OTA Measurement for IoT Wireless Device Performance Evaluation: Challenges and Solutions

TLDR: A series of solutions for improving the standard OTA measurements to meet the IoT OTA requirements and the radiated two-stage (RTS) method is introduced, including the pattern measurement error elimination and the inverse matrix auto-solving.

Abstract: The explosion of applications of Internet of Things (IoT) wireless devices urgently requires over-the-air (OTA) performance evaluations. However, the challenges mainly due to the fact that the ubiquitous IoT device applications have made it necessary for OTA measurements to be operated in accurate, fast, and cost-effective ways. This paper proposes a series of solutions for improving the standard OTA measurements to meet the IoT OTA requirements. For single-input single-output (SISO) terminals, three test techniques are introduced for speeding up their total isotropic sensitivity tests and improving the test accuracy. For IoT multi-input multioutput (MIMO) devices, the radiated two-stage (RTS) method is introduced. The detailed theories are described mathematically, including the pattern measurement error elimination and the inverse matrix auto-solving. The advantages of the RTS on MIMO system diagnosis are outlined. Besides, a smart test system was introduced, which is suitable for a general office building. Both SISO and MIMO can be conducted in this chamber, resulting in great cost saving. Thus, with innovations on hardware and methodologies, the OTA evaluations can be accommodated and helpful for the IoT industry.