From Palm Pilots to high-speed data
Germany's Fraunhofer Institute, best known for developing the MP3 audio codec, runs a photonics lab in Dresden. Earlier this year, it said it had created a wireless optical link capable of delivering data at the rate of 3Gbps.
Fraunhofer's technology isn't true VLC - it uses infrared light. So it has the backing of the IrDA, the Infrared Data Association, the organisation founded in 1993 to oversee device-to-device infrared communications standards. You know, beaming business card details from one Palm Pilot to another, or early wireless printing kit, or even linking a computer to an old Nokia phone as a modem.
A Fraunhofer boffin tweaks the Institute's IR tech
Hardly anyone builds IrDA ports into devices these days - USB, Bluetooth and Wi-Fi are faster and don't require line of sight. But the IrDA is looking to VLC to give it a new lease of life.
At the end of 2011, it pledged to work to define a new standard for 5Gbps and 10Gbps infrared communications, an effort building on the 1Gbps the existing Giga-IR standard supports. The Fraunhofer kit supports Giga-IR.
At these higher speeds, IrDA believes its updated standard could replace the likes of HDMI and USB 3.0.
D-Light delight
Meanwhile, Haas, together with Ediburgh University colleague Gordon Povey, continues to work with visible light. They and their team at the college's D-Light - "Data Light" - project have created kit capable of 130Mbps data transfer rights. A lot slower than Fraunhofer's rig, to be sure, but one delivered by off-the-shelf parts rather than custom lab components. Povey and Haas believe they can push that speed to at least 1Gbps. Other Li-Fi proponents claim 10Gbps will be possible with specially designed LED lightsources.
Both boffins also run PureVLC, a company founded to commercialise Li-Fi technology on behalf of the University, and this month PureVLC claimed to have sent the first text message send by LED to an unmodified Android handset.
Coming soon: PureVLC's 'Smart Lighting Development Kit' board
To be fair, the data rate was a low 2.5Kbps and it requires a special app to control the handset's cameras and detect the message. But PureVLC's demo showed that messages can be sent with low-cost kit and that doing so doesn't register with the human eye.
PureVLC is also promising to release a "Smart Lighting Development Kit", a full duplex VLC system that connects to standard LED light fixtures, in Q2 2012.
Next page: Practical applications
COMMENTS
So...
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.
Re: So...
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?
