在Viterbi算法中引入软值进行修正之后的算法称作SOVA算法(Soft Output Viterbi Algorithm)。SOVA算法在Viterbi算法的基础上,路径量度引入了比特先验信息,对每位译码比特以后验概率似然比的形式提供软输出,因而可提供更高的译码性能。特别,SOVA算法可用于级联码的迭代译码,采用Tuobo原理使不同分量码之间交换软信息,从而可显著提高这类码的纠错能力。 The algorithm after the soft value is introduced into the Viterbi algorithm is called the SOVA algorithm (Soft Output Viterbi Algorithm). Based on the Viterbi algorithm, the SOVA algorithm introduces bit-priori information into the path metric and provides a soft output in the form of a posterior probability-likelihood ratio for each bit to be decoded, thereby providing higher decoding performance. In particular, the SOVA algorithm can be used for iterative decoding of concatenated codes, using Tuobo’s principle to exchange soft information between different component codes, thereby significantly improving the error correction capability of such codes.