Researchers Beam 230Mb/sec Wireless Internet WIth LEDs 218
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."
No upsides either (Score:5, 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.
Re:No upsides either (Score:5, Insightful)
That's a huge upside for linking up video devices though. No interference from the neighbors, no interference from the other room.
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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
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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...
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Re:No upsides either (Score:5, Funny)
I tried that in my epilepsy classroom and everyone had a fit.
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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
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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)
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].
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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.
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That's a really neat application!
There. Fixed that for myself. Uhg.
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What people haven't mentioned, however, is that this is essenti
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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
Re:No upsides either (Score:4, Funny)
Holy shit, apparently I live in the future and I didn't realize it.
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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
If you want the signal to go through walls... (Score:2)
Very high bandwidth, it conveys a lot of information, especially in thin-walled multiple dwelling buildings.
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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.
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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.
Audio is Very High Bandwidth (Score:2)
Every instance of TMI I have ever experienced was delivered via audio frequencies. Q.E.D.
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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.
No kitty, that's my pot pie! (Score:3, Funny)
No, you can not haz beam of light interwebs. You are obviously a lolcat, and the only thing lolcats should do with beams of light is chase them. Who is a cute kitty? Who is? You! Yes you are!
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Lazercat is a lolcat, and he demands moar lazer.
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If your room has no windows.
Re:No upsides either (Score:5, Interesting)
Even if it doesn't have windows open, you can still go through a closed or even shuttered window. Telescopes replace direction antennas and have phenomenal gain and accuracy. Lasers beamed back in can return signals and don't have to be visible ( You can control transmit spectrum a lot easier than receive spectrum ). AlGaAs based photonic detectors can pick up single photons and are sensitive enough to spot light coming through a thin gap in shutters or curtains. ( think more sensitive than military NV devices ).
Now, instead of being worried about people parking in cars just up the street, you need to worry about anything you can see from your house... Thos e hills 10km away? Not far enough. The highrise across the river? Huge risk.
The good news is that tinfoil is sufficient to stop all photons, so a few rolls of tinfoil and tinfoil plated tape will be all you need to secure the wireless visible spectrum devices in your house.
Until someone burns a ten micron hole in your defenses with an infra-red laser....
GrpA
Re:No upsides either (Score:5, Funny)
People who live in glass houses shouldn't use plain text passwords.
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Why wire your house, just put mirrors everywhere.
Sorry, no. I have two daughters. It's hard enough to get them moving as it is.
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Laser based systems have the advantage you can get an acceptable SNR over longer range. They have the downside that you have to aim them.
There is also the issue of needing absolute line of sight between the laser and receiver.
Just different ones (Score:5, Insightful)
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.
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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
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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.
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IR is slow as hell and prone to interference from the sun! Sounds like a real winner
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Cats! That'll do in this stuff.
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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,
Re:Just different ones (Score:5, Funny)
Slashdot 57:30, If we covet making a spelling mistake for each wife, at some point we forsake other gods and we may do unto others before they can do unto us first on /..
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Excellent, thanks. Although things are funnier at 3:00am sometime, so anyway I'm told.
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"Gah, fucking kid!"
*reorients laser networking device that's been slightly modified*
$sudo ifup zap0
*chuckles maniacally*
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If you allow such people in your house, you really get what you deserve.
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Nah, he's just playing fast and lose with spelling.
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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
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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?
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One way glass is not one way. The moment it got dark outside the effect stops working.
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So send everyone home before it gets dark. Sounds like a win to me. :)
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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.
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Except for the receiver. Unless you plan on making you whole laptop flicker.
Oh Great (Score:2)
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
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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.
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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."
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Blast from the past (Score:5, Funny)
It's the return of IrDA!
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And junkie dolphins can have forehead communications lasers as well as SQuIDs!
Perfect!
Fraunhofer juggernaut (Score:2, Informative)
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.
FhG owns MP3 (Score:3, Informative)
Great! (Score:2)
You won't notice it (Score:2)
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.
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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.
An idea that's been around (Score:3, Interesting)
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)
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.
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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,
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Ok this is
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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
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I can imagine a very useful situation for this: Spying
Meh. Easier than that. Bounce a laser signal against any window (larger the better) where you want to hear the occupants. As the window responds to the change in internal pressure caused by the vibrations of speech, your return signal will reflect that change with a difference in the angle of the return beam. You do need to watch your beam alignment though, so that the return laser beam impacts your photoreceptor array. It's simple laser interferometry from that point. Stick the signal difference throug
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What wireless antenna that normal folks have radiates 10 watts?
What I want to know is: (Score:4, Funny)
I RTFA (Score:3, Interesting)
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?
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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)
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.
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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. {
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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 (Score:2)
This is great... but... (Score:3, Funny)
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(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)
We do the same thing at work with Interns and flashlights.
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so THAT is how those MIT guys overcame the mythical man month problem!
I remember a DIY LED netsystem.... (Score:5, Informative)
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related idea (Score:2)
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
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Granted they have to update it a bit for LCD, but...
http://en.wikipedia.org/wiki/NES_Zapper [wikipedia.org]
Where is this useful? (Score:2)
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 space commander (Score:2)
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
IrDA died for a good reason. (Score:3, Insightful)
Is it just me, or... (Score:2)
...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.
Digital video (Score:5, Funny)
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."
Desk lamps, OK, that's one way (Score:3, Interesting)
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.
Bandwidth Meter (Score:3, Funny)
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!
1975 here we come... (Score:3, Funny)
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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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According to TFM, the flickering is slight enough to be imperceptible by humans. So unless epileptics have superhuman sensitivity to tiny light variations, I doubt they will notice anything either.
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Don't worry, the flicker rate is so fast not even Bobby Fischer would complain about it.
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I have a seizure disorder, but according to my EEG I am not photosensitive. Generally you would worry about pulses below 100hz. This system sends data at megabits per second so there is no primary need to pulse at low frequencies. I a imagine that starting and stopping downloads (say) could generate visible pulses but I am sure the system could be designed not to behave that way.
I have read that usable data can be extracted from the TX/RX LEDS on some hubs and switches. I am more concerned about the 9-12Hz
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No, you can pick up any signal that leaks with an appropriate sized telescope. It's just that due to the wavelength, the telescope required to resolve an LED from four miles away will fit in a van, while the telescope required to resolve your wireless emissions would be pretty conspicuous.