• Bulletin of the Korean Space Science Society
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• 2004.10b
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• pp.351-355
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• 2004

A multibeam switching satellite system technology have started localized development to overcome the limitation of the frequency resource and geostationary orbit existing relay type satellite transponder and the required performance of the spot beam, and looked around the configuration and functions of the multibeam switching satellite communication system. This paper proposed that operation scheme and network control features for service definition, network architecture, transmission method of the natural disaster service network and public communication service network using this system.

• Journal of the Korea Society of Computer and Information
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• v.17 no.3
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• pp.85-93
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• 2012

In this paper, I designed the satellite system, using the MF-TDMA (Multi Frequency-Time Division Multiple Access) DAMA (Demand-Assigned Multiple Access) method, that allocates the satellite resources more effectively to prevent a large quantity data discard when Earth Terminals (ETs) request their satellite network resource to Network Controller (NC) by using their history information, such as traffic pattern or traffic class which have been receiving, and the network controller allocates the satellite network resource and send to earth terminals by using his history information that earth terminals have been requested already. The U.S. Military Warfighter Information Network-Tactical (WIN-T) community has selected the L-3 Linkabit MF-TDMA DAMA Network Centric Waveform (NCW) as the networking standard for full-mesh IP over SHF satellite communications. In the MF-TDMA DAMA satellite network, network controller allocates the satellite network resources and enables maximum 255 earth terminals to communicate each other for periodic satellite network resource requests of earth terminals.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.5A
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• pp.441-450
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• 2007

In this paper, it is proposed the link performance analysis results using SNRAT(Satellite Network Resource Allocation & Analysis Tool) and verified the anticipated results by satellite communication network simulator. A communication satellite cannot be corrected or fixed for the error in orbit operation after launching unlike the ground operation equipment and has a restricted operation life. So, it is important to make possible to use satellite communications in the proper time. It is expected the link BER(Bit Error Rate), throughput and AJ(Anti-Jamming) performance using SNRAT tool before launching. And it is verified the performance of the repeaters and ground equipment specification using the satellite network simulator and is extracted the optimum operational scenarios through the tests of various network operational plans.

• Current Industrial and Technological Trends in Aerospace
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• v.7 no.1
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• pp.23-31
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• 2009

Insufficient problem about resource of satellite network frequency and orbit was seriously issued, because commercialization of a satellite has been successfully achieved since 1980s. Therefore, each countries execute an advantageous policy to them for guarantying and protecting satellite network resource and perform study for preoccupying new satellite network resource. Understanding and insight of policy about occupying satellite network resource of world each countries are landmark of satellite network task. In this paper, policies of Japan, Russia and China located around Korea are especially described. Also, in this paper, the administration organization of Japan, Russia and China which are to manage satellite network is described. The KARI(Korea Aerospace Research Institute) secured satellite network frequency and orbit of the KOMPSAT(KOrea Multi Purpose SATellite)-1 and the KOMPSAT-2 and is also going to register satellite network of the KOMPSAT-3 and the KOMPSAT-5. When satellite network coordination with nearby three countries will be needed, understanding of political policy and organization let the Korea acquire coordination agreement of the other administration.

• Journal of the Korea Institute of Military Science and Technology
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• v.19 no.5
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• pp.645-653
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• 2016

The terrestrial wireless backbone network and satellite communications system have been independently developed depending on their own purposes and operational concepts, which results in different characteristics in terms of network architecture and routing protocol operation. In this paper, we propose a method for structurally integrating them in consideration of routing mechanism in an autonomous system. Our approach is that the routers of satellite network operate the OSPF in PTP mode on their interfaces connected to the routers of terrestrial wireless backbone network with grid connectivity, whereas the OSPF in satellite network whose topology is of hub-spoke type runs in NBMA mode. We perform some simulations to verify that the satellite communications system can be integrated and interwork with the terrestrial wireless backbone network by our proposed approach. From simulation results, it is also found that the increases of network convergence time and routing overhead are acceptable.

• Journal of Satellite, Information and Communications
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• v.2 no.2
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• pp.85-91
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• 2007

The satellite networks provide global coverage. The integration of terrestrial networks with a satellite network is the most attractive approach to develop a global communication system. The IP Multimedia Subsystem (IMS) is intended to be the system that will merge the internet with the telecom world. A user with a dual-mode terminal can access both the satellite network and terrestrial network. The seamless handoff between two networks and a user's QoS level is the major issue concerning this integration. In this paper, we propose IMS-based satellite/terrestrial integrated network architecture for a global communication system. Based on the proposed architecture, an inter-network handoff and end-to-end soft QoS procedure is discussed. Our proposed soft QoS scheme is also analyzed to calculate the number of rejected calls.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.10
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• pp.2687-2702
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• 1996

It is desirable that the implementation of next generation information infrastructure is the Integrated Network combining the satellite and the terrestrial network. The application of the ATM network being the dominant infrastrure of terrestrial network to the satellite network is being studied variously. Considering these concepts, this paper analyzes due to ATM transport via satellite, evaluates the degradation of QoS and proposes reliable method of ATM cell transport via satellite. Because ATM is investigated with the optical fiber which is almost error free characteristics, the practical application of ATM transport via satellite essentially need the channel coding(FEC:Forward Error Correction) to enhance BER performance. But using the FEC coding, satellite link has burst error characteristics which evoke severe performance degradation fo ATM QoS. Therefore in satellite link, we analyze burst error characteristics using experimental results of computer simulation. Then to compensate these characteristics, based on this analysis and HEC dual mode algorithm we propose various interleaver structures(Block interleaver, Intra interlever, and Inter-Intra interleaver) to improve cell transmission QoS. We execute performance evaluations of iterleaver structures by computer simulation.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1996.06b
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• pp.1-6
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• 1996

To promote academic researches on earth environment utilizing satellite data, research infrastructure such as satellite data reception processing, distribution and archival systems should be fully provided. The means to enhance the infrastructure were discussed by a working group and“Satellite Data Center via Network”has been proposed. This concept has three principles; (1) To realize necessary functions by organizing experts distributed all over Japan and connecting them by network, (2) To realize“Satellite Data Center via Network”for GMS and NOAA Satellites, which are widely used for research, and (3) Satellite data set oriented to specific research area should be generated by researchers having definite research purposes of sensor algorithms and hugh volume data processing. Utilization of the Science Information Network (SINET) has been discussed to realize this concept, and to accelerate this project an experiment“Network Utilization for Wide Area Use of Satellite Image Data”under“Cooperative Experiment on Multimedia Communication”has been introduced. And the roles of the Institute of Industrial Science, University of Tokyo to contribute this project has been described.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.505-510
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• 2006

SVLBI (Space Very Long Baseline Interferometry) has some important potential applications in geodesy and geodynamics, for which one of the most difficult tasks is to precisely determine the orbit of SVLBI satellite. This paper studies several technologies which possibly will be able to determine the orbit of space VLBI satellite. And then, according to the sorts and characteristicsof satellite and the requirements for geodetic study and the geometry of GNSS (GPS, GALILEO) satellite to track the space VLBI satellite, the six Keplerian elements of SVLBI satellite (TEST-SVLBI) are determined. A program is designed to analyze the coverage area of the space of different heights by the stations of the network, with which the tracking network of TEST-SVLBI is designed. The efficiency of tracking TEST-SVLBI by the network is studied, and the results are presented.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.3
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• pp.1260-1283
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• 2019

Low earth orbit (LEO) satellite broadband network is a crucial part of the space information network. LEO satellite constellation design is a top-level design, which plays a decisive role in the overall performance of the LEO satellite network. However, the existing works on constellation design mainly focus on the coverage criterion and rarely take network performance into the design process. In this article, we develop a unified framework for constellation optimization design in LEO satellite broadband networks. Several design criteria including network performance and coverage capability are combined into the design process. Firstly, the quality of service (QoS) metrics is presented to evaluate the performance of the LEO satellite broadband network. Also, we propose a network stability model for the rapid change of the satellite network topology. Besides, a mathematical model of constellation optimization design is formulated by considering the network cost-efficiency and stability. Then, an optimization algorithm based on non-dominated sorting genetic algorithm-II (NSGA-II) is provided for the problem of constellation design. Finally, the proposed method is further evaluated through numerical simulations. Simulation results validate the proposed method and show that it is an efficient and effective approach for solving the problem of constellation design in LEO satellite broadband networks.