Based On Ray-tracing Model Of Micro-cellular Cell Radio Wave Propagation Prediction

In order to utilize the frequency resource adequately and increase the capacity of the mobile communication system, the wireless electric wave propagation of existing mobile system always adopts the microcell structure. Forecasting the path loss characteristic of electric wave accurately can provide the necessary condition for the layout and design of wireless network, at the same time it is a precondition for the research on the microcell mobile system. In most of the instance in urban area, the antennas of the base-station are lower than the surrounding buildings, which makes the original propagation prediction models for macrocells can not be used any more. Presently, it needs some new prediction methods.On this condition, the paper put forward a new electric wave transmission model in the microcell, which based on ray tracing method of Virtual Fountain Tree. 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. It can be used in any complicated environment, can locate all paths from transmitter to receiver which avoid redundant calculation. The definition of the available area of reflection source and the diffraction source make it efficient to find all propagation paths from transmitter to receiver, the receive point is added to the tree structure also. In addition, it is a point to point that ray tracing method based on specular reflection theory which don't carry out the receive test; Furthermore, the model adopt the reverse arithmetic which exert the tree concept in data frame and establish a virtual fountain tree permanently, the program can back-search the virtual fountain tree when it is running. These operation increase the calculate speed and it result in the higher receive efficiency and precision.In chapter one, we introduce the significance of studying the task, discuss the domestic and overseas evolvement about task. At last, the advantage of the algorithms in this paper is introduced. The theory backgrounds are given in the second and third chapters. The fourth chapter puts the focus on the improved the ray-tracing method, introduce the application of the Computer Graphics to speed up the ray-tracing method. The methods how to build and display a microcell model are given. The fifth chapter introduces the software exploited from the improved model. The sixth chapter compares the improved model and references, the results indicate the improved model has higher efficiency and precision. In the end of the paper, the prediction model is summarized and some suggestions are given.