Between streaming movies, downloading games, refreshing apps and everything else, we are all greedy for more data. Sometimes, however, Wi-Fi is just too slow. Plus there are security concerns on uplinks when Wi-Fi can be intercepted.
There is another way to transmit data wirelessly, says Brian Corbett at the Tyndall National Institute in Cork, and that’s ‘Li-Fi’.
Instead of using radiowaves to send data, you use light. You point your device at a bunch of LEDs (light-emitting diodes) and they transmit data. You could use LEDs to download entire movies in seconds.
A gigabyte per second
LEDs can turn on and off very quickly, and they are tiny, Corbett explains. Each time an LED flickers its sends digital code (a 1 or 0) and it can flicker 100 million times a second. Your eye would miss that, so LEDs could be used as regular lights and transmit data. “You can send a gigabyte per second, which is an enormous amount of data,” he says.
Earlier this year, Corbett made a small cluster of LEDs made from a very hard material called indium gallium nitride. This is the layer in modern blue and green LEDs.
The cluster contained 16 individual LEDs in an area of 100 micrometres (about the width of a human hair).
“A single LED six microns across can send hundreds of megabits of data per second. When we run them as a cluster that helps send even more,” he adds.
Li-Fi in shops and in the air
He predicts that LEDs transmitting data could hit the big time in shopping centres, where visible light could transmit information to shoppers’ phones. On a flight, you could point your phone at an overhead light and download a movie. The challenge, however, is that light can scatter and the receiver has to be designed to deal with background and natural light.
LEDs are already used to transmit TV signals around apartment buildings in South Korea, although they are encased in plastic tubing to hold in and deliver the beam.
There are advantages to transmitting data through light without cables. For example, Li-Fi could be used for underwater signalling or in hospitals where Wi-Fi is not permitted.
“If you want to stop someone stealing your information when you get a direct download, it could be a big advantage to have a line of sight between your computer and the channel you are connecting to,” says Corbett.