In an earlier post I wrote about data transmission by light in the home.
But this development gives the story a new twist: Using not only the lights in buildings but also outside light sources to transmit data wirelessly.
The data hunger of our mobile devices is ever increasing and as more and more data and applications will be in the cloud we are increasingly depending on high data transmission rates. Click on the informative infograph on the left (published on MobileFuture).
But the frequencies in the electromagnetic spectrum are becoming more and more congested. You can notice this yourself when a major event happens and cell phones cannot find a network connection any longer.
The regulation bodies will certainly assign new frequencies especially from the bands that were used by analogue TV so far.
But using light rather than radio signals can open a huge frequency band, which will give us a lot of room and capacity.
“Fortuntunately the Li-Fi community is not suffering a spectrum crisis, quite the opposite. The question is, can we fully capitalise on the radio spectrum pain?”
“Think about it: around the world, there are millions of street lamps, in every city and town on every continent. One visionary has a proposal to put each and every one of these lamps to work for a new purpose beyond illuminating the street below. They could serve as wireless Internet access points, communicating to devices, as well as vehicles.”
Smartplanet explained further:
The system, which he’s calling D-Light, uses a mathematical trick called OFDM (orthogonal frequency division multiplexing), which allows it to vary the intensity of the LED’s output at a very fast rate, invisible to the human eye.
For the eye, the bulb would simply be on and providing light. The signal can be picked up by simple receivers. As of now, Haas is reporting data rates of up to 10 MBit/s per second (faster than a typical broadband connection), and 100 MBit/s by the end of this year and possibly up to 1 GB in the future.
There’s plenty of capacity, he says: “We have 10,000 times more spectrum, 10,000 times more LEDs installed already in the infrastructure. You would agree with me, hopefully, there’s no issue of capacity anymore.” The added bonus, he adds, is that the infrastructure is free, and even would promote more rapid adoption of more energy-efficient LED bulbs. “It should be so cheap that it’s everywhere,” Haas says. “Using the visible light spectrum, which comes for free, you can piggy-back existing wireless services on the back of lighting equipment.”
Plus, there would be wireless access points anywhere there is a light source. Even smartphones, with their LED displays, could serve as data sources. Consider all the possibilities, Haas elaborates:
“…In hospitals, for new medical instruments; in streets for traffic control. Cars have LED-based headlights, LED-based back lights, and cars can communicate with each other and prevent accidents in the way that they exchange information. Traffic lights can communicate to the car and so on. And then you have these millions of street lamps deployed around the world. And every street lamp would be a free access point.”
Security is another benefit, he points out, since light doesn’t penetrate through walls.
When will our phones start to have a light sensors for communication additional to the antenna?
Since it is usually dark in your pocket or bag radio frequency communication will continue to be used.
But for the data intensive transactions we might look for a street light from now on.
If we could only find a way to modulate sunlight…
- Wireless data may eventually be delivered by LED light (zdnet.com)
- Li-Fi (wired.com)
- wi-fi from LED lights? (mobile-ent.biz)
- Meet Li-Fi, The LED-Based Alternative To Household Wi-Fi | Michael Watts | Wired UK | 31 January 2012 (wired.co.uk)
- Carriers Warn of Crisis in Mobile Spectrum (InnovationToronto.com)
- GPS and the Politics of Scarce Resources (nationalinterest.org)
- New rules expand the universe of unlicensed spectrum (gigaom.com)
- New research could mean cellphones that can see through walls (talesfromthelou.wordpress.com)