Interpretation: how far is visible light communication from application?

The driver of the House hearing, lights, mobile phone will be able to have the power to call and the Internet, it sounds cool, but this advanced technology has been in the laboratory environment occurred. How long does it take for the average person to walk out of the lab? What will make a difference in our lives?

Dr. Shen Guobin at the Microsoft Research Institute in Asia is doing "visible light communications."". He first studied indoor positioning, and in 2012 began to study visible light communication, which is how indoor light sources determine people's position. Last year, his team won second place in the global indoor positioning game, IPSN.

How exactly does light transmit information?

As early as in 2004, IEEE magazine had a paper explaining how to provide a wireless network connection through a light-emitting diode (that is, a LED tube), and the specific principle is this:

LED light is originally a semiconductor chip, with the traditional filament is not the same, the chip can be particularly fast switch, such as the use of alternating current is 60 Hertz light, the human eye can not identify, flashing lights. At one turn, there is a square wave, which can be transmitted by modulation. It is the same as the radio communication of our usual telephone.

At present, many universities around the world have related research projects, most of them are carried out in the laboratory. In 2012, IEEE, a communications magazine, published a paper that allowed visible light transmission rates to reach 96Mbps.

By the end of 2013, can let the light a lamp power is 1W LED of the Fudan University in Shanghai led the lab, 4 computer under the light of the Internet, the highest rate of up to 3.25Gbps, the average net rate reached 150Mbps.

Microsoft Asia Research Group is also doing research in this area. The laboratory will try to light and the transmission rate of equipment at peak limit is not the same, want to study this possibility in conventional electronic devices, and his team at Taobao bought cheap LCD panel, a solar panel, a few dollars and you can test circuit board.

Now, Shen Guobin's team studied how to use a retro reflector (Retro-Reflector), a mirror that reflects the light path back to the LED light to form a communications between the LED and the electronic device.

They can already do so, at the light of 1 megabytes of switching frequency, from the light down to the device down to 10kb/s, and the device from the uplink speed up to 0.5kb/s.

In the Microsoft Asia Research and development center, we see this experiment with cheaper components made of: do not need to charge the line, there is no Wi-Fi signal, only one block with a LCD screen, mirror and solar panels similar mobile phone sized device. Light up the LED bulb, and the device lights up and begins to transmit data. LED lights become a common device energy source and information source.

Intelligent traffic sign and equipment without needing to be charged

Try to imagine, the lights of the roadside signs of such scenes, signs immediately to nearby vehicle navigator transmission Road, tell you arrive at the destination the most unobstructed road; the morning light, you can air detector will tell you that the outdoor air quality, temperature and humidity, and the tester display has been hanging in the bed, do not need to charge, also do not need to connect Wi-Fi or bluetooth.

Dr Shen Guobin says smart signs, devices that do not need recharging, may be the future of what they see as visible light communications. It sounds beautiful, but it's still at the theoretical stage.

"We first thought is to discuss and product department to see this is not possible in the big Microsoft product blueprint to go inside, whether we design, or our ideas, as long as they can accept, we will be very happy."

But to achieve these is not easy, the need to introduce good LED lighting, but also need to launch a reverse launcher of electronic products, while marketing. For a company, there are too many teams that need to cooperate with each other, from technology to products.

How far is the distance between the product and the research?

In 1880, a Canadian inventor Alexander Bell found an interesting play: change by adjusting the beam, transmission of voice signal, can both wireless dialogue - this is the first wireless telephone, is the use of visible light communication.

When Baer applied for the patent for this invention, even power did not appear, and he thought the "light phone" had no practical value.

In fact, no matter what scientific research projects, enterprises in a product to do, the product sector is still dominant. The product department has some problems to be solved, according to the development of technology is very fast and can be used on the products, and no related products, will be transformed into basic research products is very difficult.

In this case, the task is to research these cool technology through the paper or the internal Demo product departments to understand, hope they do product plans in the next will consider this technology." Shen Guobin says so.

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