Direct Sequence Spread Spectrum Signal Detection Parameter Estimation And DSP Implement

Direct Sequence Spread Spectrum(DSSS)signals are applicated widely in modern communication systems because of their low spectral density,low interception rate and anti-multipath interference.On the basis of reading a lot of books and literature,the paper researched the algorithms of DSSS signal detection,parameter estimation and reconstruction of pseudo random sequence in non-cooperative communication environment,and the system functions are realized on DSP by using the algorithm in this paper,including DSSS signal detection,parameter estimation and reconstruction of pseudo random sequence.Specifically,the research work of this paper mainly includes:(1)Pointing at the detection of DSSS signals,the time-domain autocorrelation method and the secondary moment method of correlation function are emphatically researched.And point at the difficult detection under low signal-to-noise ratio,improved the algorithm which based on adaptive noise canceller.The simulation experiment of MATLAB indicated that the adaptive noise canceller can availably detect DSSS signals at low signal-to-noise ratio,and promoting the anti-noise tolerance of traditional detection algorithm.(2)Pointing at the parameter estimation of DSSS signals,mainly studied the delay multiplication,cyclic spectrum,square frequency doubling methods.The Simulation data indicate that the above methods could provide estimation of more accurate parameters under low signal-to-noise ratio.Estimated parameters includes carrier frequency,chip rate and pseudo random sequence.(3)Pointing at reconstruction of pseudo random sequence,a reconstruction method based on Eigen Value Decomposition(EVD)is researched.The EVD algorithm is particular analyzed from the aspects of feature decomposition algorithm and theory of DSSS signal,and providing the simulation results and performance analysis.(4)Through the above simulation comparison analysis,selecting appropriate algorithm to realize the functions of DSSS signal detection,parameter estimation and PN sequence reconstruction in the DSP device which based on TMS320C6713.The system test results indicated that the selecting algorithms are reasonable and effective,achieving the actual requirements of detection and parameter estimation.Anyway,the paper carried out implement and verification to the detection and parameters estimation of DSSS signals.Computer simulation results and DSP actual test experiment indicate that the test results of the system reached the expected effect of the issue,and the improved algorithms have better performance compared with the original algorithms.