Now showing items 21-40 of 61

    • Cramer-Rao bounds for SNR estimation of oversampled linearly modulated signals 

      López Valcarce, Roberto; Villares Piera, Nemesio Javier; Riba Sagarra, Jaume; Gappmair, Wilfried; Mosquera Nartallo, Carlos (2015-04-01)
      Article
      Open Access
      Most signal-to-noise ratio (SNR) estimators use the receiver matched filter output sampled at the symbol rate, an approach which does not preserve all information in the analog waveform due to aliasing. Thus, it is relevant ...
    • D1. Estudio de códigos PN para mejorar el ensanchado y la eficiencia espectral del sistema CDMA síncrono y asíncrono 

      Lamarca Orozco, M. Meritxell; Rey Micolau, Francesc; Riba Sagarra, Jaume; Sala Álvarez, José; Vázquez Grau, Gregorio; Villares Piera, Nemesio Javier (2008-11-10)
      External research report
      Restricted access - confidentiality agreement
    • D2. Estructuras de detector multiusuario para CDMA síncrono y asíncrono 

      Lamarca Orozco, M. Meritxell; Rey Micolau, Francesc; Riba Sagarra, Jaume; Sala Álvarez, José; Vázquez Grau, Gregorio; Villares Piera, Nemesio Javier (2008-11-10)
      External research report
      Restricted access - confidentiality agreement
    • D3. Sincronización robusta de frecuencia y fase para M-PSK sobre CDMA 

      Lamarca Orozco, M. Meritxell; Rey Micolau, Francesc; Riba Sagarra, Jaume; Sala Álvarez, José; Vázquez Grau, Gregorio; Villares Piera, Nemesio Javier (2008-11-10)
      External research report
      Restricted access - confidentiality agreement
    • DA-GLRT burst detection and synchronization based on a chirp-like preamble 

      Rodríguez, E; Lamarca Orozco, M. Meritxell; López Salcedo, José Antonio; Rey Micolau, Francesc; Riba Sagarra, Jaume; Sala Álvarez, José; Vázquez Grau, Gregorio; Villares Piera, Nemesio Javier; Jalón, A (2008)
      Conference report
      Restricted access - publisher's policy
      A specific preamble for the tasks of signal detection and synchronization in burst digital communications is presented. The preamble resembles a chirp signal used in RADAR applications. Its main benefit is that it allows ...
    • Descripciones tiempo-frecuencia en la recuperacion conjunta de param 

      Riba Sagarra, Jaume; Vázquez Grau, Gregorio (Universidad de Málaga, 1992)
      Conference report
      Open Access
    • Dimension spreading for coherent opportunistic communications 

      Borràs Pino, Jordi; Font Segura, Josep; Riba Sagarra, Jaume; Vázquez Grau, Gregorio (Institute of Electrical and Electronics Engineers (IEEE), 2018)
      Conference report
      Open Access
      The waveform optimization problem for opportunistic communications is addressed, based on sensing the second-order statistics of the existing transmissions. We propose a minimum-norm waveform optimization that exhibits ...
    • Entropy-based covariance determinant estimation 

      Cabrera Estanyol, Ferran de; Riba Sagarra, Jaume; Vázquez Grau, Gregorio (Institute of Electrical and Electronics Engineers (IEEE), 2017)
      Conference lecture
      Open Access
      An information-theoretic approach is described to estimate the determinant of the covariance matrix of a random vector sequence (a common task in a wide range of estimation and detection problems in signal processing for ...
    • Entropy-based non-data-aided SNR estimation 

      Cabrera Estanyol, Ferran de; Riba Sagarra, Jaume (Institute of Electrical and Electronics Engineers (IEEE), 2019)
      Conference lecture
      Open Access
      A non-data-aided SNR estimation of a communication channel is addressed in this paper. The main contribution relies on the relationship between an entropy measure of a given constellation and the link quality. The main ...
    • Feasibility of precise navigation in high and low latitude regions under scintillation conditions 

      Juan Zornoza, José Miguel; Sanz Subirana, Jaume; González Casado, Guillermo; Rovira Garcia, Adrià; Camps Carmona, Adriano José; Riba Sagarra, Jaume; Barbosa, José; Blanch Llosa, Estefania; Altadill, David; Orús Pérez, Raul (2018-02-06)
      Article
      Open Access
      Scintillation is one of the most challenging problems in Global Navigation Satellite Systems (GNSS) navigation. This phenomenon appears when the radio signal passes through ionospheric irregularities. These irregularities ...
    • Frequency-domain GLR detection of a second-order cyclostationary signal over fading channels 

      Riba Sagarra, Jaume; Font Segura, Josep; Villares Piera, Nemesio Javier; Vázquez Grau, Gregorio (2014-04-01)
      Article
      Open Access
      Cyclostationary processes exhibit a form of frequency diversity. Based on that, we show that a digital waveform with symbol period T can be asymptotically represented as a rank-1 frequency-domain vector process which ...
    • Frequency-domain GLR detection of cyclostationary signals in frequency-selective channels 

      Font Segura, Josep; Riba Sagarra, Jaume; Villares Piera, Nemesio Javier; Vázquez Grau, Gregorio (Institute of Electrical and Electronics Engineers (IEEE), 2014)
      Conference report
      Open Access
      The frequency diversity exhibited by cyclostationary signals is exploited in this paper. A novel rank-1 frequency-domain representation of a digital waveform is proposed to address the generalized likelihood ratio (GLR) ...
    • HISPANET: a digital television/multimedia payload 

      Sala Álvarez, José; Sergio, Calvo; Pagès Zamora, Alba Maria; Vázquez Grau, Gregorio; Riba Sagarra, Jaume (European Spatial Agengy (ESA), 1998)
      Conference report
      Open Access
    • 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
      Open Access
      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)
      Conference report
      Restricted access - publisher's policy
      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 ...
    • 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)
      External research report
      Restricted access - confidentiality agreement
    • 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)
      External research report
      Restricted access - confidentiality agreement
      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 ...
    • 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)
      Conference report
      Open Access
      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 ...
    • 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)
      Conference report
      Restricted access - publisher's policy
      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)
      Conference report
      Open Access
      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 ...