Study Of Radio Wave Propagation Based On ADI Method Of Three Dimensional Padé-PE

With the implementation of the national "Internet+" action plan, mobile Internet technology plays a more and more important role in the life of people. At the physical level, user experience of the mobile Internet basically depends on the performance of the mobile communication system. And the planning and design of the mobile network is largely dependent on the data provided by the analysis of the radio propagation characteristics. In addition, due to the harsh requirements of the signal coverage and signal intensity in mobile communications, traditional radio propagation prediction method has been unable to adapt to the urban microcells environment which has bristly building and a growing number of obstacle. Therefore, it is very important to study an accurate and efficient prediction method of radio propagation.In the analysis of radio propagation, the parabolic equation method can more accurately processing the influenced of propagation caused by the complicated boundary as well as the different media, and also have an unparalleled advantage in the irregular terrain environment simulation. Especially for urban areas which have distribution of irregular material and shape buildings and obstacles, using parabolic equation method can easily set impedance boundary conditions, and deal with refraction and diffraction effects effectively. Therefore, this thesis study on accurate and fast solution of the three-dimensional Padé(1,1) parabolic equation based on the prediction of radio wave propagation in urban area under the integrated environment.Three-dimensional Padé(1,1) parabolic equation is obtained as a result of applying Padé(1,1) approximation in the derivation process of three dimensional parabolic equation. The calculation and analysis shows the effective angels of calculation is large greater than which calculated by traditional standard parabolic equation. Crank-Nicolson finite difference scheme of Padé(1,1) three-dimensional parabolic equation is deduced, and on this basis this thesis introducing the ADI method. The calculation shows that ADI method can greatly improve the efficiency of solving three-dimensional parabolic equation. Generalized impedance boundary conditions are deduced based on Leontovich standard impedance boundary conditions. Besides, the ADI method of three-dimensional Padé(1,1) parabolic equation with the second order impedance boundary conditions is deduced. By comparing with the calculation results of the two ray model, it is showed that the second order impedance boundary condition has larger scope of application than the standard impedance boundary condition in a certain condition.In order to accurately describe the propagation characteristics of urban microcells, this thesis will set the ground’s and buildings’surface as impedance boundary, and then simulate radio propagation with single building and multiple buildings on the ground individually. The simulation provides propagation factor spatial distribution map. Good results are obtained though the simulation of radio propagation in urban microcells under complex environment which includes weather circumstances such as rain and fog and dust, as well as ground surface cover such as woods and rivers combined with the achievements provided by our research group.