| Recently,wireless terminals' service forms are constantly changing and developing.Multiple Input Multiple Output(MIMO)multi-antenna technology has become the core solution under the development trend of high-speed wireless communication.In order to effectively evaluate the performance of wireless terminals,the "Performance Test Method Over the Air"(OTA)has become the mandatory item in the current network test.The Multi-Probes Anechoic Chamber(MPAC)is one of the most widely accepted solutions.However,the MPAC testing scheme is limited to the 2D standard channel model in the current industry,simplifying the real channel scenario.Considering the 3D MIMO technology and the accurate 3D channel model which the next generation mobile communication system relies on,the 2D MIMO OTA will no longer be applicable.To this end,the paper studies the reconstruction of 3D MIMO dynamic channel model in real high-speed rail scene in OTA multi-probes anechoic chamber.The main work content and innovations of the thesis include:1.Aiming at the lack of 3D channel model reflecting the characteristics of real external field channel in current OTA test system,this paper combines the important position of high-speed railway in wireless communication application scenario,and proposes a 3D MIMO dynamic channel modeling method based on field measurement for high-speed rail scene.Based on the measured channel parameters of the high-speed railway "Jing-Jin" line,the characteristics of the high-speed rail communication system are analyzed,and the specific scheme for establishing the dynamic 3D simulation scene is given.The large-scale and multi-path dynamic channel model in the high-speed rail environment is completed,and the shortcoming of the OTA test limited in the two dimensional channel model is solved.The simulation results show that the model can effectively restore the characteristics of the real high-speed rail field propagation channel.2.For the problem that the MPAC solution is limited to the reconstruction of the two-dimensional channel model,the paper proposes an OTA multi-probe darkr-oom reconstruction scheme based on the 3D MIMO dynamic channel model,combined with the reproducible 2D MPAC and three-dimensional dynamic channel propagation characteristics.The pre-weak synthesis method under the three-dimensional spherical probe device scheme gives a specific method for reconstructing the real high-speed rail model above-mentioned in the multi-probes darkroom,completes the whole process of the 3D MIMO OTA solution,and further optimizes the performance of the scheme by using the interpolation algorithm.The results show that the proposed scheme can reconstruct the spatial domain characteristics of the high-speed rail 3D dynamic channel model in an anechoic chamber with higher efficiency.3.In view of the problem that the OTA test system has not been upgraded to the Virtual Drive Test(VDT),the paper proposes a virtual drive 3D MIMO OTA test method.Combined with the above works,it summarizes the specific reconstruction of the real field propagation channel in the OTA darkroom.The method of hardware equipment including external field recording equipment,base station simulator,channel simulator,3D spherical multi-probes anechoic chamber is given,which solves the problem of lack of specific implementation process of OTA combining with VDT in the industry.3D MIMO OTA high-speed rail's recurrence proves the feasibility and effectiveness of the solution.In this paper,on the one hand,an MPAC solution based on 3D dynamic channel model is designed to realize 3D MIMO OTA construction;on the other hand,the real high-speed rail channel scene is reproduced,upgraded to a real virtual drive OTA test.The real performance of terminals in the actually field environment are evaluated and provide the most valuable reference data for improving chip algorithms and terminal design. |
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