Base station over-the-air testing in reverberation chamber

Base station conformance and performance testing is traditionally carried out in a conducted manner, i.e. test instruments are connected via cables to physical ports on the base station. As the complexity of the base station transceiving circuitry increases and more and more antennas are added to the transceiving links, new measurement techniques based on Over-the-Air metrics are needed. This is especially important for base stations for the new emerging 5G standard. The reverberation chamber is a good candidate for these tests, given its short test times and low test setup complexity. The reverberation chamber is already a frequently and well-proven tool in the wireless industry to assess performance of user equipment and the extension to base station testing is straightforward. This paper elaborates on the feasibility of the reverberation chamber for base station Over-the-Air testing. Several key parameters are measured and compared to results from conducted testing, showing that the metrics currently measured in conducted mode can be translated to Over-the-Air metrics with high accuracy. In addition, an analysis of major uncertainty contributions is provided. This analysis shows that there is insignificant impact on the measurement accuracy when measuring antennas with high gain in the reverberation chamber.