Researches On Propagation Characteristics Of High Frequency Wireless Channel In Indoor Office Scenarios

An accurate understanding of wireless channel propagation characteristics is one of the key factors to improve the performance of wireless communication systems.The wireless channel is used as a medium for sending and receiving signals in the communication system,and its characteristics greatly affect the communication quality of the wireless communication system.Mastering the characteristics of the wireless channel in each real scenario is a prerequisite for ensuring good performance of the communication system.At present,domestic and foreign countries have sufficient understanding of the channel characteristics of spectrum resources below 6 GHz,and future mobile communications require the support of large bandwidths.It has become the consensus of the industry to tap and utilize spectrum resources in high frequency bands.In this thesis,the propagation characteristics of high-frequency wireless channels are studied in a typical indoor office scenarios.Based on a large amount of measured data,the path loss,shadow fading,delay power spectrum and root mean square delay of high-frequency indoor wireless channels are analyzed.Channel propagation characteristic parameters such as extension are modeled and analyzed.The research results of this thesis can provide a theoretical reference and basis for the design of future high-frequency indoor short-range wireless communication systems and the network deployment of picocells.The main content and innovation are as follows:1.Researched the wireless channel propagation characteristics in indoor office scenarios in the 10 GHz frequency band.Based on a large amount of measured data,the path loss models for indoor line-of-sight(LOS)and non-line-of-sight(NLOS)scenarios are established respectively,and the statistical characteristics of the shadow effect are given.The power delay spectrum of the impulse response is obtained by the inverse Fourier transform of the measured frequency response,which gives the statistical characteristics of the time-domain root mean square delay spread.In addition,in view of the influence of obstructions on path loss in non-line-of-sight scenarios,a new type of shelter attenuation factor model is proposed.This model is based on the close-range reference model and introduces a new Shielding Attenuation Factor(SAF),use it to correct the additional loss caused by shelters.And through the least square algorithm,the path loss index n and the shelter attenuation factor SAF are respectively fitted.The research results show that in the indoor LOS scenario,the path loss has a linear relationship with the logarithmic distance of the transceiver.In the NLOS scenario,the change of the position of the shelter relative to the receiving end has an important impact on the path loss: When the shelter is stationary,the shelter attenuation factor has an exponential function relationship with the distance from the receiving end to the shelter,that is,when the receiving end is at a longer distance,the path loss caused by the shelter tends to be stable;when the shelter moves,SAF and the distance between the shelter and the receiving end has a linear relationship.2.The wireless channel propagation characteristics of X-band multi-frequency points in indoor office scenes are studied.Based on a large amount of measured data,the path loss models for the multi-frequency indoor line-of-sight and non-line-of-sight scenarios are established respectively,and the dependence of the attenuation factor parameters of the shelter on the transmission frequency is analyzed,and the shelter under different transmission frequencies is given.The statistical characteristics of the additional shading loss caused.The research results show that in the indoor LOS scenario,the path loss has a linear relationship with the logarithmic distance of the transceiver.When the measurement scenario is unchanged,the intercept will increase with the increase of frequency,and the path loss index tends to be stable.In the NLOS scenario,the change of the position of the shelter relative to the receiving end has an important impact on the path loss: when the shelter is stationary,the shelter attenuation factor SAF has an exponential function relationship with the distance from the receiving end to the shelter.As the distance increases,it gradually tends to a fixed value,and the distance required for SAF to reach the fixed value increases with the frequency.The area where the path loss is affected by the shelter gradually increases with the increase in frequency;when the shelter moves,the distance between the SAF and the shelter approximates a quadratic function relationship,and as the frequency increases,the center of symmetry of the quadratic function tends to the midpoint of the transceiver antenna,that is,under the condition that the position of the receiving end remains unchanged,the shielding object at the center of the receiving end has the least influence on the receiving end.