Effect of terrain on path loss in urban environments for wireless applications

Abstract

Path-loss prediction algorithms for advanced wireless communication system planning have long considered the effect of electromagnetic propagation over buildings between the base station and subscriber. This phenomena is particularly important in residential areas, where the houses are typically a few stories high. For the most part, the buildings were assumed to lie on level terrain, although shadowing effects by terrain in the absence of buildings has been included. Previous works have offered a number of methods to quantitatively determine these effects from path profiles. This study examines propagation over buildings when the buildings are located on terrain features (hills). The buildings, which are represented by a series of absorbing half screens, are assumed to lie in rows that are equally spaced along parallel streets, with the streets running perpendicular to the terrain slope. Numerical results are obtained using successive repetition of the Kirchhoff-Huygens approximation. A phenomenological model based on ray optics for diffraction over a smooth surface is proposed as a way to interpret the numerical results. The dependence of model coefficients on terrain parameters are obtained from the numerical results.

Statistical tuning of walfisch-bertoni pathloss prediction model based on building and street geometry sensitivity parameters in built−up terrains

“…In [16], effects of differences in height and buildings structures to the signal spread are studied to improve on the Walfisch and Bertoni model. Piazzi and Bertoni [9] find the spread loss model by assuming that the buildings which have same height and distance are located on uneven land. Chung and Bertoni [7] have presented a theoretical model.…”

Influence of Terrain in Electromagnetic Propagation on Urban Environments from the Andean Region, using COST 231- Walfisch-Ikegami Model, and GIS based Planning Tools

“…Tal como se explicó previamente, todas las alturas de los obstáculos (edificios y picos del terreno) y la altura de la antena de la BS se referenciaron a la altura del terreno justo debajo de la ubicación del MS. En la Figura 7 se aprecian las gráficas de los archivos de entrada, para los edificios y el terreno, utilizados en la zona piloto escogida para la realización del presente estudio. La Zona Piloto para Bucaramanga se identificó anticipadamente siguiendo los parámetros de análisis establecidos en la aproximación utilizada en [3] para las consideraciones del efecto del terreno sobre el Path Loss en ambientes de tipo urbano, siguiendo un modelo de colina-valle-colina en la mayoría de las direcciones. Con el objetivo de obtener resultados útiles para la ejecución de comparaciones con otros modelos, se realizaron simulaciones de forma independiente, considerando en primera instancia sólo el archivo de alturas de edificios y utilizando todos los modelos para entorno urbano habilitados dentro del CellView (para más detalles sobre los modelos ver [13, A1.4]).…”

“…Por lo anterior, la propagación de radio se ve afectada por cada uno de estos parámetros de forma diferente. Se han escrito varios trabajos alrededor del tema [3], [9] y [12], entre otros, pero la mayoría se enfocan a un tipo de ambiente en especial ya sea urbano, rural o afectado por montañas. En [3] y [12] se hacen postulaciones para ambientes urbanos en terreno montañoso, pero solo en [12] se plantea un modelo general aunque no se ha verificado.…”

“…Se han escrito varios trabajos alrededor del tema [3], [9] y [12], entre otros, pero la mayoría se enfocan a un tipo de ambiente en especial ya sea urbano, rural o afectado por montañas. En [3] y [12] se hacen postulaciones para ambientes urbanos en terreno montañoso, pero solo en [12] se plantea un modelo general aunque no se ha verificado. En el presente trabajo se valoró la propagación electromagnética sobre edificios y calles, en varios perfiles de terreno, con el fin de estimar los factores que introducen la variabilidad en la señal transmitida entre dos puntos.…”

Building Footprint Simplification Techniques and Their Effects on Radio Propagation Predictions

“…On the other hand, ray-tracing based radio propagation prediction models have shown promise in microcell environments [6,7,8,9,10,11,12,13,14]. Such techniques take into account fine-level features of a geographic area including building shapes and orientations, electrical characteristics of building materials, terrain, locations of transmitters and receivers, heights and patterns of antennas used by both base and mobile stations, and can even incorporate weather and vegetation [15,16]. Propagation predictions can play an important role in determining network parameters including coverage, transmitted-data rates, optimal base station locations and antenna patterns.…”