Research And Simulation Of Ldpc Code In Atmosphere Communication System

Free Space optical (FSO) refers to the technology of transmitting voice, data and graphics using laser bean.It has the respect advantages of optical communication and wireless communication. Free Spaceoptical shows a great expectation. All of the main counties in the world ateresearching expressly on it, hoping to climb to the summit of free spaceoptical technology.The channel of freespace optical is the free space. So in laser communication channel, because of being affected by many factors such as fog,rain, snow and atmosphere on flow, the signal's pulse is widen, the S/N is fall and the error codes increases rapidly.This is a very serious problem to the telecommunication quality. It is very import to research and develop the coding and modification technology of high speed,which has the main task of FSO.That is what done in this article. The thesis researches the performance and capacity of PPM channel of FSO; suggests the application means of the binary LDPC; suggests the combination method and application means of the Q-ary LDPC to the Q-ary PPM channel.