卷积码维特比译码算法最佳反馈深度研究

卷积码可以用维特比算法作为译码算法,由于维特比译码器复杂度随着反馈深度的增长成指数倍增长,因而译码反馈深度对译码器的复杂度影响很大甚至可能无法实用,目前有些文献中仅给出了反馈深度的大致范围,但在硬件实现和性能仿真时无法确定一个具体的数值。通过在OFDM系统中运用卷积编码和维特比译码仿真分析发现,维特比译码器反馈深度为卷积码编码器存贮长度的5倍时,既可达到性能和硬件复杂度的良好折衷,又便于实际应用。

Research of Optimal Traceback Depth of Viterbi Decoding Algorithm of Convolutional Code

This paper proposes how to choose optimal traceback depth of Viterbi decoder in OFDM systems.The decoder is largely affected by the decoder traceback depth,because the decoder complexity increases exponentially with the decoder traceback depth.There are lots of references which are analyzed theoretically the performance caused by traceback depth,but the range is so wide that it is difficult to choose precise value.According to apply convolutioanl encoding and viterbi decoding in OFDM system,we find that the optimal decoding traceback depth is 5 times of constrained length of encoder on the basis of considering a tradeoff between performance and equipment complexity,this conclusion can be applied in other communication systems.