Turbo码的一种高效改进型MAP译码算法
doi: 10.3724/SP.J.1146.2007.00390
An Efficient Improved MAP Decoding Algorithm for Turbo Codes
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摘要: 该文给出了一种改进型最大后验概率(MAP)译码算法用于实现并行级联卷积码(Turbo码)的最优译码。与基于对数域的Log-MAP算法相比较，该文给出的算法不引入对数域，但能够完全消除标准MAP算法在迭代过程中必须进行的大量指数和对数运算。计算机仿真结果表明，这种具有最优纠错性能的改进型MAP算法能够显著减少运行时间，其译码效率甚至优于牺牲了较多纠错性能的最快速的对数域MAP译码算法(Max-Log-MAP)。Abstract: This paper presents an improved maximum a posteriori probability (MAP) decoding algorithm for optimal decoding of parallel concatenated convolutional codes (Turbo codes). Compared with the Log-MAP algorithms based on logarithm domain, the proposed algorithm does not introduce logarithm domain, but it can eliminate large amount of exponential and logarithm arithmetic operations required with the standard MAP algorithm in the iterative decoding process. Simulations demonstrate that he proposed algorithm, with optimal error correction performance, can significantly reduce the running time, such that its decoding efficiency is even slightly superior to that of the fastest logarithm domain MAP algorithm(Max-Log-MAP) which sacrifices considerable error correction performance.
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