Influência do excesso de atraso do canal na taxa de transmissão para o planejamento de sistemas celulares.

Abstract

Frequency selective fading, caused by multipath time delay spread due to multipath propagation, degrades the quality of transmission causing intersymbol interference and a reduction in the rate data transmission. In this work, the influence of elements present in the propagation environment, such as buildings, trees and vehicles, is analysed modelling the environment by means of a percolation cluster in two dimensions and the propagation of the electromagnetic waves between obstacles by the technical ray tracing. This concept, used, for example, in studying the flow of liquids through porous media, can also be used to assess diffusion of electromagnetic waves among obstacles in urban areas. The motivation for applying this technique is the similarity that the satellite images of urban environments have with the proposed percolation cluster. The main contribution of this work was to obtain closed expressions for the autocorrelation function of the channel frequency response as for delay spread for three profiles of power used, in terms of parameters as the average propagation loss, the average length of the cluster site and and percolation probability.