Analysis And Modeling Of UWB Channels Propagation Characteristics For Indoor And Indoor To Outdoor

The demand for indoor positioning keeps rising with rapid development and wide application.Compared with other short-range wireless communications technology,ultra wide bandwidth wireless communication technology has shown strong anti-interference ability,high penetrability,anti-multipath fading capability and the advantages of centimeter level positioning accuracy in indoor positioning.The research of UWB channel characteristics and the establishment of the channel model are the basis and prerequisite for the design and implementation of the indoor positioning system.In this paper,path loss and multipath fading characteristics of indoor and indoor to outdoor scenes are analyzed and modeled by frequency measurement method and simulation method on account of ray tracing and uniform geometrical theory of diffraction.The frequency domain measurement is a traditional statistical analysis approach,the measurement scenarios include the indoor office with line of sight and indoor to corridor with non-line of sight.Firstly,the results are obtained from the measured scheme.The least square method and the regression significance test method are used for fitting and calibration the rules.The fitting results show that the distance dependent path loss satisfies the lognormal distribution,and the shadow fading follows the Gaussian distribution;the logarithm of subband frequency is linearly correlated with the path loss,and the frequency decay exponent satisfies the normal distribution.For the study of multipath fading,Fourier inverse transform,windowed and CLEAN algorithm are used to obtain the channel impulse response.Due to the difference of impulse response between indoor and indoor to corridor,double exponential model is used to describe the power delay profile in(PDP)in indoor environment,the average PDP of each position is processed by clustering algorithm to get the arrival time and intensity of the head signal for each cluster and each component in the cluster,the channel parameters and amplitude fading distribution are acquired on the basis of numerical analysis,mathematical statistics and calibration after data preprocessing.For indoor to corridor environment,an improved piecewise exponential model is used to describe the PDP.Second,a full-scale 3D simulation model is constructed and the analysis method that is same as frequency domain measurement is used to analyze the path loss and multipath fading in indoor and indoor to corridor.The results of simulation indicate that the path loss and multipath fading are consistent with the results of frequency domain measurements.The rationality and applicability of deterministic method for UWB channel are verifiedFinally,according to methods and conclusions of data analysis of measurement approach and simulation approach,a mathematical model is established to calculate the path loss that associated with distance and frequency,the double exponential model and the piecewise exponential model are set up respectively for the multipath fading characteristics of indoor and indoor to corridor environment.