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800Mbps Wireless Network Made With LED Light Bulbs 175

Posted by CmdrTaco
from the don't-blink-or-you'll-miss-it dept.
Mark.JUK writes "German scientists working at Berlin's Fraunhofer Institute for Telecommunications have set a new world record for Visible Light Communication technology after they succeeded in using regular red, blue, green and white LED light bulbs as the basis for building a new 800Mbps capable ultrafast Wireless Local Area Network. Dr. Anagnostis Paraskevopoulos explained: 'With the aid of a special component, the modulator, we turn the LEDs off and on in very rapid succession and transfer the information as ones and zeros. The modulation of the light is imperceptible to the human eye. A simple photo diode on the laptop acts as a receiver. The diode catches the light, electronics decode the information and translate it into electrical impulses, meaning the language of the computer.' The solution, which could be installed on ceilings and would cover approximately 10 square meters, would be ideal for HD video streaming and inside Hospitals or Aircraft where traditional Wi-Fi is often banned. However visible light signals can easily be blocked, such as when a hand is passed in front of the transmitter."
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800Mbps Wireless Network Made With LED Light Bulbs

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  • by snowgirl (978879) on Tuesday August 02, 2011 @09:42AM (#36959044) Journal

    Seriously, does anyone here on Slashdot need their summary dumbed down that far?

    • by bloodhawk (813939) on Tuesday August 02, 2011 @09:45AM (#36959084)
      Have you read some of the comments on stories lately? I fear it may not be simplified enough.
    • Apparently those IE6 users from the other article... http://tech.slashdot.org/story/11/07/31/161200/Study-Compares-IQ-With-Browser-Choice [slashdot.org]
    • by ZackSchil (560462) on Tuesday August 02, 2011 @10:01AM (#36959226)

      At least it's technically accurate and well-written in addition to being dumbed down. I'll take that over your average mystery summary, which is misleading (either in the name of sensationalism or promotion), contains several typos, and at least one meaningless buzzword.

    • by Anonymous Coward

      800Mbps, how many libraries of congress per second is that?

  • It could just as easily be seen as a security feature. Drawing the shades is easier than encasing your room in Faraday cage. And while I'm at it, since when do hospitals ban Wi-Fi? The ones I've been around (Tufts Medical Center, Children's Hospital Boston & St. Elizabeth's) have all offered it for patient and visitor use.
    • For that matter, next time you are on a flight see how many "hpsetup" and "Free Public WiFi" networks you see.
    • It could just as easily be seen as a security feature. Drawing the shades is easier than encasing your room in Faraday cage. And while I'm at it, since when do hospitals ban Wi-Fi? The ones I've been around (Tufts Medical Center, Children's Hospital Boston & St. Elizabeth's) have all offered it for patient and visitor use.

      It probably depends on the part of the hospital you're in. In the ER areas of my local hospital there are signs forbidding the use of cell phones and other wireless devices. There aren't any such signs in the waiting room.

    • Kelemvor4 is correct. I work in a hospital on server maintenance and in some areas, usually where medical equipment is used and not in patient rooms, using wifi or your phone is strictly forbidden. It interferes with the medical equipment just the same as it interferes with the landing equipment on a plane.
      • Which is to say not at all?

        • by X0563511 (793323)

          Which is to say "possibly, and with disastrous results should it occur"

          • Which is to say, every day thousands of planes land just fine with wi-fi and cellular signals beaming out from dozens of electronic devices.

            • by X0563511 (793323)

              I'm not trying to excuse it. I'm just stating that there is some reason buried down there, however shaky it may be (eg it's not just "because we said so!")

  • by Anonymous Coward

    So... how does upstream work? Does every single one of the smart lights double as a receiver too?

    • by rrossman2 (844318)

      I was wondering this as well as the summary doesn't mention a transmitter in the laptop, only a receiver

    • by ZackSchil (560462)

      Usually at a much lower speed using IR.

    • by Loether (769074)
      Not sure if you are trolling but, No, LEDs are not capable of receiving data or acting as inputs. In the summary they used the example of streaming video where of course the monitor doesn't need to send and data back. The summary said they use a simple photo diode to receive. Light Emitting Diodes and Photo Diodes are 2 separate distinct things.
      • You mean except the method shown in this instructable, http://www.instructables.com/id/LEDs-as-light-sensors/ [instructables.com] ?

        Just because it isn't very good at it doesn't mean it can't be forced to do the job.

        • by TheLink (130905)
          I suspect it'll be harder to do it while the LEDs are on and shining brightly ;).

          If you're thinking of using a separate bunch of LEDs as light sensors why wouldn't you use something better than LEDs for the task?
          • by bmo (77928)

            Because that's all you might have in the drawer at the time.

            Also, who needs a photodiode when you've got glass germanium diodes that you can shine light on?

            These fancy kids and their specialized devices...

            --
            BMO

      • by rickb928 (945187)

        Nice note, but it answers nothing. Less than nothing, you just trolled back and added nothing to the question or answer.

        Even the comment about streaming video misses the reality that to receive streaming video, you must ASK for it. As in, uplink a request. Unless we also develop prescient mindreading networks. In which case, I didn't even need to type this...

        Broadly speaking, this idea is half a network. I'm hoping they can do the other half.

        • I'd think the best bet for the return channel (assuming you didn't want to use RF) would be to use IR. By using narrow band optical filtering it should be possible to avoid too much interference from other sources and for many applications the return channel can use a relatively low data rate.

      • LED's are frequently used as photo-detectors. They aren't wildly efficient, but they do work.

        www.parallax.com/Portals/0/.../LEDLightEmitterandDetector7-31-07.pdf

        It makes the optics so much simpler if you can use just one device for TX and RX.

  • Imagine my TV and my computer screen talk to each other at 800Mbps...
  • Most of us feel pretty strongly that WiFi on planes is not dangerous and that it should be allowed as-is. But since there are some extremely stubborn and inflexible people involved in policy making. (I don't say decision making because I don't think they are capable of making any.) But what if this "LiFi" (Did I just coin a new term? I doubt it...) were deployed on airplanes and USB transceivers were sold/lend to passengers, I think that would pretty much end the controversy and debate over in-flight Wi

    • Its not a matter of feeling or not. Wi-fi has been proven to interfere with emergancy landing equipment. Don't believe me? Read for yourself. http://www.zdnet.com.au/wi-fi-proven-to-interfere-with-aircraft-339311113.htm [zdnet.com.au] http://www.flightglobal.com/articles/2011/03/10/354179/wi-fi-interference-with-honeywell-avionics-prompts-boeing.html [flightglobal.com]
      • by isorox (205688)

        Its not a matter of feeling or not. Wi-fi has been proven to interfere with emergancy landing equipment. Don't believe me? Read for yourself. http://www.zdnet.com.au/wi-fi-proven-to-interfere-with-aircraft-339311113.htm [zdnet.com.au]
        http://www.flightglobal.com/articles/2011/03/10/354179/wi-fi-interference-with-honeywell-avionics-prompts-boeing.html [flightglobal.com]

        From your article:

        A senior Boeing engineer stressed to ZDNet Australia that the levels of EMI required to affect a pilot's screen exceeds the levels produced by the normal operation of normal levels of Wi-Fi use.

        "Boeing and Honeywell have concluded that actual EMI levels experienced during a flight where there is normal operation of a Wi-Fi system will not cause any blanking of a Phase 3 display. This is not a safety issue with currently operating 737s and 777s," a Boeing engineer said.

      • by erroneus (253617)

        I know... I saw those too -- they were posted to slashdot here before. Practially speaking, though, WiFi seems to work quite nicely on the Air-Tran flights I took over the holidays and I didn't notice anything when landing either.

      • by GooberToo (74388)

        No it hasn't. They used a massively strongly signal, physical adjacent, than would ever be observed in the wild - unless the sole purpose was to create interference. Which oddly enough, was the entire purpose of the test.

        Simple fact is, there exists no credible proof WIFI has EVER interfered with an aircraft.

    • But what if this "LiFi" (Did I just coin a new term? I doubt it...) were deployed on airplanes and USB transceivers were sold/lend to passengers, I think that would pretty much end the controversy and debate over in-flight WiFi.

      It would also cost money in new equipment, so that's a bonus as well. Anything to get the consumer to pay more, or to make him need something to spend money on.

    • by pz (113803)

      Most of us feel pretty strongly that WiFi on planes is not dangerous and that it should be allowed as-is. But since there are some extremely stubborn and inflexible people involved in policy making.

      How many of you have done actual impact studies and considered things like out-of-spec transmitters, poorly repaired or perhaps modified wifi cards, etc?

      Anecdotes are not data, but I had one particular laptop that, when the wifi was (inadvertently) turned on, prevented any PA announcements on one particular flight. And it was a bone-stock laptop with a bone-stock wifi card. After that discovery, the laptop was quickly retired, taken apart for the limited salvage value, and replaced with a new one.

      It may w

      • by erroneus (253617)

        I tend to think that when you bring people with their personal crap (i.e. civilian passengers) onto a plane that does have anything that might be adversely affected by stray and random signals shielded, then someone needs to look at the company that designs and builds these flying deathtraps.

        [Car analogy] To put it another way, if talking on cell phones caused a car's systems to fail or become unreliable, I think the first thing people would claim is that it's not a problem with the phone, but a problem wit

        • by adolf (21054)

          My BMW came with a sticker in the upper-left corner of the windshield. Its text is verbatim:

          "Important: Installation and operation of non-BMW approved accessories such as alarms, radios, amplifiers, radar detectors, wheels, suspension components, brake dust shields, telephones (including operation of any portable cellular phone from within the vehicle without using an externally mounted antenna) or transceiver equipment (eg. C.B., walkie-talkie, ham radio or similar) may cause extensive damage to the vehi

  • Old modems with external LEDs (as well as other network equipment with TX/RX LEDs) were susceptible to data leakage just by reading the LED modulations. This is just faster. http://www.alge.no/ebooks/Optical_tempest.pdf [www.alge.no]
    • by Irick (1842362)
      All great innovations begin as a hack, then are further polished and improved. Discounting a novel use of a previously known phenomena is pretty closed minded.
  • by uncledrax (112438) on Tuesday August 02, 2011 @10:23AM (#36959430) Homepage

    'With the aid of a special component, the modulator, we turn the LEDs off and on in very rapid succession and transfer the information as ones and zeros.

    I bet they had something to read the modulator signals on the other side.. an Anti-Modulator perhaps?
    They could come up with some cool acronym for this system.. MOAMO ? noo.. i'm sure there's something better..

    • Re: (Score:2, Funny)

      by rickb928 (945187)

      It's a DE-modulator.

      Remember, the old MODEM acronym? Modulator/DEModulator?

      My old ham radio days still haunt me. I know too much analog shit that still works.

      • Wow, you are good at remembering words. By the way, what's that sound when something passes really close by your ear? Swosh? Wiih?

    • And to avoid inconveniencing the passenger, we could even use some non-visible spectrum... Hum... what could we use ?

      Ultra-violet light ? No... too problematic (reacts with object and produce visible light, etc.)
      Maybe some lower frequency / longer wavelength ?

      Once we solve this part, I'm sute we could use the technologies on PDAs, Phones... even to control home electronic devices from a distance.

  • Sure, this new technology is kinda cool, but it will require putting some equipment in the ceiling, and getting some network cable up there. Wouldn't it be simpler, cheaper, and more efficient to just put Ethernet plugs in the room?
    • Think of older buildings being retrofitted - if they have solid cement walls, or plaster and lathe or something crazy, running ethernet through them might be difficult. Ceiling access would be much easier in that case.
      • by rubycodez (864176)
        there are plenty of fast and cheap solutions to hanging wires on walls or entire raceway for large bundle.
      • by fnj (64210)

        That damned plaster-and-lathe construction. Would that be wood lathes embedded in the plaster, or is it metal lathes?

    • by LWATCDR (28044)

      Here are some uses I can think of.
      It may not be cheaper. Think of anyplace that you already use wifi.
      How about in a home. Maybe as a replacement for DVI? Just put your laptop near your external monitor or TV and send video to it.
      As a solution for wifi saturation. There are locations where you have a lot of wifi points and they can interfere with each other. This should be blocked by walls so it will provide a local wireless internet. Think of an office complex where each room could have it's own optical wif

    • by gbjbaanb (229885)

      sure, but a lot of people just aren't tall enough to plug their laptops in with your solution. :-)

    • by HiThere (15173)

      A ceiling mount probably isn't needed. You could probably substitute a mirror, with the transmitter somewhere else in the room. Given the summary, I don't think this is point-to-point, but rather broadcast within a small volume. And the signaling system probably *would* be Ethernet, just not over cable.

  • It's great that they have achieved this speed with such simple technology. However, I wonder how useful this technology will really be. If you set your laptop down next to the TV, I wonder what kind of interference you'll get from the rapid fluctuations in light. I know the average techy type here is a troll living in the basement but what about the unwashed masses trying to use this in rooms above ground with the shades open? I wonder how much interference will all that light introduce, especially if y

    • by nschubach (922175)

      Actually, my first thought was... (and this is a real stretch of imagination): What if alien life came to visit us and they could see the light that we could not. They'd walk into the room and be inundated with bright flashes of light and noise that we would not see. Could you imagine your reaction to that?

      • My reaction would be to send a probe that doesn't react to that. But maybe that extremely advanced alien species ins't all that smart.

  • This would be perfect to deploy in the National Radio Quiet Zone [nrao.edu]. As it is right now no one can have wireless in their home within thirty miles of the GBT [nrao.edu].

    • by ragefan (267937)

      I don't believe this stills holds true, or if so, it is not enforced. I know for a fact there are many wifi networks within 30 miles of Green Bank and quite a few (if not the vast majority) did not get clearance to have them.

  • by RivenAleem (1590553) on Tuesday August 02, 2011 @11:04AM (#36959978)

    How do I watch a movie in the dark then?

    • by w_dragon (1802458)
      Just do what we do with any annoying lights on our electronics, put some electrical tape over it. Now you can watch your movies in complete darkness!
  • ...using a "real" light bulb in 80's. Breadboarded my own special "modulator" device in fact. Of course, since I didn't have a fancy laptop then, I had to wire up a demodulator as well. Stuffed everything into two cigar boxes. You could even hear the filament "ring" when you tapped the box. Very cool!

    Damn, I should have filed a patent on it...

  • by hey (83763)

    A cool use of this might be broadcast. Everyone at a concert could receive a HD stream showing an alternate view.
    (I see there is currently a 10 m limit)

  • by argStyopa (232550) on Tuesday August 02, 2011 @12:08PM (#36960826) Journal

    "However visible light signals can easily be blocked, such as when a hand is passed in front of the transmitter."*

    *depending on the power of the light, and the translucence of the object. Visible light signals cannot be easily blocked, for example, if they are emitted by say an 80-million candlepower searchlight. For example, this would not be stopped by a hand, nor eyelids. Such might prove to complicate use on-board an airplane in other ways, however.

    • Radio signals can also be blocked by a hand. Just ask any iPhone4 user.
      • by demonbug (309515)

        Radio signals can also be blocked by a hand. Just ask any iPhone4 user.

        I was going to say that in the case of the iPhone the radio signals are being blocked by a prick, but in interest of my karma I won't.

        Oops.

    • With multiple directional receivers you could also do multipath decoding of indirect reflections.

  • Seems to me that this is a one-way digital broadcast. There's no mention about how the receiver talks back to the ... ceiling. As such, it's not really a network, is it?

    • Who cares if it is a broadcast only system; think of the possibilities of this being applied in areas outside of sending video in an airplane (what a waste- just run the wires.) Its not new but it is faster than before.

      IR light wouldn't be seen. add another LED and receiver and increase bandwidth (or lower it and just use IR.. in which case this isn't that new.)

      Think how cheap it would be to embed additional information into displays! the closed captioning could be embedded along with other information; li

      • by cadeon (977561)

        Who cares if it is a broadcast only system;

        I care. "Broadcast" is a very different with very different meanings "Network." Yes, an 800mbps light-based digital broadcast system is incredibly useful, but it's not being represented properly.

        If we don't use the right terms and describe new technology properly, who will?

        • Not reporters. Not marketing people. Not politicians. Not bloggers...

          They are always messing the language up to the masses; while the experts end up with their own jargon even if they are attempting to not create a dialect of their own.

          Point is understood; but this is a "discovery" (ok more like enhancement) of a data link layer technology and that level of tech is usually just 1 direction. It can be used within a network; duplicate it for going the other direction and then either figure out how to do full

  • This is an old technology (although easily destroyed by clouds, smoke, hands in the air, and any other intercepting body), but for sos purposes, there have been talks about using this as a default means of comm for boats out at sea in distress , so as not to use too much energy trying to send out an sos, but at the same time, keep it going long enough someone could pick it up passing by....

  • 1. Covers 10 square meters which is effectively a circle of radius of 1.6 meters. That is not very far at all.
    2. One way communication. There would have to be a transmitter and receiver at both ends pointed at each other.
    3. Line of sight only. What happens when someone stands between the receiver and transmitter? No signal.
    4. Crosstalk; How well does this system work when there are several transmitters in the room? What about incandescent lights or florescent lights? If one wanted to have full coverage for

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