基于不同外信息处理方式的Turbo迭代译码研究

Study on Iterative Decoding of Turbo Codes with Extrinsic Information in Different Versions

针对离散无记忆高斯信道,该文深入剖析了不同外信息使用方式下的两种对数域的Turbo码迭代译码算法,并借助蒙特卡罗仿真,在相同的约束条件下对两种算法的性能进行了比较。经过分析指出二者在本质上是一致的,只是成员译码器对外信息使用权重的处理不同。最后对其进行了统一的描述,并定量研究了迭代译码对外信息的依赖性。结果发现成员译码器对外信息的最佳依赖程度不受信噪比与迭代次数的影响。

In this paper, based on various methods of using extrinsic information, two logarithmic iterative decoding algorithms of Turbo codes are anatomized clearly for a discrete memoryless Gaussian channel. With Monte Carlo simulation, performance of two algorithms is compared under the same constraint condition; after analysis it is proposed that they are identical in nature, the only difference is how to deal with scale of extrinsic information for component decoder to use. Finally, a united form is used to describe two algorithms and some research is done for the dependency on extrinsic information in iterative decoding numerically, from the result it is found that SNR and iterative number do not affect the best scale of extrinsic information used in component decoder.