EURASIP Journal on Applied Signal Processing 
Volume 2005 (2005), Issue 5, Pages 670-682
doi:10.1155/ASP.2005.670

An Efficient Code-Timing Estimator for DS-CDMA Systems over Resolvable Multipath Channels

Jianhua Liu1 and Jian Li2

 1College of Engineering, Embry-Riddle Aeronautical University, 600 S. Clyde Morris Boulevard, Daytona Beach 32114, FL, USA
2Department of Electrical and Computer Engineering, University of Florida, P.O. Box 116130, Gainesville 32611-6130, FL, USA
Received 31 July 2003; Revised 26 March 2004

Abstract

We consider the problem of training-based code-timing estimation for the asynchronous direct-sequence code-division multiple-access (DS-CDMA) system. We propose a modified large-sample maximum-likelihood (MLSML) estimator that can be used for the code-timing estimation for the DS-CDMA systems over the resolvable multipath channels in closed form. Simulation results show that MLSML can be used to provide a high correct acquisition probability and a high estimation accuracy. Simulation results also show that MLSML can have very good near-far resistant capability due to employing a data model similar to that for adaptive array processing where strong interferences can be suppressed.