Lighting : Lighting April 2016 - Vol 36 Issue 2
24 LIGHTING MAGAZINE | April/May 2016 24 LIGHTING MAGAZINE | April/May 2016 Li-Fi also addresses many of the current shortfalls with Wi-Fi data transfer. For example, it provides a safe alternative to electromagnetic interference from radio frequency communications, creating new alternatives in aviation, hospitals and healthcare, and hazardous environments such as mines and petrochemical plants. The high bandwidth of Li-Fi means it could potentially become a conduit for wireless underwater communications, too. WHERE ARE THE SHORTFALLS OF LI-FI? Due to its reliance on light waves, Li-Fi cannot penetrate walls and is less effective around corners – so while it is less vulnerable to hacking, the range is much shorter. There is also the issue of turning your house lights off at night – with no light, there is no wireless connection. There is one other drawback: Li-Fi cannot work in open light, more or less ruling it out of outdoor areas where Wi-Fi lends great appeal. Stakeholders say the use of different filters can be used indoors to protect the transmission even when sunlight is present, but even so, challenges remain. According to Mark Gregory, a senior lecturer at the RMIT University’s school of engineering, these obstacles are significant setbacks for Li-Fi stakeholders if the technology is to really permeate the market. Retail chain Carrefour is one of the early adopters of Li-Fi technology, launching a world-first supermarket network in 2015 using LED lights. The technology is used to convey weekly specials to customers through their mobile devices, along with useful item information. Image courtesy of Philips. Dr Gregory questions the overall efficiency of Li-Fi technology, compared with traditional wireless systems. “The idea of using visible light, infrared or ultraviolet light has been utilised for decades with remote controls and so on,” he says. “Ultimately, yes you can use things like LED light bulbs as part of a Li-Fi network, but you’ve still got to get the LED communications to the LED bulb. At some point you’re using the Ethernet over powerlines or using Wi-Fi or a similar technology, so these are the unanswered questions. “It’s a fantastic idea, but you’ve got to solve the other problems, and that is how do you connect these things back into the network.” WHERE IS LI-FI ALREADY IN USE? The number of real-world Li-Fi case studies is thin on the ground. But with stakeholders claiming that Li-Fi is on track to become a $113bn ($160bn AUD) industry by 2022, that is expected to change significantly in the coming years. One example is the use of Visual Light Communications by French retail giant Carrefour. The chain has installed an LED-based indoor positioning system at one of its most popular outlets in Lille, France. The system connects with an app downloaded on customer’s smartphones, allowing them to browse a catalogue for promotions, find the item they’re looking for or report items that are out of stock on the shelves.
Lighting February 2016 - Vol 36 Issue 1
Lighting June 2016 - Vol 36 Issue 3