Oct 202013
 

LED light bulb Li-Fi closer – China scientists develops new Li-Fi technology: a microChipped 1 watt LED bulb can produce data speeds of up to 150 megabits per second (Mbps), very enough to provide net connectivity to four computers.

Li-Fi-LED-light-bulb

Li-Fi-LED-light-bulb

Shanghai’s Fudan University has made a breakthrough with the development of “Li-Fi” technology, in which a one watt LED light bulb can help connect four computers to the internet simultaneously. A microChipped 1 watt LED bulb can produce data speeds of up to 150 megabits per second (Mbps), IT professor at Shanghai’s Fudan University Chi Nan said. Current wireless networks have a problem: The more popular they become, the slower they are. Chi Nan has just become the latest to demonstrate a technology that transmits data as light instead of radio waves, which gets around the congestion issue and could be ten times faster than traditional Wi-Fi.

Compared with an average internet connection speed of 150 megabytes per second (Mbps), the new technology — which uses light as a carrier instead of traditional radio frequencies used for Wi-Fi — can also generate speeds as fast as 3.25 gigabytes per second (Gbps), the university said.

In dense urban areas, the range within which Wi-Fi signals are transmitted is increasingly crowded with noise—mostly, other Wi-Fi signals. What’s more, the physics of electromagnetic waves sets an upper limit to the bandwidth of traditional Wi-Fi. The short version: you can only transmit so much data at a given frequency. The lower the frequency of the wave, the less it can transmit.

LiFi-vs-WiFi

LiFi-vs-WiFi

The current wireless broadband connections are expensive and less efficient, said Xue Xiangyang, a professor at the university’s Department of Computer Science. He cited the example of wireless services in mobile phones, where although there are many base stations set up to help increase the signals, efficiency rates are as low as 5%. On the other hand, LED lighting, which could be used to replace traditional devices, can provide a safer and cheaper solution by adding a microchip on the bulb, Xu said.

The Shanghai Committee of Science and Technology asked Fudan University to work on key applications to help develop the information industry last year, and the university will now showcase ten computer samples using the new technology at the Shanghai Industry Expo next month.

Chi Nan, a member of the research team, said that Wi-Fi, which depends on an invisible wave, has the hidden danger of electromagnetic radiation, while with Li-Fi technology, the light spectrum is 10,000 times more than the radio spectrum and it does not require any new infrastructure construction. He added, however, that there is still a long way to go before Li-Fi can be used by thousands of households as it would take time to manufacture a series of products, such as the connection control and chip at a mass production level.

Chi said that Li-Fi should not be treated as a rival to Wi-Fi connection but rather as a complementary technology, as the Li-Fi connection may be disrupted when the light is blocked.

about Li-Fi

Edinburgh University's Prof Harald Haas coined the term "li-fi"

Edinburgh University’s Prof Harald Haas coined the term “li-fi”

Li-fi, also known as visible light communications (VLC), at these speeds would be faster – and cheaper – than the average Chinese broadband connection. In 2011, Prof Harald Haas, an expert in optical wireless communications at the University of Edinburgh, demonstrated how an LED bulb equipped with signal processing technology could stream a high-definition video to a computer.

He coined the term “light fidelity” or li-fi and set up a private company, PureVLC, to exploit the technology.”We’re just as surprised as everyone else by this announcement,” PureVLC spokesman Nikola Serafimovski told the BBC.

“But how valid this is we don’t know without seeing more evidence. We remain sceptical.”

This year, the Fraunhofer Heinrich Hertz Institute claimed that data rates of up to 1Gbit/s per LED light frequency were possible in laboratory conditions, making one bulb with three colours potentially capable of transmitting data at up to 3Gbit/s.

Unlimited capacity

Li-Fi-light-data-transfer

Li-Fi-light-data-transfer

Li-fi promises to be cheaper and more energy-efficient than existing wireless radio systems given the ubiquity of LED bulbs and the fact that lighting infrastructure is already in place. Visible light is part of the electromagnetic spectrum and 10,000 times bigger than the radio spectrum, affording potentially unlimited capacity.But there are drawbacks: block the light and you block the signal.

However, this is also a potential advantage from a security point of view. Light cannot penetrate walls as radio signals can, so drive-by hacking of wireless internet signals would be far more difficult, if not impossible.

Prof Chi’s research team includes scientists from the Shanghai Institute of Technical Physics at the Chinese Academy of Sciences, the report says.She admitted that the technology was still in its infancy and needed further developments in microchip design and optical communication controls before it could go mass market.Her team is hoping to show off sample li-fi kits at the China International Industry Fair in Shanghai on 5 November, the report said.

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