Study On The Uplink And Downlink Of Indoor Visible Light WLAN Based On White LED

In recent years, with the continuous improvement and development of thecommunication technology, people demand a higher quality of communication. Also,the rapid development of LED makes the indoor visible light communicationtechnology based on white LED gradually enter into people’s vision. Compared withthe ordinary incandescent lamps, LED lamps have some advantages of long servicelife, no pollution and energy saving, which are gradually replacing the incandescentlamps and becoming a new generation of light source. Besides, that LED has acharacteristic of high speed modulation because of nanosecond level of response timemakes LED become a base station of both lighting and communication.The key technologies of indoor visible light WLAN communication systembased on white LED are analyzed in this dissertation. Firstly, on the basis of researchon how the layout of light source of indoor visible light communication systeminfluences the performances of the system, and an optimal layout scheme of theindoor light source is provided. Then, research on the link ways of channel andestablish the models. The channel impulse response and the factors which may affectthe quality of communication are also analyzed. Performance analysis and simulationcomparisons are developed on the modulation methods which are suitable for theuplink and downlink of indoor visible light communication system. In thisdissertation, OOK is selected to achieve the uplink and downlink of the system.Visible light communication system based on Turbo code is proposed. Simulationresults show that visible light communication system based on Turbo code caneffectively reduce the bit error rate. Furthermore, indoor visible light WLAN basedon OCDMA and an improved indoor visible light WLAN are proposed, and thesimulation results show that all aspects of performance are improved, which makes itmeet the needs of users well.