• The Journal of the Acoustical Society of Korea
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• v.22 no.7
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• pp.579-584
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• 2003

All of propagation path loss prediction models, which have been presented up to date, are oかy for ground living space. In reality, sea surface free space is different from ground living space in physical hierarchical structure. If the propagation path prediction model for ground living space is applied to the sea surface free space, propagation path loss will be smaller than actual value, while the maximum service straight line will become shorter. Thus this paper proposed and simulated the propagation path loss prediction model for predicting propagation path loss more accurately in sea surface free space, with its focus on CDMA mobile communication frequency band. Then the simulation results were compared to actual survey to verify its practicality.

• Proceedings of the KAIS Fall Conference
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• 2010.11a
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• pp.353-355
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• 2010

본 논문에서는 터널환경에서 전파의 경로 손실 특성을 예측할 수 있도록 시뮬레이터를 개발하였다. 전파의 경로를 정확히 분석하기 위하여 image theory 방법을 이용하였으며, 직선 터널 구간뿐만 아니라 곡선 터널 구간에서도 전파 손실을 예측할 수 있도록 구현하였다. 시뮬레이터는 다양한 변수들을 입력받아 실시간으로 전파 경로를 도식화하여 결과를 보여줄 수 있으며, 송신부와 수신부의 위치를 변경하며 결과를 예측할 수도 있다. 개발된 시뮬레이터를 다양한 직석터널과 곡선터널에 적용하여 결과를 비교 분석하였다.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2000.11a
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• pp.255-258
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• 2000

최근 경제 활동의 증가로 인하여 통신 서비스에 대한 이동성, 편의성, 및 개인에 대한 요구가 증대되고 있다. 현재 세계각국에서는 이동통신 서비스인 셀룰라 이동통신과 개인 휴대 통신인 PCS(Personal Communication System)가 상용화되고 있다. 1900MHz 대역은 셀룰라 800 MHz에 비해 전파 특성상 전파환경에 따른 전파의 감쇄 및 회전손실 등으로 인한 전파 경로 손실이 증가 할 것으로 본다. 본 논문에서는 바다 해수면의 영향에 따른 800MHz대역과 1900MHz 대역에서 주파수에 따른 경로 손실 차를 실측 Data를 이용하여 비교하였으며 실측 Data를 이용하여 전파모델을 만들어 LGE에서 자체 개발한 전파 분석 시뮬레이션 툴로 Coverage 영역을 비교하였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.9
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• pp.765-772
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• 2013

In this paper, we studied the path loss model of Air Traffic Control(ATC) telecommunication radio channel at the Incheon International Airport(IIA) concourse area. We measured wave propagation characteristics on the two frequencies among VHF/UHF channel bands. The transmitting site radiated the Continuous Wave(CW). The propagation measurement was taken using the moving vehicle equipped with receiver and antenna. The transmitting power, frequency, and antenna height are the same as the current operating condition. The path loss exponent and intercept parameters were extracted by the basic path loss model and hata model. The path loss exponents at Concourse area were 3.1/3.13 and 3.01/3.38 respectively in 128.2MHz and 269.1MHz. The deviation of prediction error is 2.77/3.17 and 4.01/3.66. The new path loss equation at the Concourse area was also developed using the derived path loss parameters. The new path loss model was compared with other models. This result will be helpful for the ATC site selection and service quality evaluation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.6
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• pp.2985-2991
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• 2013

Train radio system has been constructed in the second stage of Kyung-bu high speed railway adopting TETRA(Terrestial trunk radio) standard at 851MHz frequency band. The base stations of the train radio system should be located along railway track to ensure seamless communication between train and wayside taking the path loss of train radio propagation into consideration. This paper provides a quantitative analysis of the path loss characteristics based on the measurement results of the train radio propagation along the high speed railway. The free space propagation model and Okumura-Hata model are generally used for base station design, but they predicted 10dB lower or 20dB higher than the measured path loss. Linear regression of the field measured data by applying the log-distance model shows path loss exponent is in the 2.8-3.2 range, which can be used to predict the path loss of the train radio propagation.

• Journal of the Institute of Electronics Engineers of Korea TE
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• v.42 no.2
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• pp.23-28
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• 2005

This study was to suggest the propagation path loss and predictive model of propagation path analysis in order to apply the frequency in the millimeter-wave band to the real time inter-vehicle communication system. This study was to suppose the case of inter-vehicle communication on the one-way two-lanes road in the big cites with a lot of traffic jams in order to analyze the effect by the reflected wave of multipath. As a simulation of suggested model, it found out that the propagation path by the reflected wave was about 0.1[m]$\sim$5.1[m] longer than the one by the direct wave during the transmission of 100[m] wave direct path. Also, as a result of comparing the propagation path loss, the loss would be about -0.8[dB]$\sim$-4.2[dB] larger in case of wall reflection and -0.8[dB]$\sim$-1[dB] vehicle reflection. From the result above, this researcher found out that the path loss of reflected wave produced by the walls was about -3.2[dB] larger than the path loss produced by the adjacent vehicles.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.2
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• pp.380-385
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• 2006

In this paper, a program that can be utilized to measure and analyze radio propagation characteristics is developed. This program is able to control the measurement instruments including spectrum analyzer through GPIB interface and analyze the measured data to yield mean excess delay and RMS delay spread. The measured path loss can be compared with theoretical value in free space or inside a tunnel. The measured and analyzed results can also be presented in the forms of graphs. As these tasks can be conducted on the spot of the measurements, this program is very helpful in performing and verifying the measurements immediately. In this thesis radio propagation characteristics with frequency bands of 2.45 and 5.8GHz in subway tunnels are measured by using the program. Path loss and delay spread in subway tunnel is measured and compared according to the form of antenna beam and LOS(Line of Sight) and N-LOS(Non-Line of Sight).

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.11A
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• pp.1613-1619
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• 2000

이 논문에서는 전파재널 측정 시스템을 이용하여 건물내 무선 채널의 전파특성인 실효 시간지연 확산과 경로손실을 측정하고 분석한 결과를 제시한다. 구성된 측정 시스템은 미끄럼 상관기를 이용한 대역확산 채널 측정 시스템에서 2 GHz에서 동작하며 3 m 의 분해능을 갖는다. 건물내 무선 채널 특성의 측정환경은 송신 안테나와 수신 안테나가 같은 층에 있을때, 서로 다른 층에 있을때, 그리고 사무실 안에 같이 위치할 때의환경으로구분하여 실험한다.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.1
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• pp.173-178
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• 2020

A multi-ray model has been used to interpret radio transmission losses in half-canyon structures with slope and to formulate a multi-ray propagation model depending on the angle of slopes. The cut-off angles for the third and fourth paths, which are the slope-sided reflection paths of the transmission and reception radio waves determined by the inclined angles of the slope, were calculated with the height and location of the transmitter and receiver. To predict transmission losses in an inclined plane environment, the embankment environment where the actual slope exists was modeled and simulated to calculate the loss of propagation transmission, and the radio wave transmission loss was confirmed by the measurement for the frequency band 1 to 6 GHz. Simulation results and measurement results showed similar trends in radio transmission loss, and radio transmission loss predictions and measurement results for various terrain information can be used in the design of radio propagation service.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.4
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• pp.1796-1802
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• 2011

In this paper, the radio propagation path loss prediction simulator in tunnel was developed. It used a image theory method for analysing precise radio propagation path. And it can predict radio propagation path loss in straight and curved tunnels. The simulator can plot realtime radio propagation paths using various parameters which was input by user. And it can simulate from changing transmitter and receiver positions. The predicted path loss of simulator was compared with the measurements in Chunhyun tunnel and confirmed the validity.