一种咬尾卷积译码的修正算法

Modified Algorithm of Tail Biting Convolutional Decoding

在LTE系统中,物理广播信道和物理下行控制信道均采用了咬尾卷积编码,咬尾卷积编码拥有很多优良的性能。针对咬尾卷积译码,提出了一种基于Viterbi译码的修正算法——正逆序结合译码算法,根据分支度量确定误码在数据帧的分布,最后确定采用正序还是逆序译码结果。仿真结果表明,Viterbi的修正方法有效地降低了系统误码率,而且具有普适性,适合应用于LTE系统。

In the LTE system, the physical broadcast channel and the physical downlink control channel uses tail biting convolu- tional coding, and tail biting convolutional code has many excellent properties. In this paper, a modified decoding algorithm which ealls the positive and revers e decoding algorithm is proposed, according to the branch metric to determine distribution of bit errors in the data frame. Finally, determine the positive or reverse decoding as the results. The simulation results show that the modified Viterbi method can effectively reduce the system bit error rate and is universal, suitable for LTE system.