Iterative multiuser interference reduction: turbo CDMA

Author

Alexander, Paul D. ; Reed, Mark C. ; Asenstorfer, John A. ; Schlegel, Christian B.

Author_Institution

Inst. for Telecommun. Res., South Australia Univ., The Levels, SA, Australia

Volume

47

Issue

7

fYear

1999

fDate

7/1/1999 12:00:00 AM

Firstpage

1008

Lastpage

1014

Abstract

We view the asynchronous random code division multiple-access (CDMA) channel as a time-varying convolutional code. We study the case where the users encode their data, and, therefore, the single user transmitters and the CDMA channel appear as the concatenation of two coding systems. At the receiver we employ serial turbo decoding strategies. Unlike conventional turbo codes where both the inner and outer code may be selected, in our case, the inner code is due to the CDMA channel which we assume to be random. Nevertheless, the decoding system resembles the decoder of a serial turbo code and single-user performance is obtained even for numbers of users approaching the spreading code length

Keywords

cellular radio; concatenated codes; convolutional codes; decoding; interference suppression; iterative methods; multiuser channels; radiofrequency interference; turbo codes; CDMA channel; asynchronous random code division multiple-access; cellular radio; coding systems concatenation; decoding system; inner code; iterative multiuser interference reduction; outer code; receiver; serial turbo code; serial turbo decoding; single user transmitters; single-user performance; spreading code length; time-varying convolutional code; turbo CDMA; Convolutional codes; Filters; Interference; Iterative decoding; Iterative methods; Maximum likelihood decoding; Multiaccess communication; Transmitters; Turbo codes; Viterbi algorithm;

fLanguage

English

Journal_Title

Communications, IEEE Transactions on

Publisher

ieee

ISSN

0090-6778

Type

jour

DOI

10.1109/26.774851

Filename

774851