Log-MAP译码算法改进与性能仿真

Improvement and simulation of LOG-MAP Algorithms

在介绍、分析Log-MAP译码算法的基础上,重点通过如下三方面对此算法进行调整,简化译码器的结构、减少计算的复杂度与存储量,第一,在计算向前度量、反后度量时用并利用采用Jacobian等式进行简化,减少冗余计算;第二,通过改变外部信息的值使之包含系统信息,来简化译码器结构;第三,通过采用查表法来简化校正函数的计算量。最终使用计算机对对此改进算法进行了性能仿真,经测试其译码性能与Log-MAP算法接近。

The pfindple of channel codes and turbo codes are introduced in this thesis .Secondly the principle of the decode, the deducing and the step for calculation of LOG-MAP algorithms are discussed. And then modify the algorithm, simplify the encoders structure, reduce the complexity of the algorithm and the storage of the memory needed in order to implement the decoder with digital signal processor. Thorough simulating this modified algorithm we get the satisfied results.