Parallel Interference Cancellation in Coded DS-CDMA Systems

Author:

Abstract:

This paper concerns the application of subtractive interference cancellation for an asynchronous uplink transmission in a DS-CDMA system employing different FEC coding strategies. Due to the inherent bandwidth expansion in CDMA systems, powerful low rate coding is possible. Therefore, the combination of convolutional and repetition codes (CCRPC) as well as a serial concatenation of a convolutional code, a Walsh code and a repetition code (SCCS) are considered. Besides a comparison of the different coding approaches, parallel interference cancellation (PIC) is applied to overcome the tremendous effect of multi-user interference (MUI) limiting the capacity of CDMA systems. In this context, different combinations of PIC and iterative SCCS decoding are examined. Assuming perfectly known channel impulse responses for each user it turns out that the CCRPC scheme achieve near single user performance even in the case of high system loads. High interference levels degrade the performance of the SCCS considerably even when PIC is applied. Only for low system loads SCCS outperforms the other coding schemes.

Document type:

Conference Paper

Publication:

Reisensburg, Germany, 17. - 18. January 2001

Conference:

COST 262 Workshop on Multiuser Detection in Spread Spectrum Communications

Pages:

31-38

Index:

102

Files:

Paper