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From 3D Point Cloud Data to Ray-tracing Multi-band Simulations in Industrial Scenario
... Consequently, these strengths make point clouds much more suitable than meshes for fast modeling and simulation. Up till now, some studies have already been conducted on the possible applications of point clouds in CEM [10]- [12], [35], [36], [38]- [40]. ...
... Zhang et al. employed plane fitting and Poisson reconstruction to recover 3D buildings from drone aerial photos [32]. And In [36], reconstruction method was used in industrial scenario simulations. In CG, neural networks are recently used for direct reconstructions [23], [24]. ...
The rapid computation of electromagnetic (EM) fields across various scenarios has long been a challenge, primarily due to the need for precise geometric models. The emergence of point cloud data offers a potential solution to this issue. However, the lack of electromagnetic simulation algorithms optimized for point-based models remains a significant limitation. In this study, we propose PointEMRay, an innovative shooting and bouncing ray (SBR) framework designed explicitly for point-based geometries. To enable SBR on point clouds, we address two critical challenges: point-ray intersection (PRI) and multiple bounce computation (MBC). For PRI, we propose a screen-based method leveraging deep learning. Initially, we obtain coarse depth maps through ray tube tracing, which are then transformed by a neural network into dense depth maps, normal maps, and intersection masks, collectively referred to as geometric frame buffers (GFBs). For MBC, inspired by simultaneous localization and mapping (SLAM) techniques, we introduce a GFB-assisted approach. This involves aggregating GFBs from various observation angles and integrating them to recover the complete geometry. Subsequently, a ray tracing algorithm is applied to these GFBs to compute the scattering electromagnetic field. Numerical experiments demonstrate the superior performance of PointEMRay in terms of both accuracy and efficiency, including support for real-time simulation. To the best of our knowledge, this study represents the first attempt to develop an SBR framework specifically tailored for point-based models.
... Material properties of these objects are defined based on the recommendation of the International Telecommunication Union (ITU) [14]. The entire procedure of building an RT model can be found in [15]. ...
The precise and accurate indoor positioning using cellular communication technology remains to be a prerequisite for several industrial applications, including the emergence of a new topic of Integrated Sensing and Communication (ISAC). However, the frequently occurring Non-Line-of-Sight (NLoS) conditions in a heavy multipath dominant industrial scenario challenge the wireless signal propagation, leading to abnormal estimation errors (outliers) in the signal measurements taken at the receiver. In this paper, we investigate the iterative positioning scheme that is robust to the outliers in the Time of Arrival (ToA) measurements. The Iteratively Reweighted Least Squares (IRLS) positioning scheme formulated on the Least Squares (LS) is implemented to reject the outlier measurements and reweight the available ToA samples based on their confidence. Our positioning scheme is validated under 5G frequency bands, including the C-band (3.7 GHz) and the mmWave-band (26.8 GHz) in a Ray-Tracing enabled industrial scenario with different emulation setups.
... Besides, the metallic objects, the objects made up of concrete, plastic, wood, and glass materials are also included in the RT model, and the properties of these materials are defined according to the International Telecommunication Union (ITU) recommendation [7]. We point the interested reader to [8], for the entire process chain of building an RT model from the 3D point cloud data. ...
Private fifth-generation (5G) networks are increasingly becoming the industrys' choice of wireless communication networks for accelerating production processes. In this context, the role of 5G in providing precise positioning services in indoor industrial scenarios has also been actively discussed. However, the achievable indoor positioning accuracy depends on the radio propagation conditions persisting in the scenario. In this paper, using a Ray-Tracing (RT) engine, we investigate the radio environment in C-band (3.775 GHz) as well as the mmWave-band (26.85 GHz) for a detailed 3D geometric model of the dense clutter industrial production hall under different emulation setups and categorize the dominant Non-Line-of-Sight (NLoS) MultiPath Components (MPCs). We then evaluate the achievable Observed Time Difference of Arrival (OTDoA) based positioning accuracy in the C-band and the mmWave-band by computing the position of User Equipment (UE) using only first-arriving MPCs.
In this paper, a novel three dimensional (3D) hybrid ray tracing (HRT) method for wave propagation simulation for large indoor and small cell urban environment is proposed. HRT combines two image based ray tracing (RT) methods: "standard" ray tracing (i.e., the rigorous and conventional image ray tracing) with high accuracy and "intelligent" ray tracing (i.e., visibility tree based image ray tracing) with less time consuming. To establish the accuracy of HRT, its simulation results were compared with millimeter wave (mmWave) measurements in a large indoor scenario under different visibility conditions. It shows that good predictions can be provided by HRT in many aspects, such as path loss, temporal characteristics, evolution of channel, etc. Meanwhile, mismatche and difference between measurement and simulation will be shown and be analyzed as well.
The millimeter wave (mmWave) communications and massive multiple-input multiple-output (MIMO) are both widely considered to be the candidate technologies for the fifth generation mobile communication system (5G). It is thus a good idea to combine these two technologies to achieve a better performance for large capacity and high data-rate transmission. However, one of the fundamental challenges is the characterization of mmWave massive MIMO channel. Most of the previous investigations in mmWave channel only focus on single-input single-output (SISO) links or MIMO links, whereas the researches of massive MIMO channels mainly focus on a frequency band below 6 GHz. This paper investigates the channel behaviors of massive MIMO at a mmWave frequency band around 26 GHz. An indoor mmWave massive MIMO channel measurement campaign with 64 and 128 array elements is conducted, based on which, path loss, shadow fading, root-mean-square (RMS) delay spread, and coherence bandwidth are extracted. Then, by using our developed ray-tracing simulator calibrated by the measurement data, we make the extensive ray-tracing simulations with 1024 antenna elements in the same indoor scenario, and get insights into the variation tendency of mean delay and the RMS delay with different array elements. It is observed that the measurement and the ray-tracing based simulation results have reached a good agreement.
The vision of multi Gbit/s data rates in future 5G networks requires the change to millimeter wave (mm-Wave)
frequencies for increasing bandwidth. As a consequence, new technologies have to be deployed to tackle the drawbacks of higher frequency bands, e.g. increased path loss. Development and verification of those novel technologies requires channel sounding, to measure and analyse the radio wave propagation. Due to the variety of considered frequency bands and the necessity of spatial resolved measurements for e.g. testing of beamforming approaches, measurement duration and comparability becomes problematic. This paper presents multi-band channel sounder architectures, usable to measure up to four frequency bands simultaneously. Furthermore, we present a measurement campaign, featuring full polarimetric and directional resolved dual-band measurements, which comprises the microwave band at 10GHz and the mm-Wave band at 30GHz. Preliminary analysis results are presented.
Effects of building materials and structures on radiowave propagation above about 100 MHz
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