On Probe Weighting for Massive MIMO OTA Testing Based on Angular Spectrum Similarity

Abstract

Over-the-air (OTA) radiated testing for massive multiple-input–multiple-output (MIMO) base stations (BSs) poses an urgent challenge for the extended development and deployment of the fifth-generation mobile communication systems. Conventionally, MIMO OTA uses the spatial correlation-based metric for channel emulation to evaluate the fourth-generation user terminals. However, it does not provide sufficient accuracy due to the larger dimension of massive MIMO BSs. In this letter, we propose a new criterion based on angular spectrum similarity for channel emulation in OTA testing of massive MIMO BSs. As antenna array control is critical for the performances of massive MIMO BSs, the proposed metric can reconstruct power distribution more accurately in the angular domain, thus increasing channel emulation accuracy, which will affect notable performances, such as array gain, sidelobe interference, and direction-of-arrival estimation, for massive MIMO BS OTA testing.