Over-the-air testing for dual-polarized MIMO devices: Setup design and validation

Over-the-air (OTA) testing is considered as the only feasible solution to evaluate radio performances of the fifth-generation (5G) wireless devices which feature two important technologies, i.e., massive multiple-input multiple-output (MIMO) and millimeter-wave (mmWave). The multi-probe anechoic chamber (MPAC) based OTA setup is able to emulate realistic multipath propagation conditions in a controlled manner. This paper investigates an MPAC OTA setup which is capable of evaluating the performances of 5G base stations as the devices-under-test (DUTs) which are equipped with dual-polarized antennas. Both end-to-end setup and probe configuration for the considered MPAC setup will be elaborated. Furthermore, since building a practical MPAC setup is expensive, time-consuming, and error-prone, an end-to-end software testbed is established for validation purpose to avoid technical risks before finalizing an MPAC setup. The architecture of the testbed is presented, which can emulate both the channel profiles perceived by the DUT and the physical-layer behaviors of the considered link conforming to 5G new radio (NR) specifications. Results show that the performances under the emulated channel agree well with those under the target channel, validating the accuracy and effectiveness of the MPAC method.