Research On Measurement Based Diffuse Scattering Propagation Model Parameterization At Mm Wave Frequencies

The need for large capacity and high-rate data transmission in the new generation mobile communication system promotes the development of millimeter-wave(mm Wave)communication technology research.As for the propagation characteristics,the influences on the received power,time dispersion and angle dispersion from diffuse scattering propagation phenomenon become more remarkable than sub-6 GHz,because the short wavelength of mm Wave is comparable with the surface irregularities of some objects,which makes challenges for accurate mm Wave channel modeling based on ray tracing.This thesis performs research on diffuse scattering model parameterization based on measurement for diffuse scattering propagation of indoor typical materials to achieve parameter calibration for ray tracing simulation,therefore improves the accuracy of mm Wave propagation prediction and channel analysis.The main innovative work can be devided into three parts.First,measurement for diffuse scattering propagation of indoor typical materials in the mm Wave band and analysis for resonance characteristic.A measurement platform is established for diffuse scattering propagation based on the free space method,and used to analyze the resonance characteristic of propagation coefficients in frequency domain.The variation relationship between the dielectric parameters and resonance characteristic is obtained,which provides a verification method for dielectric parameter estimation.The influence of resonance characteristic on diffuse scattering propagation is studied through measurement for spherical received power.Results show that the diffuse scattering power at non-resonance frequencies has better directivity around the specular reflection point.Second,a multi-propagation coefficient estimation method for dielectric parameters.For the problem that current estimation methods for dielectric parameters are mostly based on ideal reflection condition,a multi-propagation coefficient estimation method suitable for diffuse scattering condition is proposed.Then,a feasible plan for measuring and calculating propagation coefficients is designed.based on joint evaluation for the fitting errors between the measured and theoretical values of various propagation coefficients,accurate dielectric parameters of different types of materials are obtained,which guarantees the reliability of material parameters setting in raytracing simulation.Finally,in order to solve the efficiency problem in proposed estimation method,the multi-object optimization based on genetic algorithm is used to replace the exhaustive search method,which can achieve an 8% improvement in time efficiency while ensuring the accuracy of estimated dielectric parameters.Third,model parameterization method for diffuse scattering based on tuning priority,and ray tracing calibration.Through the measurement and ray tracing simulation for diffuse scattering power at different receiving angles,the tuning priority of each model parameter is evaluated to reduce the estimation error caused by the uncertainty for fixed parameter values,and accurate parameterization results of diffuse scattering models are obtained for different materials.Through comparisons for the power angle spectrums,the proposed diffuse scattering model parameterization method is validated for ray tracing calibration with different material types and frequencies.