Research On Indoor Short Distance Microwave Propagation Characteristics On Multi-frequency Bands

Since been born in 1980s,mobile communication has developed explosively and has been the basic information network connecting human society.Over the past 30 years,mobile communication has experienced from voice services to mobile broadband data services.The issuance of LTE license promoted high-speed data service into millions of households.High density of network and close coverage has become the most commonly used network scheme in CMCC,China Unicom and China Telcom.70%of the services occur indoor in the mobile network age.The difference between indoor distributing system signal coverage and ourdoor is that the coverage area of indoor is much less than outdoor and the microwave propagation could be more easily influenced by the obstacles on the propagation paths.Thus,indoor high quality network could not be established without precise wave propagation models.The propagation characteristic of microwave is introduced.Analyze the propagation mechanism and traditional indoor microwave propagation models and indoor wireless signal propagation characteristics in different scenarios.Study the simulation methods of microwave propagation and analyze the principle of ray-tracing and FDTD.The architectural patterns have become important factors of indoor distributed system.In view of the diffraction loss existing in the corner of corridor in buildings and the current lack of corridors propagation loss testing data,diffraction loss of T-corridor and L-corridor are selected to measure and simulate on the 0.831GHz?2.661 GHz.In order to reduce the complexity of measurement,a set of automatic test system is developed.Both experiments and simulations show that conventional diffraction propagation model does not fit T-corridor and L-corridor.Propose microwave propagation correction model of T-corridor and L-corridor.The diffraction loss of T-corridor on 0.831GHz?2.661 GHz takes empirical value of 17dB.The diffraction loss of L-corridor increases linearly with frequency on 0.831GHz?2.661 GHz,which is around 7?14dB.The average magnitude of error on T-corridor between conventional diffraction model and correction model is 10.4dB;the average magnitude of error on L-corridor between conventional diffraction model and correction model is 6.78dB.Use Wireless Insite to simulate the diffraction loss of T&L corridor.The simulation results and test results match well.Analyze the indoor microwave propagation on 5G candidate frequency bands.Study the time delay characteristic in shiedling room and analyze influence of different size of the room,polar combination of transmit and receive antennas and antenna patterns.The delay spread of small shielding room is smaller than the large shielding room.The polarization combination of transimission and receiving antennas has no significant impact.Compared to omni antenna,using directional antenna would help decrease multipath delay spread.Meanwhile,simulated the influence to multipaths delay spread in big lab with metal obstacles.Because of the blocking of metal obstacles,the propagation difference of multipaths in the room with metal obstacles is smaller than the scenario which has line of sight.Thus,the time dalay of scenario with non-line of sight is smaller than that of line of sight.At last,simulate the distribution of Angle of Arrival.In this scenario,the distribution of Angle of Arrival is uniform distribution.