Study Of Wireless Laser Communication System Based On Turbo

With the rapid development of wireless laser communication, its application is being paid more and more attention. But in the atmosphere the laser transmission is effected seriously by the random channel. So in order to improve its comuunication performance,Turbo encoding technology is employed in the article.Firstly the development of atmosphere laser communication is introduced, the reseach and development of Turbo is reviewed. Atmospheric attenuation effect and atmospheric turbulence effects are analyzed because of their effects for the atmosphere laser communication. Atmospheric channel model is established through the analysis of strong light flashing. The basic theory of Turbo is described, the structure and composition especially for the interleaver of Turbo encoder is introduced. Several algorithms of Turbo decoding are researched and compared. Through the comparing the Log-MAP algorithm is more practical. The influence factors of Turbo code performance are analyzed, the scheme of Turbo coding and decoding is confirmed. Several modulations of atmosphere laser communication are also researched and compared, PPM modulation is adopted for its excellent performance. Turbo coding and PPM modulation are combined to improve the performance of atmosphere laser communication. Through the simulation of Matlab, Turbo code can greatly overcome the influence of random atmospheric channel in the PPM modulation circumstances. The communication performance of atmosphere laser communication are greatly improved in the weak turbulent channel by means of combination PPM modulation and Turbo coding. In the end, the application of Turbo code in the atmosphere laser communication system is forecasted and the further study goals is also definited.