• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 한국방송공학회 2011년도 추계학술대회
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• pp.66-69
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• 2011

초고속 통신망의 발전으로 인터넷을 통한 고화질 비디오 서비스가 가능하게 되었으며 이에 따라 스마트TV, IPTV 서비스와 같은 방통융합서비스가 대중화 되고 있다. 그리고 이러한 추세에 맞추어 방송 이외의 매체를 통한 비디오 콘텐츠 소비가 증가하고 있고, IT사업자들과 가전사들이 방송 플랫폼 사업에 진출하는 등 전통적인 방송 산업 구조에도 변화가 일어나고 있다. 이와 같은 환경 변화에 대응하기 위해 KBS 기술연구소는 지상파 방송 기반의 하이브리드 TV 서비스를 연구하고 있고, 이를 OHTV(Open Hybrid TV)라는 이름으로 국내의 다른 방송사들 및 가전사 등과 함께 표준화하고 있다. 안정적이고 효율적으로 대용량 비디오를 전송할 수 있는 방송망과 양방향 특성을 가진 통신망을 같이 활용하는 하이브리드 TV 환경에서는 양방향 방송 서비스를 보다 효율적으로 제공하는 것이 가능할 것으로 기대된다. 이를 통해 TV 시청자에게는 개인화된 형태의 새로운 방송 서비스를 제공하고, 방송사에게는 전통적인 사업모델을 탈피하여 새로운 비즈니스 모델을 찾을 수 있는 기회를 줄 수 있다. 이미 유사한 개념의 서비스들이 국내외에서 다양하게 시도되고 있으며 본 논문에서는 OHTV 서비스 시나리오 및 요소기술과 이를 구현한 시스템을 소개한다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• 제11권1호
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• pp.93-102
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• 2011

In this paper we describe an efficient and easy to use network monitoring system which can identify network configuration automatically by means of capturing and analyzing the ARP broadcasting packets. After identifying network nodes, it gathers detail information of each node such as NETBIOS name and number of hop counts using ICMP and then shows subnet configuration with graphical method. This monitoring system also has a subset of intrusion detection system that can monitor any port scanning trial. With this automatic network configuration functions, it helps to lessen address keeping track overhead which is crucial for network monitoring so that it provides efficient network management.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 한국해양정보통신학회 2010년도 춘계학술대회
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• pp.531-534
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• 2010

Currently the functionality of the PRC-999K radio that is widely used in Korean Army is half-duplex and the broadcasting system that all subscribers have to listen when one subscriber speaks in time. Radio data communication system configures peer-to-peer network between command post and network members in military fire control system. And the system applies CSMA/CA(Carrier Sense Multiple Access/Collision Avoidance) technique to avoid data collision. Such a data transmitting/receiving time could be reduced by allocating address in serial order to each network members. By doing that, command post need to broadcast data only one time and assigned members will reply in order without data collision. This paper provides such a protocol and algorithm.

• ETRI Journal
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• 제44권5호
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• pp.715-732
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• 2022

Despite the successful launch of Advanced Television Systems Committee (ATSC) 3.0 broadcasting worldwide, broadcasters are facing obstacles in constructing void-less large-scale single-frequency networks (SFNs). The bottleneck is the absence of decent on-channel repeater (OCR) solutions necessary for SFNs. In the real world, OCRs suffer from the maleficent feedback interference (FI) problem, which overwhelms the desired input signal. Moreover, the undesired multipaths between studio-linked transmitters and the OCR deteriorate the forward signals' quality as well. These problems crucially restrict the feasibility of conventional OCR systems, arousing the strong need for cost-worthy advanced OCR solutions. This paper presents an ATSC 3.0-specific solution of advanced OCR that solves the FI problem and refines the input signal. To this end, the FI canceler and channel equalizer functionalities are carefully implemented into the OCR system. The presented OCR system is designed to be fully compliant with the ATSC 3.0 specifications and performs a fast and efficient signal processing by exploiting the specific frame structure. The real product of ATSC 3.0 OCR is fabricated as well, and its feasibility is verified via field and laboratory experiments. The implemented solution is installed at a commercial on-air site and shown to provide substantial coverage gain in practice.

• The Journal of Korean Institute of Communications and Information Sciences
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• 제31권7B호
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• pp.668-678
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• 2006

In designing a video-on-demand (VoD) system, one of the major challenges is how to reduce the viewer's waiting time maintaining a given bandwidth allocation and how to reduce the client's buffer requirements. To solve these problems, many VoD schemes were proposed. However, most VoD schemes require managing many segments of a video, frequency channel hopping, and using many channels at the same time. Therefore, to the complexity is a barrier to implementation. In this paper, we propose a fast staggered broadcasting scheme which has a simple structure and substantially improved VoD efficiency. The numerical results demonstrate that the viewer's waiting time of the fast staggered broadcasting scheme is close to the fast broadcasting scheme and the buffer requirements of this can be adapt for demanding rate by adjusting the short front part of a video sizes.

• Journal of Broadcast Engineering
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• 제17권6호
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• pp.1080-1090
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• 2012

This study investigates the users' preference of frequency reallocation and frequency auction after digital transition of terrestrial broadcasting and it focuses on the relationships between media using pattern, reception environment of broadcasting telecommunication, and expectation for the universal service and requirement for the public interest. The results show that the longer DMB viewing hours, people prefer to frequency allocation for the telecommunication side. The technical aspects such as perception on the reception environment of broadcasting don't make effect on the users' preference of frequency allocation. In addition, the more people think the universal service of terrestrial broadcasting important, the more people think it unnecessary to adopt auction system to the broadcasting frequency. These results give implication that it is the most basic condition to improve the reception environment in order to accomplish universal service duty of terrestrial broadcasting.

• Journal of Broadcast Engineering
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• 제10권2호
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• pp.221-237
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• 2005

This paper presents and analyzes field test results of Equalization Digital On-Channel Repeater (EDOCR) using ATSC(Advanced Television Systems Committee) terrestrial digital TV broadcasting system. In the field test, according to EDOCR On/Off, types of antennas and receivers we measured reception possibility, C/N(Carrier to Noise Ratio), reception power, noise and input margin at each test point. By the field test results, the reception rate of the receiver manufactured in 2004 was $33\%$ when EDOCR is off and directional antenna is used. However, the reception rate was $100\%$ when EDOCR is on. In addition, the noise margin, which determines reception quality was increased at least 6 dB, so that it is capable of constructing SFN(Single Frequency Network) using the EDOCR.

• Proceedings of the IEEK Conference
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• 대한전자공학회 2002년도 ITC-CSCC -1
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• pp.527-530
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• 2002

The frequencies for HAPS used in fixed wireless access are allocated in the millimeter wave bands. The systems using these frequencies can have a serious impact on the radio communication qualities due to rain. In this paper, we compare the specific rain attenuation using CM(combined) raindrop size distribution with those using different sevral raindrop size distributions for the frequency bands 28/48㎓. The rain attenuations using CM raindrop size distribution for the path between the earth and HAPS platform according to the elevation angle are described.

• Journal of Broadcast Engineering
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• 제5권2호
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• pp.220-226
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• 2000

A novel audio watermark algorithm, the Modified Patchwork Algorithm, is applied to the speech to show that it is effective for digital broadcasting systems. Digital broadcasting system does not separate speech from audio data. However. speech data is very important especially for educational broadcasting. Speech can carry more information than video data. Thus, intellectual property management and protection for speech data is urgent. This paper addresses the technical issues, speech watermark algorithm, and its robustness against malicious attacks.

• ETRI Journal
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• 제30권6호
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• pp.774-782
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• 2008

An operational orbit determination (OD) and prediction system for the geostationary Communication, Ocean, and Meteorological Satellite (COMS) mission requires accurate satellite positioning knowledge to accomplish image navigation registration on the ground. Ranging and tracking data from a single ground station is used for COMS OD in normal operation. However, the orbital longitude of the COMS is so close to that of satellite tracking sites that geometric singularity affects observability. A method to solve the azimuth bias of a single station in singularity is to periodically apply an estimated azimuth bias using the ranging and tracking data of two stations. Velocity increments of a wheel off-loading maneuver which is performed twice a day are fixed by planned values without considering maneuver efficiency during OD. Using only single-station data with the correction of the azimuth bias, OD can achieve three-sigma position accuracy on the order of 1.5 km root-sum-square.