LDPC码不同译码策略的对比研究.docVIP

摘 要 PAGE \* ROMAN PAGE \* ROMAN II 摘 要 在迭代译码条件下，低密度奇偶校验(LDPC)码是一类性能接近容量限的线性分组码。与Turbo码相比，LDPC码虽然有众多优点，如译码复杂度低、长码时性能更好等，但是其不足也是明显的，即一般LDPC码的迭代译码收敛速度慢并且迭代次数多。 针对上述问题，本文主要研究了LDPC码迭代译码的收敛特性，对LDPC码和积译码算法的三类不同译码策略的对比研究。论文的主要研究工作可以概括如下： 研究了和积译码算法最经典的泛洪译码策略,这是一种并行译码策略，通过仿真说明泛洪译码策略的误码率性能和平均迭代次数。 研究了和积译码算法的水平洗牌译码策略,这是一种串行译码策略，并通过仿真对水平洗牌策略和泛洪策略的收敛速度进行对比。 研究了和积译码算法的复本水平洗牌译码策略，这是一种基于水平洗牌策略的串行译码策略，并通过仿真对复本水平洗牌策略、水平洗牌策略及泛洪策略的收敛速度进行对比。 理论分析及仿真结果显示，水平洗牌策略的收敛速度比泛洪策略快很多，而复本水平洗牌策略能够进一步加快水平洗牌策略的收敛速度，从而降低水平洗牌策略的译码时延。 关键词:低密度奇偶校验码，和积算法，译码策略，水平洗牌，复本 ABSTRACT PAGE \* ROMAN II ABSTRACT Low-density-parity-check (LDPC) codes have been shown to be a class of capacity-approaching codes with iterative decoding. Compared with Turbo codes, LDPC codes have many advantages, such as low decoding complexity, better performance when long codes, etc., but their shortcomings are obvious, that is, the iterative decoding convergence of general LDPC code is slow and the number of iterations is large. In response to the above problems, this paper studies the convergence characteristics of the iterative decoding of LDPC codes, and compares the three different decoding strategies of LDPC code and sum-product decoding algorithm. The main research work of the paper can be summarized as follows: The most classical flooding strategy of the sum-product decoding algorithm is studied, which is a parallel decoding strategy. The bit error rate performance and the average number of iterations of the flooding strategy are illustrated by simulation. The horizontal shuffled decoding strategy of the sum-product decoding algorithm is studied, which is a serial decoding strategy, and the convergence speed of the horizontal reshuffle strategy and the flooding strategy is compared by simulation. The replica horizontal shuffled strategy of the sum-product decoding algorithm is studied, which is a serial decoding strategy based on the horizontal shuffled strategy, the convergence rate of the replica horizontal shuff