• Electronics and Telecommunications Trends
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• v.23 no.3
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• pp.130-137
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• 2008

최근 위성방송 기술은 고선명/고음질을 실현하고, 다양한 부가서비스를 제공하는 고품질의 디지털 전송방식으로 변화하고 있다. 이러한 위성방송의 수요확대에 다채널 데이터 전송 및 HD급 고품질의 영상을 전송할 수 있는 DVB-S2 시스템 개발에 한창이다. 본 논문에서는 DVB-S2 전송방식을 적용하기 위한 Ku-Ka 대역의 강우감쇠 등을 효과적으로 보상하여 보다 나은 위성방송 수신 가용도를 높이기 위한 방안에 대해 논한다.

• Journal of the Korean Institute of Telematics and Electronics
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• v.25 no.12
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• pp.1573-1581
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• 1988

In this paper, the analysis on the dual mode conical horn antennas is made to realize the optimum horn as the primary feed of the offset parabolic antenna for the domestic broadcasting satellite. Such analysis can give rise to the approximate equations and graphs on the beam width, which makes it possible to design the desired conical horn. It has been shown that the radiation charateristics of designed horn antenna built with the dielectric band inside the horn. The designed dual mode horn antenna may provide the useful basis to practical usage of the antenna in the domestic satellite broadcasting communication systems.

• Proceedings of the IEEK Conference
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• 2002.06a
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• pp.355-358
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• 2002

This paper describe the passive intermodulation products(PIMs) which are formed in high power Ku-band transponder and antenna subsystem on the Communication St Broadcasting Satellite(CBS)program when two transmit carriers beat together to generate harmonics that fall into the receive band. How the PIMs are initially generated and the effect of PIMs for Ku-Band payload system are analyzed by calculating the PIMs frequencies and the power level of PIMs.

• Satellite Communications and Space Industry
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• v.12 no.1 s.27
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• pp.122-128
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• 2004

• ETRI Journal
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• v.33 no.4
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• pp.487-496
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• 2011

Korea Multi-Purpose Satellite-5 (KOMPSAT-5) is the first satellite in Korea that provides 1 m resolution synthetic aperture radar (SAR) images. Precise orbit determination (POD) using a dual-frequency IGOR receiver data is performed to conduct high-resolution SAR images. We suggest orbit determination strategies based on a differential GPS technique. Double-differenced phase observations are sampled every 30 seconds. A dynamic model approach using an estimation of general empirical acceleration every 6 minutes through a batch least-squares estimator is applied. The orbit accuracy is validated using real data from GRACE and KOMPSAT-2 as well as simulated KOMPSAT-5 data. The POD results using GRACE satellite are adjusted through satellite laser ranging data and compared with publicly available reference orbit data. Operational orbit determination satisfies 5 m root sum square (RSS) in one sigma, and POD meets the orbit accuracy requirements of less than 20 cm and 0.003 cm/s RSS in position and velocity, respectively.

• Journal of Satellite, Information and Communications
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• v.9 no.2
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• pp.45-51
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• 2014

Luby transform (LT) codes are a class of ratelss codes, and they have capability of generating infinite length of parities with a given information length. These rateless codes can be effectively utilized to provide broadcasting and multicasting services where each user is in a different channel condition. For this reason, there have been a number of researches on the application of rateless codes for satellite systems. In this paper, by considering the current research status on rateless codes, we present VHLD implementation results of LT codes, for future hardware implementation for satellite systems. The results demonstrated in this paper can be utilized as a basic information on efficient utilization of rateless codes in the future satellite systems.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.6A
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• pp.499-509
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• 2005

The capacity of Satellite DMB(Digital Multimedia Broadcasting) system is limited mainly by the interference. So, to achieve the expected performance of Satellite DMB system and to minimize the interference from other Satellite DMB system, ACI(Adjacent Channel Interference) should be considered carefully. Satellite DMB system uses the Gap-filler for effective transmission in terrestrial environment, and the Gap-filler can use direct amplification or frequency conversion to satisfy the specific requirements. Therefore, amplified signal causes several effects on interference between System A(Eureka 147 DAB) and System E(ISDB : Integrated services Digital Broadcasting). In this paper, by using the outcome of system-level simulation considering the results of link-level simulation, we analyze the interferences between System A and System E under practical situation based on the exact parameters of ITU-R BO. 1130-4. We also propose the appropriate level of guard band and Cell Radius to optimize system capacity by adapting the spectrum mask given in the spec. and utilizing the interference analysis between System A and System E.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.3A
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• pp.258-264
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• 2009

In this paper, we propose an efficient cooperative diversity scheme for mobile satellite multimedia broadcasting services. The proposed scheme is a transmit diversity technique to adapt time varying channel conditions, and we do not need any channel quality information from the return link. In the proposed scheme, we utilize space-time block coding (STBC) and rate compatible turbo codes in order to realize the transmit diversity for the mobile satellite system with several repeaters. The satellite and several repeaters operate in unison to send the encoded signals, so that the receiver may realize diversity gain. The simulation results demonstrate that the proposed scheme can provide highly improved performance.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.59-62
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• 1998

Satellite communication systems will play an important role in establishing high-speed information communication network ddue to the characteristics of flexibility of bandwidth, mobile communication, wide coverage, multipoint and broadcasting. Also satellite systems have the capability to supply terrestrial B-ISDN with flexible links for accessing networks as well as trunking networks. Therefore, satellites must provide compatibility to earth-based B-ISDN signalling interface, services and network capability. This paper proposed interworking model between terrestrial B-ISDN and satellite B-ISDN signalling protocol and illustrated basic call-process procedure of satellite B-ISDN signalling protocol supporting point-to-point and point-to-multipoint connection.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.128-128
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• 2000

An antenna tracking technique, referred to as "step track", is commonly used in communication applications. In this paper, an algorithm to improve the step-tracking technique for satellite tracking is proposed. We suggest a method by which the antenna scans the azimuth, detects the satellite signal without the position information, and points quickly to the direction receiving the signal of peak level. After reaching the peak level, the step-track system maintains enough signal levels to receive satellite broadcasting normally. Performance of the Tracking Algorithm proposed in this paper are verified with simulation.