Tracking performance of coherent decision-directed delay-locked loop in quasi-synchronous CDMA

Author

Park, Ok-Sun ; Ahn, Jae-Young ; Oh, Deock-Gil

Author_Institution

Electron. & Telecommun. Res. Inst., Taejon, South Korea

Volume

2

fYear

2000

fDate

2000

Firstpage

1281

Abstract

In direct sequence code-division multiple access (DS-CDMA), the multiuser interference can be substantially reduced when the users are quasi-synchronized and special symbol-length sequences are used. If a conventional noncoherent delay-locked loop (DLL) is used in quasi-synchronous CDMA (QS-CDMA), its code tracking may be impossible. We propose the coherent decision-directed DLL (CDD-DLL) as a code tracking scheme for QS-CDMA using symbol-length spreading sequences and analyze its performance. It is shown that the CDD-DLL is an appropriate code tracking scheme for QS-CDMA

Keywords

code division multiple access; codes; delay lock loops; interference suppression; land mobile radio; multiuser channels; personal communication networks; quadrature phase shift keying; radio tracking; radiofrequency interference; sequences; spread spectrum communication; synchronisation; CDD-DLL; DS-CDMA; QPSK spreading; QS-CDMA; code tracking; coherent decision-directed delay-locked loop; direct sequence code-division multiple access; mobile communications; multiuser interference reduction; performance; personal communications; phase detector; quasi-synchronous CDMA; symbol-length sequences; symbol-length spreading sequences; tracking performance; Clocks; Degradation; Delay; Error correction; Interference; Multiaccess communication; Performance analysis; Phase detection; Quadrature phase shift keying; Tracking loops;

fLanguage

English

Publisher

ieee

Conference_Titel

Vehicular Technology Conference Proceedings, 2000. VTC 2000-Spring Tokyo. 2000 IEEE 51st

Conference_Location

Tokyo

ISSN

1090-3038

Print_ISBN

0-7803-5718-3

Type

conf

DOI

10.1109/VETECS.2000.851331

Filename

851331