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Ítem Efectos del terreno en la propagación electromagnética en entornos urbanos sobre la región andina, usando el modelo COST 231-Walfisch-Ikegami y herramientas de planificación basadas en GIS(Universidad Icesi, 2006-07-28) Ortega B., Homero; Rodríguez A., Alexis H.; Navarro Cadavid, Andrés; García A., A.PaoloEl presente artículo hace parte del desarrollo de un algoritmo que considera la influencia del relieve en la propagación electromagnética para un entorno semi-urbano, trabajando en la banda de UHF (300MHz-3GHz) utilizada en los actuales y futuros sistemas de comunicación inalámbricos (i.e. 800-900MHz en sistemas DAMPS/US-TDMA/IS-136 y GSM). El modelo base, el COST231-Walfisch- Ikegami, empleado en la investigación,demostró beneficios, junto con los Sistemas de Información Geográfica (SIG) y las Herramientas de Planificación, para el desarrollo de los estudios de propagación, estimación de coberturas y análisis de los principales factores que afectan la planificación de un sistema móvil celular. Aquí se describen los conceptos básicos utilizados para el desarrollo del algoritmo aplicado, las consideraciones sobre las cuales se llevaron a cabolas campañas de medidas y el proceso de validación de resultados que comprueban la utilidad del algoritmo desarrollado para la predicción de Path Loss. El trabajo se basó en la fusión del modelo de propagación COST231-Walfisch-Ikegami con laHerramienta de Planificación Cell-View (fundamentada en el SIG ArcView) y la realización de mediciones en la ciudad de Bucaramanga con una unidad móvil de radiocomunicacióny control del espectro radioeléctrico de propiedad del Ministerio de Comunicaciones de Colombia, seccional Bucaramanga. El estudio llevado a cabo para la banda del sistema IS- 136, mostró resultados de simulación y validación que permiten corroborarlas aproximaciones empleadas.Ítem Heuristic UTD coefficients applied for the channel characterization in an andean scenario(Institute of Electrical and Electronics Engineers Inc., 2015-07-19) Navarro Cadavid, AndresThis paper presents a comparison of three heuristic coefficients for the Uniform Theory of Diffraction (UTD), used to characterize the radiowave scattering in typical urban scenarios. The coefficients were implemented in a propagation model based on 3D ray-tracing techniques in an andean scenario. In order to evaluate each coefficient we analyze the statistical behavior of the mean and standard deviation of the absolute errors between the estimated values and the measured data of path loss in a large number of receptor points. Finally, we show the path loss prediction for each heuristic UTD coefficients proposed.Ítem Prediction of Delay Spread Using Ray Tracing and Game Engine Based on Measurement(Institute of Electrical and Electronics Engineers Inc., 2015-05-11) Gomez, JorgeIn this paper, we show results of channel delay spread estimation using a 3D ray launching tool based on Game Engines and GPU, comparing simulation results with channel measurements of a MIMO system taken in Ilmenau. We show that the accuracy of the simulation is strongly affected by the ray angular separation in the first and second diffraction, obtaining a good fit between measurements and simulation.Ítem Comparison of Uniform Theory of Diffraction Coefficients for Delay Spread and Angle Spread Estimation Using Game Engines in MIMO(Institute of Electrical and Electronics Engineers Inc., 2015-09-06) Guevara, DinaelIn this paper, we show the results of the comparison between two different sets of heuristic uniform theory of diffraction (UTD) coefficients and its influence on the results for delay spread and angle spread. We compared our simulation results with measurements in an outdoor environment, showing the influence of the UTD coefficients in the accuracy of the results. The proposed coefficients show a better behavior than a classical set of coefficients widely used in literature.Ítem Comparison of heuristic UTD coefficients in an outdoor scenario(Institute of Electrical and Electronics Engineers Inc., 2013-05-15) Rego, Cassio G.This paper presents a comparison of three heuristic coefficients for the Uniform Theory of Diffraction (UTD), used to characterize the radiowave scattering in typical urban scenarios. The coefficients were implemented in a propagation model based on 3D ray-tracing techniques for a Digital Video Broadcasting (DVB) service. In order to evaluate each coefficient we analyze the statistical behavior of the mean and standard deviation of the absolute errors between the estimated values and the measured data of path loss in a large number of receptor points in an outdoor scenario.Ítem Heuristic UTD coefficients for radiowave coverage prediction in a urban scenario(IEEE, 2015-11-03) Tami, DiegoThis paper presents a comparison of three heuristic coefficients for the Uniform Theory of Diffraction (UTD), used to characterize the radiowave scattering in typical urban scenarios. The coefficients were implemented in a propagation model based on ray-tracing techniques based in image theory. In order to evaluate each coefficient we analyze the statistical behavior of the mean and standard deviation of the absolute errors between the estimated values and the measured data of path loss in a large number of receptor points provided in the literature. Finally, we show the path loss prediction for each UTD coefficients proposed.