Blind Identification Of Interleaver And RS Code In Common Data Link

With the continuous development of communication technology and information warfare,common data link(CDL)as a standard data link is used by the United States and NATO to transmit image and signal intelligence.It has been applied more and more widely in information warfare.In order to ensure the technical advantage in confrontation with strong enemies,it is necessary to carry out research on counter-measures against CDL as soon as possible.The blind identification of interleaver and RS codes is the basis and the key for restoring the original information data.Therefore,this thesis focuses on blind recognition of CDL interleaver and RS code under non-cooperative conditions.Firstly,a blind identification algorithm of interleaver type based on normalized rank characteristics for RS code is proposed to solve the problem of interleaver type in CDL system.Unlike the prior works,the identification process is carried out for a generic case without any restriction on the codeword length n.Combining the normalized rank of analysis matrix with Gauss-Jordan elimination through pivoting algorithm,blind identification of interleaver type in common data link can be realized.The results show that this proposed method can achieve a better performance compared to the existing algorithms in high bit error rate and have less computation.Next,a blind identification algorithm of interleaver parameters based on zero-mean-ratio for common data link is proposed.Unlike the prior works,the identification process is carried out for a generic case without any restriction on the codeword length n.Combining the zero-mean-ratio with Gauss-Jordan elimination through pivoting algorithm,blind identification of interleaver parameters in common data link can be realized.The results show that this proposed method can achieve a better performance compared to the existing algorithms in high bit error rate and can realize the identification of interleaver parameters in common data link.Aiming at the problem of blind identification of RS codes in CDL system,two new blind recognition of RS code algorithms are proposed.The blind recognition algorithm based on separation of message bits and parity bits is proposed to require lower computation complexity.By using variance of probability and Galois Field Fourier transform,all parameters of the primitive RS code and shorten RS code can effectively identified and the algorithm can reduce the computational-complexity.The blind identification algorithm based on non-zero-mean-ratio is proposed to improve the error-resilient performance.By using the non-zero-mean-ratio of the analysis matrix wite the finite-field Gauss-Jordan elimination algorithm and Galois Field Fourier transform,blind identification of RS code in common data link can be realized.The error-resilient performance of the algorithm is improved compared with the existing recognition methods.