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Wireless data can be delivered by LED lights, anywhere: call it 'Li-Fi'

Data transmissions can potentially be piggybacked from any light source -- from street lamps to smartphone LED displays.

Think about it: around the world, there are millions of street lamps, in every city and town on every continent. One visionary has a proposal to put each and every one of these lamps to work for a new purpose beyond illuminating the street below. They could serve as wireless Internet access points, communicating to devices, as well as vehicles.

Harald Haas, a professor of engineering at Edinburgh University, even has a name for this new networking technology: "Li-Fi," for light-fidelity.

At a recent TED conference, Haas pitched his proposal for Li-Fi data transmission, suggesting that the applications and capacity for data would be limitless -- from using car headlights to transmit data, or employing line of sight light sources as data transmitters.

Haas says data can be transmitted via LED bulbs that glow and darken 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.

There's plenty of capacity, he says: "We have 10,000 times more spectrum, 10,000 times more LEDs installed already in the infrastructure. You would agree with me, hopefully, there's no issue of capacity anymore." The added bonus, he adds, is that the infrastructure is free, and even would promote more rapid adoption of more energy-efficient LED bulbs. "It should be so cheap that it’s everywhere," Haas says. "Using the visible light spectrum, which comes for free, you can piggy-back existing wireless services on the back of lighting equipment."

Plus, there would be wireless access points anywhere there is a light source. Even smartphones, with their LED displays, could serve as data sources. Consider all the possibilities, Haas elaborates:

"...In hospitals, for new medical instruments; in streets for traffic control. Cars have LED-based headlights, LED-based back lights, and cars can communicate with each other and prevent accidents in the way that they exchange information. Traffic lights can communicate to the car and so on. And then you have these millions of street lamps deployed around the world. And every street lamp would be a free access point."

Security is another benefit, he points out, since light doesn't penetrate through walls.

This post was originally published on Smartplanet.com