Investigation of accuracy of rain-rate and rain-attenuation prediction   models in satellite communications based on meteorological skills

Rainfall is a major destructive factor which severely reduces the quality and reliability of propagated signals in satellite communications. Hence, rain-attenuation prediction plays a vital role in the satellite radio link planning and engineering. The accuracy of the rain-attenuation prediction models depends on two things; (i) the accuracy of rain-rate information and (ii) the area of study. Therefore, selecting an appropriate rain-attenuation prediction model for a new site without having any specific prediction model and experimental measured rain-rate would be challenging. In this regard, this letter takes advantage of climatology skills to find an accurate model for such kind of areas. To do so, we study the Urmia-site (37.55° N, 45.1° E) and its communication link with the Eutelsat 25A (25.5° E), where there is no available experimental measured data and specific prediction models for that site. Therefore, based on the meteorological skills, the Yong-in site in South-Korea (37.43° N, 126.93° E) was chosen, as a homogeneous area with Urmia, which has available measured data of rainfall and rain-attenuation. Afterward, the most common used global prediction models are applied to Yong-in and the results are compared with the existing measurements. Consequently, the more accurate rain-rate and rain-attenuation prediction models are investigated and generalized to Urmia, which are the ITU-R P.837-5 model with 34% r.m.s. and the Joo-Hwan model with 18% r.m.s., respectively. Finally, the amount of rain-attenuation in different useful frequency bands (10-50 GHz) is investigated for Urmia by the Joo-Hwan model.

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Rain Rate Distributions for Microwave Link Design Based on Long Term Measurement in Malaysia

Indonesian Journal of Electrical Engineering and Computer Science ◽

10.11591/ijeecs.v10.i3.pp1023-1029 ◽

2018 ◽

Vol 10 (3) ◽

pp. 1023 ◽

Cited By ~ 1

Author(s):

Islam Md Rafiqul ◽

Md Moktarul Alam ◽

Ali Kodhim Lwas ◽

Sarah Yasmin Mohamad

Keyword(s):

Communication Systems ◽

Rain Rate ◽

Prediction Models ◽

Complex Structure ◽

Satellite Communications ◽

Rain Attenuation ◽

Integration Time ◽

Radio Link ◽

Radio Communication ◽

High Frequency Microwave

Attenuation due to rain is an important constraint in microwave radio link design especially at frequencies above 10 GHz. It restricts the path length of radio communication systems and limits the use of higher frequencies for line-of-sight microwave links and satellite communications. In order to predict the attenuation due to rain accurately rainfall intensity is required with 1-minute integration time. Rainfall is a meteorological phenomenon with complex structure due to its variability in space, duration and occurrence frequency, particularly in tropical and equatorial regions. Since, the statistical distribution of rain attenuation is obtained from the rain rate distribution for the region considered, it should be noted that the accuracy of the rain rate measurement affects the accuracy of the attenuation estimation. This paper presents rain intensity with 1-minute integration time measured for 6 years in Malaysia, it’s distribution, comparison with other prediction models and impact on high frequency microwave links.

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Analysis of rain fade slope for terrestrial links

Indonesian Journal of Electrical Engineering and Computer Science ◽

10.11591/ijeecs.v18.i2.pp896-902 ◽

2020 ◽

Vol 18 (2) ◽

pp. 896

Author(s):

Jalel Chebil ◽

Al-Hareth Zyoud ◽

Mohamed Hadi Habaebi ◽

Islam Md. Rafiqul ◽

Hassan Dao

Keyword(s):

Standard Deviation ◽

Prediction Model ◽

Rain Attenuation ◽

Measured Data ◽

Rate Of Change ◽

Tropical Regions

Rainfall can cause severe degradation to the operation of microwave links working with frequencies above 10 GHz. Many studies have investigated this problem, and one of the factors that attract the attention of researcher is rain fade slope which is the rate of change of rain attenuation. The focus of this study is on rain fade slope for terrestrial links and it is based on measurement conducted in Malaysia. This paper investigates the characteristics of the measured rain fade slope distribution for various attenuation levels. Then, the ITU-R model for rain fade slope is compared with the corresponding statistics obtained from the measured data. Significant discrepancies have been observed since the ITU-R prediction model does not fit the measured fade slope distribution for many attenuation levels. It is recommended to modify the expression of the standard deviation in the ITU-R model when implemented in tropical regions.

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Analysis of Time Diversity Gain for Satellite Communication Link based on Ku-Band Rain Attenuation Data Measured in Malaysia

International Journal of Electrical and Computer Engineering (IJECE) ◽

10.11591/ijece.v8i4.pp2608-2613 ◽

2018 ◽

Vol 8 (4) ◽

pp. 2608

Author(s):

Islam Md. Rafiqul ◽

Ali Kadhim Lwas ◽

Mohamed Hadi Habaebi ◽

Md Moktarul Alam ◽

Jalel Chebil ◽

...

Keyword(s):

Satellite Communication ◽

Satellite Communications ◽

Earth Satellite ◽

Rain Attenuation ◽

Diversity Gain ◽

Communication Link ◽

Time Diversity ◽

Communication Links ◽

System Time ◽

Diversity Technique

This paper reports a study on mitigation of propagation impairments on Earth–space communication links. The study uses time diversity as a technique for mitigating rain propagation impairment in order to rectify rain fade. Rain attenuation time series along earth-to-satellite link were measured for two years period at 12.255 GHz in Malaysia. The time diversity technique was applied on measured rain fade to investigate the level of possible improvement in system. Time diversity gain from measured one-minute rain attenuation for two years period was estimated and significant improvement was observed with different delays of time. These findings will be utilized as a useful tool for link designers to apply time diversity as a rain fade mitigation technique in Earth-satellite communications systems.

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Development of the Hypertension Index Model in General Adult Using the Korea National Health and Nutritional Examination Survey and the Korean Genome and Epidemiology Study (Preprint)

10.2196/preprints.31024 ◽

2021 ◽

Author(s):

Myung Jae Seo ◽

Sung Gyun Ahn ◽

Yong-Jae Lee ◽

Jong Koo Kim

Keyword(s):

Prediction Model ◽

National Health ◽

Prediction Models ◽

Classification Model ◽

Nutrition Examination Survey ◽

Epidemiology Study ◽

Index Model ◽

Health And Nutrition ◽

Specific Prediction ◽

And Control

BACKGROUND Hypertension, a risk factor for cardiovascular disease and all-cause mortality, has been increasing. Along with emphasizing awareness and control of hypertension, predicting the incidence of hypertension is important. Several studies have previously reported prediction models of hypertension. However, among the previous models for predicting hypertension, few models reflect various risk factors for hypertension. OBJECTIVE We constructed a sex-specific prediction model using Korean datasets, which included socioeconomic status, medical history, lifestyle-related variables, anthropometric status, and laboratory indices. METHODS We utilized the data from the Korea National Health and Nutrition Examination Survey from 2011 to 2015 to derive a hypertension prediction model. Participants aged 40 years or older. We constructed a sex-specific hypertension classification model using logistic regression and features obtained by literature review and statistical analysis. RESULTS We constructed a sex-specific hypertension classification model including approximately 20 variables. We estimated its performance using the Korea National Health and Nutrition Examination Survey dataset from 2016 to 2018 (AUC = 0.807 in men, AUC = 0.854 in women). The performance of our hypertension model was considered significant based on the cumulative incidence calculated from a longitudinal dataset, the Korean Genome and Epidemiology Study dataset. CONCLUSIONS We developed this hypertension prediction model using features that could be collected in a clinical office without difficulty. Individualized results may alert a person at high risk to modify unhealthy lifestyles.

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Rain Attenuation Prediction Model for Satellite Communications Based on The Météo-France Ensemble Prediction System PEARP

10.5194/nhess-2018-94-rc2 ◽

2018 ◽

Author(s):

Anonymous

Keyword(s):

Prediction Model ◽

Satellite Communications ◽

Rain Attenuation ◽

Ensemble Prediction ◽

Prediction System ◽

Ensemble Prediction System

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Investigation of time diversity gain for earth to satellite link using rain rate gain

Bulletin of Electrical Engineering and Informatics ◽

10.11591/eei.v8i3.1512 ◽

2019 ◽

Vol 8 (3) ◽

pp. 951-959

Author(s):

Md. Moktarul Alam ◽

Islam Md. Rafiqul ◽

Khairayu Badron ◽

Farah Dyana A. R. ◽

Hassaan Dao ◽

...

Keyword(s):

Communication Systems ◽

Rain Rate ◽

Satellite Communications ◽

Rain Attenuation ◽

Diversity Gain ◽

Potential Candidate ◽

Tropical Regions ◽

Frequency Bands ◽

Time Diversity ◽

One Year

The utilization of satellites for communication systems has expanded considerably in recent years. C and Ku-bands of frequencies are already congested because of high demand. Future directions of satellite communications are moving towards Ka and V-bands. Earth to satellite communications are moving towards higher frequency bands in future which are more sensitive to environment. Rain causes severe degradation in performances at higher frequency bands specially in tropical regions. Several mitigation techniques are proposed to design reliable system. Time diversity is one of the potential candidate for it. However, time diversity analysis requires measured rain attenuation data. For future high frequency link design those data are not available at most of the places. This thesis proposes a method to utilize 1-minute rain rate to analyze time diversity technique at any desired frequency. This paper proposes a method to utilize 1-minute rain rate to analyse time diversity rain rate gain. In proposed method, it is assumed that rain rate gain with delay can represent rain attenuation gain with delay for same period of time at same location. The characteristics of rain rate and rain attenuation almost same because the attenuation causes due to rain. One year measured rain rate in Malaysia is used to predict rain rate gain. The measured gain at 12.225 GHz signal is compared with that predicted by ITU-R based on rain rate measurement and is found good agreement. Hence it is recommended that the time diversity gain can be predicted using measured rain rate for any desired frequencies.

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Performance evaluation of some rain attenuation prediction models at coastal locations at 12 and 40 GHz

Global Journal of Earth and Environmental Science ◽

10.31248/gjees2021.095 ◽

2021 ◽

Vol 6 (2) ◽

pp. 27-37

Author(s):

Abayomi Isiaka O. Yussuff ◽

◽

Kabir Momoh ◽

Keyword(s):

Rain Rate ◽

Prediction Models ◽

Service Providers ◽

Service Level ◽

Rain Attenuation ◽

Rainfall Data ◽

Integration Time ◽

Tropical Regions ◽

Attenuation Models ◽

The Tropics

This work concerns the evaluation of the performances of some selected rain attenuation models at two different locations in Lagos, Nigeria at 12 and 40 GHz. Scarcity of rainfall data in the tropical regions resulted in abysmal research efforts into the causes and solutions to satellite signal outages, this was further exacerbated by the convective tropical rain precipitations. The globally adopted ITU-R model, had been declared unsuitable for predicting rain attenuation in the tropics by several researchers in the literature. Two-year (January 2016 to December 2017) local rainfall data were sourced from the Nigerian Meteorological Services (NIMET) for two coastal stations (Ikeja and Oshodi). Rain attenuation exceeded for rain rate at 0.01% of the time, was computed after the 1-hour rain rate integration time which was sourced from NIMET was converted to 1-minute integration time. Attenuation exceeded for other percentages of time were also obtained using statistical interpolation and extrapolation methods. The collected data were tested with ITU-R, SST, SAM, DAH and Silva Mello et al. For Ikeja at 12 GHz, the SST was observed to closely match the measurement attenuation at 0.01%≤p≤1% of time exceeded; closely followed by Silver Mello. For Oshodi also at 12 GHz, SST intersected with the measured attenuation at 0.01%≤p≤0.03%, and p=0.1% of time. However, at 40 GHz, all the prediction models performed poorly by underestimating the measurement for Ikeja, although SST showed the best effort. The SST model matched the measurement, especially at p=0.03% and p=0.5% for Oshodi at 40 GHz, closely followed by Silva Mello which matched the measurement at p=0.05% and p=0.1%, while ITU-R, SAM and DAH largely underestimated the measurement. The SST was therefore affirmed the overall best performed rain attenuation prediction model for both stations at both frequency bands; closely followed by the Silva Mello. ITU-R, SAM and DAH on the other hand performed poorly. The findings arising from this work could present useful information to satellite equipment designers and manufacturers, while at the same time ensuring that service providers conform to the required service level agreements

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