LDPC译码器的研究与设计.doc

山 东 科 技 大 学 本科毕业设计（论文） 题 目 LDPC 译码器的研究与设计 学 院 名 称 电子通信与物理学院 专业班级 电子信息科学与技术2010-2班 学生姓名 唐彤彤 学 号 201001051023 指 导 教 师 张小军 填表时间：二0一四年 月 日 摘 要 LDPC (Low Density Parity Check Codes)码，又叫低密度奇偶校验码，是一种可以由校验矩阵直接确定的编码方式，该码的码长一般较长，但是却仍能保持较高的译码性能。同时它具有接近香农极限的差错控制性能，以及译码复杂度低、吞吐率高的优点引起了人们的关注，成为继Turbo 码后信道编码界的又一研究热点。本文实现了一种基于IEEE802.15.3c 标准的LDPC 码译码器。该译码器采用归一化最小和（Normalized Min Sum）算法，其归一化因子取值为0.75，具有接近置信传播（Belief Propagation）算法的性能。根据译码算法提出了一种基于伸缩因子的量化方案，该量化方案应用于归一化最小和算法时的译码性能与浮点性能相比仅相差0.1dB。同时针对TDMP算法提出了双阈值迭代终止算法，可以节约迭代的次数，降低硬件复杂度。本文提出的几种算法，对LDPC码译码器的研究有一定的参考价值。 关键字：LDPC码；IEEE802.15.3c 标准；归一化最小和算法；TDMP；伸缩因子 Abstract LDPC codes, also known as low density parity check codes, are a kind of channel coding, and they are directly determined by the parity check matrix. The length of the codes is generally longer, but they also show high decoding performance. Meanwhile LDPC codes have attracted much attention and become an another focus in channel coding filed after Turbo codes because of their error correction capability close to Shannon limit, and low decoding complexity and high decoding throughput. The paper implements a standard LDPC decoder based on IEEE802.15.3c.The decoder uses the normalized min sum algorithm, the normalized factor is 0.75, with close to belief propagation Algorithm. According to the decoding algorithm, a quantization scheme based on the scaling factor, the decoding performance and floating point performance of the quantization scheme is applied to the normalized min sum algorithm when compared to only a difference of 0.1dB.At the same time for the TDMP algorithm is proposed for termination algorithm double threshold iteration, iteration times can be saved, reducing hardware complexity. Several algorithms are proposed in this paper, research on the LDPC decoder has a certain reference value. Keywords: LDPC codes, IEEE802.15.3c standar