Ara es mostren els items 83-102 de 134

    • Improved characterization and modeling of equatorial plasma depletions 

      Blanch Llosa, Estefania; Altadill, David; Juan Zornoza, José Miguel; Camps Carmona, Adriano José; Barbosa, José; González Casado, Guillermo; Riba Sagarra, Jaume; Sanz Subirana, Jaume; Vázquez Grau, Gregorio; Orús Pérez, Raul (2018-08-22)
      Article
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      This manuscript presents a method to identify the occurrence of Equatorial Plasma Bubbles (EPBs) with data gathered from receivers of Global Navigation Satellite System (GNSS). This method adapts a previously existing ...
    • Improved modelling of ionospheric disturbances for remote sensing and navigation 

      Camps Carmona, Adriano José; Barbosa, José; Juan Zornoza, José Miguel; Blanch Llosa, Estefania; Altadill, David; González Casado, Guillermo; Vázquez Grau, Gregorio; Riba Sagarra, Jaume; Orus-Perez, Raul (Institute of Electrical and Electronics Engineers (IEEE), 2017)
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      A generic software tool to evaluate the impact of ionospheric disturbances is presented, including low and high latitude physically-based models, and low and high frequency fluctuations. This tool has been developed ...
    • Inclusion of gradient-based schemes in high resolution method 

      Vázquez Grau, Gregorio; Vallverdú Bayés, Sisco (1988)
      Text en actes de congrés
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      This paper deals with the inclusion of adaptive schemes in high-resolution methods. Past works refer gradient and conjugated gradient approaches of Pisarenko’s spectral line decomposition method for sinusoidal in white ...
    • Informe final. Demostrador de serveis Galileo per Catalunya 

      Villares Piera, Nemesio Javier; Calvo Muntaner, Eduard; Carlavilla Márquez, Màxim; Lamarca Orozco, M. Meritxell; López Salcedo, José Antonio; Rey Micolau, Francesc; Riba Sagarra, Jaume; Sala Álvarez, José; Vázquez Grau, Gregorio (2007-09-25)
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    • Informe Número 1: Projecte SETRAM 

      Sala Álvarez, José; Rey Micolau, Francesc; Riba Sagarra, Jaume; Villares Piera, Nemesio Javier; Lamarca Orozco, M. Meritxell; Vázquez Grau, Gregorio (2008-10-01)
      Report de recerca
      Accés restringit per acord de confidencialitat
      L’objectiu del projecte SETRAM és l’especificació d’algorismes de classificació no supervisada d’informació de mobilitat d’usuaris a partir de dades de posició proporcionades per la xarxa mòbil i/o satèl.lit. En el projecte ...
    • Interference mitigation in feedforward opportunistic communications 

      Borràs Pino, Jordi; Vázquez Grau, Gregorio (2023-05)
      Article
      Accés obert
      This paper deals with scenario-aware, uncoordinated, and distributed signaling techniques in the context of feedforward opportunistic communications, that is, when the opportunistic transmitting node does not cooperate ...
    • Interference mitigation under degrees-of-freedom sensing uncertainties in opportunistic transmission 

      Borràs Pino, Jordi; Vázquez Grau, Gregorio (2019)
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      Inter-system interference may limit the performance of co-existing systems in dense heterogeneous wireless networks. Context-aware waveform design can profitably overcome this limitation. However, the latter substantially ...
    • Joint synchronization and symbol detection in asynchronous DS-CDMA systems 

      Rey Micolau, Francesc; Vázquez Grau, Gregorio; Riba Sagarra, Jaume (Institute of Electrical and Electronics Engineers (IEEE), 2000)
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      The design of accurate estimators which also consider the noise term in low SNR scenarios is paramount for achieving optimal solutions and obtaining precise symbol detectors. Particularly, this paper estimates the propagation ...
    • Known Input Power Spectrum in Adaptive L.M.S. and A. G. Algorithms 

      Vázquez Grau, Gregorio; Gasull Llampallas, Antoni; Lagunas Hernandez, Miguel A. (1986)
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      This work deals with the use of previous or colateral information to improve the behaviour of adaptive algorithms. The study is made on gradient-baseq methods due te the relatively simple and good performances that they ...
    • Known input power spectrum in adaptive L.M.S. and A.G. algorithms 

      Vázquez Grau, Gregorio; Gasull Llampallas, Antoni; Lagunas Hernandez, Miguel A. (1986)
      Text en actes de congrés
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      This work deals with the use of previous or colateral information to improve the behaviour of adaptive algorithms. The study is made on gradient-baseq methods due te the relatively simple and good performances that they ...
    • Linear phase adaptive line enhancer for improving the performance of phase synchronizers 

      Castro, F. J.; Castells, J.; Vázquez Grau, Gregorio; Sánchez, J. J. (Elsevier, 1990)
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    • 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)
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      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. ...
    • Multichannel receivers from ofdm and tdma in mobile communications 

      Lamarca Orozco, M. Meritxell; Vázquez Grau, Gregorio (IEEE IEEE, 1997)
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      This paper addresses the use of multichannel receivers for blind equalization in TDMA under frequency selective channels and OFDM systems in frequency flat fading channels. A new criteria is proposed for blind equalization ...
    • NDA waveform estimation in the low-SNR regime 

      López Salcedo, José Antonio; Vázquez Grau, Gregorio (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERING INC, 2007-12)
      Article
      Accés obert
      This correspondence addresses the problem of nondata-aided waveform estimation for digital communications. Based on the unconditional maximum likelihood criterion, the main contribution of this correspondence is the ...
    • 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
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      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 ...
    • New bounds on RAKE structures for DS-CDMA over frequency-selective Rayleigh fading channels 

      Calvo Zorrilla, Sergio; Vázquez Grau, Gregorio (IEEE IEEE, 1996)
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      An upper bound is derived for the probability of error in an asynchronous binary direct-sequence spread-spectrum multiple-access communications system operating over frequency selective Rayleigh fading channels. A coherent ...
    • Noise enhancement and SNR equivalence in Bernoulli nonuniform sampling 

      Font Segura, Josep; Vázquez Grau, Gregorio; Riba Sagarra, Jaume (2011)
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      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
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      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)
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      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 ...