Radio Wave Propagation Model Research Articles

Прогноз характеристик распространения декаметровых радиоволн на основе глобальной модели ионосферы и плазмосферы

We present the forecast results of maximal usable frequencies for mid-latitude paths on the base of complex We present the results of forecasting maximum usable frequencies (MUF) on middle-latitude paths on the basis of complex algorithm including modules of the ionosphere and plasmasphere global model (IPGM) and the model of radio wave propagation. The computation of propagation characteristics for decameter radio waves is carried out within the framework of normal wave technique. IPGM developed in ISTP SB RAS enables to compute electron concentration profiles and effective frequency of collisions using minimum number of input data and taking into account physical processes in the Earth’s upper atmosphere. To estimate the efficiency of using IPGM in long-term forecast of radio wave propagation we computed MUF for radio communication in various heliogeophysical conditions. To obtain precision characteristics of MUF forecast we used experimental data of oblique sounding on Magadan–Irkutsk, Khabarovsk–Irkutsk, Norilsk–Irkutsk paths. The paths are equipped with modern ionosphere diagnostic hardware for oblique sounding by continuous chirp signal. We also compared results of MUF forecast using IPGM with computations carried out according IRI model.

Novel Tracing Algorithm vs Remcom Wireless InSite

Abstract Results of comparison between a popular commercial software for radio wave propagation modeling versus prototype implementation of a novel algorithm proposed by the author of this paper is discussed. It is shown that both algorithms lead to very similar results while the new one is faster by a few orders of magnitude.

Radio-Wave Propagation Model for UHF Band in Different Climatic Conditions with Dyadic Green’s Function

This article proposes a deterministic radio propagation model using dyadic Green's function to predict the value of the electric field. Dyadic is offered as an efficient mathematical tool which has symbolic simplicity and robustness, as well as taking account of the anisotropy of the medium. The proposed model is an important contribution for the UHF band because it considers climatic conditions by changing the constants of the medium. Most models and recommendations that include an approach for climatic conditions, are designed for satellite links, mainly Ku and Ka bands. The results obtained by simulation are compared and validated with data from a Digital Television Station measurement campaigns conducted in the Belem city in Amazon region during two seasons. The proposed model was able to provide satisfactory results by differentiating between the curves for dry and wet soil and these corroborate the measured data, (the RMS errors are between 2-5 dB in the case under study).

Using IRI and GSM TIP model results as environment for HF radio wave propagation model during the geomagnetic storm occurred on September 26–29, 2011

This paper analyses the geomagnetic storm on September 26–29, 2011. We compare the calculation results obtained using the Global Self-consistent Model of the Thermosphere, Ionosphere and Protonosphere (GSM TIP) and IRI-2012 (Bilitza et al., 2014) model with ground-based ionosonde data of stations at different latitudes and longitudes. We examined physical mechanisms responsible for the formation of ionospheric effects during the main phase of geomagnetic storm that occurred at the rising phase of the 24th solar cycle. We used numerical results obtained from IRI-2012 and GSM TIP models as propagation environment for HF signals from an equatorial transmitter during quiet and disturbed conditions. We used the model of HF radio wave propagation developed in I. Kant Baltic Federal University (BFU) that is based on the geometrical optics approximation. We compared the obtained radio paths in quiet conditions and during the main and recovery storm phases and evaluated radio wave attenuation in different media models.

Long‐term determination of energetic electron precipitation into the atmosphere from AARDDVARK subionospheric VLF observations

AbstractWe analyze observations of subionospherically propagating very low frequency (VLF) radio waves to determine outer radiation belt energetic electron precipitation (EEP) flux magnitudes. The radio wave receiver in Sodankylä, Finland (Sodankylä Geophysical Observatory) observes signals from the transmitter with call sign NAA (Cutler, Maine). The receiver is part of the Antarctic‐Arctic Radiation‐belt Dynamic Deposition VLF Atmospheric Research Konsortia (AARDDVARK). We use a near‐continuous data set spanning November 2004 until December 2013 to determine the long time period EEP variations. We determine quiet day curves over the entire period and use these to identify propagation disturbances caused by EEP. Long Wave Propagation Code radio wave propagation modeling is used to estimate the precipitating electron flux magnitudes from the observed amplitude disturbances, allowing for solar cycle changes in the ambient D region and dynamic variations in the EEP energy spectra. Our method performs well during the summer months when the daylit ionosphere is most stable but fails during the winter. From the summer observations, we have obtained 693 days worth of hourly EEP flux magnitudes over the 2004–2013 period. These AARDDVARK‐based fluxes agree well with independent satellite precipitation measurements during high‐intensity events. However, our method of EEP detection is 10–50 times more sensitive to low flux levels than the satellite measurements. Our EEP variations also show good agreement with the variation in lower band chorus wave powers, providing some confidence that chorus is the primary driver for the outer belt precipitation we are monitoring.

English

Radio wave propagation models are extremely important in radio network planning, design as well as in interference planning. Radio propagation is essential for emerging technologies with appropriate design, deployment and management strategies for any wireless network. It is heavily site specific and can vary significantly depending on terrain, frequency of operation, velocity of mobile terminal, interface sources and other dynamic factor. Accurate characterization of radio channel through key parameters and a mathematical model is important for predicting signal coverage, achievable data rates, BER and Antenna gain. Path loss models for macro cells such as Okumura, Hata and COST 231 models are analyzed and compared their parameters.

Study on the Propagation Characteristics of Radio Wave for Indoor Non-Line-of-Sight

The propagation characteristics of radio wave have been an important topic in wireless communications. Based on the ray tracing method, the propagation of radio wave for indoor NLOS environment is simulated and analyzed. In this paper, the received power is obtained by simulation, and we will analyze the impact of various factors on the received power. Later, the study can be used to simplify indoor radio wave propagation model and provide a theoretical basis, which is in favor of indoor wireless communication network planning and optimization and can lay the foundation of the development of future technology.

Numerical Simulation of the Influence of the may 2–3, 2010 Geomagnetic Storm on HF Radio-Wave Propagation in the Ionosphere

This study is devoted to HF radio wave propagation in the ionosphere during the May 1–3, 2010 geomagnetic storm. The research results were obtained by using two models, namely, the GSM TIP environment model developed at WD IZMIRAN and the radio-wave propagation model developed at I. Kant BFU. For certain selected frequencies we show the effect of the geomagnetic storm on the radio wave propagation. We give examples of a HF radio-wave path in the channels between the F1 and F2 layers of a high-latitude ionosphere and the F2 and F3 layers of a lowlatitude ionosphere. Characteristics of these layers may significantly affect the interpretation of the oblique sounding ionograms.

Design and implement of transceiver system for hybrid rocket with coplanar wraparound antenna at 433 MHz

This study aims to implement the telematics between hybrid rockets and the ground receiving station. In order to significantly reduce the rocket weight, fibre-reinforced plastic is used for the hybrid rocket casing, on which coplanar wraparound antennas with an operating frequency of 433 MHz are designed. The antenna structure contains three coplanar printed patches, among which the middle printed patch is the primary radiator and the resonant length appears a wavelength for the metallic surface case. An RF module with high receiver sensitivity and a high-power power amplifier are included to enhance the communication coverage of hybrid rockets and the ground receiving station so that the station can effectively track the hybrid rocket. Finally, the radio wave propagation model is used for calculating the link budget such that the communication coverage between rocket transmitters and the ground receiving station can be estimated, and on-site measurement and verification are preceded.

Modelling indoor electromagnetic fields (EMF) from mobile phone base stations for epidemiological studies

Radio frequency electromagnetic fields (RF-EMF) from mobile phone base stations can be reliably modelled for outdoor locations, using 3D radio wave propagation models that consider antenna characteristics and building geometry. For exposure assessment in epidemiological studies, however, it is especially important to determine indoor exposure levels as people spend most of their time indoors. We assessed the accuracy of indoor RF-EMF model predictions, and whether information on building characteristics could increase model accuracy. We performed 15-minute spot measurements in 263 rooms in 101 primary schools and 30 private homes in Amsterdam, the Netherlands. At each measurement location, we collected information on building characteristics that can affect indoor exposure to RF-EMF, namely glazing and wall and window frame materials. Next, we modelled RF-EMF at the measurement locations with the 3D radio wave propagation model NISMap. We compared model predictions with measured values to evaluate model performance, and explored if building characteristics modified the association between modelled and measured RF-EMF using a mixed effect model. We found a Spearman correlation of 0.73 between modelled and measured total downlink RF-EMF from base stations. The average modelled and measured RF-EMF were 0.053 and 0.041mW/m2, respectively, and the precision (standard deviation of the differences between predicted and measured values) was 0.184mW/m2. Incorporating information on building characteristics did not improve model predictions. Although there is exposure misclassification, we conclude that it is feasible to reliably rank indoor RF-EMF from mobile phone base stations for epidemiological studies.

A Computational Model for Path Loss in Wireless Sensor Networks in Orchard Environments

A computational model for radio wave propagation through tree orchards is presented. Trees are modeled as collections of branches, geometrically approximated by cylinders, whose dimensions are determined on the basis of measurements in a cherry orchard. Tree canopies are modeled as dielectric spheres of appropriate size. A single row of trees was modeled by creating copies of a representative tree model positioned on top of a rectangular, lossy dielectric slab that simulated the ground. The complete scattering model, including soil and trees, enhanced by periodicity conditions corresponding to the array, was characterized via a commercial computational software tool for simulating the wave propagation by means of the Finite Element Method. The attenuation of the simulated signal was compared to measurements taken in the cherry orchard, using two ZigBee receiver-transmitter modules. Near the top of the tree canopies (at 3 m), the predicted attenuation was close to the measured one—just slightly underestimated. However, at 1.5 m the solver underestimated the measured attenuation significantly, especially when leaves were present and, as distances grew longer. This suggests that the effects of scattering from neighboring tree rows need to be incorporated into the model. However, complex geometries result in ill conditioned linear systems that affect the solver's convergence.

Evaluation and Modelling of UHF Radiowave Propagation in a Forested Environment

Wireless network optimal performance is a major interest in communication engineering. Radio wave propagation in forested environment has been the interest of much theoretical and experimental research over the years. One of the concepts is to use wireless empirical models to predict wireless link quality of service such as path loss and the received power in a transmission domain with irregular terrain. Measurement results of signal strength in UHF band obtained during the two prominent seasons; raining season (when the trees are in leaf) and dry season (when the trees are relatively out of leaf) Idanre-Apomu axis of Ondo State Nigeria were validated against theoretical estimations. However, using the least squared error fit for several sets of measurement data, an empirical model was developed and incorporated into Matlab graphical user interface (GUI) which can be deployed by wireless communication network providers in wireless networks design for path loss prediction and received power in a forested environment.

What input data are needed to accurately model electromagnetic fields from mobile phone base stations?

The increase in mobile communication technology has led to concern about potential health effects of radio frequency electromagnetic fields (RF-EMFs) from mobile phone base stations. Different RF-EMF prediction models have been applied to assess population exposure to RF-EMF. Our study examines what input data are needed to accurately model RF-EMF, as detailed data are not always available for epidemiological studies. We used NISMap, a 3D radio wave propagation model, to test models with various levels of detail in building and antenna input data. The model outcomes were compared with outdoor measurements taken in Amsterdam, the Netherlands. Results showed good agreement between modelled and measured RF-EMF when 3D building data and basic antenna information (location, height, frequency and direction) were used: Spearman correlations were >0.6. Model performance was not sensitive to changes in building damping parameters. Antenna-specific information about down-tilt, type and output power did not significantly improve model performance compared with using average down-tilt and power values, or assuming one standard antenna type. We conclude that 3D radio wave propagation modelling is a feasible approach to predict outdoor RF-EMF levels for ranking exposure levels in epidemiological studies, when 3D building data and information on the antenna height, frequency, location and direction are available.

Investigation of Path Loss of Mobile Radio Services at L-Band Frequency over Akure, South Western, Nigeria

As the migration of wireless communication network from one generation to another continue, radio wave propagation model or path loss model plays a very significant role in achieving an optimum performance as well as suitability over different locations of interest. In this research, investigation of radio communication channel behavior based on practical measurement in the L-band frequency in Akure- one of the dense urban regions of southwestern part of Nigeria has been carried out. A total number of ten base stations of MTN GSM service located across several areas in Akure were monitored. Path loss and break point distances was deduced from the Received Signal Strength (RSS) and compared with some existing path loss models. The mean and Standard deviation (SD) of each path loss model and measured path loss were estimated and compared on environmental basis; urban and suburban. Based on the regression line (log-normal model) of the measured exponent, Erceg and Cost-231 Hata path loss models show great consistency when compared with Ericson's model with Cost-231 Hata model showing the closest fit to the measured values. The results show that either the log-normal or Cost 231 Hata models may be used to estimate the path loss in mobile micro cell coverage in this region. Path loss exponents, break point distances for each location as well as fitted parameters for the suitable models were also derived. Information from this work will be useful for channel design of micro-wave band

Radio Wave Propagation and Wireless Channel Modeling 2013

Radio Wave Propagation and Wireless Channel Modeling 2013

A MODEL OF MULTIPATH PROPAGATION OF MILLIMETER RADIO WAVES OVER THE SEA SURFACE AT STRONG SHADOWINGS

A description is given of an over-sea radio-wave propagation model involving strongly shadowed parts of the sea surface. This model is of great practical consequence, since the present-day imperative of the fundamental science is to explore physical processes occurring during the wave propagation. The currently used calculation of e.m. field over the sea surface with wind-generated waves at low grazing angles are based on the hypothesis that surface roughness (sea waves) results from the perturbation (on the average) of the planar interface and exhibit minor slopes. However, in practice these radio-wave propagation conditions do not occur ever so often. We have investigated an alternative incident that is clearly indicate of strong shadowings. The shadowed surface areas preclude the reflection from quasi-planar near-horizontal, surface elements. The received data provide a totally new insight into the physical processes (mechanisms) during radio-wave scattering under strong shadowing conditions. We have made use of the numerical simulation method to determine the coordinates and the curvature of unshadowed elements which represent the wave crests. The field being reradiated by these elements is shows to be the result of the Fresnel diffraction effect and the reflections from the convex cylindrical surfaces (in the 2-D case under study). As far as Ka-band radio waves (8-mm-wavelength), we have assessed the reradiation-power path-length distribution, angular spectra of waves arriving at the receiving-antenna aperture. The knowledge of these parameters is required to analyze the direction finder operation. The authors of the present paper have revealed and analyzed the characteristic features of path length distribution and the distribution of angles of arrival (at a receiving point) of coherent and noncoherent sea surface-reradiated field components, the latter significantly affecting the accuracy of systems for measuring the angular coordinates of radiation sources, including the new modern methods of spectral evaluation.

Predicting indoor electromagnetic field strengths from mobile phone base stations using 3D geospatial modelling

Background Radio frequency electromagnetic fields (RF-EMF) from mobile phone base stations can be reliably modelled for outdoor locations, using 3D radio wave propagation models that take antenna c...

An Analytical Model of ELF Radiowave Propagation in Ground-Ionosphere Waveguides With a Multilayered Ground

A planetary crust with a low electric conductivity has a strong influence on extremely low frequency (ELF) radiowave propagation in the ground-ionosphere waveguide due to the penetration of the ground by the wave's electromagnetic field. The amount of influence it has depends on the actual structure of the ground. Accurate models of radiowave propagation in the ELF range are essential in the study of atmospheric discharges and remote sensing applications. Analytical models are still of primary interest when trying to find inverse solutions and when dealing with large objects such as spherical waveguides that consists of a planetary ground and ionosphere. In this paper, we analyze the influence of a multilayered finite conductivity ground on the propagation of ELF electromagnetic waves in the ground-ionosphere waveguide. We have developed equations that enable us to include different ground models in propagation equations using the concept of complex altitudes, and applied them to the study of ELF electromagnetic field pulses on Mars. This study shows that the structure of the ground and its electrical conductivity has a strong influence on the observed waveforms. Therefore, ELF pulses can serve as a tool for probing planetary grounds. The presented model can also be used to study Schumann resonances.

Groundwave Propagation at Short Ranges and Accurate Source Modeling [Testing Ourselves

Radiowave propagation models have long been used in long-range communication and/or radar systems. Different models use different sources. Observed and calculated results are therefore usually normalized, either against maximum or free-space values, or against values obtained above a non-penetrable flat Earth. This is acceptable and useful because excitation differences become negligible at long ranges. Today's interests and priorities in propagation modeling have shifted to quite short ranges, which necessitates accurate source modeling. Short-range propagation problems, modeling, and simulation challenges and accurate source modeling, are discussed, and several useful MATLAB codes are presented.

Radio Frequency Propagation Mechanisms and Empirical Models for Hilly Areas

Achieving better network performance is a paramount concern in wireless networks. This paper provides a survey of the basic mechanisms which influence the propagation of electromagnetic waves in hilly areas. Three empirical models: COST231-Hata, Okumura-Hata and Egli which are suitable for path loss prediction for such area are presented. By using these propagation models the broadcast signal strength are predicted for this type of environment. Measurement results of signal strength in UHF band obtained in Idanre Town of Ondo State Nigeria are presented and compared with the results predicted by using the propagation models. A modified COST231-Hata radiowave propagation model was developed and implemented with Matlab GUI (Graphical User Interface) for simulation. The model developed has 93.8% accuracy. DOI: http://dx.doi.org/10.11591/ijece.v3i3.2519