Enviaments recents

  • Cancellation of external and multiple access interference in cdma systems using antenna arrays 

    Muñoz Medina, Olga; Fernández Rubio, Juan Antonio (D. DOCAMPO, A. R. FIGUEIRAS, F. PÉREZ, 1996)
    Text en actes de congrés
    Accés restringit per política de l'editorial
    This paper deals with the problem of multisensor-multiuser detection in CDMA systems in the presence of interferences external to the system. The paper presents a new method able to estimate the spatial signature of all ...
  • Experimental result for a sdma mobile communications antenna array system 

    Goldberg, Jason Matthew; Pagès Zamora, Alba Maria; Lagunas Hernandez, Miguel A.; Rodríguez Fonollosa, Javier; Vázquez Grau, Gregorio (EE PUBL. EE PUBL., 1996)
    Text en actes de congrés
    Accés obert
    This paper presents experimental results for a Spatial Division Multiple Access cellular mobile communications system. The basestation antenna array testbed used to obtain the results is described in addition to sophisticated ...
  • Blind multiuser detection using hidden markov models theory 

    Antón Haro, Carles; Rodríguez Fonollosa, José Adrián; Rodríguez Fonollosa, Javier (BOB WERNER IEEE, 1996)
    Text en actes de congrés
    Accés obert
    We present an adaptive algorithm based on the theory of hidden Markov models (HMM) which is capable of jointly detecting the users in a DS-CDMA system. The proposed technique is near-far resistant and completely blind in ...
  • New bounds on RAKE structures for DS-CDMA over frequency-selective Rayleigh fading channels 

    Calvo Zorrilla, Sergio; Vázquez Grau, Gregorio (IEEE IEEE, 1996)
    Text en actes de congrés
    Accés obert
    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 ...
  • On the inclusion of channel's time dependence in a hidden Markov model for blind channel estimation 

    Antón Haro, Carles; Rodríguez Fonollosa, José Adrián; Rodríguez Fonollosa, Javier (BOB WERNER IEEE COMPUTER SOCIETY PRESS, 1996)
    Text en actes de congrés
    Accés obert
    We introduce several modifications to the Baum&Welch (BW) formulas used to reestimate the parameters of a hidden Markov model (HMM). The estimated parameter is the channel impulse response (CIR) of a communication system ...
  • Robust data detection in asynchronous DS-CDMA in the presence of timing uncertainty 

    Riba Sagarra, Jaume; Goldberg, J; Vázquez Grau, Gregorio (IEEE 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, ...
  • Channel estimation for transform modulations in mobile communications 

    Lamarca Orozco, M. Meritxell; Vázquez Grau, Gregorio (1996)
    Text en actes de congrés
    Accés obert
    This paper deals with data-aided channel estimation in systems using OFDM modulation. We formulate a pilot symbol-based channel estimator and compare it with the pilot-tone one proposed in [1]. Although this paper focuses ...
  • Symbol decoding based on signal subspace decomposition in msk 

    Ruiz Feliu, Rafael; Cabrera Beán, Margarita Asuncion (1996)
    Text en actes de congrés
    Accés obert
    The availability of fast processors with architectures tailored to meet the computational demand of digital signal processing algorithms is widely applied to demodulation and decodification of CPM signals in some scenes: ...
  • Duration modeling with expanded HMM applied to speech recognition 

    Bonafonte Cávez, Antonio; Vidal Manzano, José; Nogueiras Rodríguez, Albino (H. TIMOTHY BRUMMELL, WILLIAM IDSARDI CITATION DELAWARE, NEW CASTLE, DELAWARE, 1996)
    Comunicació de congrés
    Accés obert
    The occupancy of the HMM states is modeled by means of a Markov chain. A linear estimator is introduced to compute the probabilities of the Markov chain. The distribution function (DF) represents accurately the observed ...
  • Blind multiuser deconvolution in fading and dispersive channels 

    Rodríguez Fonollosa, Javier; Rodríguez Fonollosa, José Adrián; Zvonar, Z; Vidal Manzano, José (. S.N., 1995)
    Text en actes de congrés
    Accés obert
    An adaptive near-far resistant technique for the blind joint multiuser identification and detection in asynchronous CDMA systems is analyzed in fading and dispersive GSM channels.

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