Radio Propagation Simulation Research Articles

Acceleration of Tensor Interpolation-Based Radio Map Estimation

The radio map of wireless communications should be surveyed in advance when installing base stations to efficiently utilize radio waves. Generally, this is calculated using radio wave propagation simulation. Because the simulation is time-consuming, a tensor-rank minimization-based interpolation method has been proposed as fast method. However, this method interpolates the radio map using an iterative algorithm. The number of iterations required for further acceleration should be reduced; therefore, we propose a tensor interpolation using rank minimization that considers the characteristics of radio wave propagation. Furthermore, we proved that the proposed method could interpolate with fewer iterations than the existing method.

Scenario-specific radio propagation simulation from LiDAR point cloud data for smart office scenario

Recently, the cyber-physical-system (CPS) has attracted great interest in the information and communications technology (ICT) research field for the virtual test of wireless communication systems. Since the performance of wireless communication significantly depends on the radio propagation channel characteristics, the development of accurate radio propagation simulation technology becomes essential for the purpose. This paper proposed the scenario-specific radio propagation simulation method from LiDAR point cloud data. By the continuous environment measurement by LiDAR, the positions of dynamic objects like pedestrians are tracked, as well as the site-specific propagation environment characteristics and their influences are taken into the simulation. For performance evaluation, the radio propagation measurement was conducted in the 28 GHz band in an indoor office. The result showed a significant improvement in the RMSE of received power prediction. The proposed method will be utilized for the radio channel emulation in the CPS.

3G, HSPA AND 4G LTE NETWORK RELIABILITY AND ACHIEVABLE INTERNET SPEEDS ON AIRBORNE AIRCRAFT UP TO 10.000 FT ABOVE GROUND LEVEL

Nowadays, we are witnesses of 5G mobile technology advancements and many countries plan to or already have introduced this technology to public usage. However, the older technologies such as 3G, HSPA and 4G LTE, because of their physical properties, ways of datagram transfers and frequency bands used, are still very suitable for usage in cases that assume longer distances between terminal device and cell towers. Having that in mind, a research was conducted during 2021. and 2022. in order to test i.e. verify or refute the hypothesis that 3G, HSPA and 4G LTE technologies will be reliable enough to provide a satisfactory connection on aircraft flying up to 3 km (10.000 ft) above ground level, quality enough to establish Internet connection speeds of at least 1Mbps, which would be enough to serve as a medium for innovated, Internet-based data links similar to CPDLC/ACARS. Through a series of 14 airplane flights, both above plains and mountain regions, first-hand data was gathered and analyzed accordingly, so reliable conclusions about presented hypothesis could be made. Empirical research results were accompanied with research results made on well-known computer radio propagation simulator TAP7.

Design and Implementation of an Innovative High-Performance Radio Propagation Simulation Tool

Design and Implementation of an Innovative High-Performance Radio Propagation Simulation Tool

Indoor Radio Map Construction via Ray Tracing With RGB-D Sensor-Based 3D Reconstruction: Concept and Experiments in WLAN Systems

This paper proposes an RGB-D sensor-aided ray-tracing simulation framework for indoor radio map construction that models indoor information, such as walls and obstacles, as a set of cuboids. Radio maps can accelerate indoor wireless systems, including resource optimization and fingerprint-based localization. We can construct an accurate radio map using a ray-tracing algorithm with precise information about indoor structures and obstacles. However, it is difficult to acquire this indoor information because manual observations, including the placement of obstacles, are expensive. To mitigate this critical drawback, we propose the acquisition of colored point clouds using an RGB-D sensor. After the point clouds are labeled via a three-dimensional semantic segmentation task, we model the indoor information as a set of cuboids that can be immediately used for the ray-tracing simulation. Indoor experiments using wireless LANs over 5180 and 2452 MHz clarified that the proposed method accurately automates the radio-map construction process from indoor information acquisition to radio propagation simulation.

WiNE-Tap: Wireless LAN emulator with wireless network TAP devices

Conventional real-time wireless network emulators interact with physical network systems using wired LAN (Ethernet) virtualization technology, such as a TUN/TAP device, but they lack the capability of emulating the low-layer (data link sublayer and below) behavior of wireless network systems. For instance, a wireless device in ETSI ITS-G5 vehicular network systems adaptively changes its transmission power depending on the received signal strength, but existing wireless network emulators are incapable of simulating such behavior because they have no means of conveying transmission power information to the surrounding wireless devices in a virtual space. In addition, the implementations of existing network emulators vary even if they support the same network protocols and network configuration, and they rarely support multiple network simulators. The implementation of the network emulators limits the usability of network emulation because network simulators differ widely in the accuracy of their results. This paper proposes a wireless network emulation module called WiNE-Tap, which is implemented as a virtual wireless network device, to address these issues. WiNE-Tap runs in the Linux kernel space, allowing the underlying Linux system and a network simulator to exchange Linux kernel events and simulation events, such as frame transmission/reception and transmission power/RSSI changes, transparently to the user. This implementation allows the emulation of the adaptive behavior of wireless network low layers, as well as the use of any wireless network simulator. In this paper, we evacuate the performance of WiNE-Tap using Linux implementation with consideration of the simulation of radio propagation and network modes’ mobility. Some techniques for improving the timing accuracy of wireless network emulation are also described.

Evaluation of Technology-Supported Distance Measuring to Ensure Safe Aircraft Boarding during COVID-19 Pandemic

With the rise of COVID-19, the sustainability of air transport is a major challenge, as there is limited space in aircraft cabins, resulting in a higher risk of virus transmission. In order to detect possible chains of infection, technology-supported apps are used for social distancing. These COVID-19 applications are based on the display of the received signal strength for distance estimation, which is strongly influenced by the spreading environment due to the signal multipath reception. Therefore, we evaluate the applicability of technology-based social distancing methods in an aircraft cabin environment using a radio propagation simulation based on a three-dimensional aircraft model. We demonstrate the susceptibility to errors of the conventional COVID-19 distance estimation, which can lead to large errors in the determination of distances and to the impracticability of traditional tracing approaches during passenger boarding/deboarding. In the context of the future connected cabin, a robust distance measurement must be implemented to ensure safe travel. Finally, our results can be transferred to similar fields of application, e.g., trains or public transport.

Measurements and Ray Tracing Simulations for Non-Line-of-Sight Millimeter-Wave Channels in a Confined Corridor Environment

This paper presents the radio propagation measurement, simulation, and analytical results in the 41-GHz millimeter-wave band for non-line-of-sight scenarios in a confined in-building corridor environment. High gain directional antennas are used at both the transmitter and receiver to realize long-distance transmission. Directional channel characteristics of the 41-GHz band, including the path loss model, the root-mean-square delay spread, the multipath statistics, the small scale fading characteristics, the power delay profile, and the power levels received from different antenna directions at different locations, are analyzed in detail. Moreover, in the investigation of the path loss models, we employ ray tracing simulations to extend the path loss model to a more general form so that the structural characteristics of the corridor, such as the length of the line-of-sight section and the corridor corner angle, are considered as modeling parameters. The effects of different transmit/receive antenna locations on the path loss model are also investigated. The combined effects of the highly directional antennas and the confined corridor environment on the wireless channel characteristics are analyzed in detail.

On-Site Permittivity Estimation at 60 GHz Through Reflecting Surface Identification in the Point Cloud

Accurate site-specific radio propagation simulations provide an important basis for cellular coverage analysis. The quality of these simulations relies on the accuracy of environmental description and electrical properties of constituent materials. This paper presents a novel method of on-site permittivity estimation. The method utilizes an accurate geometrical database of the environment for identifying flat and smooth surfaces producing reflections. The method exploits a limited number of on-site channel sounding to extract reflected multipaths and compare them with ray tracing based on the environmental database. The permittivity of the identified reflecting surfaces is estimated by solving an inverse reflection problem. The method was experimentally tested with limited radio channel measurements at 60 GHz in a large empty office room. The identified reflecting surfaces are classified according to their mean permittivity estimates, showing their consistency with physical material evidence and the permittivity database in the International Telecommunication Union Radiocommunication Recommendation (ITU-R P.2040-1). The estimated permittivity values are visualized as a 3-D map, giving an intuitive understanding of materials constituting the environment. This paper demonstrates on-site permittivity estimation and material classification without the need for isolated measurements of composite materials in an anechoic chamber or in situ measurements of built environments.

An efficient and accurate OpenMP-MPI based 3D beam tracing method for radio propagation simulation in large scale urban environments

A modified adaptive division beam tracing (MADBT) technique based on the localized kd-tree and the OpenMP–MPI parallel techniques is presented for the simulation of radio propagation in large-scale urban environments. Beams launched from a transmitter are recursively traced by applying the MADBT method and beam trees recorded the propagation path info are generated. By traversing the beam trees, all the valid propagation (transmitted, reflected and diffracted) paths are efficiently determined. Then the receiver power strength can be calculated based on geometrical optics (GO) and uniform theory of diffraction along the arrival paths. By tracing the continuous beams instead of a number of rays, the proposed method performs higher efficiency than the widely used ray tracing method. During the beam tracing procedure, several techniques are adopted to accelerate the calculation. Firstly, a localized kd-tree is built according to the coverage area of the transmitter, which is more efficient than the global kd-tree to do the beam-triangle intersection during the tracing procedure. Secondly, a virtual simulation face is generated to speed up the searching for ray paths. Lastly, the OpenMP and the MPI parallel technique are implemented to further enhance efficiency of the proposed method. As expected, the simulated results for the realistic Malaysia urban environment show good agreement with measured results and performance high efficiency.

ロボットの遭難を防ぐための電波伝搬シミュレーションによる環境構成材料推定の高精度化

We studied how to prevent a “distress of robot” by radio wave propagation simulation. When we conducted radio wave propagation simulation, we need to set material. We need to estimate the material because it is difficult to set material constituting the environment in advance in an unknown environment. In this paper, we evaluate about estimation method of material constituting environment.

1P1-M08 電波伝搬シミュレーションのための三次元地図生成に関する研究

When the tele-operated mobile robot went over its communication range accidentally, the operation would be suspended. We named this kind of trouble "the distress of mobile robot". In order to prevent the distress of mobile robot, it is necessary to estimate communications conditions around the robot by means of radio wave propagation simulation. We aim to prove radio wave propagation simulation is effective method to prevent "the distress of mobile robot" For the simulation, the environment model around the robot is needed, which consists from its shape and permittivity. In this paper, we describe about the 3D shape map generated from depth sensory data.

Оптимизация аналитических алгоритмов трассировки лучей при моделировании процессов распространения радиоволн в городах

Оптимизация аналитических алгоритмов трассировки лучей при моделировании процессов распространения радиоволн в городах

A Simulation System of Radio Propagation Effect Evaluation Based on GIS

Construction of wave propagation effects assessment simulation system based on GIS, for enhancing the capabilities of our military radio environment awareness, forecasting, warning and assessment of the effect is significant.In this paper, the original geographic data and radio wave propagation data will be unified as vector and raster data into GIS system structure based on ArcObjects components, combined with the development of visual language Visual C++ 6.0, designed and constructed to assess the effect of radio wave propagation simulation system. designed and built a radio wave propagation effects assessment simulation system. The system has data management, scene visualization, effects assessment, graphics output function modules, Achieved wave propagation effects assessment simulation and visualization presentation.

Angular and RMS delay spread modeling in view of THz indoor communication systems

AbstractFuture wireless communication systems will most likely be operated at carrier frequencies above 300 GHz, where the indoor radio channel behaves entirely differently compared to legacy radio communication frequencies. Being highly relevant for system performance evaluations and channel modeling, the spatial as well as the temporal dispersions are studied for a representative office wireless LAN scenario in this paper. Ray tracing serves as the means for the accurate simulation of the THz radio wave propagation. Simple stochastic models are derived to approximate and reproduce the distance‐dependent behavior of the angular spread as well as of the RMS delay spread. Based on the results, the maximum symbol rates achievable without any intersymbol interference are quantified and can be shown to reach up to several 100 GSymbols/s provided that highly directive antennas are used.

1P2-G06 遠隔操作ロボットのための電波伝搬推定における障害物の影響(サーチ&レスキューロボット・メカトロニクス(2))

When the tele-operated mobile robot went over its communication range accidentally, the operation would be suspended. We named this kind of trouble "the distress of mobile robot". In order to prevent the distress of mobile robot, it is necessary to estimate communications conditions around the robot by means of radio wave propagation simulation. It is thought that the robot by means of radio wave propagation simulation about the indoor environmental uses the model who settled a plan of building for the cause. However, plan of building may be different from true environment, because many building are given equipment, enlargements and rubble. They can obstacle to the robot and the communication. In this paper, we simulated radio wave propagation on some indoor environment models. We compared that results and considered that obstacle effects tele-operated mobile robot.

Broadband Access in Complex Environments: LTE on Railway

This paper assesses the main challenges associated with the propagation and channel modeling of broadband radio systems in a complex environment of high speed and metropolitan railways. These challenges comprise practical simulation, modeling interferences, radio planning, test trials and performance evaluation in different railway scenarios using Long Term Evolution (LTE) as test case. This approach requires several steps; the first is the use of a radio propagation simulator based on ray-tracing techniques to accurately predict propagation. Besides the radio propagation simulator, a complete test bed has been constructed to assess LTE performance, channel propagation conditions and interference with other systems in real-world environments by means of standard-compliant LTE transmissions. Such measurement results allowed us to evaluate the propagation and performance of broadband signals and to test the suitability of LTE radio technology for complex railway scenarios.

1P1-P16 移動ロボットによる動的な電波状況推定のための環境形状データの自動生成(サーチ&レスキューロボット・メカトロニクス)

When the tele-operated mobile robot went over its communication range accidentally, the operation would be suspended. We named this kind of trouble "the distress of mobile robot". In order to prevent the distress of mobile robot, it is necessary to estimate communications conditions around the robot by means of radio wave propagation simulation. In this paper, we describe the environmental map suitable to electromagnetic simulation.

Measurements and simulation of ionospheric scattering on VHF and UHF radar signals: Coherence times, coherence bandwidths, and S4

Irregularities in the electron density of the ionosphere cause phase and amplitude scintillation on transionospheric VHF and UHF radar signals, particularly at lower radio frequencies. The design of radar and other transionospheric systems requires good estimates of the coherence bandwidth (CB) and coherence time (CT) imposed by a turbulent ionosphere. CB and CT measurements of the equatorial ionosphere, made using the Advanced Research Project Agency Long‐range Tracking and Identification Radar 158 MHz and 422 MHz phase coherent radar located on Kwajalein (9.4°N, 167.5°E), are presented as a function of the two‐way S4 scintillation index at 422 MHz The log linear regression equations are CT = 1.46 exp(−1.40 S4) s at 158 MHz and CT = 2.31 exp(−1.10 S4) s at 422 MHz. CT also varies by a factor of 2–3 depending on the effective scan velocity through the ionosphere, veff. The CT and CB, as a function of S4, have been compared to those from the Trans‐Ionospheric Radio Propagation Simulator, a phase screen model. A close agreement is achieved using appropriate values of veff and midrange values of phase spectral index and outer scale. Validation of CB is, however, limited by insufficient radar chirp bandwidth. Formulating the model in terms of the two‐way S4 index (an easily measurable parameter) rather than more fundamental phase screen parameters (which are difficult to obtain), improves its utility for the systems engineer. The frequency dependencies (spectral indices) of S4 and of CT are also presented to allow interpolation and some extrapolation of these results to other frequencies.

Measurements and simulation of ionospheric scattering on VHF and UHF radar signals: Channel scattering function

The design and operation of transionospheric VHF and UHF radars requires knowledge of amplitude and phase scintillation due to ionospheric scattering. Phase coherence is of particular importance where long coherent integration periods and large bandwidths are required. A thin phase screen, parabolic equation based, Trans‐Ionospheric Radio Propagation Simulator (TIRPS) is described. Modeled channel scattering functions (CSFs) are compared to experimental VHF and UHF data derived from the Advanced Research Projects Agency Long‐range Tracking and Instrumentation Radar on Kwajalein Island (9.4°N, 166.8°E). TIRPS quantitatively reproduces the experimental results, including the quasi‐parabolic profile observed in the measured CSFs under strong turbulence conditions. Variations in the simulated CSF with ionospheric phase screen parameters are also presented. Under conditions of high integrated strength of turbulence (CkL), a low phase spectral index (p = 1), indicating relatively dense small‐scale irregularities, produces pronounced range spreading. Conversely, when the spectral index is high (p = 4), indicative of strong focusing/defocusing by large‐scale irregularities, there is increased Doppler spreading and, when the outer scale of irregularities is large, a greater likelihood of asymmetry of the CSF about the zero Doppler axis.