Percorrer por autor "Morgadinho, Sérgio"
A mostrar 1 - 2 de 2
Resultados por página
Opções de ordenação
- Investigation of a Radio Propagation Model for Vegetation Scatter Dynamic Channels at BFWA FrequenciesPublication . Morgadinho, Sérgio; Richter, Juergen; Caldeirinha, Rafael F. S.; Fernandes, Telmo R.The successful deployment of wireless technologies in the micro- and millimetre frequencies relies on the understanding of radio channel propagation and accurate radio propagation models. To this extent, the dynamic effects of vegetation on radio signals are investigated, as a function of wind direction, receiver location and vegetation depth. Furthermore, a radio propagation model, based on the RET, is investigated as an approach to predict the channel dynamic effects of vegetation scatter at 20 GHz. The model is evaluated for a structured forest medium, and its performance is assessed through the use of primary, secondary and error quantification statistics.
- Time-Variant Radio Channel Characterization and Modelling of Vegetation Media at Millimeter-Wave FrequencyPublication . Morgadinho, Sérgio; Caldeirinha, Rafael F. S.; Al-Nuaimi, Miqdad O.; Cuinas, Iñigo; Sanchez, Manuel Garcia; Fernandes, Telmo R.; Richter, JürgenResults of an extensive measurement campaign to characterize and model dynamic effects on the radio channel in vegetation media at 40 GHz, are presented. Using two small trees in an anechoic chamber, narrowband fast-fading measurements, utilizing co-polarized signals, were conducted to obtain radio channel characterization. This was performed as a function of the bi-static scattering angle, wind speed, wind incidence, and tree species. Furthermore, a modelling methodology is investigated and assessed as to its feasibility as a means to model vegetation dynamics effects on propagation. A radio channel model based on a simplified set of Markovian parameters, is proposed. The model is representative of the radio signal in the three main identified propagation regions around a vegetation volume as a mean to satisfactorily model highly time-variant radio signals. The propagation regions considered are receiver angular sections (in the azimuth plane) around the tree, where the received signal behaves distinctly for each region. Model validation results are presented using one of the tree species.