LEDs promise internet at speed of light

800px-Świecący_LEDResearcher’s at China’s Fudan University in Shanghai this week claimed to have successfully trialled “li-fi” connectivity – a technology that makes use of existing installations of LEDs to provide wireless connectivity.

The technology trial in China enabled four computers using a one-watt LED light bulb with an embedded microchip to connect to the internet. Chi Nan, an information technology professor at the university, told Chinese news agency Xinhua that her team has achieved data rates of 150Mbps using the technology, which is faster than the average broadband connection in China. Furthermore, the prospects for the technology are promising as there is currently a strong movement among Chinese consumers to replace old-fashioned incandescent bulbs with LED light bulbs.

Interest in the technology has also developed elsewhere and is being actively developed by Germany’s Fraunhofer Heinrich Hertz Institute (HHI). The institute explained that “li-fi” makes it possible to use standard off-the-shelf LED room lights for data transmission. In April this year, HHI reported that data rates of up to 800Mbps were achieved using li-fi under laboratory conditions, while data throughputs of 500Mbps were demonstrated to the public.

Since then it has achieved a transmission rate in laboratory experiments of over 1Gbps per single light frequency and claimed that speeds of up to 3Gbps are feasible. French company OLEDComm even has a commercial version of the technology already available.

The LiFi protocols are defined by the international standard IEEE 802.15 committee, which was also responsible for the Ethernet 802.3 and WiFi 802.11 standards. LEDs are different from other kinds of lights because they are semiconductors. This characteristic gives them the capability to switch-on and off within a few nanoseconds.

But the technology is still a long way from being commercially successful, Fudan University’s Chi admitted, as “if the light is blocked, then the signal will be cut off,” she said. Furthermore, key related technologies, such as light communication controls as well as microchip design and manufacturing, are still in an largely experimental phases.

The University of Edinburgh’s Harald Haas first coined the term “li-fi” and said in a recent TED talk that : “In the future you will not only have 14 billion (LED) lightbulbs, you may also have 14 billion li-fi’s deployed worldwide for a cleaner, greener, and even brighter future.”

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