Bright idea: How light-based Li-Fi could unseat Wi-Fi

时间:2019-02-28 03:18:04166网络整理admin

By Nicola Jones ALEXANDER GRAHAM BELL was certain his greatest invention would change the world. He was almost right. The telephone was indeed revolutionary, letting people talk to each other across great distances as if they were in the same room. Unfortunately, Bell thought his greatest invention was not the telephone, but the photophone. That was a complete flop. Perhaps it was just ahead of its time. Because the basic idea behind it – using pulses of light to bounce information through free space – is once again set to change the way we communicate. Radio waves have been the medium of choice for sending signals wirelessly for the best part of a century. But we’re rapidly reaching a crunch in how much data we can send. That, with advances in LEDs and lasers, mean light is starting to beat radio hands down, at least for some applications. Using light you could download the equivalent of a DVD box set in the blink of an eye. The ability to send digital signals could also be built into street lights and lighting in homes and offices, giving us internet coverage almost anywhere. And since our walls aren’t generally transparent, light could be ideal for keeping communications secure. Those championing visible light communication, or Li-Fi, envision a bright future. “Everywhere I see a light I see Li-Fi,” says Harald Haas at the University of Edinburgh, UK, one of the technology’s main advocates. For Haas, light offers an alternative to radio that will let our devices exchange massive data streams without interruption. It opens up new possibilities too. For example,