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What is Li-Fi?


Wi-Fi is something we take for granted these days, although it really hasnít been ubiquitous for very long, having only been ratified as a standard in the late 90s. Itís convenient and these days fast enough for downloading software, watching HD video and transferring files between your NAS and computer.

There are some issues with it though. For one thing, Wi-Fi is not all that fast compared with the transfer speed of wireless systems. The latest and greatest Wi-Fi standard (802.11ac) will hit a theoretical 900 megabytes per second (about 7 gigabits per second), although in real world scenarios that figure is closer to 2 gigabits per second or approximately 256 megabytes per second. A real world test of Li-Fi on the other hand reached 1 gigabyte (about 8 gigabits) per second. In the lab theyíve managed 224 gigabits per second. An astounding 27 gigabytes per second.

Thereís simply no competition between Li-Fi and Wi-Fi in terms of speed. After all, Li-Fi operates in the terahertz frequency range. Way beyond what Wi-Fi can achieve.

So, what is this amazing wireless technology? Well, itís light. Plain old visible or near-visible light. Li-Fi uses LED lights flicked on and off so quickly that the human eye canít possible tell the difference. Data streams can be piggybacked onto the lights that you use to illuminate your office or home. You donít even needs line of sight, reflected light is enough for a respectable 70Mbps.

You may also wonder what happens if you want internet, but no bright lights. It turns out that these LEDs can be dimmed to the point where you canít see the light, but data transmission is unaffected.

Now, to be fair, the Li-Fi you can actually buy right now isnít any faster than Wi-fi. This is a technology yet to reach its potential, but there is one immediate issue that Li-Fi brings to the table which computing professionals may find interesting: Visible light canít penetrate walls the way that Wi-Fi radio can. This makes it much easier to secure a local network, since those not within the reach of the light canít access the systems. It would certainly help curb those Wi-Fi poaching neighbours,

Li-Fi and Wi-Fi can live next to each other quite comfortable, but maybe in the not too distant future weíll see high-performance computers and render farms connected not by miles of ethernet cabling, but by the glow of a few lightbulbs.