The Study Of The Improved Models For Propagation Prediction In Mobile Communication

Early in the process of marking out network, mobile communication corporations need to avoid the existence of no-signal areas in order to provide good services, so the study of propagation prediction in regions became an important task. As the development of mobile communication, the microcellular system has been chosen to satisfy the increasing requirement to the capacity of contemporary system for larger subscribers. Under this kind of environment, the height of basic transmitter is usually lower than the height of buildings around it, which means that the cover radius of electromagnetic wave is less than one kilometer. On the other hand, the addition of forms and capacity of wireless communication brings more and more transmitters, which engender heavier electromagnetic pollution and side affects to human bodies and environment of communications. Consequently, it's necessary to precisely analyze the propagation of EM wave in microcellular environments. In this paper, an efficient model of propagation prediction in microcellular environments is presented. The model is based on the theory of physical optics (PO), geometry theory of diffraction (GTD) and uniform theory of diffraction (UTD), and it can compute and analyze the propagation of EM wave in microcellular environments by using improved ray tracing method.For deriving from the image method, the improved model is provided with high computing efficiency. For being able to find all paths between transmitter and receiver in theory, it gets high precision. For reducing the test of crossing and blocking by improved algorism of searching paths, this model can find effectivepaths more efficiently. Another feature is that it can compute complicated environment constructed with various kinds of buildings and streets, because the new model doesn't specifically suppose the shape of each building before its computation.The significance of studying the task is introduced, and the domestic and overseas evolvement about task is discussed in the first chapter. The theory backgrounds are given in the second and third chapter. The fourth chapter puts the focus on the improved method of ray tracing. The fifth chapter introduces the software exploited from the improved model and discusses the interface method with buildings database. The sixth chapter compares the improved model and references, and presents prediction analysis of EM propagation in non-regular regions, the results indicate the improved model bears higher efficiency and precision. In the end of this paper, the prediction model is summarized and some suggestions are given.