• 한국정보통신설비학회:학술대회논문집
• /
• 2007.08a
• /
• pp.22-26
• /
• 2007

In the fibre to the home (FTTH) era, it is expected that broadband network provisioning will require thousands of optical fibres to be accommodated in a central office for optical access networks. An optical fibre line testing system could be used to reduce maintenance costs and improve service availability depending on the PON's element manager capabilities and the maintenance procedures adopted by the network supplier. When monitoring optical fibres transmitting communication lights, a wavelength of 1625 nm is used for maintenance testing. The splitter installed optical filters allow the communication light to pass but that cut off the test light in the front of optical line terminals (OLTs) and optical network terminals (ONTs). In the economic point of view, We design new planer lightwave circuit splitter embedded filtter and study it optical property.

• 한국정보통신설비학회:학술대회논문집
• /
• 2007.08a
• /
• pp.223-226
• /
• 2007

This paper first outlines the technology used in Power Line Communications(PLC) systems, and the political support being offered to the technology, from the point of view of its effect on electromagnetic compatibility (EMC). The radio spectrum needs protection from other interferers, and there is a regime in place to provide this interference avoidance/mitigation. Nevertheless, PLC has several features that mean that it is capable of creating such interference. These features are discussed, and some published field trial results are reviewed. Difficulties in achieving compatibility between the requirements for radio protection and the requirements for operation of the PLC system mean that there is no consensus as yet as to how PLC system components can be made compliant with EMC requirements. It is concluded that there is little prospect of an accommodation between the competing demands, so that if PLC is to become widespread it will be at the expense of the radio environment.

• IE interfaces
• /
• v.17 no.spc
• /
• pp.62-68
• /
• 2004

HAPS (High Altitude Platform Station) which is defined as a station located on an object at an altitude of 20 to 50 km and at a specified, nominal, fixed point relative to the earth is a promising technology capable of providing broadband multimedia services. In this study, economical aspects of HAPS service are analyzed by estimating the revenue and costs incurred by the service. To evaluate the profitability of HAPS service, the number of subscribers is estimated and then the net present value (NPV), payback period, and the rate of return on investment (ROI) are calculated under various scenarios.

• Journal of the Korean Professional Engineers Association
• /
• v.30 no.1
• /
• pp.125-136
• /
• 1997

The satellite communications system application to the Broadband ISDN(BISDN) is now being studied. Asynchronous transfer mode(ATM) is the target for BISDN and makes it possible to offer multimedia services on the simple network structure. This paper clarifies the required functions to the ATM interface between the terrestrial network and satellite TDMA system to compensate cell delay variation caused by satellite link, to improve the transmission efficiency, to do usage parameter control and to configure TDMA/ATM hardware interface.

• Journal of Korea Multimedia Society
• /
• v.14 no.3
• /
• pp.471-479
• /
• 2011

The world has witnessed a phenomenal growth in information and communication technologies (ICT). The development of new broadband communication services convergence of telecommunication with computers and recent developments in the field of communication protocol have fostered challenges as well as offerings in the wide-ranging use of ICT to support the creation of dynamic and interactive teaching and learning environment. By emergence of ICT, most of education and training institutions are struggling to integrate ICT and education and training systems. It is so important to apply proper delivery systems for utilization of the computerized teaching and learning contents in the classrooms. It will be a preliminary activity for building open and flexible distance teaching and learning systems in developing countries. In this paper, we would like to suggest and recommend the proper delivery systems for utilization of the computerized teaching and learning contents in the classrooms for education sector reform in developing countries.

• 제어로봇시스템학회:학술대회논문집
• /
• 2005.06a
• /
• pp.1563-1567
• /
• 2005

The Home network system means that information appliances, Home PCs, etc., using wired or wireless network method enable to control and share with peripheral devices such as internet, shared data, a scanner and a printer, and it is networking solution, which intelligent communication will be possible as the system which can do a remote control such as TV Set, refrigerators, air conditioners, DVD players, digital camcorders based on external network using an internet, a potable information terminal and a mobile phone whenever, wherever and freely. In this study, the home network interface solution is used one of the wired network standards, PLC (Power-Line Communication) technology, so we can construct of intelligent home network's home controller without re-build a network at home. On keeping with current waves of thought, we will focus on a home controller development with great interest which is enabled to do an effective managed control, applying intelligent home network technology which can be new paradigm like a cyber apartment.

• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.33A no.10
• /
• pp.48-60
• /
• 1996

This paper focuses on the necessities of interworking and dervation of the requirements of interworking system for interworking between 64 Kbps based N-ISDN (narrowband ISDN) and B-ISDN(broadband ISDN). Furthermore, the design and the implementation of IWF (interworking function) are presentd. We analyze two ISDN signalling systems, and propose the architecture of interworking system. And then we make the baisc call procedure model between N-ISDN and B-ISDN, and verify the dynamic behaviors through the reachability tree of petri net. IWF is designed and implemented for transforming the differences between the two signalling systems. The operational confirmity of th eimplemented program was confirmed by the local test method. The performance of IWF was evaluated throguh the simulation language SLAM-II. As the result of evaluation shows, we confirm that the processing delay is maintained within 3 ms under the utilization 0.9.

• Journal of Communications and Networks
• /
• v.12 no.6
• /
• pp.533-543
• /
• 2010

This paper proposes an orthogonal frequency division multiplexing (OFDM) waveform for the forward link of a fixed broadband satellite system. We focus on the synchronization tasks in the receiver. Our objective is to minimize the required overhead, in order to improve the spectral efficiency with regard to a single carrier waveform system. A non pilot aided algorithm is used for fine synchronization. It is preceded by a coarse synchronization stage, which relies on a limited overhead (short cyclic prefix associated to some pilots). The performance of the proposed receiver is assessed through simulation results.

• Proceedings of the IEEK Conference
• /
• 2008.06a
• /
• pp.259-260
• /
• 2008

This paper presents fractional frequency reuse (FFR) with sub-channel borrowing to improve spectral efficiency of the wireless broadband (WiBro) system. FFR has constraints on usable sub-channels to balance the interference and cell capacity. Our FFR with sub-channel borrowing allows use of the dedicated sub-channels assigned to neighboring cells. Simulation results show that the proposed FFR with sub-channel borrowing improves the performance of the WiBro system.

• Proceedings of the IEEK Conference
• /
• 2008.06a
• /
• pp.1113-1114
• /
• 2008

WiBro(Wireless Broadband) is the standard of high-speed portable internet based on OFDMA/TDD (orthogonal frequency division multiple access / time division duplexing) techniques, and the subset of consolidated version of IEEE802.16e Wireless MAN standard. In this paper, we propose the design method of WiBro system. Proposed method used KSFM neural network blind equalization with Bussgang algorithms.