Period Estimation of the PN Sequence for Direct Sequence Spread Spectrum in Multipath Environment

In this paper, an algorithm reprocessing of the power spectrum density (RPSD) is proposed to detect and estimate the PN code's period of the multipath direct sequence spread spectrum (DS/SS) signal in low SNR, which develops the previous processing method based on the single path environment. It can solve the difficult problem of PN code's period detection and estimation in multipath environment. In the algorithm, the signals' power spectrum density (PSD) is firstly obtained, and then is treated as an input signal to compute its RPSD, the PSD secondly obtained appears peak pulses representing the signals' existence. Through detecting the interval of the peak pulses, we can obtain the period estimation of the DS/SS signals' PN code in multipath environment. Theoretical analysis and simulation results show that the proposed algorithm can effectively estimate the PN code's period of DS/SS signal in multipath environment, and that the estimation performance closely relates to the multipath environment.