Study On The Duplex System Of Optical Wireless Communication Based On LED

Expected to serve in the next generation of lamps, LED offers advantageous properties such as high brightness, reliability, lower power consumption and long lifetime. The LED lighting system ,based on the fast switching of light emitting diodes and the modulation of the visible-light waves for the free space communication, is capable of the signal transmission. Compared with the traditional infrared and radio communication system, LED visible light communication system has high transmission power, no electro-magnetic interference, no need for spectrum resources and indoor no data leakage, and other advantages. Therefore, LED visible light communications system processes greater significance and development prospects, and it has also become an emerging transmission scheme for short-range and high-data-rate wireless communication. In this paper, firstly, we investigate a typical LED indoor visible-light channel model, based this, we discussed OOK,PPM,MPPM modulate, and we also discussed the course of multi-path effects, and the analysis of the system shows this OFDM modulation signal have the ability in suppression of multi-path effects. In this paper, we also investigate several dual-communication system based on the white LED character, we compared these systems, and find that receiver-emitter-apart system have highest SNR. We also discussed white LED elements, drivers and PIN character, then designed the hardware of the visible-light communication system.(1) Discussed the LED communication uplink and downlink. Based of set up of the system model, analyzed the LED communication radiation, uplink and downlink in room, then discussed the duplex links.(2) Discussed the LED communication path. Such about multi-path effects, background light disturb and module character. Based these, then use OFDM to suppression the multi-path effects.(3) Designed the duplex communication system based LED in room. Study the duplex communication system now exists. Then found these systems can not used in our system. We designed some new kinds of duplex communication system that can be used in LED communication system in room. (4) Designed LED wireless communication electronic system. We designed the LED wireless communication transmitter and receiver, then bound them together.