基于网格的缩短(38,26)BCH码的自适应维特比译码算法  

Adaptive Viterbi Decoding Algorithm for the Shortened(38,26) BCH Code Based on Trellis

作　　者：侯舒娟[1] 宋灵燕[1] 孙琳[1] 

机构地区：[1]北京理工大学信息与电子学院,北京100081

出　　处：《北京理工大学学报》2016年第11期1205-1210,共6页Transactions of Beijing Institute of Technology

摘　　要：针对伽利略搜救系统(Galileo/SAR)物理层协议中采用的缩短(38,26)BCH码,提出了一种自适应维特比译码算法(AVA).文中给出了缩短(38,26)BCH码的最优网格,在此基础上,提出了AVA,该算法在维特比译码算法(VA)的基础上设计了一个丢弃门限,只保留最有可能的路径.丢弃门限值随着信噪比的变化,可以自适应调整,使得AVA在保持与VA几乎相同的误码率性能的基础上,尽可能地降低译码复杂度.同时,文中给出了丢弃门限的估计方法,并确定了不同信噪比下的最佳丢弃门限值.仿真结果表明具有最佳丢弃门限的AVA在保持与VA误码性能几乎相同的基础上,译码复杂度有着极大程度的降低,特别是在信噪比高时,译码复杂度下降得更加明显.Galileo search and rescue system（Galileo/SAR）adopts the shortened（38,26）BCH code in its physical layer protocol.In this paper,an adaptive Viterbi decoding algorithm（AVA）was proposed.The best trellis for the shortened（38,26）BCH code was first presented.In the AVA,a discarding threshold was designed on the basis of the Viterbi algorithm（VA）,only retaining the most likely paths.The discarding threshold could vary with the different SNR and be adjusted adaptively to reduce the decoding complexity as much as possible,with almost the same error performance as the VA.Simulation results show that,the decoding complexity of the AVA reduces greatly compared with the VA,maintaining nearly the same error performance.Especially at high SNR,the decoding complexity decreases more obviously.

关 键 词：AVA 丢弃门限 缩短BCH码 伽利略搜救系统 

分 类 号：TN967.1[电子电信—信号与信息处理]