• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2015.07a
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• pp.306-307
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• 2015

본 논문에서는 ATSC (Advanced Television Systems Committee) 3.0 시스템을 위한 LDM (Layered Division Multiplexing) 기술을 제안하고, 그 성능을 전산실험을 통해 분석한다. 제안된 LDM 시스템은 기존의 TDM (Time Division Multiplexing) / FDM (Frequency Division Multiplexing) 기술에 비해 약 3 에서 9 dB 의 성능 이득을 나타낸다.

• ETRI Journal
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• v.26 no.2
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• pp.149-160
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• 2004

In this paper, we present an interactive data broadcasting system compliant with the Advanced Television Systems Committee (ATSC) standards. The proposed system provides users not only with various data broadcasting services but also remote interactive services. For various data broadcasting services, we have adopted a synchronized data injector that calculates the transmission time of synchronized data accurately and multiplexes synchronized data with the data of an MPEG-2 audio-visual program according to the calculated transmission time. To support remote interactive services, we designed and implemented a return channel server connected on a bi-directional interaction channel. Test results show that the proposed system provides both an asynchronous and synchronized data broadcasting service and remote interactive service appropriately.

• Journal of Broadcast Engineering
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• v.24 no.5
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• pp.879-891
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• 2019

This paper provides performance evaluations of various channel estimation schemes for Advanced Television Systems Committee (ATSC) 3.0 multiple-input multiple-output (MIMO) system under a fixed reception environment. ATSC 3.0 MIMO system can obtain high spectral efficiency and improved reception performance compared to conventional terrestrial broadcasting systems. The ATSC 3.0 MIMO defines Walsh-Hadamard and null pilot encoding algorithms and the amplitude and phase of MIMO pilots are different from those of single-input single-output pilots. At the receiver, linear and discrete Fourier transform (DFT)-based interpolations can be used for the channel estimation. This paper provides the various combinations of the interpolation schemes for channel estimation in time and frequency dimensions, and then analyzes the performance of the various combinations through the computer simulation. The results of computer simulation show that the combination of the linear interpolation in the time dimension and then DFT-based interpolation in the frequency dimension can obtain the best performance among the considered combinations.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2017.06a
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• pp.133-134
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• 2017

본 논문에서는 차세대 방송 표준 ATSC (Advanced Television Systems Committee) 3.0 기반 LDM (Layered Division Multiplexing) 및 스케일러블 비디오 코덱 (Scalable Video Codec) 을 활용한 지상파 방송시스템 기술을 살펴보고 그 성능을 비교 분석한다. 코어 레이어 (Core Layer)와 인핸스드 레이어 (Enhanced Layer)로 구성된 LDM 기반 PLP (Physical Layer Pipe)에, 스케일러블 비디오 코딩이 적용된 베이스 레이어 (Base Layer)와 인핸스먼트 레이어 (Enhancement Layer) 스트림을 각각 전송함으로써 하나의 RF 채널에 두 개 이상의 서비스를 전달할 경우 채널 효율을 극대화 할 수 있다. 본 논문에서는 이동 및 고정용 서비스, 즉 두 개의 서비스를 전송할 때 제안된 LDM 및 스케일러블 비디오 코덱을 사용한 기술과 TDM (Time Division Multiplexing) 및 Simulcast 를 적용한 기술과의 성능 비교를 통해 제안된 기술의 우수성을 검증하고자 한다.

• Journal of Broadcast Engineering
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• v.11 no.2 s.31
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• pp.229-241
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• 2006

In this paper we propose and analyze a novel modulation and pre-equalization method to minimize signal processing time delay for the Equalization Digital On-Channel Repeater (EDOCR) in ATSC (Advanced Television Systems Committee) terrestrial digital TV system. The proposed modulation method uses Equi-Ripple (ER) filter coefficients instead of conventional Square Root Raised Cosine (SRRC) after coefficients for VSB (Vestigial Side Bands) pulse shaping. And the proposed pre-equalization method calculates pre-equalizer filter coefficients by using baseband signal as reference signal and demodulated repeater output signal, then generates a new VSB pulse shaping filter coefficients by convolutioning ER filter coefficients and pre-equalizer filter coefficients. The newly generated pulse shaping filter does not have minimized time delay by adjusting the number of pre-taps of the filter, but also compensates linear distortions caused by ER filter and mask filter.

• Journal of Broadcast Engineering
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• v.14 no.3
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• pp.311-321
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• 2009

In a single frequency network (SFN) for Advanced Television Systems Committee (ATSC) terrestrial digital television (DTV) system, the interference due to the use of same frequency among multiple transmitters or repeaters is inevitable for receivers. This problem can be solved by adjusting transmit power and time of each transmitter and repeater. To adjust SFNs, the ATSC recommended practice (RP) introduces a transmitter identification (TxID) signal which is embedded in a signal from each transmitter or repeater. This paper proposes an efficient method to estimate the individual reception power from each transmitter or repeater based on the channel profile of SFN and the total reception power. Moreover, field test results are provided to evaluate the performance of the proposed method.

• Journal of Broadcast Engineering
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• v.13 no.3
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• pp.350-364
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• 2008

Single frequency network (SFN) design based on the Advanced Television Systems Committee (ATSC) specification, a terrestrial digital television (DTV) system, normally causes a interference problem, among signals from multiple transmitters or repeaters. To solve this, the ATSC recommended practice (RP) introduces a transmitter identification (TxID) signal embedded in a signal from each transmitter or repeater. A TxID signal analyzer is then used to detect the TxID signal, and following the analysis results, a SFN design can be adjusted. This paper discusses the generation and usages of Kasami sequence, is used the TxID signal. The configuration of the TxID signal analyzer to efficiently detect TxID signal is proposed and the results of theoretical performance analysis are provided. Moreover, computer simulation and laboratory test results are provided to evaluate the performance of TxID signal analyzer and the theoretical performance analysis.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.9C
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• pp.922-927
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• 2009

Utilization problem of the limited spectrum is the one of the most important issues in wireless communication systems. Cognitive radio technique which is finding and utilizing frequency holes is also one of those techniques. Specially, the spectrum sensing technique to detect the primary user signal is a core technology in cognitive radio area. In this paper, we propose the spectrum sensing algorithm using Bussgang theorem. The proposed algorithm calculates the statistical difference between the Gaussian noise and the primary user signal by applying Bussgang theorem to the received signal. The algorithm is not affected by noise uncertainty and can detect the primary user signal in the very low SNR environment. We evaluate the algorithm through computer simulations with 12 ATSC A/74 DTV signal captures based on IEEE 802.22 WRAN and formulate the sensing threshold for the proposed scheme.

• Journal of Broadcast Engineering
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• v.15 no.6
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• pp.803-814
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• 2010

In this paper, we propose a frame structure for modified ATSC transmission systems which is used for a terrestrial 3D HDTV broadcasting. The modified ATSC transmission systems [2] see the potential of increasing a transmission capacity at reasonable TOV (Threshold of Visibility) by modifying channel codes of conventional ATSC systems and varying modulations. We use PN symbols (Pseudorandom Noise) in a guard interval which is used for avoiding the ISI (Inter Symbol Interference) to estimate and compensate the time-varying multi path channel effectively with a maximum transmission payload. With PN symbols in the guard interval, a CIR (Channel Impulse Response) in a time domain can be estimated and a compensation in a frequency domain can be achieved for the accurate channel estimation and compensation. The prosed frame structure is applied to the modified ATSC systems and computer simulations are performed for SER (Symbol Error Rate) performances in TU (Typical Urban)-6 Channel.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2010.11a
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• pp.257-259
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• 2010

본 논문에서는 지상파 3D HDTV 방송 서비스를 제공하기 위해 수정된 ATSC (Advanced Television Systems Committee) 전송 시스템 [2]을 위한 시변다중경로채널에 강인한 프레임 구조를 제안하고 성능을 측정하였다. 수정된 ATSC 전송 시스템 [2]은 기존 ATSC 전송 시스템[1]의 채널 부호화부를 수정하고, 변조 성상도를 증가 시키면서 적정한 수준의 TOV (Threshold of Visibility)에서의 전송 용량 증대 가능성을 확인하였다. 이를 토대로, 증가된 전송 데이터 전송률에 대한 순수 데이터 전송률을 최대한 보장하면서 시변다중경로채널에서 효율적으로 채널을 추정하고 복구하기 위해, ISI (Inter Symbol Interference)를 방지하기 위한 프레임 헤더의 보호구간에 알려진 PN (Pseudorandom Noise) 심벌을 삽입하였다. PN 심벌을 보호 구간에 이용할 경우 시간 영역에서 채널 임펄스 응답 (CIR: Channel Impulse Response)을 추정하여, 주파수 영역에서의 채널 보상을 가능케 하여 정확한 채널 추정 및 보상을 수행할 수 있다. 또한 수신기의 속도에 따른 다양한 최대 도플러 주파수가 존재하는 채널에 강인한 프레임 구조들을 제안하였다. 컴퓨터 시뮬레이션을 통해 수정된 ATSC 전송 시스템에 제안된 프레임 구조를 적용하여 TU (Typical Urban)-6 채널에서의 SER (Symbol Error Rate) 성능을 측정하였다.