The internet through a light bulb


Professor Harald Haas demonstrates his LiFi technology to Rory Cellan-Jones

Imagine an office where every computer, mobile phone and tablet is connected to the internet not through an ethernet connection or via wi-fi but just through the overhead lights.

That is the vision that Professor Harald Haas lays out for me when he visits my office to demonstrate his LiFi technology.

Professor Haas has been working on this at Edinburgh University for some years, and is now running a company called Pure LiFi to try and commercialise the technology. The university itself has invested in a LiFi R&D Centre to try to kick-start an industry which might turn Edinburgh into a world centre for this technology.

Next week Professor Haas and a team which includes some of his former doctoral students will take their equipment to Mobile World Congress in Barcelona. So the demonstration in our office feels like quite a big deal - will it work, and will it impress?

They set up two laptops on a table, one with a conventional connection to the internet, linked to a piece of kit which is in turn connected to a conventional light fitting. The other computer has a bulky unit attached to it, effectively a light receiver. It's by making the light flicker very rapidly that data is conveyed from one computer to the other. It's a bit like Morse code," explains the professor, "but in a very sophisticated way, achieving very high data rates".

Professor Harald Hass with his LiFi technology

And lo and behold, it works, with the second laptop streaming a video which buffers and halts once I block off the light completely. Impressive then, but I have several questions about the practicality of getting LiFi adopted in the real world,

The clunky receiver unit looks a long way from being a finished product. The team admits there is much to do in this area, but with enough investment they believe they can miniaturise this process so that it will be a 1-sq-cm device that can be fitted into any smartphone.

Start Quote

We have deployed so many wireless access points that they interfere with each other and slow down the actual data rates”

End Quote Professor Harald Haas

Even then, there is a more important question - why when wi-fi works so well, do we need an alternative means of connecting to the internet? Wi-fi is indeed a great success, says Professor Haas, so much so that the radio spectrum is getting overcrowded: "We have deployed so many wireless access points that they interfere with each other and slow down the actual data rates. We need other pipes, fatter pipes - and light is just such a big pipe for wireless connectivity."

He also maintains that there are security benefits - light-generated internet connections do not travel through walls, so can not be intercepted like a wi-fi signal. The professor looks forward to a future where the much-hyped "internet of things" becomes a reality, where "there's wireless connectivity everywhere, your fridge talks to your toaster - this provides the means to achieve that".

It is a beguiling vision - but a lot more work needs to be done before we all start flicking a light switch to get connected.

Rory Cellan-Jones Article written by Rory Cellan-Jones Rory Cellan-Jones Technology correspondent

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  • rate this

    Comment number 56.

    There's nowhere near enough information in this article, it barely tells us anything.

    It's time the BBC employed a decent technology correspondent. I once read that Rory was supposed to inform the general public on tech, not baffle them. A good reporter could explain complex tech to non techy people. Currently, you have to investigate every tech yourself after reading each article!

  • rate this

    Comment number 55.

    Why do BBC Technology correspondents always skim the surface of some "Bright new idea" ?

    A bit of research would have shown that:-
    a) This is not a new idea.
    b) It is energy wasteful.
    c) I has the potential to interfere with other technologies.
    d) It is unnecessary !

    BBC (and other technology reporters), do your B***** homework !

  • rate this

    Comment number 54.

    Re: 46. This does still exist, and works really, really well. Look up Powerline Networking. For very old buildings with thick walls which attenuate 2.4GHz, or running Ethernet to an outhouse (e.g. for a security camera) it's awesome. Just be careful with complex distribution boxes, or industrial power which might use different phases from a 3-phase main supply. :o)

  • rate this

    Comment number 53.

    "there's wireless connectivity everywhere, your fridge talks to your toaster - this provides the means to achieve that"

    Why on earth would I want my fridge to talk to my toaster? What the hell would they talk about? Maybe they would pass snide comments about the exploits of my cat behind my (and the cat's) back...... Silly idea....

  • rate this

    Comment number 52.

    Oh no, another way of interfering with radio reception. The data is sent to the lamp via the mains in the same way that the horrible PLT devices do, so we can expect the same level of disruption to our radio listening. PLT's already demolish shortwave and Amateur Radio for hundreds of yards around, and these things will do the same.


Comments 5 of 56


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