Research And Design Of Compound Light Source For Visible Light Communication

In recent years, Visible light wireless communication has attracted much attention and being widely researched in China and abroad for its advantages, such as high transmitting power, no electromagnetic radiation, good security, less interference and less energy. White light wireless communication technology is based on Emitting Diode Light(LED), which has the characteristics of short response time and high modulation rate, so that it can realize the transmission of information through the high speed flicker signal that is imperceptible to the human eye. At present, the research of white light wireless communication, both in China and abroad, mostly focuses on electronic processing, while the study of signal light source is relatively weak that is not compatible with the progress of white light wireless communication technology. In white light wireless communication, the signal light source assume the tasks of both lighting and communication. Therefore, in the design process, it is not only to meet the requirements of lighting demand, such as color rendering, light efficiency, uniformity chrominance and brightness, but also meet the requirements of the communication light source for high speed communication, in order to achieve high quality lighting and communication.In order to improve white light wireless communication system performance, this paper studies and designs the white light wireless communication light source. First of all, through the investigation and analysis of white light wireless communication, we find out that it has a narrow bandwidth to modulate and a low energy efficiency. In response to the problems, we propose the scheme that using multi-color LED to mix white light wireless communication’s source. Multi-color white LED can increase the communication channels through WDM technology and improve the communication rate. In order to obtain high color rendering, high luminous efficiency and color temperature adjustable signal source, we adapt Genetic Algorithm to optimize three color and four color LED’s peak wavelength, and we achieve the best spectral combination about color rendering and luminous efficiency. In order to realize chrominance uniformity, we analyze the relationship among color difference, the vertical distance between LED and the target surface, the beam angle and LEDs’ distance. We present the best chrominance uniformity arrangement for three color and four color LEDs. At last, we establish the optical radiation model of circular arrangement and rectangular arrangement. By adjusting the angle between the LED center light beam and the optical axis of the system, the illumination uniformity of the target surface is achieved. We also give the relationship curves among the illumination height, the angel and the area of the uniform area. And it can provide some references for the design of white light wireless communication’s signal source.