Título: | MODELING ATMOSPHERIC MULTIPATH FADING IN LINE-OF-SIGHT MICROWAVE LINKS | ||||||||||||||||||||||||||||||||||||||||
Autor: |
PEDRO VLADIMIR GONZALEZ CASTELLANOS |
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Colaborador(es): |
LUIZ ALENCAR REIS DA SILVA MELLO - Orientador |
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Catalogação: | 11/NOV/2003 | Língua(s): | PORTUGUESE - BRAZIL |
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Tipo: | TEXT | Subtipo: | THESIS | ||||||||||||||||||||||||||||||||||||||
Notas: |
[pt] Todos os dados constantes dos documentos são de inteira responsabilidade de seus autores. Os dados utilizados nas descrições dos documentos estão em conformidade com os sistemas da administração da PUC-Rio. [en] All data contained in the documents are the sole responsibility of the authors. The data used in the descriptions of the documents are in conformity with the systems of the administration of PUC-Rio. |
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Referência(s): |
[pt] https://www.maxwell.vrac.puc-rio.br/projetosEspeciais/ETDs/consultas/conteudo.php?strSecao=resultado&nrSeq=4106&idi=1 [en] https://www.maxwell.vrac.puc-rio.br/projetosEspeciais/ETDs/consultas/conteudo.php?strSecao=resultado&nrSeq=4106&idi=2 |
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DOI: | https://doi.org/10.17771/PUCRio.acad.4106 | ||||||||||||||||||||||||||||||||||||||||
Resumo: | |||||||||||||||||||||||||||||||||||||||||
Multipath fading is the main cause of performance
degradation in high capacity line-of-sight microwave links,
increasing enhancing the effects of the thermal noise and
intersymbol interference in the bit error rate.
Tested methods are available in the literature for the
prediction of cumulative probability distribution multipath
fading in individual link but not in a microwave network
formed by several tandem links. Measurements carried out in
Brazil indicate that the usual assumption that deep fade
events in consecutive links are totally uncorrelated may be
pessimistic for tropical regions and may lead to the
prediction excessive multihop links unavailability.
Experimental data obtained in measurements of multipath
fading in 15 pairs of tandem links located in the center-
western region of Brazil were analyzed to provide
cumulative distributions of attenuation in each pair.
Similar results are available in the literature for 5 pairs
of links in Japan. Based on these results, an empirical
model was developed for the prediction of the joint
probability distribution the multipath fading in adjacent
links was developed. The attenuation simultaneously
exceeded in both links for given percentage of time can be
predicted as a function of the equiprobable values of
attenuation exceeded in the individual links, path lengths
and operation frequency. The predicted distributions show
good agreement with the experimental results and provide an
expression for the calculation of unavailability of line-of-
sight tandem links. The experimental data had been used
still to model the duration of events of attenuation for
multipath of links in visibility. One revealed that the
distribution of duration of events well is characterized by
distributions of Weibull. This characterization allows the
distinction between events of loss of quality (lowest
duration at 10 seconds) and of non-availability (higher
duration the 10 seconds).
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