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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Avalia??o do impacto em rede de sensores sem fio com utiliza??o de sistema de r?dio sobre fibra / Impact evaluation in wireless sensor network in use with radio over fiber system

Assump??o, Raphael Montali da 29 June 2011 (has links)
Made available in DSpace on 2016-04-04T18:31:31Z (GMT). No. of bitstreams: 1 Raphael Montali da Assumpcao.pdf: 4212017 bytes, checksum: 0f3ac0dc977e7baf5d1589a58db83ffd (MD5) Previous issue date: 2011-06-29 / This study analyzes the impact that Radio over Fiber technology, functioning as a transport network, causes to a Wireless Sensor Network. Phenomena present in Radio over Fiber system tnet degrade the RF signal are analyzed. For this impact verification a test bed was assembled with wireless sensors operating at the 915 MHz Range and RoF equipments. To avoid uncertainties caused by effects in radio signal propagation a channel emulation system capable of varying the attenuation imposed to the radio signal was used. In the conducted tests packet loss and received signal strength at the receiver were measured for two different modulations: FSK and MSK. In the first experiment the Wireless Sensor Network was tested without the introduction of the Radio over Fiber system, those results were used as a reference for the other tests. /n the second experiment tests with the introduction of a Radio over Fiber system creating a covering cell were made. In the third experiment a second RoF equipment was introduced to create a second covering cell. Ali the tests were repeated using a Low Noise Amplifier. The results show that it is possible to use RoF in a WSN implementation. However, the impact at the penalty introduced by the RoF on the cell covering distance was high, showing that in fact there is an impact in the covering distance. It was shown that the introduction of new covering cells adds additional penalty because of characteristics of the RoF. The introduction of the LNA was shown to be effective for fighting the degradation added by the RoF system. / O presente trabalho analisa o impacto que a tecnologia de R?dio Sobre Fibra, funcionando como rede de transporte, provoca a uma Rede de Sensores Sem Fio. S?o analisados os fen?menos presentes no sistema de r?dio sobre fibra que degradam o sinal de r?dio frequ?ncia. Para verifica??o deste impacto foi montada uma estrutura de testes com sensores Sem Fio operando na faixa de 915 MHz e equipamentos de RoF. Para evitar incertezas causadas por efeitos de propaga??o do sinal de r?dio foi utilizada uma bancada de emula??o de canal com capacidade para varia??o da atenua??o do sinal r?dio. Nos testes realizados foram medidas a perda de pacotes e a pot?ncia de sinal recebido na base receptora em duas modula??es diferentes: FSK e MSK. No primeiro experimento foram feitos testes com a Rede de Sensores Sem Fio sem a introdu??o do sistema de R?dio Sobre Fibra, cujos resultados foram utilizados como refer?ncia para os outros testes. No segundo experimento foram feitos testes com a introdu??o de um sistema de RoF criando uma c?lula de cobertura. No terceiro experimento foi introduzido um segundo equipamento de RoF criando uma segunda c?lula de cobertura. Todos os testes foram repetidos com a utiliza??o de um amplificador de baixo ru?do. Os resultados demonstram a possibilidade da implementa??o de RSSF com a utiliza??o de RoF. Entretanto, o impacto da penalidade introduzida pelo RoF na ?rea de cobertura da RSSF foi elevado, demonstrando que de fato existe uma penalidade em termos de dist?ncia de cobertura. Ficou demonstrado que a introdu??o de novas c?lulas acrescenta penaliza??o adicional devido a caracter?sticas do RoF. A introdu??o do LNA demonstrou ser eficaz para combater a degrada??o inserida pelo sistema RoF.

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