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Full-Text Articles in Engineering
A Modified Lrt-Based Spread-Spectrum Receiver Using Spatial And Temporal Processing, Jeffrey L. Cutcher
A Modified Lrt-Based Spread-Spectrum Receiver Using Spatial And Temporal Processing, Jeffrey L. Cutcher
Theses
The problem of demodulating a direct-sequence (DS) spread-spectrum signal in the presence of single-tone or narrow-band interference and multi-path is discussed. A likelihood-ratio test (LRT) receiver is presented which consists of a whitening filter and a RAKE correlator.
A modified LRT receiver structure is then considered where the whitening filter is replaced by an antenna array with corresponding tap coefficients. The array spatially removes the interference by estimating it's angle-of-arrival. Using the array has an advantage over the original LRT receiver when a narrow-band interference is present. Both receivers are identical in performance under the single-tone interference model.
A third …
An Adaptive Correlator Receiver For Combined Suppression Of Co-Channel Interference And Narrow-Band Jammers In A Slowly Fading Channel, Raymond Carbone
An Adaptive Correlator Receiver For Combined Suppression Of Co-Channel Interference And Narrow-Band Jammers In A Slowly Fading Channel, Raymond Carbone
Theses
This work deals with the adaptive correlation of a direct sequence spread spectrum signal in the presence of narrow-band, multipath and multiple user interference. The Least Mean Square and Recursive Least Square algorithms are employed for the adaptive convergence of the correlator receiver to minimize the mean squared error.
The performance of the adaptive correlator is compared with the matched filter correlator receiver and the conventional prediction filter for the suppression of narrow-band interference by calculating the bit error probability rate. The adaptive correlator is also compared with the RAKE receiver for multipath suppression and compared to the decorelating detector …
Blind Detection In Channels With Intersymbol Interference, Raafat Edward Kamel
Blind Detection In Channels With Intersymbol Interference, Raafat Edward Kamel
Dissertations
In high speed digital transmission over bandlimited channels, one of the principal impairments, besides additive white Gaussian noise, is intersymbol interference. For unknown channels, adaptive equalization is used to mitigate the interference. Different types of equalizers were proposed in the literature such as linear, decision feedback equalizers and maximum likelihood sequence estimation. The transmitter embeds sequences with the data regularly to help the equalizer adapt to the unknown channel parameters.
It is not always appropriate or feasible to send training sequences; in such cases, self adaptive or blind equalizers are used. The past ten years have witnessed an interest in …
On Issues Of Equalization With The Decorrelation Algorithm : Fast Converging Structures And Finite-Precision, Andrew James Bateman
On Issues Of Equalization With The Decorrelation Algorithm : Fast Converging Structures And Finite-Precision, Andrew James Bateman
Theses
To increase the rate of convergence of the blind, adaptive, decision feedback equalizer based on the decorrelation criterion, structures have been proposed which dramatically increase the complexity of the equalizer. The complexity of an algorithm has a direct bearing on the cost of implementing the algorithm in either hardware or software. In this thesis, more computationally efficient structures, based on the fast transversal filter and lattice algorithms, are proposed for the decorrelation algorithm which maintain the high rate of convergence of the more complex algorithms. Furthermore, the performance of the decorrelation algorithm in a finite-precision environment will be studied and …
On Generalized Adaptive Neural Filter, Zhiqiang Zhang
On Generalized Adaptive Neural Filter, Zhiqiang Zhang
Dissertations
Linear filters have historically been used in the past as the most useful tools for suppressing noise in signal processing. It has been shown that the optimal filter which minimizes the mean square error (MSE) between the filter output and the desired output is a linear filter provided that the noise is additive white Gaussian noise (AWGN). However, in most signal processing applications, the noise in the channel through which a signal is transmitted is not AWGN; it is not stationary, and it may have unknown characteristics.
To overcome the shortcomings of linear filters, nonlinear filters ranging from the median …