Imagine having Internet that is 100 times faster than your current Wi-Fi connection. Now imagine that the lightbulb above your head is the source of that connection. It might sound absurd, but this technology, coined Li-Fi, exists and may soon become a reality.
Li-Fi is short for Light Fidelity, and it is a visible light communications system invented in 2011 by physicist Harald Haas of the University of Edinburgh in Scotland. It works by encoding data in the flickering of a beam of visible light, which is transmitted by LED lightbulbs. To encode data, the current supplied to the LED is modulated at extremely high speeds, up to millions of times a second, causing the intensity of the light to rapidly brighten and dim. With signal processing technology, data can be fed into the LED, which transmits the bits of data through the flickering of its light. The rapid changes in intensity in the light beam are detected by a photo-detector and converted into electrical signal. And don’t worry, you won’t be driven crazy — the LEDs flicker at a frequency above the threshold that the human eye can detect, so to us the light will appear to be steady.
Li-Fi has obvious advantages because of its security, wide bandwidth, and high speed, and therefore has potential applications in the home and office.
Li-Fi technology is promising for a number of reasons. For one, visible light has a much wider bandwidth than radio frequency waves, which is what is currently used for Wi-Fi. A major problem faced by wireless systems today is shrinking bandwidth as more and more devices are connected; the range of the visible light spectrum is 10,000 times larger than the range used for radio transmissions, opening a whole new range of frequencies that can be used. Li-Fi has also been proven to be able to transmit much more data at much higher speeds. In real-world tests, scientists have achieved speeds 100 times faster than current average Wi-Fi speeds. Li-Fi is also more secure than Wi-Fi because light cannot penetrate walls; on the flip side, this could also be a potential downside because Li-Fi enabled LEDs would have to be placed in every room of a building. Other drawbacks include the fact that the LEDs would have to be constantly running, even during the day; however, they could be dimmed to an intensity below human visibility while still giving off enough light to transmit data. Li-Fi also does not work outdoors because of interference from sunlight, so it could not be used in public Wi-Fi networks. Despite these limitations, Li-Fi has obvious advantages because of its security, wide bandwidth, and high speed, and therefore has potential applications in the home and office.
Although Li-Fi will probably not be completely replacing Wi-Fi anytime soon, it holds great promise and will likely see tremendous growth in the future. Haas recently founded PureLiFi, a company focused on researching and developing feasible Li-Fi products and solutions. PureLiFi has already released two products to market, Li-Flame Ceiling Unit and Li-Flame Desktop Unit, which provide a high speed Li-Fi connection by connecting to an LED light fixture. In the near future, we may see Li-Fi integrated into our existing infrastructure — maybe even into that light bulb above your head.