Research And Implementation Of MIMO OTA Test System Based Multi-probes

ABSTRACT:With MIMO (Multiple Input Multiple Output) antenna system was widely used on LTE, MIMO OTA (over-the-air) testing was paid more and more attention which was created to make proper assessment of LTE terminal receiving performance. Currently, a variety of MIMO OTA test methods have been proposed and discussed such as multi-probe anechoic chamber method, reverberation chamber method, two-stage method etc. Multi-probe anechoic chamber method has become the most prevalent test methodology for multi-antenna device receiving performance because it can provide channel simulation model which is closest to real environment.The thesis focuses on measurement of multi-antenna terminal radiated performance, closely around the characteristics of MIMO channel environment and related testing standards of multi-probe MIMO OTA testing at home and abroad. On the basis of analyzing the test processes and function in different stages of multi-probe MIMO OTA testing system, describing in detail the calibration of the testing system, the validation of channel model and throughput testing of multi-antenna terminal, and developing automatic testing software system for multi-probe MIMO OTA testing. Precisely, the work can be divided into the following four parts.1. For a variety of MIMO OTA testing methods currently proposed, the thesis presents the advantages and disadvantages of the test methods and application scope through the theoretical research and comparison between the test data. Combined with the advantage of multi-probe method, the thesis expounds related instrument configuration, size of anechoic chamber, the choice of probes, test condition and process about multi-probe MIMO OTA testing system.2. Since the introduction of the MIMO channel model and its importance to the entire testing system, the validation of channel model plays a key role in the thesis. Taking SCME channel model as an example, the thesis presents four key parameters characterizing the channel model:PDP, Doppler, Spatial Correlation,XPR, and introduces the method of each parameter validation; Through a lot of actual verification testing, the thesis also presents the results of the validation to ensure that channel environment simulated by the testing system and the real channel environment match each other by compared with the theoretical value of the imported channel model.3. On the basis of theoretical research, assisting the team to develop and complete multi-probe MIMO OTA automatic test software system using C#programming language of.NET platform. My main job:providing testing system software requirements specification; participating in the software implementation of channel model validation module and multiple-antenna terminal throughput testing module; improving the related algorithm of software system and the function extension of testing system through the actual test.4. To build multi-probe MIMO OTA system hardware testing platform, connect the entire testing system through GPIB bus, and conduct related test utilizing the automatic test software system. By compare the test data between different testing systems, effectiveness and consistency of test data of the testing system can be ensured.