Ara es mostren els items 49-68 de 77

    • Minimum error entropy estimation under contaminated Gaussian noise 

      López Molina, Carlos Alejandro; Cabrera Estanyol, Ferran de; Riba Sagarra, Jaume (Institute of Electrical and Electronics Engineers (IEEE), 2023-10-12)
      Article
      Accés obert
      It is shown that Rényi's entropy of a Gaussian mixture with entropic index α∈(1,∞] is upper-bounded by the cluster with minimum variance. This basic idea leads to a clean worst-case formulation of the minimum error entropy ...
    • Multi-frequency GLRT spectrum sensing for wideband cognitive radio 

      Font Segura, Josep; Vázquez Grau, Gregorio; Riba Sagarra, Jaume (IEEE Press. Institute of Electrical and Electronics Engineers, 2011)
      Text en actes de congrés
      Accés restringit per política de l'editorial
      The problem of spectrum sensing in multi-frequency cognitive radio systems is addressed. We show that as the sensed bandwidth increases, the primary user detection is governed by a low signal-to-noise ratio (low-SNR) regime. ...
    • Multi-satellite cycle-slip detection and exclusion using the noise subspace of residual dynamics 

      Riba Sagarra, Jaume; Cabrera Estanyol, Ferran de; Juan Zornoza, José Miguel (Institute of Electrical and Electronics Engineers (IEEE), 2018)
      Text en actes de congrés
      Accés obert
      Real-time detection of cycle-slips on undifferenced carrier-phase measurements is an important task to properly exclude wrong phase trackers from precise positioning algorithms. The detection is especially challenging in ...
    • Near-far resistant CML propagation delay estimation and multi-user detection for asynchronous DS-CDMA systems 

      Rey Micolau, Francesc; Vázquez Grau, Gregorio; Riba Sagarra, Jaume (Institute of Electrical and Electronics Engineers (IEEE), 1999)
      Text en actes de congrés
      Accés obert
      Multi-user receivers in asynchronous direct sequence code division multiple access (DS-CDMA) systems require the knowledge of several parameters such as timing delay between users. The goal of this work is to present a ...
    • Noise enhancement and SNR equivalence in Bernoulli nonuniform sampling 

      Font Segura, Josep; Vázquez Grau, Gregorio; Riba Sagarra, Jaume (2011)
      Text en actes de congrés
      Accés restringit per política de l'editorial
      This paper addresses the problem of nonuniform spectral analysis and spectrum sensing by means of Bernoulli sampling. The statistical treatment of sampling shows that nonuniformly sampling below the Nyquist rate produces ...
    • Non-data-aided frequency offset and symbol timing estimation for binary CPM: performance bounds 

      Riba Sagarra, Jaume; Vázquez Grau, Gregorio (Institute of Electrical and Electronics Engineers (IEEE), 2000)
      Text en actes de congrés
      Accés obert
      The use of (spectrally efficient) CPM modulations may lead to a serious performance degradation of the classical non-data-aided (NDA) frequency and timing estimators due to the presence of self noise. The actual performance ...
    • Nonuniform sampling walls in wideband signal detection 

      Font Segura, Josep; Vázquez Grau, Gregorio; Riba Sagarra, Jaume (2014-01-01)
      Article
      Accés obert
      This work shows the existence of sampling walls in detection of wideband signals from Bernoulli nonuniform sampling (BNS) in the presence of noise uncertainty. A sampling wall is defined as the sampling density below which ...
    • Nota tècnica 1: projecte SETRAM 

      Sala Álvarez, José; Riba Sagarra, Jaume; Rey Micolau, Francesc; Villares Piera, Nemesio Javier; Vázquez Grau, Gregorio; Lamarca Orozco, M. Meritxell (2008-02-26)
      Altres
      Accés restringit per acord de confidencialitat
      Un dels aspectes més crítics per assolir una definició avançada i realista del sistema SETRAM és la identificació de les tecnologies més adequades per a la localització d’usuaris mòbils, des de les ja existents (aplicables ...
    • Novel periodogram and Capon spectral analysis based on nonuniform sampling 

      Font Segura, Josep; Vázquez Grau, Gregorio; Riba Sagarra, Jaume (IEEE Press. Institute of Electrical and Electronics Engineers, 2011)
      Text en actes de congrés
      Accés restringit per política de l'editorial
      The spectrum analysis problem based on the periodogram and Capon estimates from a nonuniformly sampled signal is addressed. The nonuniform sampling process is cast as a linear projection matrix which encompasses several ...
    • On infinite past predictability of cyclostationary signals 

      Riba Sagarra, Jaume; Vila Insa, Marc (Institute of Electrical and Electronics Engineers (IEEE), 2022)
      Article
      Accés obert
      This paper explores the asymptotic spectral decomposition of periodically Toeplitz matrices with finite summable elements. As an alternative to polyphase decomposition and other approaches based on Gladyshev representation, ...
    • On the estimation of Tsallis entropy and a novel information measure based on its properties 

      Martí Espelt, Aniol; Cabrera Estanyol, Ferran de; Riba Sagarra, Jaume (2023-06-30)
      Article
      Accés obert
      This letter explores a plug-in estimator of second-order Tsallis entropy based on Kernel Density Estimation (KDE) and its implicit regularization process. First, it is shown that the expected value of the estimator corresponds ...
    • Proyecto AVANT. Estudio de técnicas de sincronización para relaciones señal a ruido muy bajas. D11: Disseny del codificador i descodificador del turbo-codi de l'estàndard DVB-RCS 

      Lamarca Orozco, M. Meritxell; Ramírez Javega, Francisco; Rey Micolau, Francesc; Riba Sagarra, Jaume; Sala Álvarez, José; Vázquez Grau, Gregorio; Villares Piera, Nemesio Javier (2010-07-16)
      Report de recerca
      Accés restringit per acord de confidencialitat
      This document contains the instructions for the design of the DVB-RCS turbo-code. Both the algorithmic and implementation issues are addressed in the document.
    • Proyecto AVANT. Estudio de técnicas de sincronización para relaciones señal a ruido muy bajas. D12. Disseny i simulació dels algorismes de sincronització 

      Villares Piera, Nemesio Javier; Font Segura, Josep; Lamarca Orozco, M. Meritxell; Matas Navarro, David; Ramírez Javega, Francisco; Rey Micolau, Francesc; Riba Sagarra, Jaume; Sala Álvarez, José; Vázquez Grau, Gregorio (2010-07-16)
      Report de recerca
      Accés restringit per acord de confidencialitat
      In this document, the synchronization algorithms developed during the project are presented and simulated. The studied algorithms are designed for a QS-CDMA system operating in the low SNR regime, i.e., at low Es/No values ...
    • Quadratic sphericity test for blind detection over time-varying frequency-selective fading channels 

      Font Segura, Josep; Riba Sagarra, Jaume; Villares Piera, Nemesio Javier; Vázquez Grau, Gregorio (Institute of Electrical and Electronics Engineers (IEEE), 2013)
      Comunicació de congrés
      Accés obert
      This paper addresses the problem of blind detection of a wide-sense stationary (WSS) signal over fading channels. We propose a test statistic which is optimal from a correlation-matching perspective that shows invariance ...
    • REAVALUACIÓ 

      Nájar Martón, Montserrat; Pagès Zamora, Alba Maria; Riba Sagarra, Jaume; Vázquez Grau, Gregorio (Universitat Politècnica de Catalunya, 2022-07-05)
      Examen
      Accés restringit a la comunitat UPC
    • Regularized estimation of information via canonical correlation analysis on a finite-dimensional feature space 

      Cabrera Estanyol, Ferran de; Riba Sagarra, Jaume (2023-08)
      Article
      Accés obert
      This paper aims to estimate the information between two random phenomena by using consolidated second-order statistics tools. The squared-loss mutual information, a surrogate of the Shannon mutual information, is chosen ...
    • Robust beamforming for interference rejection in mobile communications 

      Riba Sagarra, Jaume; Goldberg, Jason; Vázquez Grau, Gregorio (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 1997-01-01)
      Article
      Accés obert
      The problem of robust beamformer design for mobile communications applications in the presence of moving co-channel sources is addressed. A generalization of the optimum beamformer based on a statistical model accounting ...
    • Robust beamforming for interference rejection in mobile communications 

      Riba Sagarra, Jaume; Goldberg, J; Vázquez Grau, Gregorio (1996)
      Text en actes de congrés
      Accés obert
      The problem of robust beamformer design in the presence of moving sources is considered. A new technique based on a generalization of the constrained minimum variance beamformer is proposed. The method explicitly takes ...
    • Robust data detection in asynchronous DS-CDMA in the presence of timing uncertainty 

      Riba Sagarra, Jaume; Goldberg, J; Vázquez Grau, Gregorio (IEEE, 1996)
      Text en actes de congrés
      Accés obert
      The decorrelating and minimum mean squared error data detectors for direct sequence code division multiple access (DS-CDMA) communications systems are known to exhibit low vulnerability to the near-far problem. Nevertheless, ...
    • Robust estimation of the magnitude squared coherence based on Kernel signal processing 

      Cabrera Estanyol, Ferran de; Riba Sagarra, Jaume; Vázquez Grau, Gregorio (Institute of Electrical and Electronics Engineers (IEEE), 2018)
      Comunicació de congrés
      Accés obert
      A new outlier-robust approach to estimate the magnitude squared coherence of a random vector sequence, a common task required in a variety of estimation and detection problems, is proposed. The proposed estimator is based ...