Millimeter Wave Propagation Measurement And Characteristic Parameter Estimation

Millimeter-wave communications have attracted worldwide attention to be used for the fifth-generation(5G)mobile communication systems,which can provide abundant spectrum resource and signal bandwidth to increase system capacity.Propagations at millimeter-wave bands suffer from larger power attenuation and high sensitivity to the physical objects,leading to necessity for milimeter-wave propagation measurement and reasearch on the propagation characteristic in different application scenarios.Firstly,this thesis introduces two kinds of classical millimeter wave propagation measurement techniques,which are frequency-swept method and the time domain correlation method.After comparing the application range of these two methods,based on the time domain correlation measurement principle,a wideband single input and single output millimeter wave propagation measurement system is set up by using commercial instruments.This system operates at various millimeter wave frequencies of up to 40 GHz with signal bandwidth of 300 MHz.Two GPS disciplined Rubidium clocks are utilized for frequency and timing synchronization.A rapid measurement method is presented by keeping the receiving antenna rotating continuously to improve data capturing efficiency.In addition,an automatic measurement software is designed to control the hardware measurement system automatically.Secondly,a series of millimeter wave propagation parameter estimation algorithms are presented.The propagation parameters,such as path loss exponent,time and angular dispersion parameters and cluster model parameters,describe the large scale propagation characteristic and small scale propagation characteristic of different millimeter wave bands.Finally,millimeter wave propagation measurements campaigns are accomplished in three outdoor application scenarios at 28 GHz and 39 GHz frequency bands,which are viewed as the most popular candidate bands for 5G.For each measurement scenarios,the specific propagation characteristic is analyzed,including the path loss,the.root mean square delay spread and root mean square angle spread,et.The clustering of multipath components is realized based on the improved K-Power-Means algorithm.In street scenarios,the impact of the green plants on the attenuation of millimeter wave is analyzed,while the focus in the campus and residential area scenarios are the influence of the scatterer position in the propagation environments on angular spreads and cluster parameters.The wideband millimeter wave propagation measurement system presented in this thesis is suitable for various measurement scenarios.The effectiveness of the measurement system is verified through the propagation measurement campaigns in the above three scenarios.The measurement results and the propagation characteristic parameters help to determine final 5G spectrum allocation and promote the standardization of the channel models of millimeter wave bands.