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Scalable Modeling of Human Blockage at Millimeter-Wave: A Comprehensive Analysis of Knife-Edge Diffraction, the Uniform Theory of Diffraction, and Physical Optics Against 60 GHz Channel Measurements

Published

Author(s)

Anmol Bhardwaj, Camillo Gentile, Jelena Senic

Abstract

Human blockage at millimeter-wave frequencies is most commonly modeled through Knife-Edge Diffraction (KED) from the edges of a vertical strip. Although extensively validated through controlled laboratory experiments, the method does not scale to realistic 3D scenarios with multiple human and non-human blockers and with significant multipath incident from different directions. To address this, in this paper we investigate numerical approaches based on the raytracing methods. Two electromagnetic computational methods in addition to the KED, namely the Uniform Theory of Diffraction (UTD) and Physical Optics (PO), are used to predict the human shadow loss at 60 GHz for a total of 60 blockage scenarios, comprising multiple human subjects with varying distances between the transmitter, human, and receiver. The predicted shadow loss is compared against measurements performed by the National Institute of Standards and Technology (NIST). In addition to the vertical strip shape, the human subjects are modeled as cylinders and hexagons with the UTD method, while a 3D phantom shape is used with the PO method. The shadow loss predicted by the PO method is shown to be the most accurate, overestimating fade depth by only 1.6-2 dB in the deep shadow region, and providing an overall error of 5.46 dB. However, this method is computationally intensive due to the large number of facets (8000) in the phantom shape and due to the inherent complexity of the the PO itself. Hence, this method should be limited to simpler real-life propagation scenarios. The UTD method with the hexagon shape (having 42 facets), on the other hand, is computationally inexpensive compared to the PO, but overestimates the fade depth by 3.8-4 dB in the deep shadow region and has a total error of 5.58 dB. Providing good accuracy and efficiency, the UTD method is recommended as it scales best to complex propagation scenarios.
Citation
IEEE Antennas and Propagation Magazine

Keywords

Ray-tracing, UTD, PO, knife-edge diffraction, human shadowing, mmWave, WaveFarer

Citation

Bhardwaj, A. , Gentile, C. and Senic, J. (2022), Scalable Modeling of Human Blockage at Millimeter-Wave: A Comprehensive Analysis of Knife-Edge Diffraction, the Uniform Theory of Diffraction, and Physical Optics Against 60 GHz Channel Measurements, IEEE Antennas and Propagation Magazine, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=935612 (Accessed February 24, 2024)
Created December 22, 2022, Updated January 22, 2024