• 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.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.11A
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• pp.1073-1077
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• 2010

This paper proposes a new 4-dimensional(4D) constellation-rotation(CR) method which obtains diversity gain of 4 under Rayleigh fading channels. The proposed scheme uses two consecutive CR operations for the constellation of QAM signals unlike a conventional 2-dimensional(2D) CR method using only one CR operation. The computer simulation results show that the new method outperforms the conventional one even more as both the channel code rate and the erasure ratio increase. In a point of system flexibility, the proposed scheme has a great advantage since the conventional 2D CR scheme can be simply implemented by only changing rotation angle values used in the proposed scheme.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2006.11a
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• pp.219-222
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• 2006

최근 들어 ATSC-DTV의 미래형 핵심기술로 손꼽히고 있는 송신기 식별기술(TxID ; Transmitter Identification)이 새로운 신기술로 대두되고 있으며, 이에 대한 구현성 검증은 현재 활발하게 논의 중인 재생중계기(EDOCR)와 연계된 단일주파수망(SFN; Single Frequency Network)기술의 실용화를 위한 핵심적 역할을 한다고 볼 수 있다. 하지만 종래의 TxID기술은 긴 주기의 워터마킹용 확산코드를 사용하므로 수신기 입장에서 하드웨어 부피가 크게 증가되는 문제점을 갖고 있다. 따라서 본 논문에서는 TxID 수신기 하드웨어 부피를 크게 경감시킬 수 있는 새로운 Decimated Correlation 기법을 이용한 DTV TxID 수신 신호의 효율적인 신호처리 기법을 제시하였으며, 모의실험을 통한 성능평가를 통해 제안한 알고리즘의 유용성을 입증하였다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2005.11a
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• pp.101-104
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• 2005

본 논문에서는 국내에서 채택한 ATSC-DTV (Advanced Television System Committee-Digital Television)의 단일주파 수망 (SFN; Single Frequency Network) 구성을 위한 TxID (Transmitter Identification)용 ZCD (Zero Correlation Duration)확산코드 기반의 부분상관 정합필터를 새롭게 제안하였다. 본 논문에서 제안한 정합필터의 구현 알고리즘은 TxID에 있어서 기존의 정합필터 구조를 적용할 경우에 발생되는 소비전력 문제나 하드웨어 구현의 어려움을 획기적으로 해결할 수 있다는 잇점을 갖는다. 따라서 본 논문에서는 이러한 다양한 잇점을 갖는 새롭게 제안한 ZCD용 부분상관 정합필터를 FPGA (Field Programmable Gate Array)를 이용한 디지털 하드웨어로 구현하고 그 성능을 분석함으로써 유용성을 확인하였다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2005.11a
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• pp.105-108
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• 2005

본 논문에서는 지상파 디지털 방송시스템의 단일 주파수망 (SFN; Single Frequency Network) 구성을 위해 DTV (Digital Television) TxID (Transmitter Identification)용 저간섭 ZCD (Zero Correlation Duration) 확산코드를 제시하였다. ZCD 확산코드는 코드발생기의 구현이 용이함과 동시에 ZCD특성을 가짐으로 인해서, TxID에서 발생되는 인접코드 간섭 (ICI; Inter Code Interference) 및 다중경로 간섭 (MPI; Multi-Path Interference) 문제를 확산코딩기법을 이용하여 근원적으로 해결해주는 역할을 하고 있으며, 주기를 가변적으로 조절할 수 있어 TxID를 위한 워터마킹 (Watermarking)시에 발생하는 Truncated error를 제거할 수 있다. 본 논문에서는 AWGN (Additive White Gaussian Noise) 잡음 및 ICI, MPI와 같은 다양한 간섭환경을 모의실험에 반영하여 도출된 DER (Detection Error Rate)특성을 분석함으로써, TxID용 저간섭 ZCD 확산코드의 유용성을 입증하였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.7A
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• pp.725-733
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• 2006

In this paper, we propose an algorithm which makes the frequency of output signal synchronize with frequency of input signal in Equalization Digital On-channel Repeater (EDOCR) system which was proposed to overcome the disadvantage of conventional Digital On-Channel Repeater (DOCR). Also, we verify the algorithm by using the mathematical equivalent model and analysis the performance by implying the algorithm to EDOCR. The main idea is to use the frequency offset information, which comes from carrier recovery in the receiving part of EDOCR, when the demodulated symbol is re-modulated in transmitting part. Based on the proposed algorithm, EDOCR not only makes the output signal synchronized with input signal in frequency but also emit the output signal which satisfies the ATSC transmission standard without additional equipments such as Global Positioning System (GSP).

• Journal of Broadcast Engineering
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• v.8 no.2
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• pp.109-115
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• 2003

In this paper we propose an efficient method to broadcast digital television signals using Single Frequency Networks (SFNs) in the Advanced Television Systems Committee (ATSC) transmission systems. Since the proposed schemes to synchronize multiple transmitters minimize the changes from the conventional ATSC system, the hardware complexity for the changes is very low. Our simulation results show that the proposed scheme makes less than 0.1 dB degradation at the threshold of visibility (TOV： BER= 3$\times$$10^{-6}$) in the additive white Gaussian noise (AWGN) channel. It is possible to reduce the performance degradation by increasing an initialization period of the proposed scheme.

• Journal of Broadcast Engineering
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• v.23 no.2
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• pp.293-301
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• 2018

In ISDB-T, which is Japanese digital terrestrial TV specification based on OFDM technology, 6MHz bandwidth is divided into 13 segments. Twelve segments (full-seg) are used for high definition broadcasting for fixed receivers and one segment (one-seg) for mobile receivers. Though one-seg supports high speed mobility by using QPSK modulation, it is not suitable for large display mobile devices because of its low data rate. Full-seg using 64QAM modulation also suffers from its low mobile performance. In this paper, mobile performance of ISDB-T full-seg receiver is evaluated by applying sub-carrier interference removing scheme, high speed mobile channel estimation scheme and antenna diversity scheme.

• ETRI Journal
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• v.43 no.4
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• pp.702-716
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• 2021

This work proposes suitable network configurations for single frequency networks (SFNs) with ATSC 1.0 based on network coverage calculations and the laboratory multipath handling performance of commercial receivers. SFNs are widely used for delivering terrestrial digital television services because of their efficient use of the spectrum. In Mexico the analogue television transmissions switch-off occurred on 31 December 2016. Thus it is expected the adopted ATSC 1.0 system will be in force for the next several years despite the recent standardization of the ATSC 3.0 system. As ATSC 1.0 uses 8-VSB modulation the multipath handling capability of receivers is critical for the design of SFNs. The presented network planning results help develop technical normativity for implementing SFNs in Mexico and other countries that use ATSC 1.0. SFNs with transmitter separation up to 130 km are fully covered for outdoor reception mainly due to the directivity of the receiving antenna. Moreover for indoor reception at least 70% of an SFN coverage area can be achieved with a transmitter separation of up to 60 km depending on the radiated power and the transmitter antenna height.

• ETRI Journal
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• v.44 no.5
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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.