Lighting : Lighting April 2016 - Vol 36 Issue 2
20 LIGHTING MAGAZINE | April/May 2016 April/May 2016 | LIGHTING MAGAZINE 21 20 LIGHTING MAGAZINE | April/May 2016 April/May 2016 | LIGHTING MAGAZINE 21 FEATURE Sam Charlwood discovers the world of Li-Fi: emerging light-based technology which could soon leapfrog Wi-Fi in wireless data transfer. The internet is a way of modern life. We live it and breathe it: from booking holidays, doing our banking, performing business or consuming the latest media. Until now, Wi-Fi has been a preferred mode of internet connection all over the world, in essence making use of radio waves to transmit information wirelessly across a network. Wi -Fi’s ease of use, ability to cover large spaces and adaptation to different applications has pushed it to the front of the list of technologies to propagate information wirelessly. But as the need for data consumption grows, and with most of the available radio frequency spectrum already in use with Wi-Fi, new ways of propagating information wirelessly are now being developed. Enter Li-Fi: the bourgeoning science of modulating a light source with data, rather than a radio signal in the case of Wi-Fi, to create a wireless data connection. The concept falls under the umbrella of Visual Light Communication. First developed in 2011, Li-Fi (short for Light Fidelity) is now being spruiked as a boom technology in internet ‘content consumption’ applications such as video and audio downloads, which place heavy demand on the downlink bandwidth but require minimal uplink capacity. It works just as seamlessly as a radio frequency and is best propagated by LED (Light Emitting Diodes) light bulbs – semi-conductor devices which emit a constant stream of photons. The LEDs essentially work in the same way as traditional transistors, which are commonly found in devices such as TVs, laptops and smartphones. Given the dramatic growth in the use of LEDs in different spaces, essentially making each one a wireless router, there is plenty of scope for new and improved data transfer applications. “All we need to do is fit a small microchip to every potential illumination device and this would then combine two basic functionalities: illumination and wireless data transmission,” Harold Haas, a German physicist and the face behind Li-Fi, said at its introduction in 2011. “In the future, we will not only have 14 billion light bulbs, we may have 14 billion Li-Fis deployed worldwide for a cleaner, greener and even brighter future,” Professor Haas added. Retail chain Carrefour is one of the early adopters of Li-Fi technology, launching a world first supermarket network in 2015 using in-store LED lights. Here, the French company details how Li-Fi can be used to simplify and improve the grocery shopping process. Image courtesy of Philips. Is this the internet’s light bulb moment? Shop in store Supermarket lighting acts as an indoor positioning grid 1 Each Philips light fixture sends a unique identification code using Visible Light Communication (VLC) 2 The mobile phone camera detects the code in the light and identifies its location 3 Now location aware, the mobile app delivers location-based promotions to the shopper 4 Philips LED-based indoor positioning technology is easy to scale, accurate to a sub-meter, does not require additional investments besides the light fixtures themselves, and offers at least 50% energy savings.
Lighting February 2016 - Vol 36 Issue 1
Lighting June 2016 - Vol 36 Issue 3