Maximum likelihood synchronization of DS-CDMA signals transmitted over multipath channels

Abstract

We propose a maximum likelihood approach for near-far robust synchronization of asynchronous direct-sequence code-division multiple access (DS-CDMA) systems operating over multipath channels. The algorithm is suitable for use in for instance a slotted system where each user transmits a short data burst with an embedded training sequence. The algorithm is shown to outperform the standard sliding correlator estimator. The Cramer-Rao bound is derived and is used to indicate the best performance that can be achieved by an unbiased estimator.