• Proceedings of the KIEE Conference
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• 2006.04a
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• pp.72-74
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• 2006

본 논문에서는 현재 무료로 본 방송이 진행 중인 T-DMB 제한 수신을 위한 시스템 분석에 대해 기술하였다. T-DMB 방송사업자들은 별도의 수신료를 징수하지 않고 광고 수입에 의존하게 되는데, 막대한 제작 비용이 소모되는 데이터 서비스를 위한 콘텐츠들을 무료로 서비스하게 된다면 수익 구조상 데이터 서비스에 매우 소극적이 될 것이다. 이런 이유로 일부 데이터 서비스들에 대한 유료화 필요성이 대두되면서 제한 수신 시스템의 도입이 추진되고 있다. 현재 제한 수신 시스템을 T-DMB에 적용하기 위한 방법으로 서브 채널 제한 수신, 데이터 그룹 제한 수신, MOT 제한 수신 등의 세 가지 모드가 있다. 분석 결과, T-DMB에 제한 수신 시스템을 적용할 시에, 많은 가입자 수에 따른 대역폭 부족의 문제, AV와 함께 전송되는 BIFS만 따로 스크램블링 할 수 없다는 문제, 복수의 제한 수신 사업자들의 헤드 엔드 장비간 공통 인터페이스 작성, 다양한 수신 단말기들이 공통 인터페이스 작성 둥의 문제점들에 대해서 기술하였다.

• Journal of Satellite, Information and Communications
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• v.9 no.1
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• pp.28-32
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• 2014

In this paper, we analyzed performance of signal detection for terrestrial digital multimedia broadcasting (T-DMB) system in various channel environments that applied gaussian, Rayleigh and COST 207 environments that estimate response of real channel state. In order to detect the signal, a signal detection scheme based on energy detection is employed. We generated T-DMB signals so that estimate properly simulation result. For evaluating the signal detection performance, detection probability is derived. We consider two kinds of detection segment, which are three segments and five segments. And we compare the system performances in accordance with the detection segment. From simulation results, it is confirmed that the performance of signal detection is raised as increase the number of segments. The result of this paper can be applied to implement signal detection of broadcasting system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.11B
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• pp.1618-1623
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• 2010

In this paper, we propose a new assisted global positioning system (A-GPS) using terrestrial digital multimedia broadcasting (T-DMB) data services. Because of the weak signal strength from GPS satellite and the signal blockage, it is difficult for the telematics terminal to determine the position in urban area. Proposed A-GPS system calculates pseudo range (PR) from timing information of GPS satellites and obtains the satellite information such as ephemeris from T-DMB station to determine the current position. Compared to conventional GPS system, the proposed system has better performance in terms of the fast time to first fix (TTFF), low horizontal dilution of precision (HDOP). Experimental results show that the proposed system is a feasible and robust solution.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.748-751
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• 2005

This paper introduces the testbed configuration for telematics wireless communications using terrestrial digital multimedia broadcasting (T-DMB) network. The testbed for telematics wireless communications is consisted of indoor laboratory testbed and outdoor field testbed. As a result of research, are derived testbed configurations for individual function verification at the indoor laboratory and performance test at the outdoor test road. In addition, a return channel configuration is described for interactive protocol as necessary for telematics services using T-DMB.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.9 no.1
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• pp.42-48
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• 2010

In this paper, we proposed analysis performance improvement technique for T-DMB watermarking based on MBOK spread spectrum. By applying the proposed scheme to T-DMB system, it allows additional data transmission and improves spectral efficiency of data transmission through watermarking spreading code. Using MBOK spread spectrum technique, data rate improved 2m-times existing direct sequence spread spectrum. However, since hardware complexity increase as the value of m becomes large, the method should be used with optimal situation. We analyze T-DMB watermarking techniques performance with MBOK spread spectrum and averaging. As a result, we confirm DER performance of MBOK spread spectrum scheme and it is shown system performance is improved as the number of averaging increases. The results of the paper can be applied to wireless multimedia digital broadcasting system.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.46 no.2
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• pp.52-57
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• 2009

Recently, the regular service of a terrestrial digital multimedia broadcasting(T-DMB) made faster distribution of T-DMB receiver. The problem of an illegal distribution is increasing owing to a large distribution of T-DMB receiver. In this paper, we propose a watermarking and encryption method on T-DMB bit-stream for a copy and Play control to prevent an illegal distribution of T-DMB contents. We implement our proposed method on a portable multimedia player (PMP) which has T-DMB receiver. The proposed method insert the encrypted information for control of copy and play after finding padding area of program map table (PMT) and program association table (PAT) from analysis of transport stream (TS) of T-DMB. In implementation result, we can control use of contents according to information of copy and play control. The proposed method can be used to content Protection software for blocking of an illegal distribution of T-DMB contents on a mobile T-DMB receivers.

• ETRI Journal
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• v.31 no.6
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• pp.795-802
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• 2009

This paper presents the design of an advanced terrestrial digital multimedia broadcasting (AT-DMB) baseband receiver SoC. The AT-DMB baseband is incorporated into a hierarchical modulation scheme consisting of high priority (HP) and low priority (LP) stream decoders. The advantages of the hierarchical modulation scheme are backward compatibility and an enhanced data rate. The structure of the HP stream is the same as that of the conventional T-DMB system; therefore, a conventional T-DMB service is possible by decoding multimedia data in an HP stream. An enhanced data rate can be achieved by using both HP and LP streams. In this paper, we also discuss a time deinterleaver that can deinterleave data for a time duration of 384 ms or 768 ms. The interleaving time duration is chosen using the LP symbol mapping scheme. Furthermore, instead of a Viterbi decoder, a turbo decoder is adopted as an inner error correction system to mitigate the performance degradation due to a smaller symbol distance in a hierarchically modulated LP symbol. The AT-DMB baseband receiver SoC is fabricated using 0.13 ${\mu}m$ technology and shows successful operation with a 50 mW power dissipation.

• Journal of Broadcast Engineering
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• v.13 no.6
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• pp.817-827
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• 2008

The terrestrial-digital multimedia broadcasting(T-DMB) is now provided for the public service and the number of receivers reaches 15 million at the present of August 2008. The service of T-DMB itself has been succeeded in the presence. It is however remained as a supplementary role of stationed TV. It is necessary to find an additional business model as a new media to acquire surplus escaping from the deficit of the present T-DMB service. In the present paper, data service of T-DMB is proposed as candidate of such solution. Especially, TTI(Traffic and Travel Information) service is proposed as a killer application using TPEG(Transport Protocol Experts Group). At present, TPEG has not been so popular in the sense of various user satisfaction. Thus the variety of service including bi-directional service using DMB2.0 as in the sphere of Web2.0 is necessary for the service providers. In the paper, the restriction of TPEG-POI(Point of Interest) application service using the conventional mobile communication infrastructure is indicated. To overcome such restriction, TPEG-UCM(User Created Message) application service model using individual bi-directional media which is initiated and interacting by the users is proposed. In the experiment, the application program shows the usability of the proposed method so that the implementation results show its operability.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2006.11a
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• pp.157-160
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• 2006

이 논문에서는 계층변조를 적용하는 AT-DMB (advanced terrestrial digital multimedia broadcasting) 시스템을 위한 자력 채널추정 기법을 제시하고 그 성능을 살펴본다. AT-DMB 시스템은 기존 T-DMB 시스템과의 호환성을 유지하기 데이터 전송채널의 경우 DQPSK 변조를 적용한 각 신호점을 다시 QPSK 변조하는 16-QAM 계층변조 방식을 적용한다. 또 프레임의 동기신호 및 정보채널은 기존 T-DMB 신호와 동일하게 유지한다. 이 신호들을 이용하여 자력 추정을 위한 채널의 초기치를 계산한다. 데이터 신호에 대해서는 일단 판정궤환 모드를 적용하여 채널을 추정한 후 시간 및 주파수 영역에서 인접 심볼 및 부반송파에 걸쳐 평균을 취함으로써 잡음의 영향을 감소시킨다. 모의실험을 통해 제시한 자력 채널추정 방식의 성능을 살펴본다.

• Information and Communications Magazine
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• v.25 no.4
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• pp.48-55
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• 2008

T-DMB(Terrestrial Digital Multimedia Broadcasting)는 2005년 12월 수도권을 중심으로 본방송을 개시하였으며, 2007년 8월 KBS를 시작으로 전국 서비스를 실시하고 있다. 서비스 영역이 전국으로 확대됨에 따라 휴대이동방송에 필수적인 핸드오버 기술의 필요성이 점차 증가하고 있다. 핸드오버는 사용자가 현재 서비스 권역을 벗어나 인접 권역으로 이동할 때 현재 이용 중인 서비스에 대응하는 새로운 주파수와 서비스를 자동으로 검색하여 제공하는 기술이다. 핸드오버의 성능은 핸드오버에 적합한 방송망 구성과 수신기에서 최적의 핸드오버 알고리즘 구현에 의해 결정된다. T-DMB에서 핸드오버를 도입하기 위하여 방송사들 공동으로 핸드오버 가이드라인을 작성하고 있다. 가이드라인은 핸드오버 모드, 핸드오버 정보의 정의 및 구성, 핸드오버 영역과 지역 ID, 주파수 및 앙상블 테이블과 같은 기술적인 요소와 특정 상황에서 수신기의 동작 패턴 등과 같은 비기술적인 요소를 포함한다. 본고에서는 T-DMB에서 핸드오버에 대한 기본 정보 및 요구사항, 핸드오버를 도입하기 위한 가이드 라인에 대하여 기술하고자 한다.