Urban Community Radio Wave Propagation Prediction Algorithm Research

Radio propagation in the urban cell plays an important role in modern wireless system. An accurate prediction of the propagation in the cell is very helpful when designing a mobile radio system. Previous prediction of field strength in urban areas has been made by purely empirical method, based on a large amount of experimental date in urban area. This method requires the statistical comparability of different cell. But, with the development of the mobile radio communications, higher spectral efficiency is required. Then, the cell size is smaller, which is called microcell. So, the previous prediction method can not be used. Presently , there needs some new prediction methods. In this paper, we study the GO/UTD method.In chapter one, we introduce the conception of the cell, and the necessary of the prediction of propagation. Then introduce each algorithms, its status and the advantage of the algorithms in this paper. At last we introduce the researched results in our paper.In chapter two, we study the ray tracing algorithms. Introducing two kinds method of raytracing--direct algorithms and inverse algorithms, and giving the comparative advantages ofthe two methods. Studying the inverse algorithms in detail, giving a new method about the fast inverse ray tracing. Studying the techniques to speedup the ray-tracing method, introducing the methods which are popular for the moment of the partitioning of the urban cell, including space volumetric partitioning, angular Z-buffer technique and triangulation, through the comparative advantages of these methods, and combining with the technologies of Computer Graphics, weget a new efficient ray-tracing method--a ray-tracing method based on the octtree technique.At last, we introduce some methods to improve the accuracy of the ray-tracing method.In chapter three, first we introduce some knowledge about the electromagnetic wave propagations. Then, introducing the method to calculate the wedge diffraction based on GO. And giving the comparative advantages of a few formulas about the heuristic diffraction coefficient for finite conductivity wedge. We study about how to improve the accuracy of calculating the field energy. Such as high order diffracted field, hybrid method, and so on. And getting some useful conclusion.Chapter four, introduce the combination of the Computer Graphics modeling and EM analysis code. The method how to build and display a microcell model, and how to get data from it. The API functions of the Computer Graphics software and the EM analysis codes were finished. And introduce the application of the Computer Graphics to speedup the ray-tracing method. And we give a new method about the determinate the sites of the faces and edges after the partitioning of the cell which is a foundational problem.In chapter five, we first introduce the channel preferences about the propagation in an urbanenvironment. Then expand the past traditional analysis method about it. At last, we study the method of how to analysis it based on the results of the ray-tracing, and analysis a urban cell model.In chapter six, we introduce the requirement of the base stations distribution. And studying some techniques for determining base station locations in an urban environment, including a single base station case and multi-station case.In last chapter, the main works were summarized and the future researching areas were pointed out.