Examining and Optimising Far-Field Multi-Probe Anechoic Chambers for 5GNR OTA Testing of Massive MIMO Systems

Direct far-field (DFF) testing has become the de facto standard for sub-6 GHz over the air (OTA) testing of the physical layer of radio access networks with the far-field multi-probe anechoic chamber (FF-MPAC) being especially widely deployed for the verification of massive multiple input multiple output (Massive MIMO) antennas in the presence of several users. The adoption of mm-wave bands within the fifth generation new radio (5G NR) specification has meant that, as these systems require the user equipment be placed in the far-field of the base transceiver station (BTS) antenna, either excessively large FF-MPAC test systems are required or, the user equipment is paced at range-lengths very much shorter than that suggested by the classical Rayleigh criteria. This paper explores range length effects on several communication system figures of merit and examines the consequences of testing within smaller enclosures. Results are presented and discussed.