The Uep Based Turbo Codes Image Coding Transmission Technology

Since the Turbo codes put forward for the very first time in 1993, it has very quickly become the hot point that international information theory and coding theories field study. At the same time the joint source -channel coding relative to Turbo code also caused the people's very big interest. The excellence protection of Turbo codes that others can't compare to comes from the interleaver. This thesis investigates some problems of turbo codes with emphasis on unequaled error protection with the interleaver. The main contents cover the follows :1. In brief described the channel codes theories development process , then introduced encoding and decoding of turbo codes principle and the present condition research to the Turbo codes;2. Introduced the influence of the function upon the Turbo code of interleaver, the main type of interleaver, and particularly elaborated the design method of a combined interleaver, then compared its BER to another two kinds interleavers and discussed its merit and shortcoming.3. Introduced image compresses methods and especially introduced the code structure and the encoding theories of JPEG and MPEG4.4. Compared the different position importance after analyzed the structure of JPEG code. Then analyzed the BER of the bits in different position which used the turbo code contained with the combined interleaver. Put forward a new unequal protection (UEP) method in source-channel joint coding of JPEG and turbo codes ,at last analyzed the result of this method.5. Analyzed the different important parts of the MPEG4 code, then used the Turbo codes with three kinds of rates and iterations to combine with the mpeg4 and analyzed the shortcomings of this joint source-channel coding. At last put forward another kind of scheme of UEP using MPEG4 and Turbo codes.