Wireless Channel Measurement And Modeling Using Chirp Signal

The transmission environment of the wireless communication system determines the planning of network and the design of transmission technology.Therefore,the environmental channel model obtained by the scientific channel measurement scheme can provide theoretical support for the design of the wireless communication system.The 470 MHz to 510 MHz is an international unauthorized ISM band.So far,there is a few research institutions,universities or communication organizations have conducted channel characteristic research specifically for this frequency band.Therefore,the channel characteristic of this frequency band is reserched deeply and the corresponding channel model is established in this thesis.In this thesis,the wireless channel measurement scheme is designed to meet the measurement needs of broadband micropower wireless channel.The measurement scheme includes measurement system construction,measurement parameter configuration,frame structure design and measurement data processing method design.Firstly,the processing method of measurement data is studied.In order to overcome the disadvantage that the fractional Fourier transform peak detection method does not consider the interaction between multipath components when extracting channel impulse response(CIR),a new fractional Fourier transform domain peak detection method based on Successive Interference Cancellation(SIC)is proposed.The simulation results show that the improved algorithm can extract more accurate CIR for Chirp signal than the deconvolution method,the fractional Fourier transform domain peak detection method and the fractional Fourier transform domain peak phase difference minimum method.Secondly,the measurement system is built by the basic framework of existing measurement schemes and hardware conditions,and the specific configuration of the measurement parameters is given according to the selection principle of the measurement parameters and frequency domain characteristic of Chirp signal,and the frame structure of the measurement signal is designed based on the matched filtering characteristic of Chirp signal.Finally,the R&S?SMW200A is used to simulate the wireless channel environment,and the CIR and Path loss are extracted according to the data processing method of the measurement scheme,which verifies the feasibility of the measurement scheme.In this thesis,the floating intercept model which characterizes the large-scale characteristic of the channel and the Tap Delay Line(TDL)model which characterizes the small-scale characteristic of the channel are established for indoor corridor environment,outdoor environment and indoor-outdoor environment respectively.The rationality of the channel model is verified by combining the retest data and the environmental characteristic.The established channel model lays a theoretical foundation for the research of smart grid new generation broadband micropower wireless communication system.