Hybrid acquisition of PN codes using automatic multipath censoring in DS-CDMA communications

Abstract

A hybrid PN-code acquisition scheme is proposed and studied for direct sequence code division multiple access communications in frequency-selective Rayleigh fading channels. The most important feature of the proposed system is its ability to dynamically estimate the number of multipath signals that may lie in the reference channel. The basic idea of the considered algorithm is to sort the partial correlations and carry out successive censoring tests by updating the noise estimation until the first path synchronization. Exact expressions for the probability of false alarm and the mean acquisition time are derived. The performances of the proposed system are then studied and compared with those of the adaptive hybrid acquisition processor (AHAP) and the ordered statistic hybrid acquisition processor (OSHAP).