The United States is committed to the development of wireless communications with LED intelligent lighting

Sponsored by the U.S. government, a "lighting" (SMART) program, trying to wireless communications capabilities embedded in the future of LED lighting devices, in order to provide a wider access point (access point). The investment of $185 million, for a period of 10 years, the U.S. National Science Foundation (NSF), researchers have more than 30 universities involved, including the Boston University (Boston University), New York Rensselaer Polytechnic Institute (RenssELaer Polytechnic Institute), and the University of New Mexico in the United States New Mexico (Albuquerque University of New Mexico). This project attempts to use visible light beam (visible light beams), to achieve communication between wireless devices and LED lighting equipment.

This LED based architecture can also be used for an increasing number of LED automotive communications. The overall goal is to build communication capabilities in all LED lights, while reducing the current RF band congestion. The development of infrared communication technology has a long history, the infrared data association (IrDA) in many years ago as PDA, printer and notebook computers and other equipment to develop the communication protocol; "Boston University professor Thomas Little said:" what we are doing is to grasp this opportunity, let a LED lighting networking function the train, along with the revolution the incandescent light bulb and fluorescent lamp was gradually replaced, we hope to networking technology embedded in LED lighting. "

Boston University professor Thomas Little handheld built in visible light transceiver LED lamp prototype

An optical communication function currently using infrared LED, like a remote control, will be suitable for the visible light, so that the digital device transceiver communicates with the lighting equipment; lighting equipment will connect to the Internet via a physical line. With the user must share bandwidth, based on the Wi-Fi RF access point is different, this line of sight (line-of-sight) communication through visible light is expected to make different data streams are sent to each device. The experiments have been carried out on different modulation schemes, including the use of standard binary coding, non return to zero encoder, pulse code modulation and pulse width modulation of various encoders. They said that these programs as long as the transmission rate is higher than 900 KHz, each of which can not work in the case of light flashes. The prototype, which will be shown next year, will be 1~10Mbps per second, and it will use the ready to use LED and photodiodes to handle the transmit and receive functions.

The researchers also plan to develop new semiconductor technologies that can produce visible light transceivers. The system we have developed is usually need a receiver using a photodiode; one idea is used with a reverse bias (reverse bias) LED, through the process technology, the LED part of a receiver, and the other part is made of the transmitter. "Little representation. The team will also use a variety of optical wavelengths to test, in order to use the white light of different colors, the number of data streams encoded. Optical polarization (light polarization) will also be the focus of the use of visible light for multi task communication strategy. In this program, the Boston University will focus on research and development of system level technology, including the development of the computer network application; semiconductor component development is responsible by the Rensselaer Polytechnic Institute and the University of New Mexico researchers.