The Performance Of Turbo-Decoder In Wireless Optical Communication System

Because of the enormous fading of the optical signal in wireless optical communication, the capacity of the error-correcting code must be well enough. Based on the complex of the atmospheric laser channel, we compare the well performance of turbo code which near Shannon limits to code the channel.This paper is mostly concern with the decoded part of the system. Nowadays the research of Turbo decodes focuses on the electric communication systems in design of decoding algorithm, the decoding construction and the iterative times. But it hasn't have the perfect theory to hold on in the laser communication field. In order to realize it in the apply in laser communication field, we propose a whole system in wireless optical communication of Turbo code, compared it with the uncode system and the convolutional code system. The final result shows the superiority of the Turbo code in optical communication system.The paper is divided into three parts. First,we introduce the background of the work,the character of the wireless optical communication and the principle of the Turbo codes, also we analysis the superiority of Turbo by theoretically, then we analysis the decoding algorithm especially the MAP,we modify the MAP formula, also the Log-MAP and Max-Log-MAP formula in order to use in optical channel. Last, we use the simulink in Matlab, in order to analysis the performance in different arithmetic and the interlaced length.So the finally result can show the basic principle and the method to choose the parameter.Until now, Turbo codes have become a hot point in...