Research On 3D Channel Reconstruction And Performance Test In 5G OTA

Performance testing plays an important role in the research and production of communication device.Before 5G,OTA method is only applied to UE performance test,and throughput performance of BSs can be evaluated by connecting coaxial cables to the BS antenna ports.In 5G,due to the increase of integration,only OTA method can accurately evaluate BS performance,conventional cable-conducted testing is currently not available.Therefore,on the research of 5G OTA test,both UE side and BS side should be considered.For UE OTA testing,the Multi-Probe Anechoic Chamber(MPAC)method is still recommended by standardized organizations such as CTIA and 3GPP.For BS OTA testing,cable-conducted testing will be replaced by OTA method as Massive MIMO and beamforming are used in 5G.Simplified Sectorized MPAC(SS-MPAC)is proposed for BS OTA performance testing.In this context,based on MPAC and S-MPAC,the three-dimensional channel reconstruction and probe configuration in 5G OTA testing are studied in this paper.The main research work is as follows:1.The MIMO OTA test before 5G does not consider the distribution of the angular power spectrum in the vertical dimension.5G introduces a 3D channel propagation environment and vertical dimension.At the same time,the frequency band involved in 5 G is also quite different from that of LTE.Based on 5G channel conditions,this paper uses a single-cluster channel model to simulate and analyze the influence of factors such as frequency,dimension,and angle expansion on reconstruction spatial correlation errors,and summarizes the principles that should be followed in probe configuration and probe selection.2.Research on 3D probe configuration based on 5G channel model.In view of the characteristics of the 5G channel model,the optimization of probe configuration in MPAC is studied,and a new probe configuration scheme is proposed.The new scheme improves the reconstruction accuracy and reduces the spatial correlation error without significantly increasing the cost of MPAC system.Different probe configurations are simulated and analyzed in UMa LOS,UMa NLOS,UMi LOS,UMa NLOS scenarios.In different scenarios,the proposed probe configurations can reduce RMS error by 31.4%to 51.3%on the basis of conventional configurations.3.Massive MIMO OTA test and its probe selection problem research.The BS OTA test uses the SS-MPAC method.Based on the 5G channel model,this article simulates and compares the reconstruction error of different probe configurations.The sector probe configuration reduces the RMS by 68.8%based on the ring probe configuration.The performance differences between different probe selection algorithms are compared,and the reconstruction spatial correlation errors under LOS and NLOS propagation conditions are simulated and compared.