The Urban Environment Of Radio Wave Propagation Complex Ray Analysis

Today's fast growing radio communication market places stronger and stronger demands on the design of a radio system. A proper system design requires accurate and reliable radio channel models, among which the field strength prediction models are most important. Although many researchers have been working hard during the past few decades in the area of field strength prediction, there are still numerous problems to be solved. To date, a perfect propagation model has not been found. Instead, many different prediction tools have been proposed. Each of them has advantages and disadvantages and can be applied only to particular circumstances. Further investigations of methods for increasing accuracy and decreasing computational time are necessary. At the same time, as more and more radio sources have been set up, electromagnetic pollution in urban area becomes more serious, which is harmful to people's healthy and communication system． So it is necessary to simulate the electromagnetic propagation in urban area by computer．Being an approximate HF method in evaluating EM Scattering,the complex ray method(CRM) is valuable in actual applications, mainly benefited from its simple physical model,convenient mathematical formulation and computational efficiency, especially with the scenes of scattering from complex objects．Based on the condition mentioned above, a hybrid ray model of the urban area electromagnetic wave propagation prediction was established with the foundation of ray tracing theory and complex ray theory. The Ellipse model was used to improve the efficiency and the speed of the developed ray tracing method. The complex ray theory was applied to urban environment electromagnetic wave prediction and a new method, Hybrid Ray Method(HRM), was brought forward in this article , with the use of available ray tracing method to trace the ray path and complex ray paraxial approximation theory to calculate electric field intensity of the paraxial point. The HRM avoids ray tracing of the paraxial point, so it can reduce the CPU time.Ray tracing accelerate technique, the parameters of complex ray has been discussed in this article, and some empirical formulas for choosing the complex ray parameters have been given out. The major causes of the error in the calculation have been analyzed. The HRM was applied to calculate and analyze the electric wave propagation characteristic of the Academias Street, Anthens and his neighboring streets in this article. In addition, the interface problems of software programmed in C++ language under the platform VC++ 6.0 with other software such as Matlab and AutoCAD etc. have also been discussed.