Standardized Approach for Assessing Wireless IoT Devices in Millimeter-Wave Industrial Work-Cell Channels

We present a standardized, repeatable test approach that replicates key features of measured industrial environments in a fully characterized hybrid test chamber. The hybrid chamber consists of an anechoic chamber along with movable metallic spheres that provide discrete reconfigurable multipath components (MPCs). The chamber is characterized by a synthetic-aperture system providing a reference measurement that captures the nonidealities of the chamber along with the intended spatial multipath, completing characterization of the test environment. A key feature of our approach is the propagation of correlated uncertainties through to the final system response, including uncertainties specific to synthetic apertures such as cable bending due to scanning and inexact positioner locations. The uncertainty analysis provides statistically accurate knowledge of the environment, allowing separation of measurement errors from errors related to the device or system under test. We have also extracted three exemplar channels that capture key features of a work-cell-sized industrial environment from measurements made with the same synthetic aperture. Each exemplar channel presents different, realistic angular-diverse multipath challenges to a millimeter-wave (mmWave) Internet-of-Things device, subsystem, or active antenna under test. This allows engineers to evaluate their hardware designs in a physical, repeatable test environment and also facilitates future standardization of test methods for these and other mmWave wireless devices.