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.