A modified non-coherent delay-locked loop for CDMA systems

Author

El-Tarhuni, Mohamed

Author_Institution

Electr. Eng. Dept., American Univ. of Sharjah, United Arab Emirates

Volume

2

fYear

2004

fDate

17-19 May 2004

Firstpage

1124

Abstract

A PN code tracking loop for DS-CDMA is presented with main focus on the third generation cdma2000 system. The proposed tracking scheme is based on a modified early-late delay-locked loop (DLL) structure that utilizes three non-coherent correlators and post-detection accumulations. A lock detector is used to maintain the signals aligned for a long period of time and to determine when a loss of synchronization has occurred. Analytical and simulation results for the mean hold-in time performance in AWGN and Rayleigh fading conditions are presented. It is shown that the loop can maintain lock with the incoming signal at very low signal-to-noise ratio. Tracking of time varying delays is also demonstrated.

Keywords

3G mobile communication; AWGN channels; Rayleigh channels; code division multiple access; correlators; delay lock loops; delays; pseudonoise codes; spread spectrum communication; synchronisation; AWGN; DS-CDMA; PN code tracking loop; Rayleigh fading; SNR; early-late delay-locked loop structure; lock detector; mean hold-in time; modified noncoherent delay-locked loop; noncoherent correlators; post-detection accumulation; signal-to-noise ratio; synchronization loss; third generation cdma2000 system; time varying delays; AWGN; Analytical models; Correlators; Delay; Detectors; Multiaccess communication; Performance analysis; Rayleigh channels; Signal to noise ratio; Tracking loops;

fLanguage

English

Publisher

ieee

Conference_Titel

Vehicular Technology Conference, 2004. VTC 2004-Spring. 2004 IEEE 59th

ISSN

1550-2252

Print_ISBN

0-7803-8255-2

Type

conf

DOI

10.1109/VETECS.2004.1389007

Filename

1389007