| With the rapid development of mobile Internet and Internet of things,the demand for communication speed and capacity is increasing,which brings great challenges to the design of mobile communication system.Establishing channel model is an important approach for channel characteristic analysis and mobile communication system design.For the sake of higher spectrum efficiency,the coverage area of cell is decreasing,thus the difference between cells in height and density of building is more obvious,so the statistical similarity between cells disappears,which makes experience model of radio propagation no longer effective.So it is necessary to establish an accurate prediction model of radio propagation for the analysis of channel characteristics.In this paper,a three-dimensional(3D)deterministic channel modeling platform based on ray tracing is implemented,and its effectiveness is verified based on the measured data.The main research work is as follows:(1)Implementation of 3D ray tracing platform.In this paper,based on the description file of 3D digital scenario,using Matlab software as the development platform,combined with geometrical optics,geometrical diffraction theory and uniform diffraction theory,considering the direct,reflection,transmission and diffraction propagation mechanism,the determination of ray path and calcula-tion of receiving field strength are completed,finishing implementation of 3D ray tracing platform.The accuracy of ray tracing algorithms depends on the pre-cise description of the propagation environment.This paper uses 3D modeling software to realize the digitization of indoor scenarios,which establishes global Cartesian coordinate system and assumes the solid structure of the wall,roof,floor and so on as geometric plane.At the same time,the software describes the plane material according to the actual material.The description file of the digital scenario has a clear structure,and is easy to access,analyze and process by the computer.It can meet the modeling requirements of most scenarios.For the ray validity judgment,the plane projection algorithm is used to improve the effi-ciency.When calculating the electric field,the response of the antenna is cou-pled,and that brings facilitation for the subsequent expansion.(2)Validation of ray tracing platform.The evaluation method for the effec-tiveness of the simulation platform was explored.Based on the measurement data,the prediction accuracy of the ray tracing platform in terms of power,delay and angle was verified,meanwhile the validity of the simulation platform was evaluated in conjunction with the standardized channel model.The results show that the parameters such as time delay and angle are consistent,which verifies the effectiveness of the ray tracing platform.The platform realizes refined channel modeling and can establish three-dimensional channel models under different scenarios,satisfies the re-search requirements of channel parameter characteristics.It provides a certain basis for the further research of 5G key technology in engineering field. |
