Study On Key Techniques Of Visible Light Wireless Communication Based On LED

Home users are in great need for broadband communications access globally. Meanwhile, white LED lights with a high power output are expected to replace incandescent or fluorescent lights in the future and are considered to be the next generation lighting source. Furthermore they have wide modulation bandwidth which makes high speed communication possible.Visible light communication is a novel wireless optical communication technology and rose with development of white LED fabrication techniques. White LED devices are used not only for illuminating rooms but also for an optical wireless communication system which is suitable for indoor private networks.Basic concept and architecture of visible light communication utilizing white LEDs are introduced before key techniques of realizing it are investigated. Based studies were done on radiation spectrum, voltage to current character and modulation property of white LEDs when they are used as optical transmitters. Then the configuration and systematic design techniques are concentrated concerning white LED lighting source communication with numerical analyses and computer simulations done as well as high speed modulation techniques, visible light receiver design and means to alleviate inter symbol interference along with background noise problem.High modulation using white LED is done and a portable receiver is designed to receive and demodulate the optically transmitted information. An implemented system based on commercial white LED with experimental results is shown. The system employing line-of-sight link and intensity modulation with direct detection works well at 10MHz and will open up many new applications.