The Research Of Turbo Code

This thesis is concerned with some Extrinsic Information Exchange Iterative Process based on channel coding methods. Some very important simulation results and conclusions are presented in the thesis, which will be useful for the implementation of these methods in communication system.In the first part of this thesis, the Iterative Process structure which is based on the Extrinsic Information Exchange between the SISO (Soft In Soft Out) Component Decoders of PCCC (Parallel Concatenated Convolutional Codes) is discussed. Two ways of complexity reduced decoding algorithms (Log-MAP and SOVA) are developed and simulated. After that, due to its application of PCCC in the third generation Mobile Communication System, the performance of PCCC in fading channel is considered.Turbo code is regarded as the milestone in channel encoding theory history for its performance closing to Shannon limit, which makes us covert to decrease the numbers of light weight code (error coefficient) from increasing the minimum Hanming weigh. The research and analysis are concentrated on the following:1. Introduce the development of channel coding theory and technique, and discuss the development and use of Turbo code in Chapter 1;2. Discourse upon the theory of iterative decoding about Turbo code, and give the decoding algorithm over AWGN channel, in Chapter 2;3. Give the iterative theory and simulate its performance over AWGN channel in Chapter 3;4. Research and analyze Turbo decoding algorithm corresponding to the characters of Rayleigh channel as well as simulating its performance when using in 3G in Chapter 4;5. Compare Turbo code with LDPC code after analyzing LDPC code in Chapter 5.As an optional code of 3G, the research of Turbo code is significant.Its performance over Rayleigh channel is just to solve the practical problem.