The Study On The Chaotic Spread Spectrum Sequence And Its Application

In the research of chaos spreading sequence communication , large quantity, arbitrary periods, simple production, and good quality are the requests for new chaotic sequences, it need find the new chaotic dynamic system. At present, the complete constructional theory and means for chaotic dynamic system can not be found, non-linear map can realize this in some extent by adding some molestation. In this paper, a complete constructional method of one-dimension chaotic map for collapses non-linear map is found by using the method of parameter searching, based on the character of chaotic attractor, the bifurcation diagram is drawn by simulation, the demo course from bifurcation to chaos can be found intuitively. By computing the curve of Lyapunov exponent, we can prove the chaotic characteristic of the system and observe the phenomenon of chaos and intermittent occurrence; Try to construct the multi-dimension chaotic map, and improve the chaotic characteristic by computing the maximal Lyapunov exponent; Give a construct example of chaos dynamic system in complex field.The chaos dynamic system can produce chaotic sequence by giving the initial value, the sequence can produce chaos digital sequence after the quantification and digitization by using the gate function. In this paper, the properties of the chaos digital sequence (including the real sequence and complex sequence ) is simulated and proved. The favorable auto-correlations and cross-correlations properties can be used for the spread-spectrum communication of the DS-CDMA . In this paper the characteristic of chaos spreading sequence is validated by the modeling and simulation of DS-CDMA system , the newly constructed and the traditional chaos spreading sequence are compared by simulation, and the causes of error code are analysed briefly.