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Author Topic: ITU Standard Could Make Fast Home VLC Visible Light Networks a Reality  (Read 972 times)

Bowdon

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https://www.ispreview.co.uk/index.php/2019/01/itu-standard-could-make-fast-home-vlc-visible-light-networks-a-reality.html

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The International Telecommunication Union is close to giving its final approval to a new standard (G.9991 / G.vlc), which could finally help to turn secure high-speed indoor Visible Light Communication (VLC / LiFi) networks into something that you can buy instead of WiFi.

At the root of this all is a simple idea that has taken years to develop, which involves turning a Light-Emitting Diode (LED) based home or office light bulb into a sophisticated wireless data network (like infrared). This is achieved by turning the bulb(s) on and off many times a second and by altering the length of these “flickers“, as well as other properties of the light, you can introduce digital communications (e.g. Morse Code with a torch but way more sophisticated).

The process itself happens so fast that it is imperceivable to a normal human eye, which means that the bulb will appear to work just like a regular one. The obvious difference being that with VLC (or Light Fidelity [Li-Fi] as it’s sometimes known) you’re now transmitting data using room lighting, or possibly other devices that emit light using LEDs (computer screens, desk lamps etc.).

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    Marcos Martinez, ITU Associate Rapporteur, said:

    “Security, no interference and spectrum saving are very attractive features of VLC. VLC and WiFi have different strengths, and VLC’s strengths provide a strong complement where WiFi faces challenges. Crowded spectrum is creating real problems in the deployment of WiFi and VLC can alleviate some of [that].”

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At the experimental level we’ve previously seen data rates reach as high as 224Gbps (Gigabits per second) under lab conditions, albeit usually over very short distances (a handful of metres) and across a limited field of view. Since then various proprietary VLC solutions have been developed, but these are expensive and you’re more likely to get speeds of around 40Mbps to 250Mbps (depending upon the setup and number of bulbs etc.).

The problem with proprietary standards is that you don’t encourage a proper ecosystem to develop and grow, which is why today you can search Amazon for VLC and LiFi adapters until your eyes melt but you’ll still come up empty. Even those that do sell such kit tend to aim it more toward bespoke office installations than the mainstream market. Thankfully the ITU may be about to change all that.

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    Marcos Martinez added:

    “Standards are really the only way for these different worlds to speak to one another and collaborate successfully in stimulating the growth of the VLC market. We have seen a variety of proprietary VLC solutions, but without standards it has been impossible to create an ecosystem.”
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sevenlayermuddle

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Re: ITU Standard Could Make Fast Home VLC Visible Light Networks a Reality
« Reply #1 on: January 22, 2019, 04:15:39 PM »

Hmm, a few thoughts, regarding “turning the bulb on an off many times a second”.  I’m not surprised it works, why should it not?   But...

First, I believe led controllers often already modulate on/off at a rapid rate, using a pulse width modulated signal to control brightness.  That is energy efficient and also maintains a more consistent colour, compared to simply reducing the current through the device.  Maintaining PWM to control brightness, alongside some other modulation to effect data tx might be tricky.

Second, some led installations may have no “slack”, being expected to provide the full 100% intensity that the source can provide.   As soon as you start modulating the signal you will introduce periods of darkness interspersed with light.  That can be made to happen very fast, so the human eye does not notice flicker, but it must reduce overall intensity, which might well be an issue.

Just my thoughts. :)
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niemand

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Re: ITU Standard Could Make Fast Home VLC Visible Light Networks a Reality
« Reply #2 on: January 22, 2019, 04:31:49 PM »

I'd rather shove an antenna up my hindmost than use this. Line of sight so just use higher frequency RF? :wall:
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