WTF is... Li-Fi?
Optical data transfer's new leading light?
Forget about Wi-Fi - the future of home wireless networking is, according to boffins, the light bulb.
So say a number of researchers and technologists who are looking to light to provide the next step in high-speed data networking in the home.
The principle is simple: turn a light on and off so rapidly that the human eye can't see the flicker, but a photodetector can nonetheless pick up the stream of 1s and 0s the blinking bulb is transmitting. Compress the data, and you up the throughput even more. Old-style filament bulbs and fluorescent tubes aren't up to the task, but new, LED-based lighting is.
It's not hard to envisage home lighting with an integrated photodetector - to pick up signals sent back from networked devices - and perhaps a powerline adaptor on board to maintain a connection over electrical wiring back to the router.
The technique is called Visible Light Communications - or VLC, not to be confused with the open source media player of the same name - but the companies springing up to deliver the technology are already branding it "Li-Fi". The similarity to the name "Wi-Fi" is deliberate: they hope VLC will become as ubiquitous a networking technology as 802.11 has become.
Lightbulbs, lightbulbs everywhere
One of VLC's key proponents, Harald Haas of the University of Edinburgh, reckons that isn't hyperbole. With tens of billions of regular lightbulbs installed in homes and offices across the globe, as they're replaced with LED light sources, Li-Fi can be a communications technology that can be found almost everywhere.
Li-Fi bulbs will inevitably be more costly than regular LED bulbs, but then the potential volumes will, Haas reckons, push prices right down.
More to the point, Li-Fi could be used in almost every location where regulations forbid the use of Wi-Fi: aircraft cabins and hospitals, to name but two. And light isn't affected by the spectrum regulations that govern how radio frequencies can be used.
Of course, getting it out of the lab and into the living room - and every other space illuminated by a lightbulb - is another matter.
Next page: From Palm Pilots to high-speed data
it's Infrared- as used in millions of devices for decades? But with visible light? And slower? And your lights need to be on to use your LiFi device at home? If you'll excuse the pun in my sarcasm, that sounds Brilliant. There's nothing I like more than having some irritating light at the side of the room letting me use my new Wireless keyboard, or playing computer games in a well-lit room so my phone can sync.
Which retard thought this up, and how long will it take before they come up with the "revolutionary" idea that they could use an invisible wavelength of light for it?
One of the massive advantages that visible or IR light comms have over WiFi or Bluetooth- or even NFC- is security. You can have broadcast wireless data comms all over a building- and keep the contents secret by closing the blinds. Want to make an IR pay-wave system secure? You get coatings that would scatter any 'leaking' IR and stop it from being intercepted.
Plus it's almost certainly lower-power than Bluetooth for 'normal' speeds. And at Gigabit speeds is almost uncontested in the wireless space.
And using an IR one would mean you can control your TV/SkyBox/etc without needing the daft WiFi/ Bluetooth combination my Samsung supposedly-smart-TV requires.
tl;dr: IRDA FTW, LiFi Sux, Rant over for now.
There seems to be some misconception about 'the lamp needs to be shining bright' for this to work. This is not, in fact, the case - it's well possible to dim the light down very low indeed and still get data across. In fact, data transmission should be easier in a dark room - less interference. But even in full sunlight, a dim lamp will be able to transmit data without it being visibly 'on'.
The question isn't the data rate you can cram into the visible spectrum - it's hundreds of THz wide - but avoiding interference from all the other bulbs, and also feeding data to the sockets.
Quite a good rant: I'm not sure what your point is.
Data via light is no more inherently secure than any other electromagnetic transmission. What you suggest is the normal "security by obfuscation" approach which is known to be crap. Want security then add security.
The efficiency of electromagnetic transmissions is also largely independent of the frequency. Power is directly related to data rates and distance. Want efficiency then make it directional. Given the known heat losses still inherent to LED I doubt very much that it is more efficient than Bluetooth.
And so the wheel turns.
Been here before a few times haven't we?
I seem to remember Apricot/Sirius used to offer optical networking back in the 80s, then IRDA came along late 90s/early 00s and promised to take off.
Can't wait, this time we've got the electro-sensitive bunch who will discover a brand new bandwagon of lumino-sensitivity to jump on and sue from.
To answer your question, WTF is... Li-Fi?
Is it a high quality music reproduction system used in China?