mannerisms

Ruminations on the electronics industry from David Manners, Senior Components Editor on Electronics Weekly.

Edinburgh Start-Up Uses Light Instead Of 802.11

Edinburgh start-up Visible Light Communications (VLC) is focussing on using flickering LEDs instead of WiFi for broadband communications.

 

Speeds of up to 500Mbits/sec have been achieved for the technology, called Li-Fi, but the first product from VLC – a consumer transmitter – will deliver data at 100Mbits/sec using VLC’s SIM-OFDM technology and optical spatial modulation. It is due for launch next year.

 

The technology was invented by EdinburghUniversity’s Harald Haas. “At the heart of this technology is a new generation of high-brightness light-emitting diodes,” says Haas, “very simply, if the LED is on, you transmit a digital 1, if it’s off you transmit a

0.”

 

High speeds are achieved by implementing parallel data transmission using arrays of LEDs, where each LED transmits a different data stream.

 

Also mixtures of red, green and blue LEDs can be used to alter the light’s frequency, with each frequency encoding a different data channel.

 

Because it uses light rather than radio-frequency signals, VLC could be used in aircraft, integrated into medical devices and hospitals where Wi-Fi is banned, or even underwater, where Wi-Fi doesn’t work.

 

The snag with LiFi is, of course, that it relies on line of sight.

 

VLC’s SIM-OFDM technology and optical spatial modulation allows LED light to modulate at a rate so fast as to be imperceptible to the human eye, but which can be picked up by receivers such as suitably configured smart-phone cameras at speeds of hundreds of megabits per second, enabling the light source to transmit data.

 

“At the rate we currently adopt wireless data, we will ultimately run out of radio spectrum as we cope with the long term demand of wireless data transmissions and the trillions of bytes of data communicated every month,” says VLC CEO Dr Gordon Povey, “turning a light source – a simple household LED bulb for example – into a localised data communications centre is a potentially viable alternative. Where we have an LED light source configured with VLC’s own IP, we have a powerful method of carrying data, not just in a single data stream, but thousands of data streams in parallel at high speed.”

Tags: blue leds, data stream, data transmission, high speeds, smart phone

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11 Comments

  1. David Manners
    March 05, 2012 17:18

    Ha Ha. Brilliant Lefty, quite brilliant

  2. Lefty Goldblatt
    March 05, 2012 16:31

    So when we get LED streetlights we have a backhaul channel for t’internet ?

  3. Robert
    March 02, 2012 10:34

    ahh brings back memories. does anyone remember the indoor laser FSO (free space optics) system that TI developed in the mid 90′s. It used deformable mirrors to control the laser direction pointing and a 1300nm laser (I seem to remember). I seem to remember it had a theoretical throughput of over 1Gbps (not bad for mid 90′s technology).

  4. David Manners
    March 01, 2012 15:54

    Wowee, The Baron, that is a low blow indeed

  5. The Baron
    March 01, 2012 15:52

    Can it be integrated with a spinning glitter ball?

  6. David Manners
    March 01, 2012 13:57

    Worthy of Mr Cynical, Dr Bob, but it’s a moot point.

  7. Dr Bob
    March 01, 2012 13:56

    Techno-Ponzi anyone?

  8. David Manners
    March 01, 2012 09:13

    I suppose it depends on the brightness of the LED Martijn, but I don’t know and will try to find out.

  9. martijn
    March 01, 2012 03:30

    Sounds fast, but over which distance?

  10. David Manners
    February 29, 2012 19:01

    Didn’t know they could transfer data at 500Mbps

  11. Keith
    February 29, 2012 18:53

    Sounds like the old TV infra red remote to me…

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