Research On Chaotic Mask And Chaotic Shift Keying Secure Communication

The initial value and parameter sensitivity,noise-like nature,synchronicity,and wide-band nature of chaotic signals make it widely used in secure communication.Chaotic mask and chaotic shift keying communication are the two most typical communication methods in chaotic secure communication.The traditional chaotic mask and chaotic shift keying communication almost face the problems of incoherent reception difficulty,noise sensitivity,and low system transmission efficiency.In this thesis,Rossler hyperchaos system and analytic solution hybrid chaos system are used to give corresponding improvement methods.The main work and innovation of this thesis are as follows:(1)Noise robust noncoherent chaotic mask communication systemIn order to solve the problem of incoherent reception difficulty and noise sensitivity in traditional chaotic mask communication,this thesis selects Rossler hyperchaos as the driving system of the transmitter,which is composed of two Rossler chaotic systems with different frequencies.When the frequency difference between the two systems is greater,its robustness to noise is stronger.In the receiving end,by constructing the synchronous chaotic system of the driving system and the cascaded synchronous system,the chaotic signal of the transmitting end is reproduced by the driving of the receiving signal,and the information signal is demodulated correctly to realize the incoherent receiving.Secondly,because of the existence of synchronous chaotic system and cascaded synchronous chaotic system,the transmission signal is integrated into different systems many times,which improves the security of signal transmission.Finally,the integral threshold detection method is used to demodulate the binary signal of the transmitter,further reduceing the impact of noise on the transmission system,and improving the noise robustness of the system.(2)Noise robust high efficient differential chaotic keying communication systemIn order to solve the problem of low transmission efficiency and large noise interference in traditional chaotic shift keying communication system,this thesis uses analytical solution to the polarity relationship between the driving signal and the response signal of the chaotic oscillator,so that the carrier signal only carries information signal,which avoids the problem of reference signal in the transmission signal,effectively shortens the bit duration of the transmission signal and improves the performance of the system transmission efficiency of the system.Moreover,in the receiver,by selecting a specific field in each symbol period,sampling and integrating,threshold detection and demodulation method is adopted,which reduces the impact of noise on the transmission system and effectively improves the noise robustness of the system.