• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.8 s.99
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• pp.848-854
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• 2005

The attenuation due to rain has been recognized as one of the major causes of unavailability of radio communication systems operating above about 10 GHz. To design radio links for telecommunications and to evaluate attenuation due to rainfall, it is important to have a good prediction model for rain attenuation such as a model for drop-size distribution of rainfall(DSD), a theoretical model for specific rain attenuation, and an empirical model fur effective path length through rain. In this paper, the extended generalized gamma distribution for drop-size distribution, based on the measurements in Chnugnam National University, is proposed as a new DSD model, and predicted specific attenuation characteristics using proposed DSD model and rain attenuation values in the 44 GHz satellite path using ITU-R effective path length model, are analysed. The predicted attenuation levels are also compared. It is found that an accurate prediction method for DSD is very important to reduce the prediction error in the local satellite path.

• Journal of electromagnetic engineering and science
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• v.5 no.4
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• pp.189-192
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• 2005

The measurement of unique rainfall phenomenon and rain attenuation on 38 GHz terrestrial links at South Korea in 1998 is presented. It was one of the most severe rainfall years at the measured region due to increased EI Nino signal. The rainfall rate exceeded at $0.01\%$ was 97.4 mm/h during a worst month and annual rate was 63.5 mm/h. Experimentally measured results have been compared with some models and found that the rain attenuation by system level was underestimated by the existing prediction models. As it was measured only three months, further study and measurement of rainfall and rain attenuation in this region are needed for stable millimeter-wave system operation at all times.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.7
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• pp.1248-1256
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• 2015

It is necessary to apply an exact data and a precise prediction model for a rain attenuation to design the link margin for a data link using Ku-band with the serious effect by rain. In this paper, we investigate the regional rainfall-rate distribution of Korea proposed in TTAK.KO-06.0122/R1 and compare it with the distribution provided by Rec. ITU-R PN.837-1 and Crane. And, the rain rate climate regions similar with the rainfall-rate distribution of Korea in Rec. ITU-R PN.837-1 and Crane model are selected. Finally, using Rec. ITU-R P.618-8 and Crane rain attenuation prediction model, we derive and analyze the rain attenuation for Ku-band frequency according to the time percentage of an average year and the distance of wireless communication link between unmanned aerial vehicle (UAV) and ground data terminal (GDT).

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.2
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• pp.242-251
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• 2000

Design of wireless link in Ka and mm-wave bands is critically affected by rain attenuation. In this paper, we compared and analyzed the main distributions of rain drop size to estimate the rain attenuation which can be used in domestic environment. Mie scattering theory was checked to agree with Rayleigh theory in its low frequency limit and agree with optical scattering theory in its high frequency limit. We intended to provide more specific criteria to estimate rain attenuation with a generalized approach.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.5
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• pp.701-710
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• 1999

To predict rain attenuation accurately, we must know scattering characteristics of rain-drops for real drop shapes. In this paper, the scattering characteristics of rain-drops are analyzed by an analytical model, and the differences in the characteristics of the forward scattering amplitudes for three different rain-drop shapes are compared. Using the results for the Pruppacher-Pitter's real rain-drop shaper, the specific rain attenuation in domestic environment is predicted, and the difference from the ITU-R model is compared and analyzed.

• Journal of Satellite, Information and Communications
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• v.11 no.3
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• pp.110-113
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• 2016

In this paper of ka band satellite communication using geostationary satellite is very weak to rainfall. So the rain attenuation reflect the values calculated using the satellite communication links vulnerable when designing a more reliable rainfall area distribution of rain attenuation and accurate predictive models must analyze the link budget. In this paper, by utilizing domestic distribution analysis in the recent local rainfall Crane and regional rainfall in the model and compared with the country of the regional distribution of rainfall in your area to fit the rain attenuation in Ka band frequency characteristics Crane rain attenuation prediction models were analyzed to between geostationary satellites and ground station position, distance and year time percentage(%).

• ETRI Journal
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• v.24 no.1
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• pp.31-42
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• 2002

In high-speed multimedia satellite communication systems, it is essential to provide high-quality, economical services by using efficient transmission schemes which can overcome channel impairments appearing in the satellite link. This paper introduces techniques to compensate for rain attenuation and the Doppler shift in the satellite communication link. An adaptive transmission technique with a control algorithm to adaptively allocate transmission schemes is used as a countermeasure to rain attenuation. We introduce a new rain attenuation modeling technique for estimating system performance and propose a novel Doppler shift compensation algorithm with reduced hardware complexity. Extensive simulation results show that the proposed algorithm can provide greatly enhanced performance compared to conventional algorithms. Simulation software and hardware which incorporate the proposed techniques are also demonstrated.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.7
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• pp.1755-1763
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• 1998

The rain attenuatio of a radio channel above 10 GHz can have impact on the availability of the radio channel. The severity of the rain impairments increases with frequency and varies with regional location. This paper presents an estimation method for rain attenuation for millimeter-wave propagation in domestic environments. the dropsize distribution is assumed to be exponential, and the measurement data in the various countries which are simlar to the domestic environments are compared with the theoretical one by varying the dropsize distribution. A rain-rate conversion model which can convert .tau.-minutes rain-rate data to 1-minute rain-rate data for domestic environments is also discussed. Using the converted domestic rain-rate data, probabilty distributions of rain attenuation are computed.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.65.4-65
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• 2001

In case of data transmission using the upper 10GHz frequency, rain results in attenuation of radio waves. And the most serious atmospheric effect in a satellite link is the rainfall. The attenuation of rainfall very seriously affects the quality of transmission line. Because the rain increases thermal noise and interference, and decreases the amplitude of the signal. KOWACO manages the VSAT system instead of VHF network for communication of rain and water-level data from 1998. The purpose of this system is to monitor the change of water-level and rain data during a flood duration. VHF system acquires the data by a call per a hour. But the satellite network obtains the data whenever event data occur. Thus the satellite network is more powerful than the VHF system. In study ...

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.5
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• pp.813-821
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• 2000

The engineering of satellite communication systems at frequencies above 10GHz requires a method for estimating rain-caused outage probabilities on the earth-satellite path. A procedure for predicting a rain attenuation distribution from a point rainfall rate distribution is, therefore, needed. In order to predict rain attenuation on the satellite link, several prediction models such as ITU-R, Global, SAM, DAH model, have been developed and used at a particular propagation condition, they may not be appropriate to a propagation condition in Korean territory. In this paper, a new rain attenuation prediction method appropriate to a propagation condition in Korea is introduced. Based on the results from ETRI measurements, a new method has been derived for an empirical approach with an identification on the horizontal correction factor as in current ITU-R method, and the vertical correction factor has been suggested with decreasing power law as a function of rainfall rate. This proposed model uses the entire rainfall rate distribution as input to the model, while the ITU-R and DAH model approaches only use a single 0.01% annual rainfall rate and assume that the attenuation at other probability levels can be determined from that single point distribution. This new model was compared with several world-wide prediction models. Based on the analysis, we can easily know the importance of the model choice to predict rain attenuation for a particular location in the radio communication system design.