Examinando por Autor "Murillo-Fuentes, Juan J."

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  • Miniatura
    Ítem
    Hybrid Higher-Order Statistics Learning in Multiuser Detection
    (Institute of Electrical and Electronical Engineering, 2004-11) Caamaño, Antonio J.; Boloix-Tortosa, R.; Ramos, Javier; Murillo-Fuentes, Juan J.
    In this paper, we explore the significance of second- and higher-order statistics learning in communication systems. The final goal in spread-spectrum communication systems is to receive a signal of interest completely free from interference caused by other concurrent signals. To achieve this end, we exploit the structure of the interference by designing second-order statistics detectors, such as the minimum square error, in conjunction with higher-order statistics (HOS) techniques, such as the blind source separation (BSS). This hybrid higher-order statistics (HyHOS) approach enables us to alleviate BSS algorithms of one of their main problems, that is, their sensitiveness to high levels of noise. In addition, we benefit from remarkable properties of BSS in learning such as fast learning (superefficiency) and independence of the initial settings of the problem (equivariance). We successfully applied the results of this approach to the design of multiuser detectors in code-division multiple access channels.
  • Miniatura
    Ítem
    Natural Gradient Based Blind Multiuser Detection
    (2002) Murillo-Fuentes, Juan J.; González Serrano, F.J.; Ramos, Javier; Caamaño, Antonio J.
    In this paper, novel structures for dynamic removal of multiuser interference are proposed. The natural gradient (NG) is used either to compute whitening matrices in linear blind minimum MSE or to develop new structures. As a result, we propose a family of centralized and non-centralized multiuser detectors (MUD's). The NG provides the MUD's with the equivariant and superfficiency properties, making them near-far resistant by construction and their convergence optimal. Moreover, the complexity of these structures is significantly reduced. These novel solutions are successfully applied to the multiuser synchronous CDMA channel.