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

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We describe a quasi-deterministic channel propagation model for human gesture recognition reduced from real-time measurements with our context-aware channel sounder, considering four human subjects and 20 distinct body motions, for a total of 120 000 channel acquisitions. The sounder features a radio-frequency (RF) system with 28 GHz phased-array antennas to extract discrete multipaths backscattered from the body in path gain, delay, azimuth angle-of-arrival, and elevation angle-of-arrival domains, and features camera / Lidar systems to extract discrete keypoints that correspond to salient parts of the body in the same domains as the multipaths. Thanks to the precision of the RF system, with average error of only 0.1 ns in delay and 0.2 • in angle, we can reliably associate the multipaths to the keypoints. This enables modeling the backscatter properties of individual body parts, such as Radar cross-section and correlation time. Once the model is reduced from the measurements, the channel is realized through raytracing a stickman of keypoints -the deterministic component of the model to represent generalizable motion -superimposed with a Sum-of-Sinusoids process -the stochastic component of the model to render enhanced accuracy. Finally, the channel realizations are compared to the measurements, substantiating the model's high fidelity.INDEX TERMS 6G; JCAS; camera; Lidar; joint communications and sensing; 28 GHz; phased-array antennas.

Section: Introductionmentioning

confidence: 99%

Quasi-Deterministic Channel Propagation Model for Human Sensing: Gesture Recognition Use Case

Chuang,

Caromi,

Senic

et al. 2024

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“…For example, the combination of the knifeedge diffraction-based (KED) method [14] with a vertical screen, the combination of the uniform theory of diffraction (UTD) method for wedge diffraction [15] with a prism-like model, and the combination of the UTD method for creeping diffraction [7], [16] with a circular or elliptic cylinder have been proposed. In previous research, the human body was modeled as a screen in [17], [18], a prism-like cylinder in [19], [20], and the circular and elliptic cylinders in [16]. All the conventional geometric human models were defined from the dimensions measured in advance.…”

Section: Introductionmentioning

confidence: 99%

Point Cloud-Based Prediction Models of Dynamic Human Body Shadowing at 58 GHz

Kang,

Du,

Takada

2024

As one of the channels used by the wireless gigabit (WiGig) protocol, a 58 GHz band has been deployed to realize a data rate of up to 100 gigabits per second (Gbps). Systems at the 58 GHz band point the main beam of the base station toward the mobile stations but suffer from a deep fading due to human body shadowing (HBS). To precisely predict the HBS channel considering the short wavelength at 58 GHz, a simulation method considering the detailed human geometry is needed. This paper proposes screen models and an elliptic cylinder model based on the instantaneous point clouds (PC) of human geometry for the HBS channel simulation using the uniform theory of diffraction (UTD). The proposals enable fair evaluation via a simultaneous measurement of the HBS channel and the PC. The HBS gains at the 58 GHz band in an indoor environment (6.5 m) between the measured and the simulated results based on the proposed models are compared. Compared with the conventional human model, the screen models are suitable for predicting the propagation channel cut-off by tracing the changing posture of the human body, and the elliptic cylinder model is suitable for predicting the shadowing distance by a 75% improvement.INDEX TERMS Dynamic channel, human blockage model, millimeter wave propagation, UTD simulation.

“…In the PO calculation, the field scattered from RIS can be easily calculated by the integral of the approximated surface current weighted by the phase shift of RIS [24]. Unfortunately, the traditional PO expressed by numerical integration is impractical, since it requires a large computational load, compared to the analytical approach [27]. Thus, the paper [24] involved the Fraunhofer and Fresnel approximations (see Appendix A) in the PO calculation to obtain analytical solutions, resulting in a lower computational cost.…”

Section: Introductionmentioning

confidence: 99%

UTD-Type Solution of Physical Optics Approximation for Reconfigurable Intelligent Surface Modeled by a Continuous Planar Surface

Du,

Kang,

Takada

2023

An accurate and fast prediction technique is necessary for the radiation pattern of the reconfigurable intelligent surface (RIS) to quantitatively and efficiently evaluate the performance of RIS. Based on the uniform theory of diffraction (UTD), this paper proposes a UTD-type solution of the physical optics approximation (PO) for RIS modeled by a continuous planar surface in a two-dimensional environment. The authors validate the proposal under different scenarios in an indoor environment (0.1 − 20 m) at the terahertz bands (100 − 300 GHz), by comparing them with those computed using the Fresnel approximation, the Fraunhofer approximation, PO, and the full-wave approach based on the method of moment (MoM). The simulated results show that compared to MoM, the proposal and PO achieve good accuracy with a smaller error of less than 1 dB, while the Fresnel and Fraunhofer approximations present imperfect accuracy with an error of larger than 1 dB in the near-field region. Moreover, the proposal outperforms the PO in terms of faster calculation time by approximately 70% − 76%, and the computational time of the proposal is improved by approximately 46, 190 − 125, 460 times compared to MoM. Furthermore, the computational complexities of the proposal, the Fresnel approximation and the Fraunhofer approximation are O(N 0 ), compared to that of PO and MoM by O(N ) and O(N 2 ), respectively, where N and O(•) are the number of sampling points and the notation of order, respectively. Therefore, the proposal can achieve a good balance between accuracy and computational cost.