Research On Wireless Channel Measurement And Modeling In Urban Low-Speed Scenario At 5.9GHz

In the construction of smart cities,the development of intelligent transportation is a very important step.The ITS can collect traffic information in real time,control traffic conditions and solve congestion problems on highways.The previous sensor network was promoted and upgraded to vehicular networking under the impetus of demands.In vehicular networking,V2 V is one of the key research directions.Its development is not only conducive to the field of intelligent transportation,but also can drive smart driving,unmanned vehicles and medical care.At present,there are two major directions for the V2 V communication protocol,but further testing and research are needed for industrialization and commercialization.The analysis and modeling of the characteristics for different scene channels is conducive to the optimization of the V2 V communication protocol and the design and simulation of the vehicle-mounted communication system.This paper selects the classic urban low speed scenario,designs the measurement plan and collects data.The characteristics of the channel are analyzed and modeled.The main research work of this paper is as follows:First of all,this paper designed the measurement plan,and plans the test route and equipment installation for low-speed urban scenes.In the actual measurement,TDM-allmeas sounder signal measuring instrument were used to measure the channel and collected data.The next work was to deal with the collected data.The measurement data was processed to obtain signal impulse response and GPS information.Finally,the channel was analyzed in various aspects using the processed data.In the energy domain,small-scale fading and large-scale fading were analyzed and modeled.The AIC was used to fit the optimal distribution of the level envelope of small-scale fading.In order to better analyze the characteristic factors in the optimal fitting distribution,the data collected in this paper were divided into two different stages.Combining with several classical models which are more suitable for this measurement scene,the path loss in large scale fading was studied and modeled by using the analysis method of root mean square error and grey relational degree.In time domain,power delay profile and root mean square delay spread were analyzed.For the cumulative distribution function of the root mean square delay spread,two stages of data were compared and analyzed.According to the characteristics of the power delay profile and the elliptical geometric characteristics,the reflector positioning method was designed.In the frequency domain,the delay-Doppler power spectrum is analyzed.Through studying the channel data of this scene,it is found that the surrounding environment and the distance between the signal transmitter and receiver for urban low-speed scenes have an important influence on the signal.Data conclusion: The best-fit distribution of the small-scale level envelope of this scene is Ricean distribution,the path loss has the highest matching degree with ITU-R 1411(upper bound)model,the value of 90% root mean square delay spread is within 200 ns.