Direct Sequence Spread Spectrum Signal Is Pseudo-random Code Period Estimation And Cycle Synchronization Studies

The PN sequence period estimation and synchronization of the intercepted direct sequence spread spectrum (DS/SS) signals are studied in this dissertation. The theoretical analysis and the performance analysis of several approaches are detailed under lower signal-to-noise ratio (SNR), and the experimental results show that the approaches can work well. The contributions of this thesis are listed as follows:(1) Three kinds of methods to estimate the period of PN sequences of the DS/SS signals are studied first. Comparing between fluctuation-based method and the spectrum-based method, we theoretically prove that they are equivalent with each other.(2) For the cepstrum-based PN period estimation under very low SNR ( < ?10dB), a refined cepstrum algorithm is proposed which performs better.(3) Towards the result of period estimation by the method called fluctuations of second order moments, we do some researches on period-searching, and find a basic method and another two universal methods. The period synchronization on the base of period estimation is studied and a method is given.(4) On the platform of Visual DSP, we finish the hardware simulation with processor ADSP21160 in assemble language.