Research On Blind Recognition Algorithm For Linear Block Codes Parameters

In the digital communication system,in order to resist the influence and interference of the information in the transmission process,and improve the reliability of the information transmission,the channel coding technology has been developed rapidly.Because of the increasing application of channel coding technology,the blind identification of channel coding has emerged.The purpose of channel coding recognition is to estimate the coding system and to code parameters of the intercepted code sequence with just a few or even without prior information,so as to extract the original information sequence.It has important research value in the field of communication reconnaissance,communication countermeasure and intelligent communication.This paper focuses on the blind identification of binary linear block codes.The main work of this paper is as follows:(1)The theoretical knowledge of linear block codes,the mathematical model of blind identification and the identification parameters are introduced.And pointing out that the linear block code is the object of this thesis.(2)In order to solve the problem of the poor performance of the blind identification of linear block codes,a blind identification algorithm for linear block codes based on feature fusion is proposed.Firstly,according to the actual sequence and random sequence of code weight distribution differences between the probability,the use of code weight difference and standard deviation weight information entropy respectively at the same time identification code length and synchronization point algorithms are proposed.Secondly,comparing the recognition results of the two characteristic parameters and further improve the two algorithms,a new fusion parameters to identify code length and synchronization point at the same time are proposed.Finally,the generation matrix is solved by constructing and simplifying the matrix,so as to realize the full blind identification of linear block code parameters.Theoretical analysis and simulation experience show that therecognition method is simple and a small amount of calculation.And the recognition method 90% with middle and short code length can be recognized when BER is 0.025 and has better performance more than 80% about slightly long code in 0.005 BER.(3)Aiming at the blind identification problem of high bit rate of cyclic codes with high error rate conditions,a blind identification algorithm for cyclic codes based on the maximum common factor order dissimilarity is proposed.Firstly,according to the order of the largest convention type before and after cyclic shift code,using the actual sequence and random sequence order distribution dissimilarity between the big difference,an algorithm based on dissimilarity measure function in data mining to identify the code length and synchronization point is proposed.Secondly,according to the characteristics of cyclic codes,the generated polynomial be identified by calculating the order distribution difference,so as to realize the full blind identification of cyclic code parameters.The algorithm has good fault tolerance and is easy to understand,and it has a good effect on the blind recognition of the medium and long codes under the condition of 0.013 bit error rate.