scholarly journals Empirical Model of Radio Wave Propagation in the Presence of Vegetation inside Greenhouses Using Regularized Regressions

Sensors ◽  
2020 ◽  
Vol 20 (22) ◽  
pp. 6621
Author(s):  
Dora Cama-Pinto ◽  
Miguel Damas ◽  
Juan Antonio Holgado-Terriza ◽  
Francisco Manuel Arrabal-Campos ◽  
Francisco Gómez-Mula ◽  
...  
Keyword(s):  
Wave Propagation ◽  
Radio Wave ◽  
Empirical Model ◽  
Precision Agriculture ◽  
Wave Attenuation ◽  
Multipath Propagation ◽  
Field Tests ◽  
Radio Wave Propagation ◽  
Radio Waves ◽  
Vegetation Height

Spain is Europe’s leading exporter of tomatoes harvested in greenhouses. The production of tomatoes should be kept and increased, supported by precision agriculture to meet food and commercial demand. The wireless sensor network (WSN) has demonstrated to be a tool to provide farmers with useful information on the state of their plantations due to its practical deployment. However, in order to measure its deployment within a crop, it is necessary to know the communication coverage of the nodes that make up the network. The multipath propagation of radio waves between the transceivers of the WSN nodes inside a greenhouse is degraded and attenuated by the intricate complex of stems, branches, leaf twigs, and fruits, all randomly oriented, that block the line of sight, consequently generating a signal power loss as the distance increases. Although the COST235 (European Cooperation in Science and Technology - COST), ITU-R (International Telecommunications Union—Radiocommunication Sector), FITU-R (Fitted ITU-R), and Weisbberger models provide an explanation of the radio wave propagation in the presence of vegetation in the 2.4 GHz ICM band, some significant discrepancies were found when they are applied to field tests with tomato greenhouses. In this paper, a novel method is proposed for determining an empirical model of radio wave attenuation for vegetation in the 2.4 GHz band, which includes the vegetation height as a parameter in addition to the distance between transceivers of WNS nodes. The empirical attenuation model was obtained applying regularized regressions with a multiparametric equation using experimental signal RSSI measurements achieved by our own RSSI measurement system for our field tests in four plantations. The evaluation parameters gave 0.948 for R2, 0.946 for R2 Adj considering 5th grade polynomial (20 parameters), and 0.942 for R2, and 0.940 for R2 Adj when a reduction of parameters was applied using the cross validation (15 parameters). These results verify the rationality and reliability of the empirical model. Finally, the model was validated considering experimental data from other plantations, reaching similar results to our proposed model.

SIGNAL NOISE IMMUNITY IN ALAMOUTI SYSTEMS TAKING INTO ACCOUNT PARAMETERS OF MULTIPATH COMMUNICATION CHANNELS

2020 ◽  
Author(s):  
М.А. БЫХОВСКИЙ
Keyword(s):  
Wave Propagation ◽  
Radio Wave ◽  
Noise Immunity ◽  
Multipath Propagation ◽  
Communication Channels ◽  
Spatial Diversity ◽  
Propagation Path ◽  
Communication Line ◽  
Radio Waves ◽  
Physical Features

Представлен метод анализа системы Аламоути - простейшей системы MISO, в которой для устранения интерференции лучей, приходящих в место приема, на передающем конце линии связи применяются только две передающие антенны с определенным пространственным разнесением. Метод основан на рассмотрении физических особенностей распространения радиоволн и позволяет учесть конкретные характеристики многолучевых трасс распространения между передающей и приемной станциями. Система Аламоути позволяет уменьшить флуктуации уровня сигнала, поступающего на вход демодулятора, полностью или частично устраняя интерференцию приходящих на вход приемника лучей. Получены формулы, которые позволяют оценить необходимую для обеспечения требуемой надежности приема сигналов энергетику линии связи, влияние расположения передающих антенн по отношению к трассе распространения радиоволн (вдоль или поперек трассы), а также величину необходимого пространственного разнесения передающих антенн, при котором может быть обеспечена максимально возможная помехоустойчивость приема сигналов. The paper offers the method of analysis of the Alamouti system, the simplest MISO system in which at the transmitting end of the communication line only two transmitting antennas with a certain spatial diversity are used to eliminate the interference of the rays arriving at the receiving site. The method is based on the study of the physical features of radio wave propagation and allows taking into account the specific characteristics of multipath propagation paths between the transmitting and receiving stations. The Alamouti system allows the reduction of fluctuations in the level of the signal entering the input of the demodulator, completely or partially eliminating the interference of the rays coming to the input of the receiver. The paper offers formulas that allow us to estimate the energy of the communication line, necessary to ensure the required reliability of signal reception, the influence of the location of the transmitting antennas relative to the propagation path of the radio waves (along or across the track), as well as the amount of necessary spatial diversity of the transmitting antennas at which the maximum possible noise immunity of signal reception can be ensured.

scholarly journals Forecasting characteristics of propagation of decameter radio waves using the global ionosphere and plasmasphere model

2015 ◽  
Vol 1 (3) ◽  
pp. 49-54 ◽  
Author(s):  
Сергей Пономарчук ◽  
Sergey Ponomarchuk ◽  
Галина Котович ◽  
Galina Kotovich ◽  
Елена Романова ◽  
...  
Keyword(s):  
Wave Propagation ◽  
Radio Wave ◽  
Normal Wave ◽  
Middle Latitude ◽  
Radio Wave Propagation ◽  
Radio Waves ◽  
Radio Communication ◽  
Iri Model ◽  
Decameter Radio ◽  
Minimum Number

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.

scholarly journals Characteristics of the electromagnetic environment created by radiations of user equipment of ...4G/5G/6G cellular (mobile) communications in buildings

Doklady BGUIR ◽  
2021 ◽  
Vol 19 (6) ◽  
pp. 42-50
Author(s):  
V. I. Mordachev
Keyword(s):  
Wave Propagation ◽  
Radio Wave ◽  
Flux Density ◽  
Mobile Communications ◽  
Electromagnetic Compatibility ◽  
Radio Wave Propagation ◽  
Radio Waves ◽  
Interior Space ◽  
Power Flux ◽  
Near Zone

The goal of the work is to substantiate the technique for assessing the intensity of electromagnetic background generated by the set of radiating user devices of mobile communications in multi-storey buildings. For known empirical models of radio wave propagation in buildings, expressions are obtained for the probability distribution density and expectation of the power flux density of electromagnetic fields generated inside building by these sources from various parts of the building's interior space: from the near zone with radio wave propagation conditions similar to free space; and from the far zone, for which, along with intense attenuation of radio waves due to internal obstacles, a «quasi-waveguide» propagation of radio waves along corridors and industrial premises is also possible in certain directions. Relationships are obtained for the average levels of individual components of the electromagnetic background, determined as scalar sums of power flux density values of the fields generated by the sets of radiating devices of both the near zone and the far zone as a whole or its individual parts, characterized by different conditions of radio wave propagation. A method is proposed for assessing the electromagnetic background inside buildings based on approximation of sections of the inner surface of the premises in which the observation point is located, and the outer surface of the building, in the inner space of which radiation sources are randomly distributed, by the corresponding sections of the inner and outer spherical surfaces that are the subtend areas of the corresponding solid angles, in space elements of which a different spatial densities and radiation powers of sources and different conditions of radio wave propagation are possible. The results can be used to analyze the electromagnetic ecology of habitat and the electromagnetic safety of population at the full-scale implementation of 4G/5G/6G mobile communications, as well as to analyze the electromagnetic compatibility of systems using frequency bands for mobile communications on a primary and secondary basis.

scholarly journals Research on Fast Algorithm of Radio Wave Propagation in Low-Lossy Obstacles Environment

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
An-qi Li ◽  
Cheng-you Yin ◽  
Qian-qian Zhang ◽  
Yong-ji Gan
Keyword(s):  
Wave Propagation ◽  
Radio Wave ◽  
Radio Wave Propagation ◽  
Radio Waves ◽  
Impedance Boundary ◽  
Complex Image ◽  
Surface Impedance Boundary Conditions ◽  
Decomposition Principle ◽  
Good Agreement ◽  
Discrete Complex

To predict the propagation of radio waves in the environment of dielectric ground and dielectric obstacles, a new two-way parabolic equation (2W-PE) method based on the domain decomposition principle and surface impedance boundary conditions (SIBC) is proposed. First, we decompose the obstacle area into different subdomains and derive the SIBC in each subdomain in detail; then, the discrete hybrid Fourier transform (DMFT) in the upper subdomain and finite difference (FD) algorithm in the lower subdomain is used to solve 2W-PE combined with SIBC, respectively. After that, we explain the algorithm steps in the process of calculating the total field, compared with the traditional 2W-PE, and then finally introduce the method of moments (MoM) combined with the enhanced discrete complex image (E-DCIM) method for accuracy verification of the new 2W-PE algorithm. The simulation results show that no matter how the obstacle medium parameters change, the results of 2W-PE method proposed in this paper and MoM are always in good agreement, which proves the accuracy of 2W-PE and its superiority in speed. Therefore, this paper provides a reliable and efficient method for solving the problem of radio wave propagation in the presence of obstacles, especially in the case of low-lossy obstacles.

scholarly journals VLF – RECORDER FOR THE STUDY OF NATURAL RADIO EMISSION

2019 ◽  
pp. 105-116
Author(s):  
Г.И. Дружин ◽  
В.М. Пухов ◽  
Д.В. Санников ◽  
Е.И. Малкин ◽  
И.Е. Стасий
Keyword(s):  
Wave Propagation ◽  
Radio Emission ◽  
Electromagnetic Radiation ◽  
Radio Wave ◽  
Thunderstorm Activity ◽  
Radio Wave Propagation ◽  
Radio Waves ◽  
Natural Noise ◽  
Cosmophysical Research

С целью исследования естественных щумовых электромагнитных излучений в Институте космофизических исследований и распространения радиоволн ДВО РАН разработан и создан ОНЧрегистратор, установленный на Камчатке, в экспедиционном пункте Карымшина. Непрерывные наблюдения, проведенные с помощью ОНЧ регистратора, позволили исследовать различные геофизические эффекты, связанные с распространением радиоволн, грозовой активностью, землетрясениями, циклонами. In order to study the natural noise electromagnetic radiation at the Institute of Cosmophysical Research and Radio Wave Propagation FEB RAS, a VLFrecorder was developed, created and installed in Kamchatka, in the expedition point Karymshina. Continuous observations carried out with the help of VLFregistrator allowed to study various geophysical effects associated with the propagation of radio waves, thunderstorm activity, earthquakes, cyclones.

scholarly journals Forecasting characteristics of propagation of decameter radio waves using the global ionosphere and plasmasphere model

2015 ◽  
Vol 1 (3) ◽  
pp. 49-54
Author(s):  
Романова ◽  
Elena Romanova ◽  
Котович ◽  
Galina Kotovich ◽  
Пономарчук ◽  
...  
Keyword(s):  
Wave Propagation ◽  
Radio Wave ◽  
Normal Wave ◽  
Middle Latitude ◽  
Radio Wave Propagation ◽  
Radio Waves ◽  
Radio Communication ◽  
Iri Model ◽  
Decameter Radio ◽  
Minimum Number

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.

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