Research On Millimeter Wave Channel Propagation Characteristics In 5G Typical Frequency Bands And Scenarios

Millimeter wave(mmWave)is one of key technologies in the fifth generation(5G)mobile communication system,in which channel measurements and modelling play fundamental and irreplaceable roles for 5G communication system deployment and optimization.In the paper,a mm Wave time domain channel sounder with different kinds of antennas are deployed to perform measurements and developing channel models in 5G typical frequency bands and scenarios such as channel characteristics at 26 GHz in an open office and modeling methodologies are investigated;time-varying clusters and antenna selection algorithm are studied by massive antenna measurements at 26 GHz and human blockage models at 26 and 39 GHz are devolped.Time-varying rain cell models and path loss model modifications are studied for outdoor microcells.The main and innovation work are as follows:(1)Characterization of mm Wave channel and modeling methodologiesMm Wave horn rotation measurements were carried out in an open office,and the channel propagation characteristics,channel models and statistics of channel parameters are investigated.To improve the accuracy of existed clustering algorithms,we proposed dynamic window clustering and envelope clustering algorithms in this thesis.In addition,the relationships between the statistical channel parameters and measurement distances are studied to find an optimized distance to improve the accuracy of channel modeling.(2)Time-varying cluster modeling and antenna selection algorithm in mm WaveTime-varying cluster modeling and channel characteristics are investigated by an indoor massive antenna channel measurement carried out at 26 GHz by using time-varying channel simulation and linear regression to bulid birth-death model of clusters.In addition,the correlations of different antenna elements are analyzed based on measured channel impulse responses,and an algorithm based on the correlation dictionary is built to reduce the antenna selection complexity for a mm Wave massive antenna system.(3)Mm Wave human blockage models and material penetration lossIn this thesis,a human is regarded as an absorbing screen,a single cylinder,and two-cylinders model to analyze its blockage effect at 26 and 39 GHz.KE(Knife Edges),UTD(Uniform Theory of Diffraction)and relevant electromagnetic theory to build the blockage models for a single person.On this basis,Volger’s multiple knife-edges model is used to model 1-3 person(s),and all the human blockage models are verified by measurements.Moreover,typical material and tree penetration losses are measured,based on the tree measurement data,the parameters of ITU P-833-8 model have been modified.(4)Effect of time-varying rain cells to mm Wave path loss models and multi-user system performanceBy using the EXCELL rain model and considering the effect of wind and rain-time sequence,dynamic time varying rain cell models for a single user and multiple users are developed.Based on the measurement data for an outdoor microcell at 26 and 32 GHz,the channel impulse response(CIR)model is modified by rain attenuation.The path loss models for single-and multiple frequencies as well as the multi-user system performance are analyzed by taking into account of rain attenuation,which offers theoretical background in 5G network planning and deployment.