Coding for asynchronous-CDMA systems

Author

Wu, Y.W. ; Chang, S.C.

Author_Institution

US Army CECOM RDEC, Warrenton, VA, USA

fYear

1997

fDate

29 Jun-4 Jul 1997

Firstpage

356

Abstract

A coding scheme for asynchronous code-division multiple-access (CDMA) systems with finite delays is presented in this paper. All transmitted codewords are assumed to reach the receiver within finite delay of D digits. This coding scheme combines source encoding, synchronous-CDMA (S-CDMA) spreading sequences, and interleaving to support error-free asynchronous multiple-access communications. It can support at least m(log₂m-2)/(2log_2/3)+1log₂3 users and the lower bound of its maximum code rate approaches asymptotically to (1-D/T)(log₂m)/(2log₂3) where m is the length of S-CDMA spreading sequence, and T>D+log(D+2)

Keywords

code division multiple access; concatenated codes; delays; interleaved codes; source coding; spread spectrum communication; S-CDMA; asynchronous-CDMA systems; code-division multiple-access systems; codewords; coding; error-free asynchronous multiple-access communications; finite delays; interleaving; maximum code rate; receiver; source encoding; synchronous-CDMA spreading sequences; Added delay; Arithmetic; Concatenated codes; Decoding; Delay systems; Interleaved codes; Multiaccess communication; USA Councils;

fLanguage

English

Publisher

ieee

Conference_Titel

Information Theory. 1997. Proceedings., 1997 IEEE International Symposium on

Conference_Location

Ulm

Print_ISBN

0-7803-3956-8

Type

conf

DOI

10.1109/ISIT.1997.613290

Filename

613290