| Turbo codes, which was proposed by French C.Berrou in ICC'93, is a parallel concatenation code by use of iterative decoding. The simulated result shows: if the size of random interleave in 65536, and iterative decoding repeats 18 times, when Eb / E0 ≥0.7dB and rate is 1/2, Bit error of the turbo codes is lower than 10? 5, nearly Shannon limits. The performance of turbo codes is so excellent that it has been paid attention to by mobile communication field. In the third generation mobile communication system, unreal time system has frequently used turbo codes. So turbo codes is considered the great technical result after TCM in channel theory and technology. In the dissertation, the principle of coding and decoding for turbo codes are introduced. Based on the simulation results, the key techniques for the design of turbo codes, including the design of component codes, the choice of interleave, the design of decoder, joint source-channel coding, unequal error protection, are discussed deeply. The dissertation falls into five chapters. The first chapter introduces wireless multi-media communication system, channel coding, etc. The second chapter, a few of fundamental theory and the structure of turbo encoder and decoder and described. According to this, some analyses for the performance of turbo codes are presented. In third chapter, firstly, the parameters include generator of component codes, frame , etc. The research for the key techniques of turbo codes is processed. Secondly, the design of interleave is described in the thesis. Several kinds of interleaves are studied, and their implementation methods are proposed. The influence of different interleaves on the performance of codes is developed. Finally, this dissertation analyses the turbo decoding algorithms from the aspects of performance and complexity, and draws a conclusion that Log-MAP algorithm has more applicable foreground. A new low complexity decoder structure is provided and a new type of turbo codes iterative...
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