Uso de correntropia na generaliza??o de fun??es cicloestacion?rias e aplica??es para a extra??o de caracter?sticas de sinais modulados

Autor: Fontes, Aluisio Igor R?go
Jazyk: portugalština
Rok vydání: 2015
Předmět:
Zdroj: Repositório Institucional da UFRNUniversidade Federal do Rio Grande do NorteUFRN.
Druh dokumentu: Doctoral Thesis
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Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES)
A extra??o de informa??es de sinais aleat?rios ? um problema frequente e relevante em muitas aplica??es de processamento digital de sinais. Nos ?ltimos anos, diferentes m?todos t?m sido utilizados para a parametriza??o de sinais ou obten??o de descritores eficientes de suas caracter?sticas. Quando os sinais aleat?rios possuem propriedades es- tat?sticas cicloestacion?rias, as Fun??es de Autocorrela??o C?clica (CAF) e a Densidade Espectral C?clica (SCD) podem ser utilizadas na obten??o de informa??es cicloestacion?- rias de segunda ordem. Entretanto, em sinais n?o-gaussianos, as informa??es cicloestaci- on?rias de segunda ordem s?o fracas e, neste caso a an?lise cicloestacion?ria deve ocorrer sobre informa??es estat?sticas de ordem superior. Este trabalho prop?e uma nova ferra- menta matem?tica para a an?lise cicloestacion?ria de ordem superior baseada na fun??o de correntropia. Especificamente, a teoria de an?lise cicloestacion?ria ? revisitada sob um enfoque de teoria da informa??o, e as Fun??es de Correntropia C?clica (CCF) e Densidade Espectral de Correntropia C?clica (CCSD) s?o definidas. ? comprovado analiticamente que a CCF cont?m informa??es de momentos cicloestacion?rios de segunda ordem e de ordem superior, sendo uma generaliza??o da CAF. O desempenho dessas novas fun??es, na extra??o de caracter?sticas cicloestacion?rias de ordem superior, ? analisado em um cen?rio de comunica??o sem fio com ru?do n?o-gaussiano.
Information extraction is a frequent and relevant problem in digital signal processing. In the past few years, different methods have been utilized for the parameterization of signals and the achievement of efficient descriptors. When the signals possess statistical cyclostationary properties, the Cyclic Autocorrelation Function (CAF) and the Spectral Cyclic Density (SCD) can be used to extract second-order cyclostationary information. However, second-order cyclostationary information is poor in nongaussian signals, as the cyclostationary analysis in this case should comprise higher-order statistical information. This paper proposes a new mathematical tool for the higher-order cyclostationary analysis based on the correntropy function. Specifically, the cyclostationary analysis is revisited focusing on the information theory, while the Cyclic Correntropy Function (CCF) and Cyclic Correntropy Spectral Density (CCSD) are also defined. Besides, it is analytically proven that the CCF contains information regarding second- and higher-order cyclostationary moments, being a generalization of the CAF. The performance of the aforementioned new functions in the extraction of higher-order cyclostationary characteristics is analyzed in a wireless communication system where nongaussian noise exists.
Databáze: Networked Digital Library of Theses & Dissertations
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