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    Wyświetlanie 1-10 z 10
    Tytuł:
    Propagation Path Loss Modeling in Container Terminal Environment
    Autorzy:
    Katulski, R. J.
    Stefański, J.
    Sadowski, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/308910.pdf
    Data publikacji:
    2009
    Wydawca:
    Instytut Łączności - Państwowy Instytut Badawczy
    Tematy:
    path loss modeling
    radio propagation
    Opis:
    This paper describes novel method of path loss modeling for radio communication channels in container port area. Multi-variate empirical model is presented, based on multidimensional regression analysis of real path loss measurements from container terminal environment. The measurement instruments used in propagation studies in port area are also described.
    Źródło:
    Journal of Telecommunications and Information Technology; 2009, 3; 38-42
    1509-4553
    1899-8852
    Pojawia się w:
    Journal of Telecommunications and Information Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Characterization of Propagation Models in Wireless Communications for 4G Network
    Autorzy:
    Al-Aamri, Nawal
    Nadir, Zia
    Al-Lawati, Hassan
    Suwailam, Mohammed Bait
    Powiązania:
    https://bibliotekanauki.pl/articles/2055256.pdf
    Data publikacji:
    2022
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    path loss model
    prediction
    4G
    RMSE
    Opis:
    Estimating the pathloss and signal strength of the transmitted signal at specific distances is one of the main objectives of network designers. This paper aims to provide generalized pathloss models appropriate for urban areas in Muscat the capital city of the Sultanate of Oman environment. The research includes studying different models of pathloss for the 4G cellular network at Muttrah Business District (MBD) at Muscat. Different models (Free Space model, Okumura Hata, Extended Sakagami, Cost231 Hata, ECC-33 Hata – Okumura extended, Ericsson, Egli, and SUI) are used with 800MHz. The results of the prediction models are compared with real measured data by calculating RMSE. The generalized models are created by modified original models to get accepted RMSE values. Different cells at MBD are tested by modified models. The RMSE values are then calculated for verification purposes. To validate the modified pathloss models of 4G, they are also applied at different cells in a different city in the capital. It has approximately the same environment as MBD. The modified pathloss models provided accepted predictions in new locations.
    Źródło:
    International Journal of Electronics and Telecommunications; 2022, 68, 1; 137--143
    2300-1933
    Pojawia się w:
    International Journal of Electronics and Telecommunications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Determination of Probability Distribution Function for Modelling Path Loss for Wireless Channels Applications over Micro-Cellular Environments of Ondo State, Southwestern Nigeria
    Autorzy:
    Abiodun, Chukwutem Isaac
    Ojo, Joseph Sunday
    Powiązania:
    https://bibliotekanauki.pl/articles/1075736.pdf
    Data publikacji:
    2019
    Wydawca:
    Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
    Tematy:
    Path loss
    normal distribution
    probability distribution function
    wet and dry season
    Opis:
    In this research, the most appropriate probability distribution function for modelling RF signal path loss values in both wet and dry season months over urban, suburban and rural environments of Ondo State are presented. The data used consist of a drive test measurement campaign carried out in a typical urban, suburban and rural areas of Ondo State, South-western Nigeria in both wet and dry season months. The received signal strength (RSS) values were collected and recorded in log files alongside other environmental parameters using TEMS investigation tools. Path loss values were deduced from the measured RSS values. Some selected probability distribution function namely: gamma, lognormal, extreme value, logistic, Weibull and normal distributions function were fitted to the measured path loss values and the best suited one determined using three different metric measures. Results obtained show that normal distribution presents the best probability distribution curve for modelling the RF signal path loss over different micro-cellular environments of Ondo State. A typical result of the rural environment indicates that in wet season months, the normal distribution has RMSE of 7.060 dB, Relative Error of 12.480 % and R2 of 0.988, in dry season months, the RMSE is 9.060 dB, Relative Error of 13.450 % and R2 of 0.985. When compared with other distribution models, the same trend could be seen in other environments, although with different values of RMSE, Relative error and R2. The mean and the standard deviation parameters for the normal distribution estimated, vary seasonal-wise and are environment dependent. However, the rural environment exhibited a wider seasonal variations when compared with the other environments. The results of this research is useful as a first-hand information in the planning of future wireless propagation channels in the studied environments.
    Źródło:
    World Scientific News; 2019, 118; 74-88
    2392-2192
    Pojawia się w:
    World Scientific News
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Investigation of QoS Performance Evaluation over 5G Network for Indoor Environment at millimeter wave Bands
    Autorzy:
    Qamar, Faizan
    Hindia, Mohammad Nour
    Abbas, Talib
    Dimyati, Kaharudin Bin
    Amiri, Iraj Sadegh
    Powiązania:
    https://bibliotekanauki.pl/articles/226266.pdf
    Data publikacji:
    2019
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    5G
    millimeter wave
    CI-path loss
    propagation channel
    channel characterization
    small cell
    Opis:
    One of the key advancement in next-generation 5G wireless networks is the use of high-frequency signals specifically those are in the millimeter wave (mm-wave) bands. Using mmwave frequency will allow more bandwidth resulting higher data rates as compared to the currently available network. However, several challenges are emerging (such as fading, scattering, propagation loss etc.), when we propagate the radio signal at high frequencies. Optimizing propagation parameters of the mm-wave channels system are much essential for implementing in the realworld scenario. To keep this in mind, this paper presents the potential abilities of high frequencies signals by characterizing the indoor small cell propagation channel for 28 GHz, 38 GHz, 60 GHz and 73 GHz frequency band, which is considered as the ultimate frequency choice for many of the researchers. The most potential Close-In (CI) propagation model for mm-wave frequencies is used as a Large-scale path loss model. The results have been collected concerning the capacity of users to evaluate the average user throughput, cell-edge user throughput, average cell throughput, spectral efficiency and fairness index. The statistical results proved that these mm-wave spectrum gives a sufficiently greater overall performance and are available for use in the next generation 5G mobile communication network.
    Źródło:
    International Journal of Electronics and Telecommunications; 2019, 65, 1; 95-101
    2300-1933
    Pojawia się w:
    International Journal of Electronics and Telecommunications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    An Empirical Propagation Model for Corridors in Office Buildings
    Autorzy:
    Kosz, P.
    Powiązania:
    https://bibliotekanauki.pl/articles/227038.pdf
    Data publikacji:
    2017
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    wireless systems
    radio wave propagation
    propagation model
    propagation path loss
    indoor environment
    test stand
    Opis:
    This paper presents an empirical propagation path loss model for corridors in office buildings. The proposed model estimates changeable character of radio signal attenuation, based on a special approach as a combination of the simple free-space model with the author’s model. The measurement stand and measurement scenario are described. The propagation path loss research have been made in corridor for different frequencies in range 30 MHz to 290 MHz. A significant number of measurement results were allowed an analysis of the radio wave propagation conditions in the environment. In general, the propagation path loss increases for each measurement frequencies with length of propagation route. Based on measurement data, the new empirical propagation path loss model was developed. For this purpose, the regression analysis was made. The novelty of this model is that it could be used for estimate propagation path loss in measured environment for different radio wave frequencies. At the end, in order to justification the practical usefulness of described method for estimate a radio wave attenuation, the statistical evaluation was made. Thus, the results of the statistical analysis (ME, SEE and R2 values) are satisfactory for each measured radio wave frequency.
    Źródło:
    International Journal of Electronics and Telecommunications; 2017, 63, 1; 5-10
    2300-1933
    Pojawia się w:
    International Journal of Electronics and Telecommunications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    An Optimized Propagation Model based on Measurement Data for Indoor Environments
    Autorzy:
    Morocho-Yaguana, M.
    Ludeňa-González, P.
    Sandoval, F.
    Poma-Vélez, B.
    Erreyes-Dota, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/308451.pdf
    Data publikacji:
    2018
    Wydawca:
    Instytut Łączności - Państwowy Instytut Badawczy
    Tematy:
    indoor
    ITU model
    log-distance model
    loss measurement
    one-slope model
    path loss
    propagation measurements
    propagation models
    radio propagation
    Opis:
    Propagation is an essential factor ensuring good coverage of wireless communications systems. Propagation models are used to predict losses in the path between transmitter and receiver nodes. They are usually defined for general conditions. Therefore, their results are not always adapted to the behavior of real signals in a specific environment. The main goal of this work is to propose a new model adjusting the loss coefficients based on empirical data, which can be applied in an indoor university campus environment. The Oneslope, Log-distance and ITU models are described to provide a mathematical base. An extensive measurement campaign is performed based on a strict methodology considering different cases in typical indoor scenarios. New loss parameter values are defined to adjust the mathematical model to the behavior of real signals in the campus environment. The experimental results show that the model proposed offers an attenuation average error of 2.5% with respect to the losses measured. In addition, comparison of the proposed model with existing solutions shows that it decreases the average error significantly for all scenarios under evaluation.
    Źródło:
    Journal of Telecommunications and Information Technology; 2018, 2; 69-75
    1509-4553
    1899-8852
    Pojawia się w:
    Journal of Telecommunications and Information Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    A Statistical Calibration Method of Propagation Prediction Model Based on Measurement Results
    Autorzy:
    Kelner, Jan M.
    Kryk, Michał
    Łopatka, Jerzy
    Gajewski, Piotr
    Powiązania:
    https://bibliotekanauki.pl/articles/226022.pdf
    Data publikacji:
    2020
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    calibration of propagation model
    empirical measurements
    path loss model
    propagation
    parabolic equation method
    radio environment maps
    Opis:
    Radio environment maps (REMs) are beginning to be an integral part of modern mobile radiocommunication systems and networks, especially for ad-hoc, cognitive, and dynamic spectrum access networks. The REMs will use emerging military systems of tactical communications. The REM is a kind of database used at the stage of planning and management of the radio resources and networks, which considers the geographical features of an area, environmental propagation properties, as well as the parameters of radio network elements and available services. At the REM, for spatial management of network nodes, various methods of propagation modeling for determining the attenuation and capacity of wireless links and radio ranges are used. One method of propagation prediction is based on a numerical solution of the wave equation in a parabolic form, which allows considering, i.a., atmospheric refraction, terrain shape, and soil electrical parameters. However, the determination of a current altitudinal profile of atmospheric refraction may be a problem. If the propagation-prediction model uses a fixed refraction profile, then the calibration of this model based on empirical measurements is required. We propose a methodology for calibrating the analyzed model based on an example empirical research scenario. The paper presents descriptions of the propagation model, test-bed and scenario used in measurements, and obtained signal attenuation results, which are used for the initial calibration of the model.
    Źródło:
    International Journal of Electronics and Telecommunications; 2020, 66, 1; 11-16
    2300-1933
    Pojawia się w:
    International Journal of Electronics and Telecommunications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Performance Analysis of Empirical Radio Propagation Models in Wireless Cellular Networks
    Autorzy:
    Rahul, Rahul
    Bansal, Bajrang
    Kapoor, Rajiv
    Powiązania:
    https://bibliotekanauki.pl/articles/1075552.pdf
    Data publikacji:
    2019
    Wydawca:
    Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
    Tematy:
    2G
    3G
    4G
    5G Cellular Networks
    Cell Coverage
    Path Loss
    Radio Propagation Models
    Opis:
    This paper presents the performance analysis of different empirical radio propagation models used in wireless cellular networks. It particular, the parameters such as path loss and cell coverage area are studied for different cellular networks from second generation (2G) to fifth generation (5G). Accurate prediction of path loss and coverage area is highly desirable for planning of any wireless communication systems. Considering the urban terrain, the comparison is made between Hata model, Stanford University Interim (SUI) model, and modified SUI models. As a motivation for new millimeter wave (mm-wave) cellular systems, i.e., for 5G communication, the analysis is performed at 28 GHz. Considering -75 dBm as the desired minimum received power, it is observed that 2G communication (at 900 MHz using Hata model) experiences the lowest path loss and thus results into largest coverage area. The path loss is observed to be maximum for the future mm-wave systems (at 28 GHz using modified SUI model) that directly imply the smallest coverage area.
    Źródło:
    World Scientific News; 2019, 121; 35-41
    2392-2192
    Pojawia się w:
    World Scientific News
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Tłumienia łącza kierunkowego w zakresie fal milimetrowych na bazie modyfikacji modelu empirycznego
    Directional link attenuation in millimeter-wave range based on empirical model modification
    Autorzy:
    Pawlak, Dawid
    Kelner, Jan M.
    Powiązania:
    https://bibliotekanauki.pl/articles/24065010.pdf
    Data publikacji:
    2022
    Wydawca:
    Wojskowa Akademia Techniczna im. Jarosława Dąbrowskiego
    Tematy:
    łączność bezprzewodowa
    propagacja fal radiowych
    modele tłumienia
    wielo-eliptyczny model propagacyjny
    anteny kierunkowe
    kierunkowe łącze radiowe
    fale milimetrowe
    systemy 5G
    badania symulacyjne
    wireless communication
    radio wave propagation
    path loss model
    multi-elliptical propagation model
    directional antennas
    directional radio link
    millimeter waves
    5G systems
    simulation studies
    Opis:
    Systemy telefonii komórkowej piątej i następnych generacji będą wykorzystywały nie tylko zakresy częstotliwości poniżej 6 GHz, lecz także pasma w zakresie fal milimetrowych oraz terahercowych. Z praktycznego punktu widzenia podejście to wymaga stosowania anten kierunkowych lub systemów z formowaniem wiązki. w celu zapewnienia większej efektywności energetycznej łącza bezprzewodowego istotne jest, aby wiązki radiowe po stronie nadawczej i odbiorczej były współosiowe. Modele tłumienia są powszechnie wykorzystywane przy projektowaniu systemów i sieci łączności radiowej. należy jednak podkreślić, że w literaturze nie ma dostępnych odpowiednich metod modelowania tłumienia dla przypadków braku współosiowości wiązek antenowych. w artykule zaproponowano sposób modyfikacji modelu tłumienia bazujący na wieloeliptycznym modelu propagacyjnym. w tym celu opracowano specjalne oprogramowanie w środowisku MATLAB, które posłużyło do przeprowadzenia badań symulacyjnych. w dalszej części przedstawiono przykładowe wyniki adaptacji empirycznych modeli tłumienia w zakresie fal milimetrowych, które otrzymano, wykorzystując opracowany program.
    The upcoming fifth and next generation mobile phone systems will use not only the frequency bands of sub-6 GHz but also the millimeter-wave and terahertz bands. From a practical viewpoint, this approach requires the use of directional antennas or beamforming systems. To ensure greater energy efficiency of the wireless link, the radio beams on the transmitting and receiving sides should be aligned ones. Path loss models are commonly used for designing the radio communication systems and networks. However, in the literature, there are no adequate methods of attenuation modelling available for the cases of misalignment of antenna beams. in this paper, a method of modifying the path loss model, based on a multi-elliptical propagation model, is proposed. For this purpose, dedicated software was developed in the MATLAB environment, which was used to conduct simulation tests. In the remainder of the paper, exemplary results of the adaptation of empirical path loss models in the range of millimeter-waves are presented, which were obtained using the developed program.
    Źródło:
    Biuletyn Wojskowej Akademii Technicznej; 2022, 71, 3; 69--92
    1234-5865
    Pojawia się w:
    Biuletyn Wojskowej Akademii Technicznej
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Post-critical deformation states of composite thin-walled aircraft load-bearing structures
    Autorzy:
    Kopecki, T.
    Bakunowicz, J.
    Lis, T.
    Powiązania:
    https://bibliotekanauki.pl/articles/280986.pdf
    Data publikacji:
    2016
    Wydawca:
    Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
    Tematy:
    skin
    loss of stability
    finite element method
    composite
    equilibrium path
    Opis:
    The study presents results of experimental examination of a model representing a fragment of an aircraft wing structure with the skin made of a glass fibre/epoxy composite. For such a system, the deformation pattern has been found and the representative equilibrium path determined. The finite element method has been used to develop the corresponding numerical model, the correctness of which has been then verified by comparing the obtained results with the course of the relevant experiment. Conformity of the results allowed one to determine usefulness of the applied methods in the assessment of mechanical properties of modified solutions involving integral skin stiffening elements.
    Źródło:
    Journal of Theoretical and Applied Mechanics; 2016, 54, 1; 195-205
    1429-2955
    Pojawia się w:
    Journal of Theoretical and Applied Mechanics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-10 z 10

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