An analysis of the 3-stage search process in W-CDMA

This paper considers the PN acquisition and search mechanism in the wideband CDMA standard proposed by the 3rd Generation Partnership Project (3GPP) committee. In the 3GPP system, no synchronization requirement is assumed between base-stations (BS). In this case, since neighboring BS use different spreading sequences, the mobile must first determine the spreading sequence being used by the base station(s) from which the mobile receives sufficiently strong signals. To facilitate acquisition, the total set of spreading sequences is divided into groups, and the group identification is transmitted over a synchronization channel. The mobile must then execute a three-stage algorithm for acquisition and cell search. We describe this algorithm and present an analysis of the three-stage search process. We also show that the analytical results are consistent with simulation results.