China achieves wireless Internet access via lightbulbs

China achieves wireless Internet access via lightbulbs

Summary: Using technology dubbed Li-Fi, scientists have pulled off getting online four computers under a one-watt LED lightbulb, which could eventually be a more cost-effective alternative to Wi-Fi in the country.

TOPICS: Networking, China, Wi-Fi

Chinese scientists have made headway with successful experiments using Li-Fi technology, where wireless signals are sent by lightbulbs, according to Xinhua News.

chi nan fudan university
Professor Chi Nan, Fudan University. (credit: Fudan University)

Four computers under a one-watt LED lightbulb may connect to the Internet under the principle that light can be used as a carrier instead of traditional radio frequencies, said Chi Nan, an IT professor at Shanghai's Fudan University.

She explained a lightbulb with embedded microchips can produce data rates as fast as 150 Mbps, much higher than the average broadband connection in China.

Current wireless signal transmission equipment is expensive and low in efficiency, noted Chi in the article. "As for cell phones, millions of base stations have been established around the world to strengthen the signal but most of the energy is consumed on their cooling systems," she explained, but noted the energy utilization rate was only 5 percent."

However, Chi noted there was still a long way to go in making Li-Fi commercially successful. "If the light is blocked, then the signal will be cut off," she explained. The professor added the development of key related technologies were still in the experimental phase, such as light communication controls, microchip design and manufacturing.

The term Li-Fi was coined as early as 2011 by Harald Haas, a professor of engineering at Edinburgh University, with the name standing for "light-fidelity". The technology made use of LED bulbs that glow and darken faster than the human eye can see, and LED lights being semiconductors could be programmable.

Haas had suggested that the applications and capacity for data would be limitless, ranging from using car headlights to transmit data, or employing line of sight light sources as data transmitters.

Topics: Networking, China, Wi-Fi


Loves caption contests, leisurely strolls along supermarket aisles and watching How It's Made. Ryan has covered finance, politics, tech and sports for TV, radio and print. He is also co-author of best seller "Profit from the Panic". Ryan is an editor at ZDNet's Asia/Singapore office.

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  • it is not clear

    what is being acheived by changing the wave length to visible light, other than proving that it can be done. naturaly it can. one could use audio waves as well, so what.

    the article does not explain how the signal gets to the transmitter in the first place.

    as to the point Chi made about power efficiency, the wi-fi transmitter power consumption is so low, it is not clear why anyone cares.
    • Lets take a deeper look

      This is a great idea. Light travels very fast, is relatively direct, and has little to obfuscate it and corrupt data. You can also see when you're not in range, or when you're signal is being blocked by an object. Radio frequencies can be blocked by objects as well, keep in mind.

      Using sound makes very very very little sense. To put sound out of the auditory threshold would give no insight to whether or not you're receiving the signal, and would also require very expensive equipment to analyse this data, where as photodiodes/resistors are very cheap and can easily be integrated onto several surfaces on the devices exterior with ease and discretness. Ontop of all of that sound is easily obfuscated, any other sounds will harmonize with the signal, though this can use a DSP to refine input it would take alot of processing power.

      I think Li-Fi is a great idea, but I don't see it taking off. What I see happening is this technology will be used in homes and businesses as something similar to Bluetooth and possibly a creative new way to replace QR codes. Its really innovative, but it doesn't really fit the scenerio for wifi.
      Travis Sturzl
      • Seems You Have Some Common Sense!

        These others don't quite understand this whole concept. Whereas Ryan Huang and the highly esteemed Professor Chi Nan of Fudan University do understand it very well. It's not a matter of taking in the USA. Where an individual's energy usage is higher than any other population in the first place. It a mater of this being in China, where energy is so expensive for the average person, that they work very hard to conserve it.

        China right now is utilizing LED technology, faster than any other population in the World. Maybe that's because that's where it's all made, but even so the only way Americans use it or any other population is in LED flashlights. But there's the rub right there.... that's all it takes is every person with a LED Flashlight basically being able to put this technology to work all over the world.

        So to deny that it could take off in a very big way, not only in China the in the whole World at large belies your seeming cognizant of just what a breakthrough Professor Chi Nan has achieved by actually using the minute power of an LED light in harnessing a decent Wifi connection in such a way that anybody with a LED flashlight or LED in the device itself has the potential to get connected to the information age. No doubt that the Chinese will be the first to take full advantage of Li-Fi.... simply because they are willing to give a try. Since it's so very cost effective for even those with the means to get connected by any other means!

        Whereas Americans and most other people (except maybe in Africa too) in this World, simply don't have the need or desire to save money and will simply continue to pay the average $60 a month for fast internet access!!! ^_*
    • What???

      I think it best if you not respond to any articles. People migth think that you are...well, I must sign off now.
  • What if...

    ...I have CFLs only? What if I use incandescent lamps or candles? Can it be done too? Modulating the wick length so the flame can flicker with the data? Now, that'd be rad!
    Aristarco Palacios
    • They are using special light fixtures

      The fixtures are wired into both the power line and an ethernet connection to a router, so they are not only LED bulbs, they are SPECIAL LED bulbs.

      Think of it as "wireless fiber optic," which also uses light, except that a laser is not needed if you are not depending on the coherence and single wavelength of the beam to keep it in the fiber, just an LED.
  • Great news!

    I've seen a prototype on a year or more ago so I really believe in it.
    This will come with no radiation, almost impossible to hack from the neighbors and more advantages.
    • TED talk URL

      Big questions - 1) what is the backchannel - answer, none, unless you build an LED emitter dongle for your PC; and 2) how do you get the data to the lightbulb socket in the first place - the answer being you basically need a wired network anyway, so this only replaces the last few feet - might as well use wifi or bluetooth. It's ingenious tech for its own sake but I really don't see this having any practical advantages.
  • not sensible

    pretty sure that instead of using a lightbulb, a wifi hotspot transceiver could be adapted to fit in the light socket or wall electrical outlet. so i don't think this invention will do anyone any good.
    • Ummm what?

      I'm sorry but "sticking a transceiver into a light socket" is not a power viable solution. Power usage is determined by the device, not the socket. You clearly have no idea how electricity works.
      Wes King
  • Utilizing?

    Hum, I miss the memo that must have read, "we will now utilize utilize rather than utilize use.
  • Them 75 sent words:

    Yeah, some of us don't make enough money to use them expensive words, but you college edumicated types seem to like to throw them around, just to show off.

    Word of advice: on the Internet, as in those Grand Newspapers of Old, it is usually best to try to stick to a writing style deliberately scaled to the 4th grade level. That way, peoples like Bubba and me will better be able to follow your article without feeling the need to point out that we think you are sounding pretentious.

    Calimore Callierionde
  • Half of the story

    Li-Fi sounds fascinating but there is a lot of information missing about the technology. How does the reverse channel work (from the user back to the Internet)? What makes light better? Is it cheaper somehow or better for long distance? Can it work outdoors in daylight or is it only for indoor use? Lets give the Chinese a chance with this technology since additional means to connect to the Internet are always welcome. For now I suspect a lot has been lost in translation.
  • many people look down the idea just because they see "China"

    Many people don't accept the idea just because they read "China" in the article!
    hey guys, not happy to see "China"? hmmm..what about get use to it?
    • Great idea

      1. under sea water, the whole water zone would be conductors. Electromagnetic wave would have a hard time to travel in them.
      2. Would be great to set a central light emitter on a public table and provide physically static connection to nearby laptops. This hopefully would allow more than 1TB/s fiber level connectivity in the future.
      3. Any router @ 2.4GHz practically is burning hot when you touch with hand. This perhaps is the logical next step up when we are demanding TB connectivity.
      4. Still a long way to go to TB, but if fiber can do it, don't see why a LED can't do it.
      Grant Li
  • Fiber-optic without the fiber.

    Just as WiFi is a network without the cable, LiFi uses high-speed LEDs driven by high-frequency electronics, but without the fiber-optic cable. And like WiFi, it must add data complexity in the form of addressing and crypto to serve more than one client machine.
    It would be easy enough to modify a common WiFi router to drive an LED instead of modulate a radio signal. Does Fudan University's system use the electrical wiring as a signal carrier? That would be revolutionary, bypassing my DSL coming into my modem/router. But how to maintain data integrity and security, and, as so many others have asked above, how to talk back to it?
    Laptops and printers with IR communications used to be fairly common. I suppose they were used because networks were so expensive and RS-232C serial was such a nightmare to set up. The simplicity (for us users, anyway) of USB connections probably killed IR, along with the fact that it's so easy to lose a light connection with a stray sheet of paper.
    A 1-watt LED is very bright. Not the brightest on the market, but much brighter than any of the cheap LED flashlights for sale next to the checkout stand. It will require a heatsink, and with its associated driver circuitry will still draw a fair amount of current.
    The fact that I don't see much of an advantage to LiFi may reflect more on my feeble imagination than on the technology.
  • Oceanography and (naturally) submarine warfare would benefit

    Assuming you use blue or UV LED's rather than white, I could imagine an underwater data sensor, or "squid-cam" perhaps, using the LED link to a network of repeater buoys on the surface which would connect to satellites. As a sidebar item above mentioned, the technology could allow divers (with helmets) to communicate, much as radio connects astronauts in spacesuits.

    And of course, the military would be interested in this also. Submarines could communicate with their home bases through internet repeater buoys (and encrypted data, of course), but on the other hand, destroyers could find submarines via passive "viewing" for LED flashes (a lot harder after the civilians flood the oceans with science probes, which is for once a good MILITARY argument for funding civilian research).

    At the end of a military conflict, however, harbor mines with light receivers could be commanded en masse, by a highly encrypted signal, to disarm themselves and drop their anchor chains, so they could be safely recovered at the surface. By planning this when the mines are MADE, there will be less chance of legacy mines sinking ships in peacetime when the war is over (or when sanctions are lifted, if the mines are used for that purpose). And why not something similar for land mines, too; called the Diana Protocol perhaps?