Research On Propagation Characteristics And Modeling Of High Frequency Signal In Blocking Environment

With the development of smart devices, the demand of mobile data gradually increases, and the mobile communication systems have been focused on more than 6GHz high-band wireless communication. However,due to the low coverage of high-frequency communication system, the future mobile communication will be deployed in more complex hotspots,which makes the research on propagation characteristics of high frequency signal in blocking environment much more important. Moreover, the condition of the wireless channel directly determines the quality of the mobile communication, thus the research of the wireless channel is the first prerequisite to construct the new mobile communication system. In this paper, based on the actual wireless channel measurement, with the background of wireless signal propagation theory, the reflectivity and human body shadowing of high-frequency communication are studied. The change rule and the formula of the reflection characteristic of the high frequency signal is studied, and this paper gives the reflection scattering profile of the actual measurement. In addition, the human body shadowing is measured, and the human body shadowing model with orientation factor and low complexity under the 28GHz frequency band is given.Firstly, this paper investigates the research progress of the reflection characteristics of high-frequency signals at home and abroad. Since the lack of the actual measurement for different cases and frequency bands,and the research of reflection characteristics is not deep enough, we design and carry out measurements in terms of different incidence angles,polarization, incidence distance. The reflectivity curves were obtained by processing the measured data, and the results were fitted and analyzed by the electromagnetic field theory. The results show that the reflectivity curve is consistent with Fresnel theory, and the reflectivity of high frequency signal can be described by Fresnel formula. At the same time, the reflection loss does not change with the change of the incident and reflected distance except for some fluctuation under near field condition. In addition, paper also gives the scattering spectrum of glass.Secondly, this paper analyzes the research progress of human body shadowing. Considering that the measurement sceneries of human body shadowing is not comprehensive enough and the measurement data is seriously deficient, the actual measurement under different scenes is designed and studied. Measurement sceneries for the different human body orientations and different transmitting and receiving distance are studied.The measurement results show that the human body shadowing gain is in the range of -15.62dB to -6.29dB under the measurement condition. When the distance between the transmitting and receiving antenna is above 16m,the human body shadowing gain is greater than -10dB. Moreover, the human body shadowing gain increases as the distance between the ends of the transmitting and receiving increases, and the human body gain has a minimum value when the person is on the line-of-sight (LOS) path and near the receiving end or transmitting position. In addition, the orientation of the human body has a great impact on human body shadowing gain, and it can produce 4.63dB change when the orientation of human body changes 90°.Finally, a new human body shadowing model is proposed based on the actual measurement, because the existing human body shadowing model has some disadvantages in directionality and computational complexity. The proposed model takes into account the orientation and position of the human body and uses the parameters that are easy to calculate and estimate, making the model easy to estimate the influence of human body shadowing. At the same time, because the signal diffraction mainly occurs in the vertical direction of the side of the human body, so according to the required estimation accuracy, you can choose two methods to estimate, which are double diffraction method and multiple diffraction method. The results show that the model is effective.In summary,based on the actual measurements, this paper studies the reflection characteristics and human body shadowing characteristics of the high-frequency signal in the blocking environment, and proposes a new human body shadowing model. Which provides a theoretical basis for the research and practical deployment of new technologies for high-band mobile communications in the future.