Research On Low Complexity Channel Reconstruction For 5G MIMO OTA Testing Based On Multi-probe Anechoic Chamber

With the arrival of Fifth Generation(5G)era,in order to meet the requirements of communication system for low latency and high speed,multi-input multi-output(MIMO)technology and millimeter wave(mmWave)communication have gradually become the key technologies to achieve efficient transmission.Over the air(OTA)test is considered to be the only feasible solution for 5G MIMO test.On the one hand,the antenna system of 5G equipment is generally highly integrated,and the traditional conduction test cannot be realized;On the other hand,the 5G communication system is highly dependent on the characteristics of the antenna array,that is,the overall test must be conducted through the OTA method.Among them,the multi-probe anechoic chamber method is considered to be the most promising MIMO OTA test method by many standard organizations.This paper mainly studies the 5G MIMO OTA test method based on the multi-probe anechoic chamber,and studies the low-complexity channel reconstruction method from three aspects:optimizing the 5G multi-probe anechoic chamber probe configuration,reducing the test complexity of the mmWave frequency band,and simplifying the channel reconstruction of complex dynamic scenes.(1)In view of the contradiction between the accuracy of channel reconstruction and the high cost of multi-probe in three-dimensional multiprobe anechoic chamber,this paper proposes a probe selection scheme based on differential evolution algorithm.The simulation results show that compared with the traditional Multishot algorithm,this scheme can not only synthesize a more accurate target channel with fewer probes,reduce the system cost and configuration complexity,but also be applicable to a variety of probe configurations and channel models,with better flexibility and portability.(2)In view of the complexity of the antenna system of the mm Wave equipment and the difficulty in obtaining the specific structure of the internal antenna system of the tested equipment,this paper first proposes a black-box test scheme based on the typical antenna configuration,and proposes the average angle power spectrum similarity as an evaluation index to evaluate the accuracy of the reconstructed channel in the anechoic chamber,effectively reducing the impact of the antenna array position and operating mode on the channel reconstruction,so as to improve the reconstruction accuracy of the target channel.(3)In view of the high complexity of the test system and the low accuracy of the radio resource management performance test caused by the dynamic and changeable channel environment in the actual scene,this paper proposes a partition probe configuration strategy and a switching circuit based on beam directivity,which can reconstruct the dynamic switching characteristics of the channel with a low complexity to ensure the smooth and accurate switching of the dynamic scene in the test area,so as to realize more accurate test of equipment MIMO performance.