The estimation of the PN sequence´s period of the DSSS signals in narrowband interference environment

In this paper, a combination method is presented to estimate the PN sequence´s period of the direct sequence spread spectrum (DSSS) signal in strong narrow-band interference environment. An overlapping windowed FFT algorithm is first used to transform the received data signals to the frequency-domain where the elimination or drastical attenuation of the strong narrow-band interference is performed. Then a reprocessing of the power spectrum density algorithm is proposed to detect and estimate the Pseudo-random code (PN) sequence´s period of the DSSS signal in low SNR, which solves the difficult problem of PN sequence´s periodic detection and estimation of weak DSSS signals with interference. Theoretical analysis and simulation results show that the proposed algorithm can effectively estimate the PN sequence´s period of DSSS signal, and the estimating performance closely relates the low SNR.