Must include strong encryption
Any standard(s) developed from here on better mandate strong encryption - with no backdoors. Otherwise it's unfit for purpose.
Estonian vendor sparks Li-Fi hypegasm with gigabit demo
We've talked about Li-Fi – using modulated LEDs as data channels – before at The Register, but last week's announcements warrant revisiting the idea. Photons make good communications channels: that's why the Internet's fattest pipes are optical fibre. Even the idea of using ambient light carry data has been around for nearly …
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Monday 30th November 2015 04:05 GMT Charles Manning
Process gain
" the Chinese experiments at the Shanghai Institute of Technical Physics in 2013 also demonstrated that the LEDs can be dimmed to near-darkness and still communicate."
They likely get that from using "process gain" somewhat similar to how GPS signals are modulated.
If you transmit with a specific pattern and oversample using the same pattern you can still extract info at really low levels, but of course that nobbles throughput somewhat.
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Monday 30th November 2015 08:00 GMT Richard 12
Where's the back channel and back haul?
Sure the lamp in the ceiling can transmit 1Gb/s.
But my device has to get data back to it. It can't be that bright and line-of-sight implies directionality.
Aside from that, the lamp needs to get the data in the first place.
Powerline would get forcibly killed due to the RF interference it creates if it ever became genuinely popular, while wifi is better sent directly to the end device.
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Monday 30th November 2015 09:08 GMT Bob H
Re: Where's the back channel and back haul?
Backhaul via WiFi is my feeling, this can really be just a secondary re-enforcement channel for high bandwidth downlink (given that in most cases user's traffic is async). As for the connection to the lightbulb? I am thinking GbE or 2.5GbE with 802.3at Type 2 PoE is the answer, you'll get 25W per bulb which should be sufficient for each fixture of an LED bulb system.
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Monday 30th November 2015 23:31 GMT Richard 12
Re: Where's the back channel and back haul?
Very funny.
Nobody is going to run Cat6 to their existing light fittings, and PoE is the wrong solution to the wrong problem. Even assuming they actually use copper and not CCA, the cable and switch PSU losses are ridiculously high. Might even burn down the building.
Yes there is a company trying to push PoE for powering and controlling light fittings, fortunately almost nobody is that stupid.
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Monday 30th November 2015 09:45 GMT Andy E
Headaches anyone?
Presumably the traffic is undetectable by the human eye which perceives a continuous level of light with no flicker. However, once the Luddites get wind of this there are going to be people who develop headaches and claim they can't work in buildings that use the technology. It happened with WiFi. Whats the optical equivalent to a tin foil hat?
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Monday 30th November 2015 21:24 GMT keep-it-calm-or-more
Re: Headaches anyone?
I get very annoyed by lights blinking at 50-60hz, i can see it and it irritates my eyes. Most people around me don't see nor feel it. But the tech here is talking about gigahertz scale. Definitely there's nobody around who could feel that. Besides, the leds that you have around already blink at high frequency (the dc adapters and dc-dc converters are good but far from perfect).
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Monday 30th November 2015 20:39 GMT Swarthy
Lemme see if I have this....
You have light bulbs broadcasting data to receiving devices in a room, the devices cannot leave the room, or else they'll be listening to (watching?) a different light bulb; but, this limitation is also a benefit, because the lights in room A will not permeate to room B and cause interference. So you have (semi-?)static placement for devices to receive a data signal... why not use cables then?
The main use I could see for this would be to replace Bluetooth in stores/other indoor locations to broadcast
alertsMarketing guff.I mean, you could encode the modulation of the light to address specific devices, and have devices return signal via a LED mounted with a clear line of sight to the lights above...But then everybody would be walking about with a (LED circuit) chip on their shoulder.
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Tuesday 1st December 2015 01:11 GMT Steve Evans
Re: Lemme see if I have this....
If all the bulbs are on the same data network, they could hand over as you move from room to room... Basically your device replies via whichever back-haul method they pick (WiFi, IR LED pointing up towards the lamp etc) with the ID of the bulb it can see (ID being constantly broadcast from all enabled light sources), and tada, your data stream is switched across to that source bulb instead.
So you can walk about consuming your stream of data, and as a secondary effect (which I'm sure will be quickly exploited in frightening ways) the location of your device can be tracked. Could be useful in a shopping centre to direct lost and bemused males to the nearest sanctuary (bar).
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Biting the hand that feeds IT
