Abstract To improve the bit error rate (BER) performance of direct sequence code division multiple access (DS-CDMA), fast Fourier transform (FFT) can be applied to the received signal sequence to carry out joint frequency-domain equalization (FDE) and antenna diversity combining. We have reported that the application of FDE to DS-CDMA can significantly improve the BER performance for a large sp...

As the channel frequency selectivity becomes severer, the bit error rate (BER) performance of direct sequence spread spectrum (DSSS) signal transmission with rake combining degrades due to an increasing inter-path interference (IPI). Frequency-domain equalization (FDE) can replace rake combining with much improved BER performance in a severe frequency-selective fading channel. For FDE, accurate...

Single-carrier (SC) transmission with space-time block coded (STBC) transmit diversity can achieve good bit error rate (BER) performance. However, in a high mobility environment, the STBC codeword orthogonality is distorted and as consequence, the BER performance is degraded by the interference caused by the orthogonality distortion of STBC codeword. In this paper, we proposed a novel frequency...

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 t...

Recently, the decision feedback channel estimation based on the minimum mean square error criterion (DF-MMSE-CE) using a fixed DF filter coefficient has been proposed to improve the channel estimation accuracy for DS-CDMA with frequency-domain equalization (FDE). In this paper, we propose adaptive DF (ADF)-MMSE-CE, in which the DF filter coefficient is adapted to changing channel conditions bas...

Cepstral normalization has been popularly used as a powerful approach to produce robust features for speech recognition. A new approach of Powered Cepstral Normalization (P-CN) was recently proposed to normalize the MFCC parameters in the r1-th order powered domain, where r1 > 1.0, and then transform the features back by an 1/r2 power order to a better recognition domain, and it was shown to pr...

This work is mainly focused on showing experimental results using a combination of two methods for noise compensation which are shown to be complementary: classical spectral subtraction algorithm and histogram equalization. While spectral subtraction is focused on the reduction of the additive noise in the spectral domain, histogram equalization is applied in the cepstral domain to compensate t...

In this paper, an equalization technique for OFDM and MC-CDMA systems in a time-varying multipath fading environment is described. A loss of subchannel orthogonality due to time-variation of multipath channels leads to interchannel interference (ICI) which increases the error oor in proportion to Doppler frequency. A simple frequency domain equalizer which can compensate the e ect of time-varia...

DS-CDMA can achieve good bit error rate (BER) performance in a severe frequency-selective fading channel by using frequency-domain equalization (FDE) based on MMSE criterion instead of rake combining. FDE requires accurate channel estimation (CE). Recently, a decision feedback (DF)MMSE-CE using a fixed DF filter coefficient has been proposed. The DF filter coefficient is an important design par...

Frequency-domain equalization (FDE) based on the minimum mean square error (MMSE) criterion can provide better downlink bit error rate (BER) performance of direct sequence code division multiple access (DS-CDMA) than the conventional rake combining in a frequencyselective fading channel. FDE requires accurate channel estimation. In this paper, we propose a new 2-step maximum likelihood channel ...