Iterative Frequency-domain Int Cancellation for DS

Abstract— The bit error rate (BER) performance of DSCDMA in a frequency-selective fading channel can be significantly improved by the use of frequency-domain equalization (FDE). However, for a small spreading factor SF, the residual inter-chip-inference (ICI) degrades the BER performance. In this paper, we propose an iterative frequency-domain ICI cancellation (FD-ICIC) scheme for DS-CDMA. In the proposed scheme, the equalization weight is updated for each iteration taking into account the residual ICI with FDE. It is found by computer simulation that the proposed iterative FD-ICIC can significantly improve the BER performance and the Eb/N0 reduction for BER=10 from no ICI cancellation case is as much as 4.2 dB when SF=4. The BER performance at the 2nd iteration approaches the theoretical lower bound by about 0.7 dB (including a 0.5 dB loss due to the GI insertion).