Objective MIMO Measurement

Over-the-air (OTA) measurements are the standardized methods to evaluate radio performance in wireless systems. Handling multiple input and multiple output (MIMO) situations in OTA measurements is critical for the fourth generation (4G) long-term-evolution (LTE) and upcoming fifth generation (5G) wireless systems. In MIMO OTA measurements, different kinds of devices have different maximum power levels and may be tested in different transmit power levels. Since transmit power level can affect device physical temperature that will proportionally increase the noise temperature and change the throughput of the device under test (DUT), the throughput of DUT is related to its transmit power. Lack of considering the thermal effects of the DUT will result in measurement uncertainty in MIMO OTA test. This paper proposes a new MIMO measurement method based on radiated two-stage approach for LTE systems to illustrate the relationship between the transmit power and the measured MIMO throughput. With this new MIMO measurement method, the measured MIMO performance is a function of the transmit power level of the DUT at its thermally stable condition. The proposed method reduces the measurement uncertainty for the MIMO throughput measurement and provides a reference for optimal functional and EMC designs