Characterization of mmWave and sub-6 GHz Propagation Channels in Manufacturing Scenarios.

The emergence of 5G and 5G-Advanced (5G-A) communication networks brings new features and capabilities, such as simultaneous use of multiple frequency bands. Precise and reasonable channel models in a real propagation environment are essential for evaluating multi-band cooperative algorithms. In this work, a measurement campaign characterizing multi-band large- and small-scale propagation channels was conducted in indoor industrial scenarios. Firstly, large-scale channel measurements were performed to characterize path-loss and shadow fading in the frequency bands from 3.5 to 39 GHz. Additionally, an alpha-beta-gamma (ABG) model was adopted to fit the path-loss model. Compared with 3GPP 38.901 channel model, the path-loss model derived from the line-of-sight (LoS) environment is similar, while both the measured frequency- and distance-dependent parameters in the path-loss model tend to be larger for non-LoS (NLoS) locations. We then constructed a long-distance bi-directional millimeter-wave (mmW) channel sounder using a radio-over-fiber (RoF)-extended vector network analyzer (VNA) and a virtual antenna array. The Space-Alternating Generalized Expectation-maximization (SAGE) algorithm was applied to estimate the multi-path components (MPCs) in delay and angular domains. Similar distributions of the dominant MPCs are observed for 26.5 GHz and 39 GHz frequency bands in the delay, angel of departure (AoD) and angel of arrival (AoA) domains. Besides, the delay and angle composite spreads in the 26.5 GHz band are larger than those in the 39 GHz band. More importantly, the spatial consistency as a function of UE position is presented for 26.5 GHz band, showing that multi-path delay varies linearly with the Tx-Rx distance.