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An artistic rendering of the new light-driven wireless network in action.  (Source: Boston University)
Could the networks of the future run on light

Solid-state lighting is one of the hottest topics in the tech industry, and with good reason.  The Department of Energy is sponsoring a $20M USD "L Prize" for advances in LED lighting, a type of light which uses solid-state components (diodes).  The research is a big deal as lighting currently consumes 22 percent of the electricity in the U.S.  If the DOE accomplishes its goals of reducing lighting energy use by 50 percent, it would save billions of dollars and reduce environmental impact.

New research from Boston University's College of Engineering, funded by a National Science Foundation grant, indicates that LEDs may be not only the integral lighting component of the future, but may also form the backbone of future wireless networks.

BU Engineering Professor Thomas Little describes the new research, stating, "Imagine if your computer, iPhone, TV, radio and thermostat could all communicate with you when you walked in a room just by flipping the wall light switch and without the usual cluster of wires.  This could be done with an LED-based communications network that also provides light - all over existing power lines with low power consumption, high reliability and no electromagnetic interference. Ultimately, the system is expected to be applicable from existing illumination devices, like swapping light bulbs for LEDs."

The primary goal of the research is to develop LEDs that do exactly that -- transmit information wirelessly via controlled blinking. 

Little continues, "This is a unique opportunity to create a transcendent technology that not only enables energy efficient lighting, but also creates the next generation of secure wireless communications.  As we switch from incandescent and compact florescent lighting to LEDs in the coming years, we can simultaneously build a faster and more secure communications infrastructure at a modest cost along with new and unexpected applications."

Professor Little and his colleagues imagine LED lighting in the room being hooked up to computer circuitry, which uses existing lighting to implement a wireless network which provides data to computers, personal digital assistants, television and radio reception, telephone connections and thermostat temperature control.  Prototypes of the new network design, according to Professor Little, should start at around 1 to 10 Mbps.  Better yet, bandwidth would be greater than in existing radio frequency (RF)-driven networks.

In the new network, each LED light bulb would act as an access point.  Another perk of the new design is beefed up security.  Unlike RF networks, the new signal would not pass through walls or other opaque objects.  This would help prevent snooping and connection theft.  The new system would also use much less power than RF, as solid state lighting is energetically cheaper to the strong radio signals needed for wireless internet. 

The flickering which drove the network would be performed so fast the human eye could not see it.  The network would ideally be able to operate outdoors as well as indoors.  The first test deployment may be outdoors, with a likely candidate being car interiors.  Professor Little continues, "This technology has many implications for automobile safety.  Brake lights already use LEDs, so it's not a stretch to outfit an automobile with a sensor that detects the brake lights of the car in front of it and either alerts an inattentive driver or actively slows the car."

While the technology seems very promising, one quandary is how to make the communication bidirectional.  Professor Little and his team have not elaborate on this tricky point yet in the initial press.  In order to send data requests, you would need a means of receiving light from devices such as cell phones or laptops, however, you ideally would want to avoid having to have a bright blinking transmitter on your device walls covered in sensors. 

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RE: Another problem
By Googer on 10/7/2008 11:03:39 PM , Rating: 2
Blinking won't be a problem. Here's an example:

Your CRT TV or computer monitor "blinks" at least 30 or 60 times per second and you never notice it. The data transmitted from the lights, will blink at millions of times per second to transmit data at 10mb/s. It's so fast that no living creature should be ever notice it.

I'd also like to add that similar technology was demonstrated near the mid 1990's for the retail industry. Except they decided to modify and use the existing incandescent lights or fluorescent tubes. If memory serves correctly, IBM and a few universities had their hands on the project.

RE: Another problem
By HavocX on 10/8/2008 7:19:21 AM , Rating: 2
Lots of people notice 60 Hz flickering, and it drives me crazy. I've read that most people stops being able to notice flickering at around 75 Hz.

RE: Another problem
By MrPoletski on 10/8/2008 1:16:56 PM , Rating: 2
That's because the flickering of a CRT is a little more complex than that. It is *drawn* 60 times per second and the phosphor has a decay time after the electron beam has stopped energising it (converting it to light).

What also flickers at 50hz or 60 in the Us, is strip lights. They flicker at mains frequency and you can only just see it if you look at them right out of the corner of your eye (because your eye has better colour perception in the main vision and better contrast perception in the peripheral).

This light will not be interfered with by daylight per say, because the LED will give out a particular wavelength, so any detector will be able to filter out everything else leaving the signal.

What is going to be an issue with it is signal interference due to reflections. with your light sensor pointing in the wrong direction, it could pick up multiple diffuse reflections from all directions. The issue is them combining with a large difference in path length and the light interfering deconstructively. 10Mbits would mean the path difference need be less than 30m, doable. 100Mbit less than 3m, difficult.

RE: Another problem
By Myg on 10/8/2008 11:33:46 AM , Rating: 2
"Your CRT TV or computer monitor "blinks" at least 30 or 60 times per second and you never notice it. The data transmitted from the lights, will blink at millions of times per second to transmit data at 10mb/s. It's so fast that no living creature should be ever notice it."

Unless of course; they plays FPS games.

RE: Another problem
By aguilpa1 on 10/9/2008 7:05:49 PM , Rating: 1
As I recall a CRT flickering a 60Hz was horrible and only good CRT's that could hit 75Hz or higher at high resolution where worth having. I can't imagine being bathed in a room full of lights flickering at 60Hz..., heck NO! If they are not 75Hz or higher, there is no way I would ever buy into that.

"Can anyone tell me what MobileMe is supposed to do?... So why the f*** doesn't it do that?" -- Steve Jobs

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