• Annual Conference of KIPS
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• 2004.05a
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• pp.707-710
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• 2004

In the case of terrestrial DMB(Digital Multimedia Broadcasting) system that offers mobile multimedia broadcasting services, transmission error must be considered. Although DMB transmission system provides the error protection functions of convolution coding and Reed-Solomon (204,188,t=8) coding, additional error resilience video coding methods are needed to satisfy the requirement of BER lower than $10^{-8}$. In this thesis, we propose and evaluate effective error resilience coding schemes using the MPEG-4 redundant slice for MPEG-4 video services in the DMB environment. In this scheme, we analyze the drift error caused by transmission error based on the random noise concept and the redundant slice selection algorithm that selects the most influential slice in the view of the drift error increment.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.6
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• pp.17-22
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• 2010

In this paper, integral TS(Transport Stream) demultiplexer of a multi-modal receiver is proposed according to the multiple standards of European terrestrial digital broadcasting DVB-T(Digital Video Broadcasting Terrestrial), and mobile terrestrial digital broadcasting T-DMB(Terrestrial Digital Multimedia Broadcasting). This USB based integral receiver could recover the multi-modal broadcasting audios by memory sharing technique which was utilized to decrease the load by the control of streaming multi-modal broadcasting. As a result of performance analysis for a proposed integral TS demultiplexer, the CPU occupational efficiency of windows based integral demulitiplexing is improved compared with DVB-T, and T-DMB respectively.

• Journal of Korea Society of Industrial Information Systems
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• v.12 no.1
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• pp.54-60
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• 2007

The Digital Multimedia Broadcasting(DMB) system is developed to offer high quality multimedia content to the mobile environment. The system adopts the MPEG-4 standard for the main video, audio and other media format. For providing interactive contents, it also adopts the MPEG-4 scene description that refers to the spatio-temporal specifications and behaviors of individual objects. With more interactive contents, the scene description also needs higher bitrate. However, the bandwidth for allocating meta data, such as scene description is restrictive in the mobile environment. On one hand, the DMB terminal renders each media stream according to the scene description. Thus the binary format for scene(BIFS) stream corresponding to the scene description should be decoded and parsed in advance when presenting media data. With this reasoning, the transmission delay of the BIFS stream would cause the delay in transmitting whole audio-visual scene presentations, although the audio or video streams are encoded in very low bitrate. This paper presents the effective optimization technique in adapting the BIFS stream into the expected bitrate without any waste in bandwidth and avoiding transmission delays inthe initial scene description for interactive DMB content.

• Proceedings of the Korean Information Science Society Conference
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• 2007.06c
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• pp.223-228
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• 2007

근래 주목받는 키워드인 유비쿼터스(Ubiquitous), UCC(User Created Contents) 등은 기술적 발달과 함께한 사람들의 행동 양식 변화를 잘 반영하고 있다. 기술적인 측면에서 모바일 환경으로의 진화는 사람들에게 시공간적 제약을 없애주었으며, '호모 루덴스'로 표현된 유희적 인간의 개념은 현대인의 행동 양식을 잘 표현했다. 이중 지상파 이동 멀티미디어 방송(Digital Multimedia Broadcasting, DMB)은 방송에 있어서 시공간적 제약을 없앤 대표적인 사례이며, 'EDUTAINMENT(에듀테인먼트)'는 교육에 유희를 결합한 실례라고 하겠다. 특히 DMB는 정보와 유희의 욕구를 기본적으로 충족시킬 수 있는 방송이라는 매체를 이용한다는 점에서 에듀테인먼트의 기술적 기반이 될 수 있으며, 이를 통해 저 연령의 학습자에게 유희와 교육을 동시에 제공함으로써, 학습효과를 높일 수 있는 장점이 있다. 본 논문에서는 DMB 시스템을 위한 유아 대상의 에듀테인먼트 어플리케이션을 설계하고, 구현한다. 이 어플리케이션을 위해 스토리텔링, 음악과 악기 선택 시스템, 타임라인 및 자유표면 게임 시스템 등 DMB 시스템에 적절하며, 에듀테인먼트의 조건을 충족하는 몇 가지 방법론을 제안하여 방송을 통해 콘텐츠와 대상자가 서로 상호작용 할 수 있도록 한다. 이를 위해서는 기존 방송의 음성, 영상 서비스를 넘어 상호작용의 필수적인 요소라고 할 수 있는 데이터 서비스를 요구하며, 이는 MPEG-4 Part 11: BIFS(Binary Format for Scenes) 기술을 기반으로 그 구현에는 VRML에 기초한 BT(BIFS Text) 언어를 사용한다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.11a
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• pp.7-10
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• 2009

지상파디지털멀티미디어방송(Terrestrial-Digital Multimedia Broadcasting: T-DMB) 시스템 수신기는 이동 환경에서 방송신호의 원활한 수신을 요구한다. 따라서, 일정 레벨 이상의 전계강도와 단일 주파수 망(Single Frequency Network: SFN) 구축을 반드시 요구하게 된다. 본 논문에서는 단일 주파수 망을 통해 T-DMB 신호를 서비스하기 위해 설치하고 있는 등화형 T-DMB 동일채널 중계기(Equalization-Digital Multimedia Broadcasting On-Channel Repeater, E-DMBR)의 성능 및 신호 품질을 측정하기 위한 T-DMB RF 신호 모니터링 장비(T-DMB Monitoring System : DMR)에 대한 요구사항을 고찰하고, 그러한 요구사항을 만족하기 위한 모니터링 장비의 구조 및 구현 방법을 제안하며, 이를 이용한 개발 사례에 대한 결과를 보인다.

• Journal of Satellite, Information and Communications
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• v.1 no.2
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• pp.83-88
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• 2006

Future communication systems are to be designed to support and serve multimedia and multipledata transmission. Nowadays, requirement of mobile subscribers for the various information such as movie, GPS(Global Positioning System) information, news-is increasing significantly. However, due to practical reasons, the capacity and number of capable channels are limited. To solve this problem, a large number of methods and schemes have been proposed and are under research. In this paper, we demonstrate how satellite DMB (Digital Multimedia Broadcasting) system works with hierarchical modulation scheme. By using hierarchical modulation, we can analyze the capacity. Meanwhile, system performance os evaluated and compared to conventional DMB system without using hierarchical modulation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.5A
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• pp.537-545
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• 2006

As the T-DMB service is launched, some service requirements become necessary to send local programs such as advertisement and specific programs at the local broadcasting station while re-transmitting the broadcasting signal coming from the central or other station. In this paper, we propose a signalflow required for the effective splicing in the T-DMB system which usesboth MPEG-2 and MPEG-4 system specifications, and we illustrate the reconfiguring process into the ensemble stream that is widely used for the transmission of the T-DMB signal. Moreover, its performance is confirmed by comparing the images decoded at the recevier when the transport stream is swiched by using the splicer implemented through the proposed techniques.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.6
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• pp.9-14
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• 2009

In this paper, we proposed spreading code slicing technique for efficient transmitter detection in AT-DMB system with single frequency network. At the transmitter, the spreading code for transmitter identification inserted using slicing technique on forehead of null symbol and then transmitted. In this point, it requires high correlation characteristic spreading code. At the receiver, peak to peak value calculated by correlation process before signal demodulation. The transmitter information by proposed technique is employed to implement the single frequency network (SFN) which is proposed for solving a frequency inefficiency problem of the MFN. The results of the paper can be applied to wireless multimedia digital broadcasting system.

• Journal of the Korea Society of Computer and Information
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• v.10 no.2 s.34
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• pp.169-177
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• 2005

The Conditional Access System is a complete system for ensuring that broadcasting services be accessible to only those who are entitled to receive them. Secure key management and efficient delivery mechanism are very important design factors to this system. In this paper, we propose secure and efficient protocols which would be well fitted to a Pay TV system including the satellite DMB. Further. by applying our protocol to the existing conditional access system, we propose a new system that properly enables the control of conditional access to the Pay TV in satellite DMB environment.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.5
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• pp.501-505
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• 2008

In this paper, we present a multi-turn circular loop antenna for portable terrestrial DMB. In order to satisfy the two contradictory requirements of small antenna size and high receiving capability, the proposed antenna's diameter and turns are fixed to be 4 mm and 80 turns, respectively and its quality factor $\mathcal{Q}$ is set 1 in order to have high transfer function. The fabricated antenna length is 30 mm as small and its measured gain is -15 dBd. The antenna receiving power is verified by measurement very comparable with the receiving power of a commercial terrestrial DMB monopole antenna of length 190 mm.