Design And Application Research Of Interleaver About Turbo Code

Turbo code is a new class of error-correcting coding technique in communication transmitting system whose performances are close to Shannon limit. It is considered as the most exciting and potentially important development in coding theory in recent years.Its invention has changed the conventional design principles of the coding scheme from the attempt to increase the minimum Hamming distance of the code to the goal of reducing the number of code words with low Hamming weights. Since 1993, Turbo codes was proposed by C. Berrou etal, it has already become researching hotspot gradually in the coding information field with its interleaver is an aspect of researching field.We analysed the fundamental principle of turbo coding and decoding systemically and introduce iterative decoding algorithm, including Maximum a posteriori probabilities (MAP algorithm), MAX-LOG-MAP algorithm, LOG-MAP algorithm and SOVA algorithm, and making a comparison to complexities of these algorithm. Interleaver of Turbo coding is the point of our study .The class about basic interleavers has been analysed and each species has been introduced simply. Two changes have been proposed about original determinacy according to its property and design rules, along with analyzing functions and principles of interleaver deepgoing. First, keeping odd-even technique interleaver is proposed in order to increasing coding rate and equalization protection for informations. Second,carried the original interleaver on circularly-moving-interleave,through moving determining interleaver for increasing ecoding performance more.Then considered the top of two kinds of improvements synthesized to achieve odd-even moving interleaver.Through simulation experiments ,the conclusion is that the performances of iterative interleaver are not as same as expected after improving which are more favorable .We need do more research on it. Having an improvement of determinacy interleaver is under the circumstance that aims at short interleave, which can improve the functions of Turbo in the same condition. Moreover, this kind of interleaver can be actualized simply using hardware equipments and is valuable. We also made comparisons about simulation experiments of these interleavers and analyzed advantages or disadvantages of each one. While we can choose suitable interleaver according to the characteristics of different communication operation.]...