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1
Liao, Xiaoqian, and Sheng Xu. "Comparative study of the polar region ionospheric NmF2 and IRI-2016 models." Journal of Physics: Conference Series 2306, no. 1 (November 1, 2022): 012003. http://dx.doi.org/10.1088/1742-6596/2306/1/012003.
Повний текст джерелаАнотація:
Abstract The propagation of radio waves can be significantly affected by the ionosphere, which have a serious impact on broadcasting, communication, positioning and navigation. The International Reference Ionosphere (IRI) provides multiple ionospheric parameters for given location, time and date. In order to study the applicability of the IRI-2016 model in polar ionosphere, long-term observations from the dynasonde at Tromso (TRO), EISCAT Svalbard Radar (ESR) at Longyearbyen (LYB) and digisonde DPS-4 at Zhongshan (ZHS) were used to analyze the prediction accuracy of IRI model, with the help of mathematical statistics, correlation coefficients and time series. The data of F2 layer peak electron density (NmF2) are sorted as monthly medians of NmF2 for each hours, months, and solar activities. The results show that there is a good correlation between IRI prediction and observations during solar minimum years, with the correlation coefficients larger than 0.8 except winter at Longyearbyen, better than that during solar maximum years. The correlation decreases as latitude increases. It is the best at Tromso, and better at Zhongshan than at Longyearbyen. This suggests that the IRI-2016 model is mostly applicable at the auroral latitude station Tromso. But the IRI-2016 model has poor applicability at the cusp latitude station, both Zhongshan and Longyearbyen.
2
Anduaga, Aitor. "The formation of ionospheric physics – confluence of traditions and threads of continuity." History of Geo- and Space Sciences 12, no. 1 (April 7, 2021): 57–75. http://dx.doi.org/10.5194/hgss-12-57-2021.
Повний текст джерелаАнотація:
Abstract. This paper examines how ionospheric physics emerged as a research speciality in Britain, Germany, and the United States in the first four decades of the 20th century. It argues that the formation of this discipline can be viewed as the confluence of four deep-rooted traditions in which scientists and engineers transformed, from within, research areas connected to radio wave propagation and geomagnetism. These traditions include Cambridge school's mathematical physics, Göttingen's mathematical physics, laboratory-based experimental physics, and Humboldtian-style terrestrial physics. Although focused on ionospheric physics, the paper pursues the idea that a dynamic conception of scientific tradition will provide a new perspective for the study of geosciences history.
3
Kolyadenko, Yu Yu, and N. А. Chursanov. "5 G communication network signal propagation models." Radiotekhnika, no. 205 (July 2, 2021): 161–68. http://dx.doi.org/10.30837/rt.2021.2.205.17.
Повний текст джерелаАнотація:
The next generation 5G / IMT-2020 technology, like any new technology, brings its own specific features to all aspects related to the practice of its application. One of these particularly important aspects is electromagnetic compatibility. At the stage of preparation for the introduction of 5G radio networks, called NewRadio, it is necessary to take early measures to assess effectively the electromagnetic compatibility conditions for these networks based on a thorough analysis of the features of 5G technology. Correct and accurate assessments of these conditions means successful provision of the electromagnetic compatibility of radio equipment of new networks.
The World Radio Communication Conference WRC-15 identified new radio frequency bands for 5G, including centimeter and millimeter wave bands. In general, this RF spectrum is located in three regions: below 1 GHz, 1 GHz to 6 GHz, and above 6 GHz (up to 100 GHz). From the EMC standpoint, the following can be distinguished as the main features of this spectrum: different nature of losses during signal propagation, in particular, a significant influence of additional factors (gases – oxygen, water vapor, etc.) on the level of losses previously unknown in cellular communication.
The mathematical model of signal propagation of 5 G communication networks has been developed which takes into account: the attenuation of signals in free space; attenuation of signals caused by the influence of walls and floor slabs, loss of signal energy, when space is filled with various objects; attenuation of signals caused by loss of energy of radio waves, when propagating through rains; signal attenuation due to loss of radio wave energy due to fog; signal attenuation, when propagating through tree leaves, slow and fast random fading.
4
Ren, Huantao, Qiangjun Xie, Jiajing Chai, and Yi Xue. "Analysis of Signal Reception Mechanism of Sky Wave Long-distance Maritime Communication." MATEC Web of Conferences 232 (2018): 04065. http://dx.doi.org/10.1051/matecconf/201823204065.
Повний текст джерелаАнотація:
Based on the principle of high frequency radio propagation, the signal reception mechanism of sky wave communication over oceans is investigated. Due to long distance signal transmission, the energy loss is inevitable, especially in the space and on the sea surface. Firstly, we establish the space propagation loss model by the ionospheric absorption, the free space propagation characteristics and other extra loss. Referring to the reflection principle of smooth ground and the Kirchhoff approximation, the energy loss models of the calm sea surface and the turbulent sea surface are obtained respectively. Then, through combining the space propagation loss model and the sea surface propagation loss models, we give out a formula of receiving point field strength. According to the signal to noise ratio, we summarize a complete and concise sky wave maritime communication calculation process, through which multi hops number of the receivable sky wave signal can be calculated accurately. The experimental results show the effectiveness.
5
Dorogov, A. Yu, and A. I. Yashin. "SOFTWARE PACKAGE FOR MODELING HF-BAND PACKET RADIO NETWORKS." H&ES Research 12, no. 6 (2020): 26–37. http://dx.doi.org/10.36724/2409-5419-2020-12-6-26-37.
Повний текст джерелаАнотація:
It is noted that the complexity and constant variability of the ionosphere structure, the presence of many factors affecting the propagation of radio waves in such an environment, as well as the complex topology of communication networks lead to the need the computer modeling of data transmission in HF-band networks. The existing models of representation of ionospheric processes and digital radio channels are described. It is shown that to solve the problems of designing a radio data transmission network, complex modeling is necessary, taking into account the network topology, signal propagation losses in the radio channel, noise level, type of digital modulation, and radio forecast of communication conditions. In this paper, we consider a modeling complex for packet radio networks of HF-band data transmission with changing communication conditions. The complex consists of a set of interacting models implemented in the Matlab software environment. The software model for predicting communication conditions complies with ITU-R recommendation P. 533–13 of the International Telecommunication Union (ITU). The description of the model for the "Point-to-point" and "Area" modes is given and the results of its application for calculating extended radio lines are shown. The initial data and system parameters of the model are described. A model of the HF-band digital radio channel is presented. The communications System Toolbox package, which is part of the Matlab software environment, is used for this modeling. The model's input and output data are described. A model of Ionospheric Wave Frequency Dispatcher service of the radio network has been developed. This model is intended for building a wave schedule for stable operation of HF radio lines in the network. The rules for building a two-frequency and multi-frequency wave schedule are described. A scheme for modeling the operation of a packet radio network under changing communication conditions is proposed. The complex allows you to evaluate the probabilistic and temporal characteristics of radio lines and zonal radio coverage depending on geographical coordinates, time, month, solar activity and selected system parameters for a period of up to one year. Examples of using the modeling complex are given. The purpose of this work is to formulate the problem of simulation of HF radio networks under changing communication conditions.
6
Krasheninnikov, Igor, and Givi Givishvili. "Possibilities of Estimating F2 Layer Peak Plasma Frequency Using HF Radiation from High Apogee Satellites over Arctic Region." Remote Sensing 13, no. 21 (October 21, 2021): 4225. http://dx.doi.org/10.3390/rs13214225.
Повний текст джерелаАнотація:
Based on the results of mathematical modeling, we consider the possibility to estimate the plasma frequency F2 layer maximum of the polar ionosphere (critical frequency, foF2) using frequency-sweeping radiation from a highly elliptical spacecraft orbit in the Arctic zone. Our modeling concerning the energy problem of radio sensing consisted of analyzing wave field parameters, received field strength, and SNR on two radio paths with the distances 1900 and 2500 km along the earth’s surface, with the satellite height varying from 10,000 to 30,000 km. Radio path orientations were selected to be close to the classical limit cases of radio wave propagation in the anisotropic ionospheric plasma: quasi-longitudinal approximation and, to a large extent, the quasi-transversal one for the quiet midday and midnight conditions. As a result of these simulations and following specific spacecraft conditions, working with an optimal probing signal was proposed for the appropriate emission power for the onboard transmitter. In the inverse problem of radio sounding of an ionized media, common mathematical inaccuracy in foF2 calculated from the transionogram, frequency dependence of the probing signals magneto-ionic group delay, was estimated. Considering and founding a possible realization of the method, physical prerequisites are discussed based on the experimental data of radio waves passing the 16,000 km long radio path for Moscow–Antarctica (UAS Vernadsky).
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الهذيلي, محمد احمد احمد, محمد محسن الشدادي, and عبدالباسط محمد البشة. "Analytical Study of Path Loss in Radio Wave Propagation Models of the GSM Cellular Communications Networks in the City of Sana'a." Journal of Science and Technology 23, no. 1 (October 28, 2018): 41–56. http://dx.doi.org/10.20428/jst.v23i1.1399.
Повний текст джерелаАнотація:
The rapid growth of wireless communication technologies has increased the importance of a proper network planning. Before the actual installation of the network and to ensure that the network is adequately covered, network designers rely heavily on wave propagation models, which are a set of mathematical expressions, and graphs derived from comprehensive field measurements and it is used to represent radio wave properties of a particular environment. The research aims to find a mathematical model to predict the propagation path loss of radio waves in Sana'a city for the appropriate planning of cellular communication systems. In this sense, the researcher applied a practical study to the city of Sana'a by taking three cells (base station) in three different regions (urban and suburban areas and the open area). The research focuses on three stages (the stage of measurements, the stage of analysis and the stage of analysis and comparison). In the results, we obtained three values for path loss constants a and c for the three regions, through which we obtain the logarithmic curves, which in turn has been transformed into mathematical models to be used as a reference for radio planning engineers in the city of Sana'a, the capital of the Republic of Yemen.
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Alpatov, Viktor, Susanna Bekker, Stanislav Kozlov, Andrey Lyakhov, Valentin Yakim, and Sergey Yakubovsky. "ANALYZING EXISTING APPLIED MODELS OF THE IONOSPHERE TO CALCULATE RADIO WAVE PROPAGATION AND A POSSIBILITY OF THEIR USE FOR RADAR-TRACKING SYSTEMS. II. DOMESTIC MODELS." Solar-Terrestrial Physics 6, no. 3 (September 22, 2020): 60–66. http://dx.doi.org/10.12737/stp-63202008.
Повний текст джерелаАнотація:
We consider the ionospheric models that are suitable for over-the-horizon HF and UHF band radars. Namely, there are three such models: the numerical model developed by IZMIRAN and Fedorov Institute of Applied Geophysics, the numerical model designed by ISTP SB RAS and IDG RAS, and the probabilistic model worked out by IDG RAS. We briefly describe these models and report the results of the analysis of their compliance with radar requirements. Probabilistic models are shown to be most promising; hence, they must be placed at the frontier of ionosphere simulation.
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Alpatov, Viktor, Susanna Bekker, Stanislav Kozlov, Andrey Lyakhov, Valentin Yakim, and Sergey Yakubovsky. "ANALYZING EXISTING APPLIED MODELS OF THE IONOSPHERE TO CALCULATE RADIO WAVE PROPAGATION AND A POSSIBILITY OF THEIR USE FOR RADAR-TRACKING SYSTEMS. II. DOMESTIC MODELS." Solnechno-Zemnaya Fizika 6, no. 3 (September 22, 2020): 73–81. http://dx.doi.org/10.12737/szf-63202008.
Повний текст джерелаАнотація:
We consider the ionospheric models that are suitable for over-the-horizon HF and UHF band radars. Namely, there are three such models: the numerical model developed by IZMIRAN and Fedorov Institute of Applied Geophysics, the numerical model designed by ISTP SB RAS and IDG RAS, and the probabilistic model worked out by IDG RAS. We briefly describe these models and report the results of the analysis of their compliance with radar requirements. Probabilistic models are shown to be most promising; hence, they must be placed at the frontier of ionosphere simulation.
10
Aksenov, Oleg, Stanislav Kozlov, Andrey Lyakhov, Vyacheslav Trekin, Yuriy Perunov, and Sergey Yakubovsky. "ANALYZING EXISTING APPLIED MODELS OF THE IONOSPHERE FOR CALCULATING RADIO WAVE PROPAGATION AND POSSIBILITY OF THEIR USE FOR RADAR SYSTEMS. I. CLASSIFICATION OF APPLIED MODELS AND THE MAIN REQUIREMENTS IMPOSED ON THEM FOR RADAR AIDS." Solar-Terrestrial Physics 6, no. 1 (April 1, 2020): 69–76. http://dx.doi.org/10.12737/stp-61202008.
Повний текст джерелаАнотація:
We review modern HF–X band radars covering over-the-horizon problems. The ionosphere significantly affects wave propagation in all the bands. We describe available correction techniques, which use additional evidence on the ionosphere, as well as models of different degrees of complexity. The fact that the field of view cannot be covered by ground-based instruments as well as the growing requirements to the precision and stability of the radars result in the impossibility of ionospheric correction with up-to-date models, hence the latter require further elaboration. We give a virtually full classification of the models. The article summarizes the requirements to the models for the radars depending on their function.
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Aksenov, Oleg, Stanislav Kozlov, Andrey Lyakhov, Vyacheslav Trekin, Yuriy Perunov, and Sergey Yakubovsky. "ANALYZING EXISTING APPLIED MODELS OF THE IONOSPHERE FOR CALCULATING RADIO WAVE PROPAGATION AND POSSIBILITY OF THEIR USE FOR RADAR SYSTEMS. I. CLASSIFICATION OF APPLIED MODELS AND THE MAIN REQUIREMENTS IMPOSED ON THEM FOR RADAR AIDS." Solnechno-Zemnaya Fizika 6, no. 1 (March 30, 2020): 86–96. http://dx.doi.org/10.12737/szf-61202008.
Повний текст джерелаАнотація:
We review modern HF–X band radars covering over-the-horizon problems. The ionosphere significantly affects wave propagation in all the bands. We describe available correction techniques, which use additional evidence on the ionosphere, as well as models of different degrees of complexity. The fact that the field of view cannot be covered by ground-based instruments as well as the growing requirements to the precision and stability of the radars result in the impossibility of ionospheric correction with up-to-date models, hence the latter require further elaboration. We give a virtually full classification of the models. The article summarizes the requirements to the models for the radars depending on their function.
12
Maliuk, Victor, Oleksandr Iohov, Stanislav Horielyshev, Victor Olenchenko, Oleksandr Oleschenko, Olena Novykova, and Kirill Tkachenko. "Bounds Calculation Method of Electromagnetic Availability Zone of Radio Emission Source." Advances in Military Technology 17, no. 2 (October 22, 2022): 341–56. http://dx.doi.org/10.3849/aimt.01739.
Повний текст джерелаАнотація:
The article deals with the problem of determining the electromagnetic availability zone of the radio transmitter of the radio communication channel in the UHF/VHF range on the terrain map of the area. This problem was solved using well-known mathematical models of radio signal propagation, depending on the characteristics of the specific area. Based on the wave algorithm, a bounds calculation method of electromagnetic availability zone is proposed, using a digitized radiation pattern of radio means. The conducted calculations show the effectiveness of the method in the tasks of assessing the performance of a mobile radio communication channel and its security at local combat operations in the conditions of operation of an enemy radio reconnaissance receiver or a radio interference system.
13
Leble, Sergey, Sergey Vereshchagin, Nataliya V. Bakhmetieva, and Gennadiy I. Grigoriev. "Study of a Gas Disturbance Mode Content Based on the Measurement of Atmospheric Parameters at the Heights of the Mesosphere and Lower Thermosphere." Atmosphere 12, no. 9 (August 31, 2021): 1123. http://dx.doi.org/10.3390/atmos12091123.
Повний текст джерелаАнотація:
The main result of this work is the estimation of the entropy mode accompanying a wave disturbance, observed at the atmosphere heights range of 90–120 km. The study is the direct continuation and development of recent results on diagnosis of the acoustic wave with the separation on direction of propagation. The estimation of the entropy mode contribution relies upon the measurements of the three dynamic variables (the temperature, density, and vertical velocity perturbations) of the neutral atmosphere measured by the method of the resonant scattering of radio waves on the artificial periodic irregularities of the ionospheric plasma. The measurement of the atmosphere dynamic parameters was carried out on the SURA heating facility. The mathematical foundation of the mode separation algorithm is based on the dynamic projection operators technique. The operators are constructed via the eigenvectors of the coordinate evolution operator of the transformed system of balance equations of the hydro-thermodynamics.
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Luo, Yiyang, Leonid Chernogor, Kostiantyn Garmash, Qiang Guo, Victor Rozumenko, and Yu Zheng. "Dynamic processes in the magnetic field and in the ionosphere during the 30 August–2 September 2019 geospace storm: influence on high frequency radio wave characteristics." Annales Geophysicae 39, no. 4 (July 15, 2021): 657–85. http://dx.doi.org/10.5194/angeo-39-657-2021.
Повний текст джерелаАнотація:
Abstract. The concept that geospace storms are comprised of synergistically coupled magnetic storms, ionospheric storms, atmospheric storms, and storms in the electric field originating in the magnetosphere, the ionosphere, and the atmosphere (i.e., electrical storms) was validated a few decades ago. Geospace storm studies require the employment of multiple-method approaches to the Sun–interplanetary medium–magnetosphere–ionosphere–atmosphere–Earth system. This study provides general analysis of the 30 August–2 September 2019 geospace storm, the analysis of disturbances in the geomagnetic field and in the ionosphere, as well as the influence of the ionospheric storm on the characteristics of high frequency (HF) radio waves over the People's Republic of China. The main results of the study are as follows. The energy and power of the geospace storm have been estimated to be 1.5×1015 J and 1.5×1010 W, and thus, this storm is weak. The energy and power of the magnetic storm have been estimated to be 1.5×1015 J and 9×109 W, i.e., this storm is moderate, and a characteristic feature of this storm is the duration of the main phase of up to 2 d. The recovery phase also was lengthy and was no less than 2 d. On 31 August and 1 September 2019, the variations in the H and D components attained 60–70 nT, while the Z-component variations did not exceed 20 nT. On 31 August and 1 September 2019, the level of fluctuations in the geomagnetic field in the 100–1000 s period range increased from 0.2–0.3 to 2–4 nT, while the energy of the oscillations showed a maximum in the 300–400 to 700–900 s period range. During the geospace storm, a moderately to strongly negative ionospheric storm manifested itself by the reduction in the ionospheric F-region electron density by a factor of 1.4 to 2.4 times on 31 August and 1 September 2019, compared to the its values on the reference day. Appreciable disturbances were also observed to occur in the ionospheric E region and possibly in the Es layer. In the course of the ionospheric storm, the altitude of reflection of radio waves could sharply increase from ∼150 to ∼300–310 km. The atmospheric gravity waves generated within the geospace storm modulated the ionospheric electron density; for the ∼30 min period oscillation, the amplitude of the electron density disturbances could attain ∼40 %, while it did not exceed 6 % for the ∼15 min period. At the same time, the height of reflection of the radio waves varied quasi-periodically with a 20–30 km amplitude. The results obtained have made a contribution to the understanding of the geospace storm physics, to developing theoretical and empirical models of geospace storms, to the acquisition of detailed understanding of the adverse effects that geospace storms have on radio wave propagation, and to applying that knowledge to effective forecasting of these adverse influences.
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Xu, Xiang, Chen Zhou, Run Shi, Binbin Ni, Zhengyu Zhao, and Yuannong Zhang. "Numerical study of the generation and propagation of ultralow-frequency waves by artificial ionospheric F region modulation at different latitudes." Annales Geophysicae 34, no. 9 (September 21, 2016): 815–29. http://dx.doi.org/10.5194/angeo-34-815-2016.
Повний текст джерелаАнотація:
Abstract. Powerful high-frequency (HF) radio waves can be used to efficiently modify the upper-ionospheric plasmas of the F region. The pressure gradient induced by modulated electron heating at ultralow-frequency (ULF) drives a local oscillating diamagnetic ring current source perpendicular to the ambient magnetic field, which can act as an antenna radiating ULF waves. In this paper, utilizing the HF heating model and the model of ULF wave generation and propagation, we investigate the effects of both the background ionospheric profiles at different latitudes in the daytime and nighttime ionosphere and the modulation frequency on the process of the HF modulated heating and the subsequent generation and propagation of artificial ULF waves. Firstly, based on a relation among the radiation efficiency of the ring current source, the size of the spatial distribution of the modulated electron temperature and the wavelength of ULF waves, we discuss the possibility of the effects of the background ionospheric parameters and the modulation frequency. Then the numerical simulations with both models are performed to demonstrate the prediction. Six different background parameters are used in the simulation, and they are from the International Reference Ionosphere (IRI-2012) model and the neutral atmosphere model (NRLMSISE-00), including the High Frequency Active Auroral Research Program (HAARP; 62.39° N, 145.15° W), Wuhan (30.52° N, 114.32° E) and Jicamarca (11.95° S, 76.87° W) at 02:00 and 14:00 LT. A modulation frequency sweep is also used in the simulation. Finally, by analyzing the numerical results, we come to the following conclusions: in the nighttime ionosphere, the size of the spatial distribution of the modulated electron temperature and the ground magnitude of the magnetic field of ULF wave are larger, while the propagation loss due to Joule heating is smaller compared to the daytime ionosphere; the amplitude of the electron temperature oscillation decreases with latitude in the daytime ionosphere, while it increases with latitude in the nighttime ionosphere; both the electron temperature oscillation amplitude and the ground ULF wave magnitude decreases as the modulation frequency increases; when the electron temperature oscillation is fixed as input, the radiation efficiency of the ring current source is higher in the nighttime ionosphere than in the daytime ionosphere.
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Hadi, Khalid Abdul-Kareem, and Marwa D. Abdulkareem. "The Suggested Reciprocal Relationship between Maximum, Minimum and Optimum Usable Frequency Parameters Over Iraqi Zone." Baghdad Science Journal 17, no. 3(Suppl.) (September 8, 2020): 1058. http://dx.doi.org/10.21123/bsj.2020.17.3(suppl.).1058.
Повний текст джерелаАнотація:
In this work, the relationship between the ionospheric parameters (Maximum Usable Frequency (MUF), Lowest Usable Frequency (LUF) and Optimum working Frequency (OWF)) has been studied for the ionosphere layer over the Iraqi zone. The capital Baghdad (44.42oE, 33.32oN) has been selected to represent the transmitter station and many other cities that spread over Iraqi region have represented as receiver stations. The REC533 communication model considered as one of the modern radio broadcasting version of ITU has been used to calculate the LUF parameter, while the MUF and OWF ionospheric parameters have been generated using ASAPS international communication model which represents one of the most advanced and accurate HF sky wave propagation models. The study has been conducted for the annual and seasonal time periods of the years (2009 and 2014) of the solar cycle 24. The results of the seasonal and annual tests have indicated that the interrelationship between the MUF and OWF with LUF was a fourth order polynomial equation, while the reciprocal relationship between the MUF and OWF was a simple relationship that could be represented by a linear regression equation. The reciprocal relationships between MUF, LUF and OWF parameters (present values) have shown a good fitting with the data generated using the international models (predicted values) and theoretical values calculated from the criterion equation.
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Inyurt, Samed, Omer Yildirim, and Cetin Mekik. "Comparison between IRI-2012 and GPS-TEC observations over the western Black Sea." Annales Geophysicae 35, no. 4 (July 14, 2017): 817–24. http://dx.doi.org/10.5194/angeo-35-817-2017.
Повний текст джерелаАнотація:
Abstract. The ionosphere is a dynamic layer which generally changes according to radiation emitted by the sun, the movement of the earth around the sun, and sunspot activity. Variations can generally be categorized as regular or irregular variations. Both types of variation have a huge effect on radio wave propagation. In this study, we have focused on the seasonal variation effect, which is one of the regular forms of variation in terms of the ionosphere. We examined the seasonal variation over the ZONG station in Turkey for the year 2014. Our analysis results and IRI-2012 present different ideas about ionospheric activity. According to our analysed results, the standard deviation reached a maximum value in April 2014. However, the maximum standard deviation obtained from IRI-2012 was seen in February 2014. Furthermore, it is clear that IRI-2012 underestimated the VTEC values when compared to our results for all the months analysed. The main source of difference between the two models is the IRI-2012 topside ionospheric representation. IRI-2012 VTEC has been produced as a result of the integration of an electron density profile within altitudinal limits of 60–2000 km. In other words, the main problem with regard to the IRI-2012 VTEC representation is not being situated in the plasmaspheric part of the ionosphere. Therefore we propose that the plasmaspheric part should be taken into account to calculate the correct TEC values in mid-latitude regions, and we note that IRI-2012 does not supply precise TEC values for use in ionospheric studies.
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Zeng, Wenbo, Yigang He, Bing Li, and Shudong Wang. "3D Multiple-Antenna Channel Modeling and Propagation Characteristics Analysis for Mobile Internet of Things." Sensors 21, no. 3 (February 2, 2021): 989. http://dx.doi.org/10.3390/s21030989.
Повний текст джерелаАнотація:
The demand for optimization design and performance evaluation of wireless communication links in a mobile Internet of Things (IoT) motivates the exploitation of realistic and tractable channel models. In this paper, we develop a novel three-dimensional (3D) multiple-antenna channel model to adequately characterize the scattering environment for mobile IoT scenarios. Specifically, taking into consideration both accuracy and mathematical tractability, a 3D double-spheres model and ellipsoid model are introduced to describe the distribution region of the local scatterers and remote scatterers, respectively. Based on the explicit geometry relationships between transmitter, receiver, and scatterers, we derive the complex channel gains by adopting the radio-wave propagation model. Subsequently, the correlation-based approach for theoretical analysis is performed, and the detailed impacts with respect to the antenna deployment, scatterer distribution, and scatterer density on the vital statistical properties are investigated. Numerical simulation results have shown that the statistical channel characteristics in the developed simulation model nicely match those of the corresponding theoretical results, which demonstrates the utility of our model.
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Isaac Kuma Yeboah, Richard Brace, Kwabena Agyapong-Kondua, Matthew Asiedu, and Henrritta Kuma Yeboah. "Fabrication and optimization of bi-quad antenna and energy-efficient balanced RF power amplifier for 5G-LTE multi-carrier applications." ITU Journal on Future and Evolving Technologies 3, no. 3 (December 15, 2022): 874–85. http://dx.doi.org/10.52953/wcqw1171.
Повний текст джерелаАнотація:
Wireless technology is presently one of the most actively researched fields of digital communication systems. Wireless communication technologies are insufficient without an understanding of antenna design and operation. A wide range of radio frequency equipment, including microwave antennas, microwave ovens, cordless telephones, and medical devices, utilize the 2.4 GHz band. In this article, a parabolic mesh dish was used to build and improve a bi-quad antenna with a central working frequency of 2.445 GHz. The bi-quad antenna was put in a parabolic mesh dish to optimize wave propagation. The findings show that the antenna obtained a signal strength range of 70% to 80%, increasing the directivity of WLAN coverage. The bi-quad antenna feed was placed in the center of a mesh dish, which assists in focusing radio waves onto the antenna. The bi-quad antenna outperformed the omnidirectional antenna, which had a signal strength of 56%. The results of each antenna test were separately simulated in MATLAB. The combined impact of bi-quad and parabolic was then duplicated using mathematical models, resulting in a unique waveform propagation pattern known as para-quad, which improved performance. A balanced RF power amplifier was conceived and built in this study. A 2.620 - 2.690GHz frequency range on a large signal Si-LDMOS transistor model achieves 53% PAE, 41dBm power output, and 14 dB gain at the P1dB saturation point.
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Abadi, Prayitno, Umar Ali Ahmad, Yuichi Otsuka, Punyawi Jamjareegulgarn, Dyah Rahayu Martiningrum, Agri Faturahman, Septi Perwitasari, Randy Erfa Saputra, and Reza Rendian Septiawan. "Modeling Post-Sunset Equatorial Spread-F Occurrence as a Function of Evening Upward Plasma Drift Using Logistic Regression, Deduced from Ionosondes in Southeast Asia." Remote Sensing 14, no. 8 (April 14, 2022): 1896. http://dx.doi.org/10.3390/rs14081896.
Повний текст джерелаАнотація:
The occurrence of post-sunset equatorial spread-F (ESF) could have detrimental effects on trans-ionospheric radio wave propagation used in modern communications systems. This problem calls for a simple but robust model that accurately predicts the occurrence of post-sunset ESF. Logistic regression was implemented to model the daily occurrence of post-sunset ESF as a function of the evening upward plasma drift (v). The use of logistic regression is formalized by y^=1/[1+exp(−z)], where y^ represents the probability of post-sunset ESF occurrence, and z is a linear function containing v. The value of v is derived from the vertical motion of the bottom side of the F-region in the evening equatorial ionosphere, which is observed by the ionosondes in Southeast Asia. Data points (938) of v and post-sunset ESF occurrence were collected in the equinox seasons from 2003 to 2016. The training set used 70% of the dataset to derive z and y^ and the remaining 30% was used to test the performance of y^. The expression z=−2.25+0.14v was obtained from the training set, and y^≥0.5 (v ≥ ~16.1 m/s) and y^<0.5 (v < ~16.1 m/s) represented the occurrence and non-occurrence of ESF, respectively, with an accuracy of ~0.8 and a true skill score (TSS) of ~0.6. Similarly, in the testing set, y^ shows an accuracy of ~0.8 and a TSS of ~0.6. Further analysis suggested that the performance of the z-function can be reliable in the daily F10.7 levels ranging from 60 to 140 solar flux units. The z-function implemented in the logistic regression (y^) found in this study is a novel technique to predict the post-sunset ESF occurrence. The performance consistency between the training set and the testing set concludes that the z-function and the y^ values of the proposed model could be a simple and robust mathematical model for daily nowcasting the occurrence or non-occurrence of post-sunset ESFs.
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Mengistu Tsidu, Gizaw, and Mulugeta Melaku Zegeye. "Comparison of quiet-time ionospheric total electron content from the IRI-2016 model and from gridded and station-level GPS observations." Annales Geophysicae 38, no. 3 (June 16, 2020): 725–48. http://dx.doi.org/10.5194/angeo-38-725-2020.
Повний текст джерелаАнотація:
Abstract. Earth's ionosphere is an important medium of radio wave propagation in modern times. However, the effective use of the ionosphere depends on the understanding of its spatiotemporal variability. Towards this end, a number of ground- and space-based monitoring facilities have been set up over the years. The information from these stations has also been complemented by model-based studies. However, assessment of the performance of ionospheric models in capturing observations needs to be conducted. In this work, the performance of the IRI-2016 model in simulating the total electron content (TEC) observed by a network of Global Positioning System (GPS) receivers is evaluated based on the RMSE, the bias, the mean absolute error (MAE) and skill score, the normalized mean bias factor (NMBF), the normalized mean absolute error factor (NMAEF), the correlation, and categorical metrics such as the quantile probability of detection (QPOD), the quantile categorical miss (QCM), and the quantile critical success index (QCSI). The IRI-2016 model simulations are evaluated against gridded International Global Navigation Satellite System (GNSS) Service (IGS) GPS-TEC and TEC observations at a network of GPS receiver stations during the solar minima in 2008 and solar maxima in 2013. The phases of modeled and simulated TEC time series agree strongly over most of the globe, as indicated by a high correlations during all solar activities with the exception of the polar regions. In addition, lower RMSE, MAE, and bias values are observed between the modeled and measured TEC values during the solar minima than during the solar maxima from both sets of observations. The model performance is also found to vary with season, longitude, solar zenith angle, and magnetic local time. These variations in the model skill arise from differences between seasons with respect to solar irradiance, the direction of neutral meridional winds, neutral composition, and the longitudinal dependence of tidally induced wave number four structures. Moreover, the variation in model performance as a function of solar zenith angle and magnetic local time might be linked to the accuracy of the ionospheric parameters used to characterize both the bottom- and topside ionospheres. However, when the NMBF and NMAEF are applied to the data sets from the two distinct solar activity periods, the difference in the skill of the model during the two periods decreases, suggesting that the traditional model evaluation metrics exaggerate the difference in model skill. Moreover, the performance of the model in capturing the highest ends of extreme values over the geomagnetic equator, midlatitudes, and high latitudes is poor, as noted from the decrease in the QPOD and QCSI as well as an increase in the QCM over most of the globe with an increase in the threshold percentile TEC values from 10 % to 90 % during both the solar minimum and the solar maximum periods. The performance of IRI-2016 in simulating observed low (as low as the 10th percentile) and high (higher than the 90th percentile) TEC correctly over equatorial ionization anomaly (EIA) crest regions is reasonably good given that IRI-2016 is a climatological model. However, it is worth noting that the performance of the IRI-2016 model is relatively poor in 2013 compared with 2008 at the highest ends of the TEC distribution. Therefore, this study reveals the strengths and weaknesses of the IRI-2016 model in simulating the observed TEC distribution correctly during all seasons and solar activities for the first time.
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Batanov, V. V., and L. E. Nazarov. "The models of transionospheric transmission channels with amplitude fading of signals." Electromagnetic Waves and Electronic Systems, 2021. http://dx.doi.org/10.18127/j15604128-202105-02.
Повний текст джерелаАнотація:
Descriptions of statistical models of narrow-band transionospheric radio lines with amplitude fading of signals due to the influence of the earth’s ionosphere are given. The models are based on the analytical description of signal propagation in randomly inhomogeneous media that generate temporal variations in signal amplitudes due to their reflection and scattering on ionospheric inhomogeneities. These analytical descriptions represent Rytov’s approximate solutions for the wave equation without taking into account the anisotropy due to the influence of the Earth’s magnetic field. The stationarity of the radio line associated with the temporal and spatial statistical characteristics of random temporal and spatial fluctuations of the electron density of ionospheric irregularities is considered as a parameter of the models that is important for applications. By calculating the considered models of radio lines with the parameters of the standard mid-latitude ionosphere, estimates of the temporal stationarity of radio lines for a number of velocities of movement of ionospheric irregularities are obtained. The calculated estimated values of the temporal stationarity of the considered radio lines due to the influence of the ionosphere are useful in the development of satellite information systems, in the selection of optimal signal structures and in the development of procedures for their processing during reception and synchronization.
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Орманов, А. Б., and Е. А. Бахтиярова. "Research on the nature of 4G propagation in various environments." INTERNATIONAL JOURNAL OF INFORMATION AND COMMUNICATION TECHNOLOGIES, no. 1(1) (February 15, 2022). http://dx.doi.org/10.54309/ijict.2020.1.1.028.
Повний текст джерелаАнотація:
В работе рассмотрены характеры распространения сигнала технологии 4G в различных средах. Приведены методы математических моделей и алгоритмы распространения радиоволн в сотовых сетях мобильной связи. Рассмотрены различные влияния препятствий на пути от базовой (БС) до мобильной (МС) станции на распространение радиосигнала. Показаны: 1. Построение математических моделей РРВ в ССМС в различных средах. 2. Построение алгоритма численного расчета РРВ в ССМС на программе Mathcad.3. Сравнительный анализ препятствий. The paper considers the ways of propagation of the 4G signal technology in various environments. In the technical part of the work some tasks of network coverage of radio waves are considered, analyses and systematization of existing and developing methods of radio planning of mobile communication networks are performed. Methods of mathematical models and algorithms of radio wave propagation in mobile networks are presented. Various effects of obstacles on the path from the base (BS) to the mobile (MS) station on the propagation of the radio signal are considered.
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Bakhtiiarov, Denys. "Methods of evaluation and forecasting of levels of electromagnetic radiation in urban environments (in Ukrainian)." European Scientific e-Journal, 2020. http://dx.doi.org/10.47451/inn2020-12-001.
Повний текст джерелаАнотація:
Abstract: This article is devoted to the decision of the actual scientific and applied problem which consists in the development of a method of definition of levels of the basic and secondary electromagnetic radiations in the urban environments at the expense of perfection of models of their distribution. The necessity in the increased efficiency of use of devices of monitoring of an electromagnetic situation on the basis of the analysis of features of distribution of electromagnetic radiations in the urban environment and lacks of the existing mathematical device for their description is proved. The nature of the interference and the distance in real operating conditions and the corresponding graphical and mathematical dependences were obtained, which formed the basis of the method of improving the models of electromagnetic radiation propagation. Scientific methods of synthesis of the detailed structural scheme of processes of detection and localization of uncontrolled and unlicensed devices of information transmission on radio channels, including development Bakhtiiarov, D.I., Lavrynenko, O.Y., Lishchynovska, N.O., Komarnytskyi, O.O. (2020). Methods of evaluation and forecasting of levels of electromagnetic radiation in urban environments (in Ukrainian). Actual issues of modern science. No. 1. Vol. 2, add. Collection of Scientific Articles, 06-2 (06), __- __. European Scientific e-Journal. Hlučín-Bobrovníky: “Anisiia Tomanek” OSVČ. ESEJ: inn2020-12-001 DOI: 10.47451/inn2020-12-001 Бахтіяров, Д.I., Лавриненко, O.Ю., Ліщиновська, Н.O., Комарницький, O.O. (2020). Методи оцінювання та прогнозування рівнів електромагнітних випромінювань в урбанізованих середовищах. Actual issues of modern science. No. 1. Vol. 2, add. Collection of Scientific Articles, 06-2 (06), __-__. European Scientific e-Journal. Hlučín-Bobrovníky: “Anisiia Tomanek” OSVČ. 2 of the software for definition of a zone of electromagnetic accessibility indoors are substantiated. An original approach, algorithm of functioning and methods of synthesis of search means in the conditions of radio interference and detection of sources of electromagnetic radiation are developed. Key words: secondary electromagnetic radiation; electromagnetic reach; radio wave propagation; Hut model; COST 231 MWM; monitoring of the electromagnetic environment, attenuation factor