Conventional OFDM employs a guard interval to combat delay spread distortion oftransmitted data. This reduces the efliciency of the OFDM transmission. The combined OFDM-Equalization strategy described here employs an Adaptive Equalizer to combat delay spread distortion and thereby facilitates the use of very short guard intervals and thus a more eflcient OFDM modulation scheme. The OFDM receive...

In this paper we investigate layered space-time equalization (LSTE) architectures for multiple-input-multiple-output (MIMO) frequency selective channels. At each layer or stage of detection, a MIMO delayed decision feedback sequence estimator (MIMO-DDFSE) is used to tentatively detect a group of selected data streams, among which a sub-group of data streams are output and are canceled from the ...

This paper presents a turbo equalization (TEQ) scheme, which employs a radial basis function (RBF)-based equalizer instead of the conventional trellis-based equalizer of Douillard et al. Structural, computational complexity, and performance comparisons of the RBF-based and trellis-based TEQs are provided. The decision feedback-assisted RBF TEQ is capable of attaining a similar performance to th...

It has previously been shown that a least-mean-square (LMS) decision-feedback filter can mitigate the effect of narrowband interference (L.-M. Li and L. Milstein, 1983). An adaptive implementation of the filter was shown to converge relatively quickly for mild interference. It is shown here, however, that in the case of severe narrowband interference, the LMS decision-feedback equalizer (DFE) r...

At a communications receiver the observed signal is a corrupted version of the transmitted signal. This distortion in the received signal is due to the physical characteristics of the channel, including multipath propagation, the non-idealities of copper wires and impulse noise. Equalization is a process to combat these distortions in order to recover the original transmitted signal. Roughly st...

In this paper the behavior of the decision feedback equalizers (DFEs) adapted by the decision-directed or the constant modulus blind algorithms is presented. An analysis of the error surface of the corresponding criterion cost functions is first developed. With the intention of avoiding the ill-convergence of the algorithm, the paper proposes to modify the shape of the cost function error surfa...

—Recently, several approaches have been proposed for the equalization of orthogonal frequency-division multiplexing (OFDM) signals in challenging high-mobility scenarios. Among them, a minimum mean-squared error (MMSE) block linear equalizer (BLE), based on a band LDL factorization, is particularly attractive for its good trade-off between performance and complexity. This paper extends this app...

We propose channel estimation and direct equalization techniques for transmission over doubly selective channels. The doubly selective channel is approximated using the basis expansion model (BEM). Linear and decision feedback equalizers implemented by time-varying finite impulse response (FIR) filtersmay then be used to equalize the doubly selective channel, where the time-varying FIR filters ...

A multi-layered perceptron neural network with backpropagation algorithm (MLP/BP) is realized as a waveform equalizer for distorted nonreturn-to-zero (NRZ) data recovery in band-limited channels. Moreover, the proposed approach can tolerate sampling clock skew and channel response variance. According to simulation results, the proposed design can recover severe distorted NRZ data with better pe...

An equalizer algorithm is presented which is suitable for use with a differential detector operating in a time dispersive channel. Although differential detection allows the stringent requirements on frequency stability generally imposed on coherent receivers to be relaxed, its performance is more severely degraded by intersymbol interference. The algorithm described in this paper, which has be...