Research On Millimeter Wave Propagation Characteristics In Indoor Environments Based On Ray Tracing Method

With the continuous development of mobile Internet and Internet of Things technologies,the requirements of high speed,low latency and large capacity of the Fifth Generation(5G)mobile communication promote the development of millimeter wave technology.The millimeter wave has the characteristics of wide bandwidth and short wavelength,and suitable for indoor short-distance communication.In the indoor environment,the influence of scenario,frequency band and other factors make the electromagnetic wave propagation more complicated,and the shadow fading,depolarization and multipath effect of signals are more obvious.Moreover,in the case of short wavelength,the diffuse scattering phenomenon on the surface of the object cannot be ignored.In addition,the development of the Internet and the Internet of Things technology has brought about a large number of wireless communication services and personal communication systems in indoor environments,and indoor wireless propagation characteristics research is becoming more and more important.Therefore,it is urgent to conduct more in-depth research on the indoor millimeter wave channel model and propagation characteristics.The main content of this thesis is as follows:First,the indoor millimeter wave channel model and channel measurement method are described.In the indoor wireless communication systems,the ray tracing method approximates high frequency electromagnetic waves to geometric rays,which can accurately track the propagating rays and calculate the field strength,and is suitable for indoor millimeter wave channel modeling.Among the channel measurement methods,the direction detection scanning method and the frequency domain scanning method have the advantages of high time delay resolution and short-distance transmission,and are suitable for indoor millimeter wave channel measurement.Secondly,an efficient and complete ray tracing algorithm is proposed,which uses mirror image method and takes the influence of diffuse scattering phenomenon into consideration.The algorithm is mainly implemented from modules such as scene,material characteristics,antenna,path search,diffuse scattering,and field strength.Based on the algorithm proposed in this thesis,26 GHz and 38 GHz channel simulations are carried out in the indoor environment of short corridor,long corridor and stairs,respectively.The simulation results are compared with the measured results,which verify that the improved ray-tracing algorithm has high accuracy and applicability in predicting indoor millimeter wave propagation characteristics.Finally,the propagation characteristics of millimeter wave in typical indoor environments are analyzed.In this thesis,the millimeter wave propagation characteristics of short corridors,long corridors and staircase environments with different frequencies(26 GHz and 38 GHz),different polarization configurations(Vertical-to-Vertical and Vertical-to-Horizontal),and different scenarios(line-of-sight and non-line-of-sight)are studied in detail.The investigated channel parameters include path loss,crosspolarization discrimination and root mean square delay spread.In addition,in the long corridor environment,the influence of different transmitting antenna heights(1.4 m and2.4 m)on the radio wave propagation characteristics is also considered,and corresponding setting suggestions are given.In summary,this thesis has carried out an in-depth research on indoor millimeter wave channel model and propagation characteristics,which provides significant guidance for the research of 5G millimeter wave in indoor wireless communication system.