Indoor Wireless Channel Modeling Based On 3D Ray Tracing

Wireless channel modeling is the basis for analyzing wireless channel characteristics and predicting the performance of wireless communication systems.Traditional statistical wireless channel modeling can hardly meet the demand of accurate channel modeling in indoor environment.As a deterministic channel modeling method,ray tracing technology can track and calculate each multipath and acquire information such as signal power,time delay,departure angle and arrival angle.So ray tracing can be used to establish a more accurate indoor wireless channel model.Comparing with the traditional two-dimensional ray tracing method,the three-dimensional ray tracing counterpart introduces the vertical dimension into calculation.Hence it reflects channel characteristics more comprehensively.Firstly,this thesis studies related ray tracing theories,which include its basic theories,current research status,method classifications,acceleration algorithms and development trends.Then,a three-dimensional visible ray tracing simulation software platform is built according to an actual measured indoor construction.Next,the logic design and function realization of the simulation software are described in detail and the consistency of the software is tested and verified.With this simulation software,deterministic wireless channel parameters of the measured indoor room and the three dimensional images of the rays can be obtained.Secondly,this thesis studies and simulates the signal scattering phenomenon that affects the ray tracing results.The current research status and significance of signal scattering are briefly described.Then,the effective roughness model is used to simulate power of scattered signals generated by rough wall surfaces,and results are well repeated similar to the literature.Finally,the thesis studies clustering algorithms to classify ray tracing simulation results.After properly sorting a large number of multipath signals into clusters,statistical channel parameters of each cluster are obtained,including large-scale path loss,delay spread and angle spread.These results are compared with the Spatial Channel Model Extension(SCME),through which the ray tracing model shows some consistence with the SCME model in a typical indoor scenario.In addition,an improved method is proposed for the KP-Means clustering algorithm.By comparing our improved clustering result with other ones,we find that our clustering algorithm achieves a more satisfactory result in both theory and intuition.