Matched filter acquisition for CDMA systems in multipath channels

Abstract

This paper introduces analytical results of a DS/CDMA spread spectrum system in which code acquisition is performed using a code matched filter in a multipath channel. The performance measure is the mean acquisition time, T/sub MA/. Constant false alarm rate criteria (CFAR) are used as the threshold setting rule for the comparator. Due to an increase in mean acquisition time because of multipath propagation, a method is proposed which takes into account the multipath components. The powers of all the multipath components are combined already in the acquisition process by using chip level post detection integration (CLPDI). The task of the method is to increase the probability of finding the burst of multipath components, i.e., to decrease the mean acquisition time of finding the existence of the multipath profile. The numerical results indicate that the acquisition performance can be improved significantly, especially when a large number of users is operating at the same time in the CDMA system.