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

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: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.

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

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.