Radio Wave Propagation Loss Research Articles

A three‐dimensional parabolic equation with fast reordered‐alternate direction decomposition in atmosphere duct environment

AbstractIn the design and optimisation of marine wireless communication and navigation systems, a thorough investigation of radio wave propagation characteristics under atmospheric ducting conditions is essential. The authors aim to enhance the efficiency of radio wave propagation loss prediction in marine atmospheric ducting environments, proposing a prediction model based on Fast Reordered‐Alternate Direction Decomposition (FR‐ADD). By approximating the diffraction term into three independent components, exploiting the commutative properties of the Fourier transform to reduce the spatial dimensions, and incorporating a rapid algorithm for the parabolic equation, the model optimises the stepping process and significantly improves computational efficiency. Simulation experiments demonstrate that, in the long‐distance and complex marine ducting environments, the model not only maintains prediction accuracy but also substantially reduces computational load and prediction time, effectively realising over‐the‐horizon propagation prediction. In the experiment of radio wave propagation characteristics in the Yellow and Bohai Seas, the simulation data from the FR‐ADD model showed significant correlation with actual measurements and simulations from the AREPS software, confirming the method's efficiency and practicality.

The Influence of PE Initial Field Construction Method on Radio Wave Propagation Loss and Tropospheric Duct Inversion

Parabolic equations (PE) are commonly employed for calculating the spatial propagation loss of wireless signals. The initial field is a crucial factor. To investigate the impact of construction accuracy on the calculation of radio wave propagation loss, we selected the half-wave dipole antenna and its Gaussian approximation to examine the influence of wide-angle PE modeling. We analyzed the disparities between the actual antenna pattern and the Gaussian beam approximation, as well as the discrepancies in the corresponding initial field and the calculation of radio wave propagation loss in PE modeling. The simulation results indicate that the error of the Gaussian approximation increases as the angle of departure from the antenna main beam increases, with a relative error of approximately 30% in the initial field. A comparison between the experimental test of the broadcast signal and the simulation calculation reveals that the model based on the actual antenna aligns more closely with the measured value on a flat underlying surface. However, in mountainous areas with significant fluctuations, the simulation results are consistent with each other and higher than the measured value. The inversion results obtained through the particle swarm optimization algorithm demonstrate that the model based on the actual antenna exhibits superior inversion accuracy for the tropospheric atmospheric duct structure.

The Analysis and Verification of IMT-2000 Base Station Interference Characteristics in the FAST Radio Quiet Zone

In this study, we aim to analyze the electromagnetic interference (EMI) regarding the Five-hundred-meter Aperture Spherical radio Telescope (FAST) caused by base stations in the International Mobile Telecommunications-2000 (IMT-2000) frequency band. By analyzing the frequency bands used by the transmitting and receiving devices and the surrounding environmental parameters and utilizing an approach to predicting radio wave propagation loss that is based on deterministic methods, we conclude by comparing the predicted received power at the FAST with its interference protection threshold. Our analysis demonstrates that, currently, only 55.31% of IMT-2000 base stations in the FAST radio quiet zone (RQZ) meet the protection threshold. Additionally, this article verifies the applicability and accuracy of the radio wave propagation model used in the research based on field strength measurements. Overall, this study provides valuable insights for improving the electromagnetic environment surrounding FAST and reducing the EMI caused by mobile communication base stations. It also provides corresponding analysis methods and useful suggestions for analyzing electromagnetic radiation interference in other radio telescopes.

An Accurate Maritime Radio Propagation Loss Prediction Approach Employing Neural Networks

The radio propagation loss prediction model is essential for maritime communication. The oceanic tropospheric duct is much more complicated than the atmospheric structure on land due to the rough sea surface influence, and it leads to difficulties in loss prediction. Classical radio wave propagation loss prediction models are either based on complicated electromagnetic wave theories or rely on empirical data. Consequently, they suffer from low accuracy and a limited range of application. To address this issue, a novel maritime propagation loss prediction approach is proposed, which fully exploits the data for training. In this new approach, 3D sea surface contour profiles are generated based on the Pierson–Moskowitz spectrum theory and the direction expansion formula Stereo Wave Observation Program (SWOP), by sweeping the parameters. The full-wave propagation procedure of radio signals over the sea surface is simulated by commercial EM analysis software CST Studio Suite. Based on the large quantity of simulated data, the BP neural network is employed to fit the radio propagation loss and obtain the sea surface radio wave propagation prediction model. Other classical machine learning methods are also compared to validate the proposed approach. Traditional empirical model construction relies on observation data. This approach, for the first time, proposed an automatic scheme which covers the whole procedure from the data generation to prediction model training. It avoids the requirements for on-site observation, as well as significantly decreases the cost of experiments. The application scope of the prediction model such as propagation distance range and working frequency range could be adaptive through adjustments for simulated sea size and simulated working frequency. This approach is validated to save 99% of prediction time in comparison with the full-wave simulations. The prediction model trained via our proposed method could obtain the coefficient of determination R2 which is over 0.92, demonstrating the superiority of this method.

Prediction of Radio Wave Propagation Loss in Ultra-Rugged Terrain Areas

When designing and maintaining a wireless network, engineers need to first evaluate the impact of a specific propagation environment on radio wave propagation. Currently, although many popular propagation models (PMs) are available for reference, their analysis and validation in ultrarugged terrain areas (uRTAs) are still underexplored. This article aims to implement an uRTA PM (uRTAPM), which consists of two modes, i.e., the point-to-point (uRTAPM-P2P) and the point-to-area (uRTAPM-P2A) modes, to meet the requirements of practical applications. First, we consider the digital elevation model (DEM) data sets and three types of propagation, i.e., line of sight (LOS), non-LOS (NLOS), and multiobstacle propagation. Second, we propose a cone multipath model to simulate the NLOS diffraction behavior caused by mountains. Third, we utilize a triangulated irregular network (TIN) to finely divide the terrestrial surface of uRTAs. Finally, based on numerical calculations, compared with the existing commonly used PMs, the uRTAPM is found to reveal more details about the propagation loss (PL) caused by the terrain in uRTAs. The measurements demonstrate that the mean absolute error (MAE), root-mean-square error (RMSE), and standard deviation (SD) between the uRTAPM predicted values and the actual measured values are lower than those of other methods.

Correlation between Railway Cutting Scenarios Parameters and Wireless Path Loss Exponent

ABSTRACT Due to the particularity of radio wave propagation characteristics in railway scenarios, the relationship between the scenarios and radio wave propagation loss has yet to be studies. In this paper, several common wireless channel path loss models of public network and the path loss measurement data of railway deep cutting scenarios are compared and analyzed, the correlation degree between the structural parameters and the path loss exponent of cutting scenarios is calculated, and the correlation between the parameters of cutting scenarios and ideal cutting scenarios is analyzed. The preliminary conclusion is that the Hata model in open ground environment conforms better to the path loss characteristics of the high-speed railway’s cutting scenario. The width of width sum and the width difference between crown and bottom of cutting scenarios are closely related to the path loss exponent. And the path loss exponent is more reasonable when the cutting scenarios parameters are within a certain range. The research results have some guiding significance for the collaborative work between cutting scenarios construction and wireless network construction.

Analysis and Verification of Core Factors in Radio Wave Propagation Loss

Radio wave propagation prediction can calculate the radio frequency link parameters such as field strength coverage and reception of power, which is an important foundation of electromagnetic compatibility (EMC) analysis and frequency coordination. This paper reviews the advances in the research of radio wave propagation by the International Telecommunication Union (ITU) and the International Radio Science Consortium (USRI), analyzes the core influencing factors related to the propagation of radio waves, including the propagation environment and the propagation model used in the calculation which EMC analysis system has been verified. The related content can provide reference for electromagnetic compatibility analysis and the border coordination.

OPTIMISATION OF RADIO TRANSMITTER LOCATIONS IN MOBILE TELECOMMUNICATION NETWORKS

Multiple factors have to be taken into account when mobile telecommunication network providers make decisions about radio transmitter placement. Generally, area coverage and the average signal level provided are of prime importance in these decisions. These criteria give rise to a bi-objective problem of facility location, with the goal of achieving an acceptable trade-off between maximising the total area coverage and maximising the average signal level provided to the demand region by a network of radio transmitters. This paper establishes a mathematical modelling framework, based on these two placement criteria, for evaluating the effectiveness of a given set of radio transmitter locations. In the framework, coverage is measured according to the degree of obstruction of the so-called ‘Fresnel zone’ that is formed between handset and base station, while signal strength is modelled taking radio wave propagation loss into account. This framework is used to formulate a novel bi-objective facility location model that may form the basis for decision support aimed at identifying high-quality transmitter location trade-off solutions for mobile telecommunication network providers. But it may also find application in various other contexts (such as radar, watchtower, or surveillance camera placement optimisation).

Propagation Path Loss Prediction Model of Multi-Sensor Network in Forest

During the process of carrying on the master plan and design of multi-sensor network in forest, We must consider the coverage of the signal, how to find the best position, through predicting it from launching and checking to accepting the loss value of the electromagnetic wave checked, Can carry on planning and design. Based on the radio wave propagation loss model in free space and the characteristics of radio wave propagation in forest, this paper proposes the generalized predicting model of radio wave propagation loss, To validate the model, a radio propagation measurement campaign was carried out, The modeling results by measuring the parameters of some trees are good agreement with that of the literature

Improved algorithm of atmospheric refraction error in Longley-Rice channel model

Longley-Rice channel model modifies the atmospheric refraction by the equivalent earth radius method, which is simple calculation but is not accurate. As it only uses the horizontal difference, but does not make useof the vertical section information, it does not agree with the actual propagation path. The atmospheric refractionerror correction method of the Longley-Rice channel model has been improved. The improved method makes useof the vertical section information sufficiently and maps the distance between the receiver and transmitter to theradio wave propagation distance. It can exactly reflect the infection of propagation distance for the radio wavepropagation loss. It is predicted to be more close to the experimental results by simulation in comparison with themeasured data. The effectiveness of improved methods is proved by simulation.

Radio wave propagation loss in the VHF to microwave region due to vehicles in tunnels

An experiment was undertaken to determine how obstacles in tunnels affect microwave propagation loss. The major emphasis of the study was on determining the propagation loss due to the following parameters: number, location, and size of vehicles, and cross-sectional shapes of tunnels. The laboratory experiments was performed using tunnel models with arched and rectangular cross sections. The dominant mode was transmitted into these tunnels from entrances. Different readings of field strength were taken along the length of the tunnels to determine the effect that vehicles can have on the propagation characteristics. The scale ratio of the tunnel dimensions to the wavelength is about 2-3. It is shown that the basic propagation loss due to vehicles in tunnels is determined mainly by the number and the size of the vehicles. Vehicle location and tunnel cross-sectional shape do not affect the propagation loss significantly.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>