相位模糊下基于软判决的卷积码识别方法  

Convolutional code recognition method based on soft decision under phase ambiguity

作　　者：简熠 JIAN Yi(Southwest China Institute of Electronic Technology,Chengdu 610036,China)

机构地区：[1]中国西南电子技术研究所,四川成都610036

出　　处：《现代电子技术》2024年第9期35-39,共5页Modern Electronics Technique

摘　　要：QPSK数据流通常具有相位模糊的问题,传统方法常采用卷积码遍历识别码字起始位置的译码算法,这将导致算法计算量大、资源占用高等诸多问题。因此,提出一种基于软判决的卷积码起始位置识别与QPSK相位模糊消除的译码方法,以有效提升译码算法性能。首先,推导了卷积码编码序列与校验矩阵之间的数学表达式,明晰了卷积码码字起始位置与相位模糊的逻辑关系;然后,求解CCSDS标准卷积码的校验矩阵,以方程成立的概率作为判决的度量,该方法适用于各种码率的删除卷积码,具有工程实用性;最后,通过仿真分析验证了所提出方法的有效性。研究表明该方法无需遍历卷积码的码字起始位置和相位模糊,且鲁棒性较强,所需数据量较小,随着数据量的增大和卷积码码率的降低,识别准确率逐渐提高。QPSK(quadrature phase shift keying)data streams often suffer from phase ambiguity.In the traditional methods,for example,decoding algorithms,convolutional codes are often used to traverse and identify the starting position of code words,which will lead to various problems,such as high calculational complexity and resource occupation.Therefore,a decoding method based on soft decision for identifying the starting position of convolutional codes and eliminating QPSK phase ambiguity is proposed to effectively improve the performance of the decoding algorithms.The mathematical expressions between the convolutional code encoding sequence and the check matrix are derived,and the logical relationships between the starting position of the convolutional code word and phase ambiguity are clarified.The check matrix of the CCSDS(consultative committee for space data system)standard convolutional code is solved,and the probability of the equation being established is used as the measure of the decision.This method is suitable for deleting convolutional codes at various bit rates and has engineering practicality.The effectiveness of the proposed method has been verified with simulation analysis.The research has shown that the method does not require traversing the starting position of convolutional codes and the phase ambiguity,has strong robustness,and requires a small amount of data.As the data volume increases and the convolutional code rate decreases,the accuracy improves gradually.

关 键 词：卷积码 码字起始位置 相位模糊 校验矩阵 软判决 QPSK 

分 类 号：TN911.7-34[电子电信—通信与信息系统]