Study On Blind Decoding Of Turbo Codes In Non-cooperative Targets

In the communication of non cooperative target,the data information transmitted by the target can be intercepted from the communication channel.And the data intercepted from the channel is usually coded,therefore,it is necessary to analyze the parameters of channel coding.Turbo codes are gradually popularized for the transmission rate can nearly to the Shannon's theoretically limit.They are widely used in satellite communications and other related fields.It is of great significance to study deeply the blind decoding techniques of Turbo code parameters.In this paper,the blind decoding technique of Turbo codes is studied.Firstly,the paper introduced the main identification methods of Turbo code and analyzed the research status of Turbo code identification with the analysis technology.Secondly,the paper analyzed the existing Turbo code technology briefly,and discussed the advantages and disadvantages of the existing methods.Aiming at the blind identification of Turbo codes with error code,two solutions are proposed in this paper.First,the method based on code weight correlation is used to analyze the interleaver length and the weaving starting point of Turbo codes.According to the characteristics of interleaver interleaving will not change the codeword weight of the data sequence,through establish the sequence of codeword weight difference.the sequence will have the characterstic of periodic law.Analyzing and solving the generated code weight difference sequence,and then get the interleaver length and the starting point of the data interleaver.Second,a graph based matching method for identifying interleaver relations.According to the characteristics,that the interleaves just change the relative position of the data,not modifie the information of content,constructing two intertwined relationship graph.Using graph matching method,solve the complete matching graph,which can using to solve the interleaving interleaved relations.Theoretical analysis and simulation experiments show that two methods are both have good results can be obtained in the case of error code.