Wideband transhorizon channel characterization

Ndzi, David; Austin, J.

doi:10.1029/2000rs002552

Cited by 1 publication

(1 citation statement)

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“…The investigation was conducted using a wideband channel sounder, the details and design principles of which are described in Austin et al [1997]. The sounder has previously been used to characterize various channels, and details can be found in Ndzi et al [2001] and Savage et al [2002]. The sounder transmits a 31.25 MHz bandwidth pseudorandom Gaussian noise (PRGN) sequence simultaneously at 1.3, 2 and 11.6 GHz.…”

Section: Experimental System and Data Processingmentioning

confidence: 99%

Radio wave propagation through vegetation: Factors influencing signal attenuation

et al. 2003

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[1] The paper describes an extensive wideband channel sounding measurement campaign to investigate signal propagation through vegetation. The measurements have been conducted at three frequencies (1.3, 2 and 11.6 GHz) at sites with different measurement geometries and tree species. The data have been used to evaluate current narrowband empirical vegetation attenuation models and study the prevailing propagation mechanisms. Evaluation of the modified exponential decay (MED), maximum attenuation (MA) and nonzero gradient (NZG) models show that on a site by site basis, the NZG model gives the best prediction of excess attenuation due to vegetation. The MA model has been found to be the worst of the three models. The studies have shown that the measurement site used to obtain the NZG model parameter values given in International Telecommunication Union (ITU) [2001] is influenced by metal lampposts and passing traffic, and thus was based on corrupted data. The results show that the leaf state, measurement geometry and vegetation density are more important factors influencing signal attenuation than tree species or leaf shape. Generally, the 11.6 GHz signal was attenuated much more than the 1.3 and 2 GHz signals by vegetation in-leaf, but the differences in attenuation were not significant in the out-of-leaf state. A successful excess attenuation model due to vegetation must consider the measurement geometry and vegetation descriptive parameters as well as any contributions from ground reflection and/ or diffraction over the top or round edges of the trees.

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Section: Experimental System and Data Processingmentioning

confidence: 99%