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Báo cáo hóa học: " Research Article Application of the Evidence Procedure to the Estimation of Wireless Channels"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Research Article Application of the Evidence Procedure to the Estimation of Wireless Channels | Hindawi Publishing Corporation EURASIP Journal on Advances in Signal Processing Volume 2007 Article ID 79821 23 pages doi 10.1155 2007 79821 Research Article Application of the Evidence Procedure to the Estimation of Wireless Channels Dmitriy Shutin 1 Gernot Kubin 1 and Bernard H. Fleury2 3 1 Signal Processing and Speech Communication Laboratory Graz University of Technology 8010 Graz Austria 2 Institute of Electronic Systems Aalborg University Fredrik Bajers Vej 7A 9220 Aalborg Denmark 3 Forschungszentrum Telekommunikation Wien ftw. Donau City Strasse 1 1220 Wien Austria Received 5 November 2006 Accepted 8 March 2007 Recommended by Sven Nordholm We address the application of the Bayesian evidence procedure to the estimation of wireless channels. The proposed scheme is based on relevance vector machines RVM originally proposed by M. Tipping. RVMs allow to estimate channel parameters as well as to assess the number of multipath components constituting the channel within the Bayesian framework by locally maximizing the evidence integral. We show that in the case of channel sounding using pulse-compression techniques it is possible to cast the channel model as a general linear model thus allowing RVM methods to be applied. We extend the original RVM algorithm to the multiple-observation multiple-sensor scenario by proposing a new graphical model to represent multipath components. Through the analysis of the evidence procedure we develop a thresholding algorithm that is used in estimating the number of components. We also discuss the relationship of the evidence procedure to the standard minimum description length MDL criterion. We show that the maximum of the evidence corresponds to the minimum of the MDL criterion. The applicability of the proposed scheme is demonstrated with synthetic as well as real-world channel measurements and a performance increase over the conventional MDL criterion applied to maximum-likelihood estimates of the channel parameters is observed.