Research On Blind Recognition Technologies Of Communication Signal Randomization

Today,with the rapid development of wireless communication technology,communication security has been paid more and more attention,and the modes of wireless communication are becoming more and more complicated and diversified.Because the access mode is not authorized,it is more and more difficult for non-cooperative communication to intercept and analyze the signal.As the key technologies to enhance the reliability of data transmission,communication signal randomization technologies,such as frequency hopping,interleaving and scrambling,are the key for the receiver to analyze the signal in non-cooperative communication.Therefore,the research on blind recognition of communication signal randomization key technologies not only has important theoretical value,but also has important practical significance.In this thesis,the blind recognition techniques of frequency hopping,interleaving and scrambling in communication signal randomization are studied,the specific work and contribution are as follows:Firstly,the basic principles and models of frequency hopping,interleaving and scrambling are studied.The research of frequency hopping part includes the basic principle of frequency hopping communication,the characteristics of frequency hopping communication,the mathematical model and main parameters of frequency hopping communication signal;the research of interleaving part includes the basic principle of interleaving,the model and characteristics of matrix interleaving and convolutional interleaving;the research of scrambler part includes the basic components of scrambler,linear feedback shift register,self-synchronous scrambler and synchronous scrambler.Secondly,this thesis studies the blind recognition technology of frequency hopping(FH)parameters,and proposes an improved scheme of blind recognition of frequency hopping parameters based on the double window spectrum difference(DWSD).Aiming at solving the problem that the accuracy of frequency hopping time recognition is unsatisfactory in the case of low signal-to-noise ratio,the improved scheme eliminates the interference time of the preliminary estimated frequency hopping time by using the nature of frequency hopping time as an arithmetic sequence.Simulation results show that the proposed FH blind recognition scheme has better performance in low SNR compared with the existing schemes.Thirdly,this thesis studies the blind recognition technology of interleaving parameters,and proposes an improved interleaving blind recognition scheme based on Gauss Jordan elimination through voting(GJETP).The proposed scheme establishes the model of random row vector extraction from data analysis matrix,optimizes the rank criterion algorithm based on GJETP,reduces the impact of bit error on the performance of rank criterion algorithm,and improves the blind recognition performance of interleaving parameters.The simulation results demonstrate that the proposed scheme has better performance than the existing schemes.Finally,this thesis studies the blind recognition technology of self-synchronized scrambler based on linear block code.We propose an improved blind recognition scheme of self-synchronized scrambler based on entropy function,which combines the improved algorithm of rank defect matrix recognition with the existing blind recognition technology of self-synchronized scrambler.The proposed scheme optimizes the recognition algorithm of linear block code length,and improves the blind recognition performance of self-synchronized scrambler.Simulation results indicate that the proposed scheme is more suitable for high bit error environment than the existing schemes.Compared with the existing algorithms,the blind recognition schemes of frequency hopping,interleaving and self-synchronized scrambler proposed in this thesis have better performance,and have excellent application value.