Li-Fi , or light fidelity, refers to 5G wireless communication systems using light from light-emitting diodes as a medium instead of traditional radio frequencies, as in technology using the trademark Wi-Fi. Li-Fi signals work by switching bulbs on and off incredibly quickly – too quickly to be noticed by the human eye. And although Li-Fi bulbs would have to be kept on to transmit data, the bulbs could be dimmed to the point that they were not visible to humans and yet still functional.
Li-Fi is expected to be ten times cheaper than Wi-Fi. It has the advantage of being able to be used in electromagnetic sensitive areas such as in aircraft and nuclear power plants without causing interference. The light waves cannot penetrate walls which makes a much shorter range, though more secure from hacking, relative to Wi-Fi.
Direct line of sight isn't necessary for Li-Fi to transmit signal. Light reflected off of the walls can carry 70 Mbps. Both Wi-Fi and Li-Fi transmit data over the electromagnetic spectrum, but whereas Wi-Fi utilises radio waves, Li-Fi uses visible light. While the US Federal Communications Commission has warned of a potential spectrum crisis because Wi-Fi is close to full capacity, Li-Fi has almost no limitations on capacity. The visible light spectrum is 10,000 times larger than the entire radiofrequency spectrum. Researchers have reached data rates of over 10 Gbps, which is more than 250 times faster than superfast broadband.
The fastest speed previously reported was 3Gbit/s, achieved earlier this year by the Fraunhofer Heinrich Hertz Institute in Germany. Chinese researchers also claimed this month to have produced a 150Mbp/s connection, but some experts were doubtful without seeing further proof.
Professor Harald Haas is widely recognised as the “father of LiFi.” He is Chair of Mobile Communications at the University of Edinburgh and co-founder of pureLiFi. The term Li-Fi was coined by Edinburgh University's Prof Harald Haas during a TED talk in 2011 (see below for video) though the technology is also known as visible light communications (VLC).
Many experts claim that Li-Fi represents the future of mobile internet thanks to its reduced costs and greater efficiency compared to traditional Wi-Fi.
Both Wi-Fi and Li-Fi transmit data over the electromagnetic spectrum, but whereas Wi-Fi utilises radio waves, Li-Fi uses visible light. This is a distinct advantage in that the visible light is far more plentiful than the radio spectrum (10,000 times more in fact) and can achieve far greater data density.
This most recent breakthrough builds upon this by using tiny micro-LED bulbs to stream several lines of data in parallel. The research was carried out by the Ultra Parallel Visible Light Communications project, a joint venture between the universities of Oxford, Cambridge, Edinburgh, St Andrews and Strathclyde, and funded by the Engineering and Physical Sciences Research Council.
Existing LED light bulbs could be converted to transmit Li-Fi signals with a single microchip, and the technology would also be of use in situations where radio frequencies cannot be used for fear of interfering with electronic circuitry.
The makers of Li-Fi note that this quality might actually be an advantage in some scenarios, making Li-Fi more secure than Wi-Fi with hackers unable to access unsecured internet connections from out of sight of the transmitter.
More on: http://en.wikipedia.org/wiki/Li-Fi
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