Ignacio Santamaría

A Spectral Clustering Approach to Underdetermined Post-Nonlinear Blind Source Separation of Sparse Sources (2009)

Steven Van Vaerenbergh, Ignacio Santamaría, Senior Member

Abstract — This paper proposes a clustering-based approach for solving the underdetermined (i.e. fewer mixtures than sources) post-nonlinear blind source separation (PNL BSS) problem when the...

Code Combination for Blind Channel Estimation in General MIMO-STBC Systems (2009)

Javier Vía, Ignacio Santamaría, Jesús Pérez

The problem of blind channel estimation under space-time block coded (STBC) transmissions is addressed. Firstly, a blind channel estimation criterion that generalizes previous works is proposed. The...

Performance Analysis of SNR-Based Scheduling Policies in Asymmetric Broadcast Ergodic Fading Channel (2009)

Jesús Pérez, Jesús Ibáñez, Javier Vía, Ignacio Santamaría

We analyze the performance of SNR-based scheduling algorithms in broadcast ergodic fading channels where multiuser selection diversity is exploited. At each channel state, the user with the highest...

Nonlinear System Identification using a New Sliding-Window Kernel RLS Algorithm (2008)

Steven Van Vaerenbergh, Javier Vía, Ignacio Santamaría

Abstract — In this paper we discuss in detail a recently proposed kernel-based version of the recursive least-squares (RLS) algorithm for fast adaptive nonlinear filtering. Unlike other previous...

Stochastic Blind Equalization Based on PDF Fitting using Parzen Estimator (2008)

Marcelino Lázaro, Ignacio Santamaría, Deniz Erdogmus, Carlos Pantaleón, Jose C. Principe

Abstract — This paper presents a new blind equalization approach that aims to force the probability density function (pdf) at the equalizer output to match the known constellation pdf. Quadratic...

Extensión de la SVM para regresión a tramos (2008)

David Ramírez, Ignacio Santamaría, Steven Van, Vaerenbergh Javier Vía, Dpto Ingeniería

Abstract—In this paper, a new technique for unidimensional regression based on support vector machines is presented. The method is based on the addition of new linear restrictions to the standard...

Adaptive Kernel Canonical Correlation Analysis Algorithms for Nonparametric Identification of Wiener and Hammerstein Systems (2008)

Steven Van Vaerenbergh, Javier Vía, Ignacio Santamaría

This paper treats the identification of nonlinear systems that consist of a cascade of a linear channel and a nonlinearity, such as the well-known Wiener and Hammerstein systems. In particular, we...

A Nonlinear MESFET Model for Intermodulation Analysis Using a Generalized Radial Basis Function Network (2007)

Ignacio Santamaría, Marcelino Lázaro, Carlos J. Pantaleón, Jose A. García, Antonio Tazón, Angel Mediavilla

In this paper we use a Generalized Radial Basis Function (GRBF) network to model the intermodulation properties of microwave GaAs MESFET transistors under dynamic operation. The proposed model...

Design of Simultaneous Sampling Systems Based on Fractional Delay Lagrange Filters (2007)

David Luengo, Carlos J. Pantaleón, Jesús Ibáñez, Ignacio Santamaría

Abstract—Digital filtering is a common approach to achieve simultaneous sampling of several input signals acquired with a multiplexing delay. In this brief, an error bound is obtained for Lagrange...

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Jesús Ibáñez-díaz, Carlos Pantaleón, Ignacio Santamaría, Tomás Fernández, David Martínez, Lqwurgxfhg E Wkh, ...

Precise and representative power amplifier models are a key factor in order to simulate an entire communication system and essential in order to introduce linearization techniques (e.g.,...

BAYESIAN ESTIMATION OF A CLASS OF CHAOTIC SIGNALS (2007)

Carlos Pantaleón, David Luengo, Ignacio Santamaría

Chaotic signals are potentially atractive in a wide range of signal processing applications. This paper deals with Bayesian estimation of chaotic sequences generated by tent maps and observed in...

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Marcelino Lázaro, Ignacio Santamaría, Carlos Pantaleón

The design of microwave and millimeter-wave circuits and the increasing integration of hybrid and monolithic circuits has reinforced the need of accurate large and small-signal device models to...

Chaotic Ar(1) Model Estimation (2007)

Carlos Pantaleon David, David Luengo, Ignacio Santamaría

Chaotic signals generated by iterating nonlinear difference equations may be useful models for many natural phenomena. In this paper we propose a family of chaotic models for signal processing...

A new EM-based training algorithm for RBF networks (2003)

Marcelino Lázaro, Ignacio Santamaría, Carlos Pantaleón

In this paper, we propose a new Expectation–Maximization (EM) algorithm which speeds up the training of feedforward networks with local activation functions such as the Radial Basis Function (RBF)...

Modeling Nonlinear Power Amplifiers in OFDM Systems from Subsampled Data: A Comparative Study Using Real Measurements (2003)

Luis Vielva, Carlos Pantaleón, Marcelino Lázaro, Jesús Ibáñez, Ignacio Santamaría

A comparative study among several nonlinear high-power amplifier (HPA) models using real measurements is carried out. The analysis is focused on specific models for wideband OFDM signals, which are...

Modeling Nonlinear Power Amplifiers in OFDM Systems from Subsampled Data: A Comparative Study Using Real Measurements (2003)

Ignacio Santamaría, Jesús Ibáñez, Marcelino Lázaro, Carlos Pantaleón, Luis Vielva

A comparative study among several nonlinear high-power amplifier (HPA) models using real measurements is carried out. The analysis is focused on specific models for wideband OFDM signals, which are...

An Efficient method for Chaotic Signal Parameter Estimation”,Proc (2000)

Carlos Pantaleón, David Luengo, Ignacio Santamaría

Chaotic signals represent a new class of signals that can be applied in a wide range of signal processing applications. This paper describes an efficient method for parameter estimation of chaotic...

Optimal Estimation of Chaotic Signals Generated by Piecewise-Linear Maps (2000)

Carlos Pantaleón, David Luengo, Student Member, Ignacio Santamaría

Abstract—Chaotic signals generated by iterating piecewise-linear (PWL) maps on the unit interval are highly atractive in a wide range of signal processing applications. In this letter, optimal...

Specific DSP based monitoring system for hydro-generator sets”, ICSPAT (1998)

Jesús Ibáñez, Carlos J. Pantaleón, Ignacio Santamaría, David Luengo, Marcelino Lázaro, Departamento De, ...

Abstract – This paper presents a specific DSP based acquisition system developed for monitoring the behavior of low speed hydro-generator sets. The designed unit can acquire up to 16 channels and...