Research And Improvement Of Differential Chaos Shift Keying Technology

With the rapid development of information technology,people have higher requirements for the integrity and security of information transmission in wireless communication,and the chaotic digital keying technology can meet the requirements of secure communication to a certain extent.Differential Chaos Shift Keying(DCSK)is one of the typical representatives of chaotic digital modulation technology.This technology uses chaotic signals with special properties as carrier signals to carry data information,which not only makes the circuit simple,but also does not need chaos synchronization.Therefore,chaotic keying communication technology has attracted great attention of researchers.However,the information transmission rate of DCSK is low and the confidentiality is poor because of the transmission reference(T-R)mode.Aiming at the defects of DCSK technology,this thesis studies the following solutions:1.Aiming at the problem of low transmission rate of DCSK information,a Correlation Delay-Differential Chaos Shift Keying(CD-DCSK)communication system without inter signal interference is studied.Based on the idea of Correlation Delay Shift Keying(CDSK)transmitter using adder,it is combined with DCSK technology to improve the efficiency of information transmission.In order to solve the problem of poor Bit Error Rate(BER)performance of the new system,a chaotic signal generator which can generate two orthogonal signals is used to eliminate the interference between carrier signals generated by the new system.The BER performance of the new system is analyzed by using the Gaussian approximation(GA)method,and the simulation results are verified.The results show that compared with the same DCSK system,the information transmission rate of the new system is improved by 50%.2.Aiming at the low data transmission rate of Short Reference Differential Chaos Shift Keying(SR-DCSK)system,a Short Reference Multi-User Differential Chaos Shift Keying(SR-MU-DCSK)communication system is studied.By using the orthogonality of Walsh code to transmit the information of multiple users,the data transmission rate can be greatly improved.The BER performance is analyzed by GA method,and the simulation results are verified.The results show that the transmission rate and energy efficiency of SR-MU-DCSK system are greatly improved.3.To solve the problems of low information rate and bad BER performance in DCSK system,a High Rate Differential Chaos Shift Keying(HR-DCSK)communication system is studied.The transmitted signal frame is expanded from 2 time slots to 3 time slots,and 4 bits data information can be modulated by using Hilbert transform technology.The BER performance of HR-DCSK system is analyzed by GA method,and the simulation results are verified.The results show that compared with the DCSK system and HE-DCSK system under the same conditions,the information transmission rate and BER performance of HR-DCSK system are significantly improved.In addition,the High Rate Differential Chaos Shift Keying with Multiple Input Multiple Output(MIMO-HR-DCSK)communication system based on HR-DCSK system is deeply studied.The BER performance of MIMO-HR-DCSK system is greatly improved by combining HR-DCSK modulation technology with multi antenna technology.The BER performance of MIMO-HR-DCSK system is theoretically analyzed by GA method,and the results of theoretical analysis are verified by simulation experiments.The results show that the more the number of receiving and transmitting antennas,the better the BER performance of the system.Compared with the MIMO-DCSK and the MIMO-HE-DCSK systems under the same conditions,the MIMO-HR-DCSK system has significantly improved the information rate and BER performance.