Papers by gianpiero panci
Ieee Transactions on Signal Processing, Jul 1, 2008
This paper introduces a novel, not data aided, phase-offset estimator for quadrature amplitude mo... more This paper introduces a novel, not data aided, phase-offset estimator for quadrature amplitude modulated (QAM) signals. Contrarily to near-efficient existing phase acquisition techniques, this estimator does not require a preliminary gain adjustment stage while its accuracy preserves the slope of Cramer-Rao bound for medium-high signal-to-noise ratio (SNR) ranges, where it typically outperforms existing blind estimators, with significant improvement for dense and cross QAM constellations. Moreover, it needs only a very rough estimate of the SNR. Like other gain-control-free blind phase-offset estimators, it measures the amount of the cyclic shift by which the (four-folded) phase probability density function (pdf) is rotated under an unknown phase-offset. Estimation of the phase-offset-induced cyclic shift is conducted first by measuring the received data phase pdf by a canonical phase histogram procedure, then by estimating the phase-offset-induced cyclic shift through a cyclic cross correlation-based procedure between the measured phase histogram and a reference phase pdf evaluated within the zero phase-offset hypothesis. Actually, the estimation procedure is presented in a generalized version that considers a tomographic projection of the bidimensional (magnitude/phase) pdf of suitable nonlinear transformations of the received data. The tomographic projection performs a magnitude weighing on the pdf, and this, in turn, results in an improved overall estimation accuracy, as shown by theoretical analysis and numerical simulations here performed to assess the estimator performance.
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2011 Tyrrhenian International Workshop on Digital Communications Enhanced Surveillance of Aircraft and Vehicles, 2011
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Ieee Transactions on Signal Processing, Dec 1, 2009
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2008 16th European Signal Processing Conference, Aug 1, 2008
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2004 12th European Signal Processing Conference, Sep 1, 2004
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2000 10th European Signal Processing Conference, Sep 1, 2000
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2006 14th European Signal Processing Conference, 2006
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ABSTRACT
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IEEE transactions on pattern analysis and machine intelligence, 2006
In this paper, we present a texture classification procedure that makes use of a blind deconvolut... more In this paper, we present a texture classification procedure that makes use of a blind deconvolution approach. Specifically, the texture is modeled as the output of a linear system driven by a binary excitation. We show that features computed from one-dimensional slices extracted from the two-dimensional autocorrelation function (ACF) of the binary excitation allows representing the texture for rotation-invariant classification purposes. The two-dimensional classification problem is thus reconduced to a more simple one-dimensional one, which leads to a significant reduction of the classification procedure computational complexity.
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2007 IEEE International Symposium on a World of Wireless, Mobile and Multimedia Networks, 2007
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2008 IEEE International Conference on Acoustics, Speech and Signal Processing, 2008
In this paper we present theoretical performance analysis for a blind frequency offset estimator ... more In this paper we present theoretical performance analysis for a blind frequency offset estimator for cross quadrature amplitude modulated constellations. The estimator is based on applying a tentative frequency offset compensation by means of a nonlinear transformation of the received signal samples and on estimating an accumulation function in different angular windows. For perfect frequency offset compensation, the measurements are suitably clustered and their accumulation, named "constellation phase signature" (CPS), is a peaked function of the window orientation. Hence, the frequency offset estimator is selected by maximization of the peakness of the accumulation function. The performance analysis is shown to match the numerical simulations for medium to high values of SNR.
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Theory and Applications, 2007
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Proceedings 2003 International Conference on Image Processing (Cat. No.03CH37429), 2003
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2008 15th IEEE International Conference on Image Processing, 2008
ABSTRACT Fast and bit-saving video bit-rate switching is an important is- sue in video streaming ... more ABSTRACT Fast and bit-saving video bit-rate switching is an important is- sue in video streaming systems on a time varying channel as the one offered by a wireless mesh network, or the one sensed during a vertical handover. The recent H.264 video coding standard supports the seamless switching among,bitstreams coded at different bit-rates by means of suitably coded frames, named,Switching
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Seventh International Symposium on Signal Processing and Its Applications, 2003. Proceedings., 2003
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2006 IEEE International Conference on Acoustics Speed and Signal Processing Proceedings, 2006
We introduce a new blind phase offset estimator for general quadrature amplitude modulated (QAM) ... more We introduce a new blind phase offset estimator for general quadrature amplitude modulated (QAM) signals. The estimator is based on the computation of a suitable phase distribution that we call "signature". The signature is defined as the phase-dependent distribution of the received signal magnitude after the application of a nonlinear transformation. The signature of a QAM signal is constituted by
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IEEE Transactions on Signal Processing, 2001
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IEEE Transactions on Signal Processing, 2000
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IEEE Transactions on Signal Processing, 2000
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IEEE Transactions on Signal Processing, 2000
This paper introduces a novel, not data aided, phase-offset estimator for quadrature amplitude mo... more This paper introduces a novel, not data aided, phase-offset estimator for quadrature amplitude modulated (QAM) signals. Contrarily to near-efficient existing phase acquisition techniques, this estimator does not require a preliminary gain adjustment stage while its accuracy preserves the slope of Cramer-Rao bound for medium-high signal-to-noise ratio (SNR) ranges, where it typically outperforms existing blind estimators, with significant improvement for dense and cross QAM constellations. Moreover, it needs only a very rough estimate of the SNR. Like other gain-control-free blind phase-offset estimators, it measures the amount of the cyclic shift by which the (four-folded) phase probability density function (pdf) is rotated under an unknown phase-offset. Estimation of the phase-offset-induced cyclic shift is conducted first by measuring the received data phase pdf by a canonical phase histogram procedure, then by estimating the phase-offset-induced cyclic shift through a cyclic cross correlation-based procedure between the measured phase histogram and a reference phase pdf evaluated within the zero phase-offset hypothesis. Actually, the estimation procedure is presented in a generalized version that considers a tomographic projection of the bidimensional (magnitude/phase) pdf of suitable nonlinear transformations of the received data. The tomographic projection performs a magnitude weighing on the pdf, and this, in turn, results in an improved overall estimation accuracy, as shown by theoretical analysis and numerical simulations here performed to assess the estimator performance.
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Papers by gianpiero panci