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."

Comments

sounds overly optimistic

[Anonymous Coward]

"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.

Re:sounds overly optimistic

[russotto]

I wonder whether they can also mudulate the phosphors at 1 Gbps, but I doubt so.

You wouldn't need to; enough of the original LED color gets through the phosphors to detect.

This isn't exactly a new idea; it's been known for years that you can read the data from an old-style modem's Tx and Rx LEDs from across the room.

Re:sounds overly optimistic

[Khyber]

"Nobody uses RGB for room lighting"

You're wrong. In fact, not only can an RGB diode produce great white light, we have diode packages that can essentially cover the entire visible spectrum and thus create any CCT known with greater efficiencies than a white diode, which, again, you're wrong - it's a UV diode with a phosphor on it, not a blue diode.

Re:sounds overly optimistic

[Teun]

So?

Where did you read they want to use the regular/primary room lights for this sort of communication?

Harold Haas - links

[SternisheFan]

Harald Haas: Communications technology innovator: Harald Haas is the pioneer behind a new type of light bulb that can communicate as well as illuminate – access the Internet using light instead of radio waves.

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

Re:Harold Haas - links

[CastrTroy]

Any wireless network is going to need encryption. This is the reason why we have WPA for our radio frequency wireless networks. You could probably use the exact same security protocols as I'm pretty sure they don't depend on the medium you are transferring over.

Re:Harold Haas - links

[Teun]

Ah!

I've just put in my patent application for * to include 'via light'.

Next week you can find me on my personal tropical island.

Visible Light Wireless Network

[Anonymous Coward]

Epileptic seizures sure make the download time breeze by.

Re:Visible Light Wireless Network

[ColdWetDog]

When you first heard one of the "a horse walks into a bar" jokes, did you reply by citing a law the bans horses from bars and then explain that the premise of the joke was simply untenable?

I hope that your grasp of sarcasm is better than your grasp of humor.

You see, this is a problem with kids these days. They didn't grow up with "Mr. Ed" or "Green Acres" (or "I Dream of Jeanie" for that matter, but I digress). The subtle twists of cross species humor are just lost on them.

And no, Dick Cheney doesn't count.

Link to article

[Vario]

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

Scientist?

[mark_reh]

Maybe engineer is a better term...

Pre-existing technology

[SternisheFan]

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.

Re:Pre-existing technology

[ColdWetDog]

Maybe because he's pushing several orders of magnitude more data through the system than your 20 khz headphones?

Size matters.

Re:Who gives a flying monkey's??

[ColdWetDog]

All of that is Obama's fault.

Re:How does it work through walls?

[Dthief]

FTA: The cheap LEDs, which could for example be placed on the ceiling or in room lights and tend to have coverage of around 10 meters, essentially blink on and off extremely fast to transmit the data (not visible to your naked eye). This would make it extremely useful for short range and high-speed networks that may also require something more secure than wifi (i.e. light doesn’t travel so well through solid walls etc.). So it IS the room lighting, and yes, it is not meant for long range wireless. But you could link everything in a room to it.

PARCTAB

[stenvar]

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.

Congratulations, Dear all at HHI!

[udippel]

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!?)