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German Scientists' Visible Light Network Hits 3Gbps
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."
"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.
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
Here is the TED talk video:
http://www.ted.com/talks/harald_haas_wireless_data_from_every_light_bulb.html
Epileptic seizures sure make the download time breeze by.
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
Fast download rates, okay. But what about the return/upload path?
No sig. Move along - nothing to see here.
Scientists have been inventing cool shit for years - I'm still on an 8 Mb copper line and no my smart phone doesn't last up to twenty times longer these days (as promised); no it doesn't charge itself from kinetic energy or some photosensitive bacteria either.
Maybe engineer is a better term...
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.
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.
So basically they discovered Disco.
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-board systems using this technology one day.
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.
Instead of using this for in-room communication, make a device that uses LEDs for line of sight transmissions over longer distances. A high speed neighborhood network would be fantastic without the frequency congestion of radio wave transmissions, the need for digging that comes with wired networks and the licensing requirements of laser based optical networks. Yes, I know about Ronja..
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. 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.
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!?)
Yeah, this tech sounds nice, but if LEDs are so fast and cheap, why aren't there ~$20 1 gigabit fiber optic network cards? I would love to switch from copper to fiber, which has a big upgrade potential. That would be very useful for a new building that will last for 50 years.
Using light to transmit data, that's really novel. I wonder if to avoid eavesdropping you could coerce the light to travel in some sort of cable. Maybe made of fiber...
That's 'Living Impaired' you insensitive clod!
...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 equivalent of the big kitchen junk drawer full of bits that almost never get used.
at the presentation, you would know the uses: operating theaters, smart traffic lights that communicate with cars, much more available channels so if/when wireless gets exhausted this won't, security (light doesn't pass through walls), and my personal favorite:
it doesn't fry your brain like wireless - no tinfoil hat required.
Actually, this stuff can be used to improve health while communicating, a far cry from wifi radio microwaves which are heavily linked to and documented to cause brain tumors.
That's a lot of German porn.
who prays for Satan? Who in 18 centuries has had the humanity to pray for the 1 sinner that needed it most? ~Mark Twain
I prefer to watch my online porn in a dark room. So making my room dark means cutting my internet connection?
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 the view from the cockpit in real-time while I was flying. If we build really high capacity broadcast networks (like the over-the-air TV used to be), then we'll find uses for them we've never thought about at all. This may even make a computer useful in a class room. I don't believe most of this requires encryption. Mostly an asymmetric network gets us video and large data requests over a cheap, local, and very limited range network. If you want encryption for small slices of data, us the WiFi to do a key exchange.