Innovative ideas of LED lighting for visible light communication

Along with the society to the development of high power solid state lighting based on LED, a bold innovative ideas appear in some far sighted engineers in mind. Their advice is: why not let the LED pass / break fast enough so that the human eye is unable to distinguish and use them to transmit data?

This is the theoretical basis of visible light communication (VLC). In support of advanced technology, a new LED lamp can also access to wired backbone network, wireless communication equipment to achieve any indoor omnipresent, and does not increase the burden on the already crowded radio frequency bandwidth. Many industry standards organizations and government agencies that have been heavily funded are developing visible light communications. The prospect of the visible light communication is very broad, because the traditional lighting market amounts to trillions of dollars, and the transformation to the solid state lighting has already begun. According to Strategies Unlimited predicted, LED lighting market will exceed $1 billion this year, 2014 is expected to increase to about $7 billion 300 million.

Of course, the focus of solid-state lighting is to reduce greenhouse gas emissions, because the power consumption of LED lamps is much lower than the current standard lighting products. But the huge market has stimulated the development of almost every major electronic research organization into visible light communications applications.

Most of the visible light communication application and not to replace other wireless technologies such as Bluetooth, Wi-Fi, WiMax and LTE, the application of RF wireless communication goal is currently unable to implement the applications, such as hospitals and aircraft applications, this situation may RF signal interference life-saving equipment; the robot -- they can use virtual landmarks the headlights for navigation so as to realize the information transmission; signs -- when the mobile phone camera pointing to it can provide additional information.

Japan's visible light Communications Alliance members include CASIO, NEC, Samsung, Matsushita Electric Engineering, SHARP, Toshiba and NTT Docomo and other telecom operators, the alliance is committed to add ".7" to promote the work of IEEE 802.15 wireless personal area network standards committee, in order to enhance the visible light communication with the same frequency and infrared wireless status. The 802.15.7 Committee has just approved the draft version of the wireless VLC standard at the working group level, "but we still have a lot of problems to solve. "IntEL IEEE 802.15.7 laboratory scientists, technology editor Rick Roberts pointed out that committee.

"The reason why IEEE is interested is the widespread adoption of LED. The current LED technology is mainly used for lighting, but if the wireless market has also been developed from the past experience we know the need for interoperability standardization. "Roberts said," our standardization work began in 2008 and is expected to be completed next year. "

According to Roberts, the 801.15.7 Committee's first task is to implement the first lighting, communications second standards. Visible light communication is the only kind of wireless communication that can be seen with the naked eye. He pointed out that, for example, visible light communication is not suitable for remote control, because people usually watch TV in a dark room. You don't want to see the remote control flashing light? Communication with the LED will not cause light flashes, and visible light communications must be adapted to the way people usually use lighting sources, such as light adjustment. "

Figure 1: just as the brake light tells the driver to stop, VLC can send the same message to the engine control unit to avoid collision.

VLC opens up space for creative applications

Visible light communication is expected to form a series of new applications, although with Wi-Fi or infrared can be achieved, but through the visible light will be more convenient or more secure. For example, the use of mutual interference between adjacent RF signals may limit Wi-Fi, and basically no visible light interference problems; adjacent beams can cross through, as long as their destination can be different. For security reasons, some places prohibit the use of radio communications, such as hospitals and aircraft. Visible light communication is an ideal alternative in these situations, because LED lighting has long been in use, and the visible light communication does not interfere with the signal transmission of important tasks. At the same time, visible light communication also has the potential of high data capacity.

Visible light communication can realize the new application of various types, "Roberts said," I especially love is intelligent LED signs, it can display the 'Joe restaurant', but if you come up with a mobile device and pointing to the sign, you can also download more information -- for example, the address of a restaurant menu even coupons. You have to develop your imagination, and there are a lot of new possibilities. "

Samsung Corp is based on visible light communication test using backlight LCD flat panel display LED, so that users can download information from all the product information to the website address. "We believe that LCD backlight communication is one of the best applications of visible light communication, because the LCD backlight is turning to the use of LED. "Vice president of Samsung Corp LCD business Scott Birnbaum said. Just as IEEE started his own standardized efforts in 2008, the National Science Foundation also took a fancy to the "Dao Guang" and added the VLC research program in its smart lighting Engineering Research Center (ERC) program.

Smart lighting ERC is a $18 million 500 thousand investment in, involving more than 30 colleges and universities, including Rensselaer Polytechnic Institute (RPI), Boston University and University of New Mexico. "As the whole society is developing towards solid state lighting, we