Introducing the new Li-fi: the Wi-fi that uses LED light
Engineers are tapping into LED technology to create a ‘new’ form of data transmission and beat the broadband “capacity crunch” of modern societies.
The new technology – called ‘Li-Fi’ by its pioneer Professor Harald Haas – is a bidirectional, high-speed and fully networked wireless communications, similar to the more familiar Wi-fi. Unlike conventional Wi-fi however – which relies on radio-frequency waves – Li-fi use visible, infra-red and near ultraviolet light to transmit data. As such, it accesses a much wider window of the electromagnetic spectrum and hence can carry much more information than the competing Wi-fi, potentially offering a concrete solution to the RF-bandwidth limitations that developed societies are experiencing daily.
The idea of using light to transmit information is really not ‘new’, after all, Alexander Graham Bell and his assistant, Charles Sumner Tainter, invented the first working photophone more than a hundred years ago in 1880. What is different in Li-fi, is the delivering medium: the technology uses light from light-emitting diodes (LEDs) achieving networked, mobile and high-speed communication.
“I believe this is a revolution in internet technology,” Haas commented, “and my mission is to make the world believe it as well.” LEDs are great as they can modulate light intensity very quickly – in fact, so rapidly that our naked eye can’t register it, but sensitive photodetectors certainly can – achieving high-rate bitstream. “Some of our latest work has shown that we can achieve 100 Gigabit per second, compared to the fastest Wi-fi of 7 Gigabit, so we are about 10 to 20 times faster using Li-fi,” Haas continued.
Li-fi is also free for everybody, people use LED lights everywhere; Haas again: “Wherever you see an LED light you need to think of it as a high speed data transmitter – from your kettle, your fridge, from the street light in front of your house, car headlights, traffic lights.” The potential of this technology is limitless, from domestic and social applications to healthcare and offshore safety.
The technology also has security advantages. “Wi-fi can go through walls and other opaque object,” Haas said, “Li-fi does not. If you think of a café with a Wi-fi router, everyone can access that router and can intercept your communication if you are on the same network. But in that café, people [using Li-fi] will be sitting under different lights getting a different signal, so for someone to intercept your link they would have to be sitting very close to you and you would notice that.”
The technology has already been tested in the Oracle Arena, home of the Golden State Warriors basketball team. “In a stadium like that, everybody wants to access to the internet, for example to see replays of action from the game. These individualised replays are not available using Wi-fi because they would use too much bandwidth. But with LEDs we can provide this bandwidth and give people what they want.”
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