Tokyo, Japan, October 5, 2004--If an idea being developed by the Visible Light Communications Consortium (VLCC) bears fruit, the short-range wireless IR and radio transmissions widely used as links and controls (such as in TV remotes) will be complemented by visible-light communication (VLC) emanating from lighting fixtures. The key: light-emitting-diode (LED) technology, which allows high-bandwidth modulation while at the same time serving its main purpose as white-light illumination.
The VLCC's technology will be unveiled at CEATEC Japan 2004 (Tokyo; October 5-9, 2004). CEATEC Japan is a large international exhibition for the information-technology and electronics sectors, including the fields of imaging, information, and communications, expected this year to draw 200,000 visitors and 700 exhibitors. Masao Nakagawa, president of the VLCC, and Shinichiro Haruyama, the organization's vice president, both of whom work in the Department of Information and Computer Science at Keio University (Tokyo), will describe the technology.
"I have spent many years researching mobile communications using radio waves," says Nakagawa. "This thinking led me to the possibility of adding data to visible light generated by equipment, including lights we use every day, traffic signals, and illuminated signs, and using the result for communication.."
Several years ago, members of the Institute of Electronics, Information and Communication Engineers (Tokyo) conducted basic research on this concept. At the same time, rapid advances were made in boosting the performance and expanding the applications of LEDs. The VLCC, with Nakagawa as head, came into being in November 2003 and now has a membership of 15 Japanese companies.
One application of VLC is in position detection. Locating someone with cellular telephones and car-navigation systems that use radio waves can be inaccurate, a drawback that becomes more pronounced when equipment is used in underground shopping malls or inside buildings.
A major advantage of VLC is that we can use the infrastructure around us without having to make any changes. For example, the transmission of positional information entered into individual indoor LED-lighting devices and sent to a cellular telephone or similar device enables position detection that is accurate to within several meters. Theoretically, precision is possible to within several millimeters, and it is at this level that the true power of visible light communications will be realized, such as in controlling robots. To give another example, all sorts of information can be sent to cars and pedestrians using LED traffic signals.
Visible-light communications can transmit large quantities of data. If the machines that send and receive data are placed a few centimeters apart, the visible light makes it obvious at a glance which pieces of equipment are communicating--doing away with other forms of verification that have been necessary up until now.
"Regardless of the extent of the business potential of visible-light communications, we won't know the direction product development will take until its applications become more clearly defined," says Haruyama. "Professor Nakagawa took up this topic in his address at CEATEC Japan last year. This year, however, there will be a number of actual systems on display. We are calling 2004 'Year One for Visible Light Communications,' and we are very keen to see this uniquely domestic technology find a worldwide audience."
Four exhibits showcase the possibilities of VLC
Thanks to the support of companies belonging to VLCC, there will be four exhibits at this year's CEATEC Japan showcasing the possibilities of VLC in easy-to-understand formats:
1. Light and sound collaboration
In this exhibit, supported by Keio University, Agilent Technologies Japan, Ltd., and Sony Corporation, musicians each play a different instrument under red, green, and blue lights. When visitors wearing headphones turn in the direction of one of these lights, they will be able to hear only the sound of the instrument receiving that particular colored light. By making the most of the visibility of this light, visitors will be able to instinctively choose the information they want to receive.
2. LED traffic-signal-communication system
This exhibit is supported by Nippon Signal Co., Ltd. and Nagoya Institute of Technology. The traffic signals we see everyday are gradually being replaced by LEDs. As shown in this exhibit, if VLC is applied in this area, it will be possible to send all sorts of information from traffic signals to cars and pedestrians waiting for lights to change. Visible-light communication is beginning to receive attention as a new communications medium for intelligent transport systems.
3. Illumination ID: receiving light via mobile terminals and light tags
This exhibit is supported by Keio University, NEC Corporation, and Matsushita Electric Works, Ltd. Visible light is used to send ID information from LEDs to mobile phones and other mobile terminals. Even in places such as in underground shopping malls, where radio waves cannot easily reach, extremely accurate position information and image and text data can be transmitted instantaneously. Though LEDs are commonly used to display whether a device is on or off, light tags go further, as they can send detailed information on a device from an LED to a mobile terminal.
4. Visible-light communications applied to cellular-telephone displays
This exhibit is supported by Cyber Solutions Laboratories, Nippon Telegraph, and Telephone Corporation. There is a form of communication, based on visible light with varying hues, that uses existing cellular-telephone displays. Simply holding the handset up to a large screen transmits the telephone's ID. Also, merely pointing the phone in the direction of desired information on-screen causes the relevant information to be downloaded onto the phone. One attraction of this technology is that it uses existing infrastructures.