Research On Wideband Channel Measurement And Fading Characteristics Of Industrial Internet Of Things

With the deep integration of industrialization and information technology,interconnection between various aspects of industrial production has gradually become possible.Therefore,industrial internet of things(IIoT)emerges,which can greatly improve the efficiency and reliability of industrial production and will be an important trend of manufacturing development in the future.As one of the key technologies of IIoT,the wireless communication technology provides solutions for building information-based,intelligent production management and control networks.However,at present,the reliability,latency,and network capacity of industrial wireless communication still cannot fully meet the development needs of IIoT,which will undoubtedly bring risks and challenges to intelligent manufacturing.The transmission rate,capacity,and quality of wireless communication systems are all constrained by the characteristics of the wireless channel.Therefore,only when the characteristics of the wireless channel are fully understood can physical layer technologies be adapted to achieve a reasonable communication system design,so that wireless communication technologies can better support the development of IIoT.This thesis carries on the wideband channel measurement under the welding workshop of an automobile factory,combining theoretical analysis with practical measurement data,and discusses the wireless channel propagation characteristics under different scenarios in different frequency points of the factory.First of all,the related achievements of industrial channel measurement at home and abroad are reviewed,and the basic channel characteristics of wireless communication are introduced.Then,according to the research needs,the factory wireless channel measurement equipment,the extraction method of channel impulse response and the data processing method are described in detail.Finally,based on the measured data,the fading characteristics of broadband wireless channel are analyzed,and the variation law of relevant channel parameters with the distance between the transmitting and receiving antennas is obtained.The channel characteristics in the Line-of-Sight(LOS)and Non-Line-of-Sight(NLOS)scenarios of the three high and low frequencies are compared and analyzed.Results show that the path loss exponent has no obvious relationship with the frequency,but is related to a variety of comprehensive factors under the factory environment.In addition,since there are more highly reflective metal materials in the industrial environment and the factory metal environment is bad,the channel fading of the NLOS scenarios in the same frequency band will be more obvious than the channel fading of the LOS scenarios.The higher the transmission frequency is,the more vulnerable it would be to the bad environment of the factory.By analyzing the channel parameters of two different channels scenarios,it can be clearly seen that the number of welding robots has little influence on the received signal power,while welding robot has relatively large influence on the small-scale fading,and this effect is most obvious when the signal is measured at high frequencies.The research in this thesis provides a theoretical basis for channel standardization work of IIoT and the relevant researches of new technology,which will promote the development of wireless communication in China's industrial internet of things.