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That theory about LED lightbulbs transmitting data? It's true. Li-Fi is here.

Erika Morphy | Sept. 15, 2015
Yes, multiple tests have shown that LED lighting fixtures can transmit wireless data at very competitive high speeds. A commercial product started shipping several months ago.

Prototype fixtures developed by researchers at Kennedy Space Center, using light-emitting diodes (LEDs) to send data. Credit: NASA/Kim Shiflet

What if every light bulb in the world could also transmit data?

In July 2011, Harald Haas, a professor of engineering at Edinburgh University,  poised that rhetorical question to a TED Global audience.

Then he went on to answer it. Broadband would be plentiful, nearly as limitless as oxygen itself, as it flowed from a standard-off-the-shelf LED (light-emitting diode). Society would come to view the way we transmit data now, which is via electromagnetic waves - specifically, radio waves - as quaint, at least when we were not scoffing in memory at its costs and frequency limitations.

Haas wasn't dabbling in science fiction. His theory was that the data could be transmitted via the visible light spectrum, or VLS. Like radio waves, VLS is part of the electromagnetic spectrum, but it is the "good" part, Haas explained to the audience. It's not like gamma rays, which can be dangerous, or ultraviolet light, which are also unsafe. Infrared can possibly be harnessed, but again at low levels for safety reasons.

The visible light spectrum though, sandwiched in the middle, is inherently safe to use, he said.

Before I describe Haas' theory and subsequent developments in detail, I would like to jump ahead in this story now to tell you that broadband transmission via the visible light spectrum - which is also called Li-Fi - is here, and there are multiple practical use cases for the technology.

Actually the theory of VLS has been here for quite a while, but it is posed to be here in a big way, now that the National Aeronautics and Space Administration (NASA) is working with it.

At the start of the month, NASA announced it had signed a Space Act agreement with the CEO and Chairman of Light Visually Transceiving (LVX) System Corp., John Pederson, to license researchers at the Kennedy Space Center to develop visual light communications applications.

NASA's interest is to use Li-Fi to supplement the International Space Station's Wi-Fi system, and possibly enhance it with such features as Global Positioning Satellite Routing Systems architecture.

"A future manned spacecraft making a trip to Mars could be a candidate for this kind of communications system," says principal investigator and research physicist Eirik Holbert. "Also, a deep-space habitat operating on the surface of the planet could use VLC."

But Li-Fi is also suited for more humble use cases such as providing broadband in a coffee shop or company headquarters.

Any building with LED light fixtures could be set up to use VLC technology, Holbert said. LEDs in lighting fixtures communicate by flashing or blinking too fast for the human eye to discern.


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