058)

          Holy shit, apparently I live in the future and I didn't realize it.

        • by TheLink (130905)
          Wonder how well it does against pranksters :).
    • Re: (Score:3, Interesting)

      by DigitAl56K (805623) *

      Leaking through walls is not always a feature. I can't get the maximum benefit of my Wifi setup because I live in an apartment building and all my neighbors have devices chattering on every channel. All their routers are probably defaulted to high power, and there's nothing I can realistically do to improve my situation except switch to 802.11n/5G, which I did, and now I'm seeing more routers on that frequency range too.

      I don't want to lose my through-walls access, but if it could be heavily supplemented by

    • The Fraunhofer Institute also has an audio-frequency wireless solution that will go through walls, with the proper amplification.

      Very high bandwidth, it conveys a lot of information, especially in thin-walled multiple dwelling buildings.
      • The Fraunhofer Institute also has an audio-frequency wireless solution that will go through walls, with the proper amplification.

        Very high bandwidth, it conveys a lot of information, especially in thin-walled multiple dwelling buildings.

        Unfortunately the teenagers who drive down the street at night also have this technology, though there's about zero information content to the "boom boom boom" sound it makes. It certainly penetrates walls, thick or thin, and is definitely audible.

      • Very high bandwidth
        I dunno if you were being serious or trying to make a joke but the bandwidth and hence the data rate of audio are very limited (yes better modulation and techniques like MIMO can get more data rate out of the same bandwidth but there are limits)

        I bet you would really struggle to get even a couple of hundred kilobits per second reliably out of free space audio transmission and that's assuming it was acceptable to drown out all other sound over most of the audio band.

    • Oddly enough the concept Is about 8 years old [slashdot.org] Granted back in them old days 10Mbs was still common, 100Mbs were still expensive to network and Gigabit networks were just starting to be put on some of the high end systems. But the idea has been around and as a possible security risk. I don't see this as a replacement for home networking but for site line of site it may be useful. but I would expect the technology real advantage would be in just hacking from analysising the lights on you 100mbs switch.

  • by MozeeToby (1163751) on Thursday March 11, 2010 @06:43PM (#31445762)

    LED wireless signals would theoretically have none of these downsides.

    Nope, instead it'll have a whole range of different ones, such as requiring line of site.

    • Re: (Score:3, Funny)

      by wealthychef (584778)
      I don't think "site" means what you think it means.
      • Re: (Score:2, Insightful)

        by Uranium-238 (1586465)
        You know what he meant really and he's quite right too. People could dick with these connections by putting a piece of paper infront of the transmitter or receiver. This just sounds like a uesless idea.
        • Forget people being a dick, how about people just innocently wandering between transmitter and reciever? Or the user himself accidentally setting something down in the way? Too many ways to screw it up.

          I think we had a story about LOS wireless before, and really, same as then, the only use I can see for it is in lab environments, where you usually don't have people wandering around in undefined patterns. Attach unit to roof on a per-row basis, aim all computers in that row at that reciever, and no one can a

          • by tlhIngan (30335)

            Forget people being a dick, how about people just innocently wandering between transmitter and reciever? Or the user himself accidentally setting something down in the way? Too many ways to screw it up.

            I think we had a story about LOS wireless before, and really, same as then, the only use I can see for it is in lab environments, where you usually don't have people wandering around in undefined patterns. Attach unit to roof on a per-row basis, aim all computers in that row at that reciever, and no one can a

            • Re: (Score:3, Informative)

              by twidarkling (1537077)

              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.

            • Re: (Score:3, Insightful)

              by h4rr4r (612664)

              IR is slow as hell and prone to interference from the sun! Sounds like a real winner

          • by Gilmoure (18428)

            Cats! That'll do in this stuff.

        • Re: (Score:2, Funny)

          by mrclisdue (1321513)

          If we continue to make a spelling mistake in each reply, at some point approaching infinity, we may have reconstructed the bible: to discover that you read it first on /..

          chers,

        • That's why we should just skip LED's and go straight to lasers. Or lightning. Need to download really big file? Try our 'lightning fast wireless service'.
          • Yeah but since this is /. you have to go the extra step and think of some of the creative uses you could put those to. For instance, say your neighbor's kid keeps waking you up by playing outside your window every morning.

            "Gah, fucking kid!"
            *reorients laser networking device that's been slightly modified*
            $sudo ifup zap0
            *chuckles maniacally*
        • by Surt (22457)

          If you allow such people in your house, you really get what you deserve.

      • Nah, he's just playing fast and lose with spelling.

    • by Chris Burke (6130)

      Yeah I like how being able to go through walls is listed as a downside. Though I guess if leeches are your biggest concern, it is an improvement. They'd still exist, but you'd be a lot more likely to notice the guy sitting outside your window with a laptop than if he was in his own home.

      I remember in college making a radio and a wireless speaker system on the same breadboard, using an LED to transmit the audio from the radio to the amplifier. It was a pretty cool thing to do in a lab, but it didn't occur

      • In businesses security is a big issue, and being able to stop a wireless signal at the office wall would be a huge plus.
        • Re: (Score:3, Insightful)

          by Chris Burke (6130)

          And losing your network connection because you were sitting at the wrong end of the conference table in your meeting would be a huge minus.

          And having the signal stop at the wall but not at the window sounds like a major ding to the "huge plus", not to mention a recipe for a false sense of security.

          In either case you'd have to secure your wireless network in a traditional fashion. So, why not just do that, and get the benefit of non-line-of-sight communication too?

    • by sootman (158191)

      My dad used to tell me not to stand in his light when he was reading or working on something. Someday my kid will be yelling at his kid to stop blocking his Internet.

  • A Desklamp? Other light fixtures? What's next, the overheard fluorescent lights??

    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
    • Re: (Score:3, Informative)

      by noidentity (188756)

      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 [cnet.com] due to being tied directly to the (serial) data line, rather than a low-pass filtered version of it.

      • Apparently the National Security Agency, the federal agency responsible for military intelligence and the security of the U.S. government's communications, believes the threat to be low-risk.

        Said a spokesman on his way into the building carrying a large box labeled "Etalons, 550nm, Tunable."

  • by jpmorgan (517966) on Thursday March 11, 2010 @06:44PM (#31445774) Homepage

    It's the return of IrDA!

  • by Anonymous Coward

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

    (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

  • So now I'll have a strobe light effect every time I check my email!
    • So now I'll have a strobe light effect every time I check my email!

      As long as the modulation they use on the LEDs is DC-free, your eyes won't pick up this strobing. A traditional light bulb flickers at 100 or 120 Hz, and you probably don't notice it. So you definitely won't notice flicker that's a million times faster.

      • by harrkev (623093)

        Since they got 230MB per second, you can safely assume that the modulation will be in the gigahertz. Good luck seeing that. If they use something like 8B/10B encoding, then they will get a guaranteed 50% duty cycle, so there will never be any brightness variation visible to the human eye.

  • by dtmos (447842) * on Thursday March 11, 2010 @06:57PM (#31445990)

    US patent 6,542,270 [uspto.gov] ("Interference-robust coded-modulation scheme for optical communications and method for modulating illumination for optical communications"), issued April 1, 2003, assigns direct sequence spread spectrum-type codes to each overhead fluorescent light, so that communication and location-determination can be performed. The chip frequency of the coding scheme is fast enough that there is no human-audible or -visual effect, and supportable by electronic ballasts.

  • Utterly Stupid.... (Score:3, Insightful)

    by loose electron (699583) on Thursday March 11, 2010 @06:57PM (#31445992) Homepage

    If you really want to use optical communocation you might as well go infrared so you don't need to see it, similar to your TV remote.

    Then you have all the problems (visible light or infrared) of orientation, line of sight and similar.

    Hopefully the creator of this gadget has not quit their day job.

    utterly stupid.

    • by femto (459605)

      Not as dumb as you think. By using visible light, the system gets to use infrastructure that will be in place anyway. (Think this will be combined with data over powerlines? You betcha.) That saves energy and costs. In addition, the transmitter power is much higher than would be used for IR, so one gets greater SNR and higher speed data. The lighting system of a building also lights up every nook and cranny, overcoming most line of sight issues. Finally, the visible spectrum is pretty well unregulated,

    • just because you don't see any potential applications it doesn't mean it's "utterly stupid". Line of sight is not so difficult if all I want is to stream from my laptop to the tv to watch a HD movie with some friends.

      Ok this is /. No friends, forgot.
    • by MattskEE (925706)

      I'm not sure if this was part of their reasoning, but it could be that there is more noise in the infrared region. There is quite a bit in visible as well to be sure, but just somebody walking around is emitting some infrared. Indoors if you control the lights you might control most of the visible spectrum.

      There might also be issues scaling up the transmit power for high signal to noise ratios in the low bandgap materials needed for IR LEDs. Quite a bit of effort has already gone into scaling up power le

  • by killmenow (184444) on Thursday March 11, 2010 @06:58PM (#31446006)
    What happens if you cross the beams?
  • I RTFA (Score:3, Interesting)

    by harrkev (623093) <kfmsdNO@SPAMharrelsonfamily.org> on Thursday March 11, 2010 @06:59PM (#31446026) Homepage

    I RTFA. It says that they achieve the bandwidth by filtering out the blue light. This makes sense, as white LEDs are actually blue LEDs with phosphors added to get the other colors. Phosphors are similar to glow-in-the-dark stuff, so they retain light for a little while. Presumably, the blue filter is only needed over the receiver.

    The one questions is: how does your laptop equipped with this technology talk back? Will your laptop have a multi-watt emitter on the top (read "bright white light") lighting up the room for the upstream traffic?

    • by Chris Burke (6130)

      The one questions is: how does your laptop equipped with this technology talk back? Will your laptop have a multi-watt emitter on the top (read "bright white light") lighting up the room for the upstream traffic?

      Naw, it's like some satellite internet connections. You use the LED for download, and upstream you use dialup. I'm sure it'll catch on. :)

  • Oh, and ... (Score:4, Informative)

    by dtmos (447842) * on Thursday March 11, 2010 @07:04PM (#31446116)

    Those interested in this LED-based technology can check out the IEEE 802.15.7 Visible Light Communication Task Group [ieee802.org]. Members of the Fraunhofer Institute are regular contributors to the standard.

    • Re: (Score:3, Informative)

      by xigxag (167441)

      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 [fraunhofer.de]," within which are various institutes [fraunhofer.de]. 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 [fraunhofer.de] in Berlin. {

      • by dtmos (447842) *

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

        Not if they want the standard to be approved. 802.15 voters do not take kindly to approving standards for which they will then have to pay royalties to use. Politically, it's almost impossible to get a royalty-bearing patented technology into an 802.15 standard.

  • I accidentally the entire visible spectrum.
  • by troylanes (883822) on Thursday March 11, 2010 @07:14PM (#31446256)
    I'm an epileptic you insensitive clod!
    • (pre woosh)

      Photo sensitivity in seizure disorders is generally for pulses below 20Hz and definitely below 100Hz. It is legitimate to ask why bicycle head and tail lights are allowed to pulse at 9-12Hz.

  • big whoop (Score:5, Funny)

    by pablo_max (626328) on Thursday March 11, 2010 @07:22PM (#31446330)

    We do the same thing at work with Interns and flashlights.

  • by Ogi_UnixNut (916982) on Thursday March 11, 2010 @07:47PM (#31446622) Homepage
    ...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/ [twibright.com]
    • by EkriirkE (1075937)
      I've been looking for this site again forever, thanks! It's applied to many-a-slashdot story claiming to have invented something similar
  • A light pen that 'reads' an 'imperceptible flickering' LCD screen to both figure out which point its touching, and the data the PC wants to send at that point

  • This would be
    [a] a dedicated technology you need to explicitly buy gear for, rather than use what you implicitly get in nearly every device you buy - phone, lappie, printer, home SAN, what have you.
    [b] they wont sell as many radios as the wifi people do, so dont expect anywhere near the same price for a device with a radio on it.
    [c] Wifi would advance faster (in bandwidth and price primarily). As would Wireless USB, Bluetooth 4.0, etc.
    [d] you'd need to go back to the days of pointint irda devices. Consumer

  • zenith made the first remote controls, they used ultrasonic chimes for signaling. A side affect was the TV would change channels when people dropped pots and pans.

    IR sucks. visible sucks even more, because there happens to be a lot of interference. I suppose they could compensate for static levels of ambient light, but you still need line of sight, which is a pain... and you need light, which is a pain if you're watching a movie in the dark on a laptop or so...

    RF is really the only way for mobile stuff. Fix

  • by teh dave (1618221) on Thursday March 11, 2010 @08:33PM (#31447112)
    In case they hadn't noticed, IrDA is dead for a good reason. The fact that the last two versions of it are much faster than Bluetooth (2.x) is irrelevant, it's too much of an inconvenience for most of its potential users in comparison to Bluetooth. It was great before Bluetooth came about and I used the latest versions of it with my old phone because it was much faster than Bluetooth, and I never had a problem with it for that purpose. Most potential users prefer the convenience of Bluetooth though, for obvious reasons. My new phone doesn't have IrDA, and hardly any new phones do, and as far as consumers go, that technology is all but dead. I can see LED networking going the same way.
  • ...does this seem like absolutely nothing groundbreaking at all. OK, we can transmit information by pulsing LEDs. People have been doing that for years. The fact you don't put an optical fiber in front of it doesn't seem all that interesting.

  • by BillX (307153) on Thursday March 11, 2010 @09:10PM (#31447460) Homepage

    I assume the 230Mb/s is for stuff like delivering digital video to your TV without plugging cables.

    "Wow, this movie looks even better in digital!"

    "Here, let me turn the lights out so we can wa...oh."

  • by HuguesT (84078) on Thursday March 11, 2010 @10:09PM (#31447866)

    Now how do we communicate the other way ? Like from the laptop back to the router ? How do I twiddle the house lights from there. Inquiring minds want to know.

    BTW what kind of light sensor did they use ? Cheap hopefully.

  • by multimediavt (965608) on Thursday March 11, 2010 @11:58PM (#31448490)

    Downloading from couch with laptop facing "array" across room, 100% signal strength

    Dog walks into room between laptop and array, 30% signal strength while dog passes

    Child walks in room and stands in front of you to talk to you, 0% signal strength until conversation ends, or kid dies for cutting off your slashdot post mid submit!

    Wife walks in with credit card bill with pr0n charges, array gets smashed and you get served.

    No good can come from this!

  • by flyingfsck (986395) on Friday March 12, 2010 @01:14AM (#31448788)
    Geez, I played with LED data links when I was in high school and LEDS came in all colours provided that it was red. Years later I used the power LED of a device (woohoo, we had green too by then) for a debug data link. Now you *really* got to get off my lawn...
    • by pclminion (145572)

      Years later I used the power LED of a device (woohoo, we had green too by then) for a debug data link.

      And your data link was 230 megabits per second?

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