Lighting : Lighting April 2016 - Vol 36 Issue 2
22 LIGHTING MAGAZINE | April/May 2016 22 LIGHTING MAGAZINE | April/May 2016 According to Robin Braun, a Professor of Telecommunications Engineering at the University of Technology Sydney, Li-Fi is one of several promising mediums being trialled to propagate data connections. “We live in an untethered world,” he says. “There have been many attempts to carry data in different ways, including lasers and whatever possible thing that will propagate. Li-Fi is just another way of using something that propagates data through space.” HOW IS LI-FI DIFFERENT TO WI-FI? Light-based wireless communication doesn’t use cables or radio waves, instead flickering the light from a special LED to transmit data just like your Wi-Fi adapter would. The transmission is imperceptible to the human eye, even though regular LED lights switch on and off many times per second. When your wireless device, such as a smartphone, detects traditional radio waves, it connects to your wireless router which then connects to the internet. The philosophy behind Li-Fi is similar, but instead of wireless radio waves being sent in all directions, the shooting light connects directly to your smartphone or Li-Fi device. Li-Fi was developed as an alternative to carrying data on radio frequencies, which according to Professor Haas “is heading to saturation point”. He says the only way out of this dilemma is to find new ways to transmit data wirelessly. WHAT ARE THE ADVANTAGES OF LI-FI? The overwhelming advantage of Li-Fi is the speed at which data can be transferred. According to stakeholders, Li-Fi delivers real-world internet download speeds of up to 1 gigabyte per second – around 100-times faster than average Wi-Fi internet connections available to consumers on the Australian market. That means a full-length film could be downloaded in a matter of seconds. The reason behind the increase is thanks, in part, to the fact LED lights carry high intensity and bandwidth, which is directly proportionate to big data rates. In addition, while radio frequency communication requires radio circuits, antennas and complex receivers, Li-Fi employs similar modulation methods to low-cost infra-red communications devices such as remote control units. “There very likely are going to be applications and commercial products for Li-Fi, and they would offer very high data rates,” Professor Braun says. The principle behind Wi-Fi and Li-Fi are similar, as this diagram shows. The key difference being one uses radio waves to transmit data, the other modulates a light source. Image courtesy of Harold Haas.
Lighting February 2016 - Vol 36 Issue 1
Lighting June 2016 - Vol 36 Issue 3