Ara es mostren els items 13-23 de 23

    • 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. ...
    • 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 ...
    • 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 ...
    • 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 ...
    • 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 ...
    • Robust non-linear precoding for downlink multiuser multiple-input multiple-output orthogonal frequency-division multiplexing systems with limited feedback 

      Font Segura, Josep; Su, Y.; Wang, Xiaodong (2012-08-14)
      Article
      Accés restringit per política de l'editorial
      The authors consider the robust Tomlinson–Harashima precoding (THP) for downlink multiuser multiple-input multiple-output orthogonal frequency-division multiplexing systems with quantised feedback. The authors discuss ...
    • Sampling walls in signal detection of Bernoulli nonuniformly sampled signals 

      Font Segura, Josep; Vázquez Grau, Gregorio; Riba Sagarra, Jaume (2013)
      Text en actes de congrés
      Accés restringit per política de l'editorial
      In this work, we show the existence of sampling walls in signal detection of nonuniformly sampling wideband signals in the presence of noise uncertainty. A sampling wall is the sampling rate below which the target error ...
    • Single and multi-frequency wideband spectrum sensing with side-information 

      Font Segura, Josep; Vázquez Grau, Gregorio; Riba Sagarra, Jaume (2014-10-01)
      Article
      Accés obert
      This study addresses the optimal spectrum sensing detection based on the complete or partial side-information on the signal and noise statistics. The use of the generalised-likelihood ratio test (GLRT) involves maximum-likelihood ...
    • Sphericity minimum description length: asymptotic performance under unknown noise variance 

      Font Segura, Josep; Riba Sagarra, Jaume; Vázquez Grau, Gregorio (Institute of Electrical and Electronics Engineers (IEEE), 2015)
      Text en actes de congrés
      Accés obert
      This paper revisits the model order selection problem in the context of second-order spectrum sensing in cognitive radio. Taking advantage of the recent interest on the generalized likelihood ratio (GLR), the asymptotic ...
    • Wideband cognitive radio: monitoring, detection and sparse noise subspace communication 

      Font Segura, Josep (Universitat Politècnica de Catalunya, 2014-07-24)
      Tesi
      Accés obert
      We are surrounded by electronic devices that take advantage of wireless technologies, from our computer mice, which require little amounts of information, to our cellphones, which demand increasingly higher data rates. ...