• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.10a
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• pp.737-740
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• 2003

SFN (Single Frequency Network) and OCR (On Channel Repeater) are often considered for the efficiency of frequency allotment in digital TV. In this paper, we discuss the performance and evaluate some coverage criterions for SFN and OCR. Also, we propose MATLAB simulator for coverage planning and estimation.

• ETRI Journal
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• v.36 no.2
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• pp.188-196
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• 2014

This paper describes a simple delay diversity technique for terrestrial digital multimedia broadcasting (T-DMB) and digital audio broadcasting in a single-frequency network (SFN). For the diversity technique, a delay diversity scheme is adopted. In the delay diversity scheme, a non-delayed signal is transmitted in the first antenna, and delayed versions of the signal are transmitted in each additional antenna. For an SFN environment with multiple transmitters, delay diversity can be executed by controlling the emission times of the transmitters. This SFN delay diversity scheme does not require any hardware changes in either the transmitter or receiver, and perfect backward compatibility can be acquired. To evaluate the performance improvement, laboratory tests are executed with various types of commercial T-DMB receivers as well as a measurement receiver. The improvement in the bit error rate performance is evaluated using a measurement receiver, and an improvement of the threshold of visibility value is evaluated for commercial receivers. Test results show that the T-DMB system can obtain diversity gain using the described technique.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.9
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• pp.2218-2230
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• 2012

In this paper, we propose an efficient channel delay estimation method for orthogonal frequency-division multiplexing (OFDM) systems, especially over doubly-selective fading channels which are selective in both the symbol time domain and subcarrier frequency domain. For the doubly-selective fading channels in single frequency network (SFN), long and strong echoes exist and thus the conventional discrete Fourier Transform (DFT) based channel delay estimation system often fails to produce the exact channel delay profile. Based on the analysis of the discrete-time frequency response of the channel impulse response (CIR) coefficients in the DFT-based channel delay estimation system, we develop a method to effectively extract the true CIR from the aliased signals by employing a simple narrow-band low-pass filter (NB-LPF). The performance of the proposed system is verified using the COST207 TU6 SFN channel model.

• 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.4
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• pp.463-478
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• 2008

A Distributed Translator Network(DTxR) is a cost-effective and frequency-effective method which can use existing transmission utilities and can be constructed in a shorter time as compared with Multiple Frequency Network(MFN) or Single Frequency Network(SFN) using On Channel Repeater(OCR). In order to verify the feasibility of DTxR, this field test was done in 30 points of north-west area in Seoul using 3rd, 5th, and 6th generation DIV receivers. Electric field strength, noise margin and ease of reception were measured and subjective evaluation of video quality was done in these points during the field test. With the test result, an improvement of receiving quality was obtained and an ease of reception was increased in case of the 5th. and 6th. receiver. From the results, we conclude that DTxR is a feasible method in DIV networks.

• Electronics and Telecommunications Trends
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• v.19 no.4 s.88
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• pp.1-9
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• 2004

본 고에서는 미국식(ATSC) 지상파 디지털 TV 방송을 단일 주파수 망(SFN)을 통해 서비스하기 위해 필요한 기술적인 사항에 대하여 고찰하고, ATSC 방송 방식에서 SFN을 구성하기 위한 방법을 제안한다. SFN구성은 방송 주파수의 이용 효율을 높이고, 방송 구역 내에서 안정적인 전파 세기를 보장한다. 이러한 SFN 구성을 위한 기술은 복수 개의 송신기를 이용하는 방법(DTX)과 복수 개의 디지털 동일 채널 중계기(DOCR)를 이용하는 방법으로 나뉘어진다. ATSC 방식에서는 두 가지 방법 모두 사용하여 SFN 구성이 가능하나, 복수 개의 송신기를 이용하는 방법은 현재의 기술 기준을 변경해야 한다는 제약이 따른다. 반면 다수 개의 DOCR를 이용하는 방법은 기존의 송신기와 함께 SFN 구성이 가능하여 망 구성이 용이하다.

• Journal of Broadcast Engineering
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• v.13 no.3
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• pp.365-379
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• 2008

In this paper we consider technological requirements of the on-channel repeater to broadcast the terrestrial digital multimedia broadcasting (T-DMB) signals using single frequency networks (SFN) and propose the configuration and implementation method of the equalization on-channel repeater (OCR) that meet such requirements. The proposed equalization OCR not only has short time delay, but shows high output power and good quality of output signal by removing a feedback signal due to incomplete antenna isolation and multipath signal existing between the main transmitter and the OCR. In addition, computer simulations and laboratory tests results are provided to figure out performance of the proposed equalization OCR.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.3A
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• pp.205-214
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• 2011

In 3rd generation project partnership long term evolution, wireless multicast techniques which send the same data to multiple users under single frequency networks have attracted much attention. In the multicast system, the transmission mode needs to be selected for efficient data transfer while satisfying the multicast coverage requirement. To achieve this, users' channel state information (CSI) should be available at the transmitter. However, it requires too much uplink feedback resource if all the users are allowed to transmit their CSI at all the time. To solve this problem, in this paper, the multicast coverage prediction is suggested. In the proposed algorithm, each user measures its transition probabilities between the success and the fail state of the decoding. Then, it periodically transmits its CSI to the basestation. Using these feedbacks, the basestation can predict the multicast coverage. From the simulation results, we demonstrate that the proposed scheme can predict the multicast system coverage.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2017.06a
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• pp.131-132
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• 2017

본 논문에서는 차세대 ATSC 3.0 표준 기반 단일주파수망 (Single frequency network, SFN) 지상파 방송시스템에서의 송신기 식별 (Transmitter identification, TxID) 기술을 살펴보고 그 성능을 분석한다. SFN 기반 지상파 방송은 복수의 송신기를 동일한 주파수 대역에서 운용하는 것에서 발생하는 간섭으로 인한 영향을 최소화하기 위해 적절한 망 설계를 필요로 한다. 용이한 망 설계를 위해, ATSC 3.0 물리계층 표준은 TxID 기술을 통해 개별 송신기에서 전송된 신호를 판별할 수 있도록 지원한다. 이에 본 논문에서는 ATSC 3.0 표준에서 지원하는 TxID 신호 생성 및 검출 기술을 소개한다. 더불어, 전산 실험을 통해 해당 TxID 기술의 식별 성능이 TxID 신호의 삽입 준위가 매우 낮은 환경에서도 보장됨을 확인한다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.4
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• pp.151-156
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• 2010

In this paper, several computer simulations are investigated to confirm the DVB-H system performance and to find proper single frequency network cell coverage. From the result, we confirm that 2K mode transmission is more robust to Doppler frequency than 8K mode. The result of this paper can be partially applied to the design the single frequency network.