Haas's discovery is based on a subset of optical technology called visible light communication (VLC), or Li-Fi, as it has been dubbed. VLC exploits a hack of human perception: light-emitting diodes can be switched on and off faster than the naked eye can detect, causing the light source to appear to be on continuously. Rapid on-off keying enables data transmission using binary code: switching on an LED is a logical "1", switching it off is a logical "0". Thereby flows the data.
The potential applications are enormous: divers working at depths could use light to communicate; air passengers could connect to the internet through the LEDs inside the aircraft. Haas sees the technology potentially disrupting industries from telecoms to advertising.
Research into VLC has been conducted in earnest since 2003, mainly in the UK, US, Germany, Korea and Japan. Experiments have shown that LEDs can be electronically adapted to transmit data wirelessly as well as to provide light. VLC is faster, safer and cheaper than other forms of wireless internet, advocates say -- and so could eliminate the need for costly mobile-phone radio masts. (...)
A VLC industry is beginning to cohere. Last autumn a report by industry researcher Global Business Intelligence, Visible Light Communication (VLC) -- A Potential Solution to the Global Wireless Spectrum Shortage, mentioned half a dozen companies that are active in the field, including Casio and Intel. Samsung and Boeing were not named, but are also thought to be exploring VLC. Last October, a group of companies from Germany, Norway, Israel and the US formed the Li-Fi Consortium to promote optical wireless communications.
It's easy to see why VLC could disrupt the way data is delivered. It offers relatively high bandwidth -- and visible light is free and safe. Imagine being able to use your laptop or tablet wherever in the world you can find a modified LED light. No more scrambling for access codes, or searching for hotspots, or risking leaks and electromagnetic interference, because artificial light, unlike radio waves, doesn't penetrate walls. You can control its beam, like a torch; and even if that torchlight is dimmed to the point of appearing switched off, you remain connected, as the LED signal is still operating.
Evangelists emphasise VLC's advantages in hazardous conditions or tough environments. They say it will transform air travel by allowing overhead cabin lights to connect mobiles and laptops in-flight; and that it will improve conditions for those working underwater -- on oil rigs, for example -- where radio waves cannot penetrate. Traffic lights could better regulate traffic flow using data; and LED car lights might alert drivers when other vehicles are too close. More pervasively, anyone seeking an internet connection could connect using light from streetlamps and electric shop signs.
by Michael Watts, Wired UK | Read more:
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