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Research And Implementation Of Key Technologies For Spread Spectrum Hopping Communication Syste

Posted on:2022-05-12Degree:MasterType:Thesis
Country:ChinaCandidate:J Y DaiFull Text:PDF
GTID:2568307067485964Subject:Communication and Information System
Abstract/Summary:PDF Full Text Request
The hopping spread spectrum communication system combines the advantages of frequency hopping technology and direct sequence spread spectrum technology,forming good anti-fading,anti-interference and anti-interception capabilities,and can effectively resist the increasingly complex interference technology and eavesdropping in the modern communication environment means.In order to solve the problems of traditional hopping spread spectrum system design optimization,frequency hopping sequence design optimization,and high-speed frequency hopping synchronization scheme design that appear in high-speed hopping spread spectrum communication systems,this article focuses on these three directions and uses continuous phase modulation(CPM,Continuous Phase Modulation)signal-based key technology in the hopping spread spectrum communication system has been researched and implemented.Firstly,it introduces the current domestic and foreign research status of hopping spread spectrum communication structure,frequency hopping sequence design and frequency hopping synchronization algorithm.In-depth analysis of the basic principles and key technologies of traditional frequency hopping communication theory has laid the foundation for further improving the performance of all aspects of the hopping spread spectrum communication system.Secondly,in view of the problem that the anti-interference performance of the conventional hopping spread spectrum communication system needs to be improved,a generalized differential hopping spread spectrum communication system is proposed,which combines frequency hopping,modulation and coding,and transforms the anti-interference mode from avoiding interference to use decoding technology and frequency hopping sequence for demodulation and error correction.Aiming at the problem that the frequency hopping sequence not only needs to combat Doppler shift and time delay,but also needs to meet the requirements of wide interval frequency hopping in engineering,a Welch-Costas sequence based on the vertical direction with a cyclic shift containing a gap line is proposed.The wide interval frequency hopping sequence is used as the family diagram of frequency hopping sequence in the frequency hopping communication system.The two-dimensional Hamming correlation characteristics of the generated sequence are simulated to verify the superiority of the characteristics of the frequency hopping sequence.Aiming at the problem that the frequency hopping synchronization acquisition module needs to improve the acquisition performance of commonly used pseudo-codes,a new method of using random CPM signals instead of truncated Gold codes for synchronization acquisition is proposed.Next,the genetic algorithm is used to search and optimize the related characteristics of the orthogonal signal set established by the CPM signal.Finally,through the simulation of the capture performance of the optimized signal set and its application in the hopping spread spectrum communication system,the superiority of the method is verified.Finally,the generalized differential hopping spread spectrum communication system based on continuous phase modulation combined with the above design is given on the ISE platform the FPGA realization principle of the key modules of the system and the modelsim function simulation is carried out.
Keywords/Search Tags:Hopping spread spectrum communication, differential frequency hopping, frequency hopping sequence, CPM signal, frequency hopping synchronization, TOD
PDF Full Text Request
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