Made available in DSpace on 2014-12-17T14:55:26Z (GMT). No. of bitstreams: 1 FranciscoAA_Capa_ate_11.pdf: 7331054 bytes, checksum: 95b093e73afc9c2e5df63a5d0c5b2c6b (MD5) Previous issue date: 2005-07-06 / A 2.5D ray-tracing propagation model is proposed to predict radio loss in indoor environment. Specifically, we opted for the Shooting and Bouncing Rays (SBR) method, together with the Geometrieal Theory of Diffrartion (GTD). Besides the line-of-sight propagation (LOS), we consider that the radio waves may experience reflection, refraction, and diffraction (NLOS). In the Shooting and Bouncing Rays (SBR) method, the transmitter antenna launches a bundle of rays that may or may not reach the receiver. Considering the transmitting antenna as a point, the rays will start to launch from this position and can reach the receiver either directly or after reflections, refractions, diffractions, or even after any combination of the previous effects. To model the environment, a database is built to record geometrical characteristics and information on the constituent materials of the scenario. The database works independently of the simulation program, allowing robustness and flexibility to model other seenarios. Each propagation mechanism is treated separately. In line-of-sight propagation, the main contribution to the received signal comes from the direct ray, while reflected, refracted, and diffracted signal dominate when the line-of-sight is blocked. For this case, the transmitted signal reaches the receiver through more than one path, resulting in a multipath fading. The transmitting channel of a mobile system is simulated by moving either the transmitter or the receiver around the environment. The validity of the method is verified through simulations and measurements. The computed path losses are compared with the measured values at 1.8 GHz ftequency. The results were obtained for the main corridor and room classes adjacent to it. A reasonable agreement is observed. The numerical predictions are also compared with published data at 900 MHz and 2.44 GHz frequencies showing good convergence / Este trabalho apresenta um modelo 2,5D de tra?ado de raios para predi??o de propaga??o em ambientes interiores (indoor). Especificamente, optou-se pelo M?todo dos Raios For?ados (SBR) em combina??o com a Teoria Geom?trica da Difra??o (GTD). Considera-se que, al?m de propaga??o em visada direta (LOS), podem ocorrer os mecanismos de reflex?o, refra??o e difra??o (NLOS). No M?todo dos Raios For?ados (SBR), a antena transmissora lan?a um feixe de raios que pode ou n?o alcan?ar o receptor. Considerando a antena transmissora como elemento pontual, os raios s?o lan?ados dessa posi??o, podendo alcan?ar o receptor diretamente ou mediante reflex?es, refra??es, difra??es, ou pela combina??o dessas modalidades de propaga??o. Para o modelamento do ambiente, um banco de dados ? constru?do para armazenar as caracter?sticas geom?tricas e informa??es dos materiais constituintes do cen?rio. O banco de dados funciona independentemente do programa de simula??o, possibilitando robustez ? implementa??o e maior flexibilidade para a representa??o de outros ambientes. Cada mecanismo de propaga??o ? tratado separadamente. Na propaga??o em linha de visada, o raio direto oferece maior contribui??o ao sinal recebido, enquanto o raio refletido, refratado e difratado apresentam maior influ?ncia quando a propaga??o ocorre com obstru??o. Neste caso, o sinal transmitido alcan?a o receptor por diversas trajet?rias, ocorrendo desvanecimento por m?ltiplos percursos. O canal de transmiss?o, no sistema m?vel, ? simulado deslocando-se o transmissor ou o receptor ao longo do ambiente. A valida??o do m?todo ? verificada atrav?s de simula??es e medi??es. As perdas de percurso calculadas s?o comparadas com os valores medidos, na freq??ncia de 1,8 GHz. Os resultados s?o obtidos para ambientes de corredor e salas de aula adjacentes. Uma boa converg?ncia ? observada. Os resultados num?ricos deste trabalho s?o tamb?m comparados com os dispon?veis na literatura especializada, na freq??ncia de 900 MHz e 2,44 GHz, mostrando boa concord?ncia