• Title/Summary/Keyword: Propagation Measurements

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LTE Signal Propagation Model-based Fingerprint DB Generation for Positioning in Emergency Rescue Situation

  • Cho, Seong Yun
    • Journal of Positioning, Navigation, and Timing
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    • v.9 no.3
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    • pp.157-167
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    • 2020
  • Fingerprinting method is useful when estimating the location of a requestor based on LTE signals in an urban area. To do this, it is necessary to acquire location-based signals everywhere in the service area for fingerprint DB generation in advance. However, there may be signal uncollected area within a wide service area, which may cause a problem that the positioning accuracy of the requestor is low. In order to solve this problem, in this paper, signal propagation modeling is performed based on the obtained measurements, and based on this model, the signal information in the non-acquisition region is estimated. To this end, techniques for modeling signal propagation according to a method using measurements are proposed. The performance of the proposed techniques is verified based on the measurements obtained on a test bed selected as Seocho-gu, Seoul. As a result, it can be seen that signal propagation modeling performed based on multidivision segmented measurements has the most performance improvement.

Ultra Broadband Indoor Channel Measurements and Calibrated Ray Tracing Propagation Modeling at THz Frequencies

  • Priebe, Sebastian;Kannicht, Marius;Jacob, Martin;Kurner, Thomas
    • Journal of Communications and Networks
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    • v.15 no.6
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    • pp.547-558
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    • 2013
  • Ultra broadband communication systems operated at THz frequencies will require the thorough knowledge of the propagation channel. Therefore, an extensive measurement campaign of 50 GHz wide indoor radio channels is presented for the frequencies between 275 and 325 GHz. Individual ray paths are resolved spatially according to angle of arrival and departure. A MIMO channel is recorded in a $2{\times}2$ configuration. An advanced frequency domain ray tracing approach is used to deterministically simulate the THz indoor propagation channel. The ray tracing results are validated with the measurement data. Moreover, the measurements are utilized for the calibration of the ray tracing algorithm. Resulting ray tracing accuracies are discussed.

Acoustical Properties of Polyester Sound Absorbing Materials (폴리에스테르 흡음재의 음향특성)

  • 주경민;용호택;이동훈
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2001.11b
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    • pp.1347-1352
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    • 2001
  • In this study, the acoustic properties of polyester sound absorbing materials with three different bulk densities were investigated by calculating and measuring the acoustic parameters in terms of characteristic impedance, propagation constant, and absorption coefficient. For the calculations, Delany and Bazley's empirical equation was used together with the experimentally obtained specific flow resistivities under steady flow conditions. For the experimental measurements, the well-known two-thickness method was accessed. The experimentally measured values of characteristic impedance and propagation constant were generally agreed well with the corresponding calculated values. Based on the comparisons between the calculations and measurements, it was found that the magnitude of the absorption coefficient was closely related to the characteristic impedance and the real part of the propagation constant. Especially, the maximum magnitude of the absorption coefficient was depended upon the imaginary part of the propagation constant indicating the phase change of the propagation constant.

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Propagation Measurements and Estimation of Channel Propagation Models in Urban Environment

  • Zakaria, Yahia;Ivanek, Lubomir;Glesk, Ivan
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.11 no.5
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    • pp.2453-2467
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    • 2017
  • Wireless communication is a telecommunication technology, which enables wireless transmission between the portable devices to provide wireless access in all types of environments. In this research, the measurements and various empirical models are analysed and compared in order to find out a suitable propagation model to provide guidelines for cell planning of wireless communication systems. The measured data was taken in urban region with low vegetation and some trees at 900 MHz frequency band. Path loss models are useful planning tools, which permit the designers of cellular communication to obtain optimal levels for the base station deployment and meeting the expected service level requirements. Outcomes show that these empirical models tend to overestimate the propagation loss. As one of the key outputs, it was observed that the calculations of Weissberger model fit with the measured data in urban environment.

Prediction model of wave propagation inside buildings including specular and diffracted transmission and reflection

  • Kim, Seong-Cheol
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.23 no.6
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    • pp.1592-1601
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    • 1998
  • The growing use of unlicensed wireless systems has spurred interest in the 2.4 Ghz ISM band. In order to facilitate the efficient design of such systems, understandings of the propserties of radio wave propagation in buildings is necessary. Many authors have reported about statistical propagation models based on the extensive measurements in buildings. However, measurement based statistical analysis will not be enough for the optimum deployment of the communication systems in the specific building. Aviding expensive measurements in the individual buildings prior to installation, or adjustments afterwards, theoretical prediction models have been developed to predict the path loss and delay spread from the building floor plane. Predictions shows good agreements with measurements except for a few environments which was surrounded by heavy scatterers.

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Radio Propagation Measurementsand Path Loss Formulas for Microcellular Systems

  • Har, Dong-Soo
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.28 no.4A
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    • pp.238-246
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    • 2003
  • In this paper, we will provide a comprehensive review of radio propagation measurements conducted to date for mobile radio systems at frequency bands used for cellular and personal communications services in microcellular systems. Path-loss results were measured by using narrowband signal and multipath propagations were characterized by wideband measurements. This paper includes unpublished empirical path loss formulas for Oakland city of non-uniform building heights, and presents a comparison with path loss formulas obtained from typical low-rise building environments in order to discuss street grid dependence on route-specific building profile. We will also compare some empirical models developed based on the measurements with a few well-established theoretical prodiction models.

Propagation Measurements of Various Directional Beam in Subway funnel Environments for IEEE 802.11 Wireless LAN (IEEE 802.11 무선랜을 위한 지하철 터널 환경에서 다양한 지향성 빔의 전파측정)

  • 박노준;송문규;강영진
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.8 no.2
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    • pp.232-238
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    • 2004
  • In this paper, radio propagation in a subway tunnel is investigated using fan beam antennas, circular polarization antennas and directional antennas at 2.4㎓ and 5.8㎓ band, respectively. The results of narrowband channel measurements show that received power level for NLOS(Non-Line-Of-Sight) path is decreased drastically as compared with LOS(Line-Of-Sight) path. Wideband channel measurements are obtained using a PN sliding correlation method. The parameters of the channel such as mean access delay and RMS delay spread are compared as to different types of directional beam at IEEE 802.11 WLAN(Wireless Local Area Network) band including 2.4㎓ and 5.8㎓ bands, respectively.

Flame Propagation Characteristics of Propane-Air Premixed Mixtures (프로판-공기 예혼합기의 화염전파 과정에 관한 연구)

  • Bae, Choong-Sik
    • Journal of the Korean Society of Combustion
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    • v.1 no.2
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    • pp.21-29
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    • 1996
  • Flame propagation characteristics of propane-air mixtures were experimentally investigated in constant-volume combustion chambers. Flame propagation process was observed as a function of mixture strength, initial mixture temperature and initial mixture pressure in quiescent mixtures. A cylindrical combustion chamber and a spherical combustion chamber contain a pair of parallel windows through which optical access into the chamber can be provided. Laser two beam deflection method was adopted to measure the local flame propagation, which gave information on the flame size and flame propagation speed. Pressure development was also measured by a piezoelectric pressure transducer to characterize combustion in quiescent mixtures. Burning velocity was calculated from flame propagation and pressure measurements. The effect of flow on flame propagation was also investigated under flowing mixture conditions. Laser two beam method was found to be feasible in measuring flame propagation of quiescent mixtures. Flame was observed to propagate faster with higher initial mixture temperature and lower initial pressure. Combustion duration was shortened in the highly turbulent flowing mixtures.

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UWB Propagation Measurements in Body Area Network Scenarios (인체 영역 통신 환경에서의 초광대역 방사 측정)

  • Lee, Joon-Yong;Kim, ChangKyeong;Ha, Dong-Woo
    • Journal of the Institute of Electronics and Information Engineers
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    • v.49 no.11
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    • pp.36-43
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    • 2012
  • Ultra-wideband propagation measurement results for body area network scenarios are presented. We assumed several different scenarios for around-body and on-body propagations, and for each scenario, we conducted both time domain and frequency domain measurements in an anechoic chamber. For the around-body case, we investigated the effects of human body parts blocking line-of-sight, which could be accounted for by diffraction. On-body measurement results indicate a more complicated propagation mechanism exists in on-body propagation than in around-body propagation and antenna characteristics are affected.