Digital Twins of Electromagnetic Propagation Environments for Live 5G Networks—Part II: High-Fidelity Emulation in the MPAC Setup

This article tackles one of the key challenges for over-the-air (OTA) testing of multiinput multioutput (MIMO) devices, that is, accurately reproducing the electromagnetic (EM) propagation environment of live 5G networks within multiprobe anechoic chamber (MPAC) setups. We propose a digital twin (DT) emulation framework to reconstruct the fading environment of live 5G networks in the laboratory with high fidelity. This framework consists of two steps: first, high-accuracy wireless channel acquisition in the field, and subsequently, EM environment reconstruction within the MPAC setup in the laboratory. Initially, a home-developed passive channel sounding system, which has been introduced in detail in Part I of the work, is adopted to accurately capture the multipath parameters for 5G commercial networks. Then, the obtained channel data is used to synthesize the EM environment in the MPAC setup, creating a DT of the EM propagation environment that mirrors the deployment field conditions. To assess the accuracy of the DT, the variation in the reference signal received power (RSRP) of a commercial smartphone across different orientations is chosen as the evaluation metric, which has been measured both in the field and laboratory. Measurement results demonstrate a good alignment between the real world and the emulated DT, validating the effectiveness of the proposed framework.