Research On Indoor Channel Propagation Characteristics Of Millimeter Wave/Submillimeter Wave

The development of wireless communication technology has greatly accelerated the growth of mobile network data traffic,and the upgrade of communication parameters such as large capacity,high speed,and low delay has further aggravated the depletion of low frequency spectrum resources.In order to meet the growing demand of wireless communication,it is necessary to research and develop frequency band(i.e.,millimeter wave/submillimeter wave).The millimeter/submillimeter wave has abundant continuous bandwidth resources,and has the advantages of narrow beam and little influence by weather.Therefore,as the 5G communication band,the millimeter wave and even the higher frequency submillimeter wave have received extensive attention from academia and industry.However,millimeter/submillimeter wave has short wavelength and high frequency.Band characteristics such as high transmission loss and sensitivity to communication scenarios also bring new challenges to channel research and scenario selection.As the main communication scenario,the indoor scenario itself has great research significance.Also,the "Indoor 5G Scenarios White Paper" published by Huawei in 2019 has shown that more than 80%of data services will occur indoors in the future.Indoor scenarios often have relatively short communication distance and more fixed scene layout,so the application of millimeter/submillimeter wave in indoor short-range high-speed communication not only has great application prospects,but also can give full play to the advantages of this band.Considering that the main communication parameters such as communication rate,communication quality and system capacity are affected by the channel characteristics,the practical application of millimeter/submillimeter wave in 5G needs sufficient understanding of the channel characteristics of this band,to support the design of communication system and the optimization of physical layer technology.Therefore,a full understanding of the channel characteristics of the millimeter/submillimeter wave band is a premise for realizing the actual application and scenario deployment of this wave band.This thesis focuses on the millimeter/submillimeter wave band,and the parameters such as path loss,Ricean K-factor and reflection coefficient are extracted based on the channel measurement,to study the propagation channel characteristics of indoor scenarios and the reflection characteristics of typical building materials.The specific research contents are as follows:1.Research on the propagation characteristics of industrial Internet of things(IIoT)scenarios.The machine shop was selected as a typical indoor IIoT scenarios,and the channel measurement was performed in the 5G authorized frequency bands(i.e.,4.9 and 28 GHz).Based on the measured data,the path loss and Ricean K-factor were extracted to study the trend of channel parameters with different distances.According to line-of-sight(LOS)and non-line-of-sight(NLOS)scenarios,the high and low frequency points are analyzed.At the same time,combined with the characteristics of more metal materials in the machine shop,taking the indoor office scenarios in 3GPP TR 38.901 communication standard as reference,the channel transmission characteristics of IIoT scenarios are analyzed.2.Research on the influence of antenna height in IIoT scenarios on signal propagation.Due to the large size of the industrial scenario,the antenna can be deployed over a wide height range.So,the effect of the antenna height on the channel parameters is more significant.This thesis investigated the occupation area of the objects with different heights,and plotted the cumulative distribution function(CDF)of the scatterer heights.Based on the CDF diagram,four kinds of comparative measurement arrays with different antenna heights were designed,and the channel measurement was carried out.The path loss and Rician K factor were extracted to study the trend of channel characteristics with increasing antenna height.3.Research on indoor short-distance propagation characteristics and reflection characteristics of typical building materials.In the higher frequency band,220 GHz-330 GHz,there are fewer existing measurements.This thesis first selected indoor short-distance communication scenarios,carried out channel measurements at 310 GHz.The path loss and Ricean K-factor were extracted,and the trend of these parameters in 0.2-2.27 m short-range communication scenario at 310 GHz is studied.Combined with the free space path loss model,the channel characteristics of the test environment were compared and analyzed.At the same time,because the signal wavelength of 220 GHz-330 GHz is similar to the size of the scattering surface of various scatterers,the actual propagation characteristics are affected by the actual propagation scene and the main scatterers,which will be more obvious than the traditional communication frequency band.Therefore,the reflection characteristics of this band will have greater significance for the study of channel propagation characteristics.In this thesis,five types of typical indoor building materials are selected to measure the reflection characteristics at 220-330 GHz.Based on the measured materials and the incident angle,the reflection characteristics of 220-330 GHz are analyzed and summarized.In summary,for indoor scenarios,a millimeter wave/submillimeter wave band channel test platform is developed.Based on the channel parameters measured by the platform in IIoT and indoor short-distance scenarios,this thesis studies the channel propagation characteristics of millimeter wave/submillimeter wave band and the reflection characteristics of typical building materials.The research in this thesis provides a theoretical basis for channel standardization of IIoT,and also provides more accurate reflection parameters in the 220-330 GHz band for ray tracing and other simulation technologies,as a basis for indoor depth coverage research.