Fundamental analysis for visible-light communication system using LED lights
White LEDs were invented the 1990’s. The white LED has lower power consumption, lower voltage requirements, longer lifetime, smaller size, faster response, and cooler operation. We have proposed an indoor visible light wireless communication system that utilizes multiple white LED lighting equipment. In this system, the equipment is used not only for illuminating rooms but also for an optical wireless communication system. It functions as the main lighting equipment. One problem is we tend to install many lighting sources on a ceiling in order to illuminate the room as evenly as possible. While the number of sources permits site diversity transmission over LOS links, the optical path difference between the multiple sources triggers inter symbol interference (ISI), which significantly degrades system performance. This paper overcomes the ISI problem by proposing an adaptive equalization system. The adaptive equalization system with the effectual interval alleviates the influence of shadowing.