scholarly journals Modification of ITU-R Parameters to Improve the Prediction of Tropospheric Scintillation for Tropical Regions

2018 ◽  
Vol 7 (3.12) ◽  
pp. 1078 ◽  
Author(s):  
John Philip B ◽  
Sarat K Kotamraju ◽  
Ch Sri Kavya
Keyword(s):  
Prediction Model ◽  
Satellite Communication ◽  
Tropical Region ◽  
Communication Link ◽  
Efficient System ◽  
Tropical Regions ◽  
Signal Degradation ◽  
Tropospheric Scintillation ◽  
Beacon Signal ◽  
Rapid Fluctuation

Scintillation is the rapid fluctuation of the received signal. It is caused by the variation in the refractivity structure of the atmosphere profile. This phenomenon leads to the signal degradation and is significant in low fade margin links and at low elevation angles. So, analyzing the scintillation intensity and its statistics are vital for a system designer to design an efficient system for the satellite communication link. This paper presents the methodology to extract the scintillation intensity from the raw beacon signal and comparison of ITU-R scintillation prediction model with the measured results to test its acceptability over tropical region. When compared with measured results, ITU-R model overestimates the scintillation fade. Hence the parameters of the time percentage factor are modified to obtain near fit to the measured results.

Simulative Investigation on the Effect of Different Parameters on the Performance of IsOWC System

2017 ◽  
Vol 38 (3) ◽  
Author(s):  
Mehtab Singh
Keyword(s):  
Communication Systems ◽  
Satellite Communication ◽  
Communication Link ◽  
Optical Wireless ◽  
Antenna Aperture ◽  
Aperture Diameter ◽  
Pointing Errors ◽  
Signal Degradation ◽  
Communication Links ◽  
Radio Frequency Signals

AbstractInter-satellite communication links are very crucial between satellites orbiting around the earth in order to transmit information between them and also for the purpose of data relaying from one satellite station to other stations and ground stations. Inter-satellite optical wireless communication (IsOWC) links involve the application of optical wireless signals as compared to radio frequency signals used in traditional satellite communication systems. One of the major problems leading to the performance degradation of IsOWC link is the signal degradation due to satellite vibrations also known as pointing errors. In this paper, the performance of an IsOWC communication link has been investigated for different system parameters such as data transmission rates, antenna aperture diameter, transmission power levels, operating wavelength and responsivity of photodiode by analyzing

scholarly journals Propagation Measurement on Earth-Sky Signal Effects for High Speed Train Satellite Channel in Tropical Region at Ku-Band

2015 ◽  
Vol 2015 ◽  
pp. 1-10
Author(s):  
Abdulmajeed H. J. Al-Jumaily ◽  
A. Sali ◽  
J. S. Mandeep ◽  
Alyani Ismail
Keyword(s):  
High Speed ◽  
Satellite Communication ◽  
Tropical Region ◽  
Propagation Models ◽  
Tropical Regions ◽  
Mobile Satellite ◽  
And Performance ◽  
Propagation Measurement ◽  
The Tropics ◽  
Satellite Transmission

Recent advances in satellite communication technologies in the tropical regions have led to significant increase in the demand for services and applications that require high channel quality for mobile satellite terminals. Determination and quantification of these requirements are important to optimize service quality, particularly in the Malaysian region. Moreover, the tests on current satellite propagation models were carried out at temperate regions whose environmental characteristics are much different from those in Malaysia. This difference renders these propagation models inapplicable and irrelevant to tropical regions in general. This paper presents the link characteristics observations and performance analysis with propagation measurements done in tropical region to provide an accurate database regarding rain and power arches supply (PAs) attenuations in the tropics for mobile scenarios. Hence, an extension for improving the performance assessment and analysis of satellite/transmission has been achieved. The Malaysia propagation measurement for mobile scenario (Malaysia-PMMS) enables first-hand coarse estimation and attenuation analysis, because the attenuation resulting from rain and PAs becomes easily amenable for measurement. Parallel to that, the measured attenuation has been compared with that of the simulated output at noise floor level. The underlying analytical tool is validated by measurements specific at tropical region, for dynamic model of mobile satellite links operating at higher than 10 GHz.

scholarly journals Study of tropospheric scintillation effects in Ku-band frequency for satellite communication system

2020 ◽  
Vol 10 (3) ◽  
pp. 3136
Author(s):  
Nadirah Abdul Rahim ◽  
Hanis Nabilah A. Mulop ◽  
Khairayu Badron
Keyword(s):  
Electromagnetic Waves ◽  
Satellite Communication ◽  
Elevation Angle ◽  
Small Scale ◽  
Band Frequency ◽  
Clear Sky ◽  
Tropospheric Scintillation ◽  
Sky Conditions ◽  
Beacon Signal ◽  
Ku Band

Scintillation is a rapid fluctuation of an electromagnetic waves in terms of phase and amplitude due to a small-scale inconsistency in the transmission path (or paths) with time. Scintillation exists continuously throughout a day whether during raining or clear sky conditions. The raw signal data need to exclude other propagations factors that include signal fluctuations to further understand the scintillation studies. This paper presents the analysis of tropospheric scintillation data from January 2016 till December 2016 at Ku-band frequency of 12.202 GHz beacon signal. The experimental data from MEASAT 3B were collected and analyzed to see the effect of tropospheric scintillation. The elevation angle of the dish antenna is 77.45o. The highlighted objectives are to analyze the scintillation data at Ku-band, and to compare and validate the results with other scintillation models. The result shows that the stipulated scintillation analysis has higher amplitude, which is 0.73 dB compared to other scintillation analysis which has lower scintillation amplitude: 0.45 dB (Karasawa), 0.42 dB (ITU-R), 0.4 dB (Nadirah & Rafiqul), 0.42 dB (Van De Kamp) and 0.11 dB (Anthony & Mandeep).

scholarly journals Characterization of concurrent ku band tropospheric scintillation and rain attenuation in Malaysia

2019 ◽  
Vol 15 (2) ◽  
pp. 956
Author(s):  
Ibtihal Fawzi Elshami ◽  
Jafri Din ◽  
Lam Hong Yin ◽  
Ali I Elgayar
Keyword(s):  
Communication Systems ◽  
Satellite Communication ◽  
Power Spectral Analysis ◽  
Rain Attenuation ◽  
Significant Information ◽  
Tropical Regions ◽  
Significant Impairment ◽  
One Year ◽  
Tropospheric Scintillation ◽  
Ku Band

<span>Tropospheric scintillation in satellite communication systems operating at frequencies over 10 GHz is a significant impairment, especially in tropical regions, as attenuation affects scintillation dramatically. This work concentrates on tropospheric scintillation in equatorial Johor Bahru, Malaysia, based on a one-year Ku-band propagation measurement study utilising a direct broadcast receiver and an automatic weather station. This study aimed to investigate the relationship between wet scintillation and rain attenuation using experimental measurements. The power spectral analysis has been carried out to determine required cut-off frequency of filtering to separate out rain attenuation and scintillation effects. The results can provide significant information on the fluctuations of wet scintillation at Ku-band earth space link in tropical regions.</span>

A 2 × 20 Gbps hybrid MDM-OFDM–based high-altitude platform-to-satellite FSO transmission system

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Vel Murugan Gomathy ◽  
T. V. Paramasivam Sundararajan ◽  
C. Sengodan Boopathi ◽  
Pandiyan Venkatesh Kumar ◽  
Krishnamoorthy Vinoth Kumar ◽  
...  
Keyword(s):  
High Altitude ◽  
Orthogonal Frequency Division Multiplexing ◽  
High Speed ◽  
Satellite Communication ◽  
Input Power ◽  
Transmission System ◽  
Communication Link ◽  
Space Optics ◽  
High Altitude Platform ◽  
Mode Division Multiplexing

AbstractIn the present study, the application of free space optics (FSO) transmission system to realize a long-reach high-altitude platform (HAP)-to-satellite communication link has been exploited. High-speed information transmission without interference is accomplished using orthogonal frequency division multiplexing (OFDM). Further, the information capacity of the proposed system is increased by employing mode division multiplexing (MDM). We have investigated the proposed MDM-OFDM-HAP-to-satellite FSO transmission system performance over varying FSO range, diameter of the receiver, pointing errors, and input power. Also, an improved transmission performance of the proposed system using a square root module is reported.

scholarly journals Breeding Temperate Japonica Rice Varieties Adaptable to Tropical Regions: Progress and Prospects

Agronomy ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 2253
Author(s):  
Myrish Pacleb ◽  
O-Young Jeong ◽  
Jeom-Sig Lee ◽  
Thelma Padolina ◽  
Rustum Braceros ◽  
...  
Keyword(s):  
The Philippines ◽  
Tropical Region ◽  
Japonica Rice ◽  
Rice Varieties ◽  
Temperate Japonica ◽  
Tropical Regions ◽  
Tropical Environments ◽  
Increasing Demand ◽  
Northeast Asian ◽  
The Tropics

Temperate japonica rice is mainly cultivated in temperate regions. Many temperate japonica varieties have a superior grain quality that is preferred in Northeast Asian countries such as Japan, Korea, and China. The changes in consumers’ preferences in Southeast Asia and Western countries has contributed to increasing the demand for temperate japonica. Most temperate japonica varieties developed in temperate regions typically exhibit extra-early flowering under the short-day conditions in the tropics, which usually results in severely reduced yields. Since 1992, we have been developing temperate japonica varieties that can adapt to tropical environments to meet the increasing demand for temperate japonica rice, having released six varieties in the Philippines. Especially, the yield of one of the temperate japonica varieties, Japonica 7, was comparable to the yields of leading indica varieties in the Philippines. Here, we discuss the current breeding initiatives and future plans for the development of tropical-region-bred temperate japonica rice.

scholarly journals Analysis of rain fade slope for terrestrial links

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

<p><span>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.</span><span> The focus of this study is on rain fade slope for terrestrial links and it is </span><span>based on measurement conducted in Malaysia</span><span>.</span><span> This paper investigates the characteristics of the measured rain fade slope distribution </span><span>for various attenuation levels</span><span>. Then, </span><span>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.</span></p>

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

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

<p><span>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.</span></p>

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