BER Analysis of CDMA Uplink Transmission Using Frequency-interleaving

Abstract The use of frequency-domain equalization (FDE) based on minimum mean square error (MMSE) criterion can significantly improve the downlink bit error rate (BER) performances of DSand MC-CDMA in a frequency-selective fading channel. However, the uplink BER performance degrades due to strong multi-user interference (MUI) since different users’ signals go through different channels and hence the orthogonality among users is distorted. We have proposed joint orthogonal frequency-interleaving and MMSE-FDE to DSand MC-CDMA. In this paper, the conditional BER is derived for the given set of channel gains. The average BER performance is numerically evaluated using the derived conditional BER and is confirmed by computer simulation. Keyword DS-CDMA, MC-CDMA, Frequency-domain equalization, Frequency-interleaving

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