• Journal of Broadcast Engineering
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• v.8 no.3
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• pp.217-227
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• 2003

This paper describes an implementation of the slide-show functionality, which is one of the services that can be provided by the Digital Multimedia Broadcasting (DMB). While the existing analog radio broadcasting services provide audio only, DMB slide-show is the functionality that can deliver still images associated with the audio. For example, it can deliver the photographs of the singer, album cover images, or the lyrics of the song that correspond to the audio. There are two modes for the transmission of the slide-show. Firstly. the program-associated data (PAD) field within the DMB audio frame can be utilized and secondly, the slide-show data can be transmitted, after being multiplexed, with other service data as individual data stream separated from the audio. This paper describes PC-based implementations of a transmitter-side module that inserts slide-show data into the PAD area within audio bitstream and a receiver-side application module that plays the slide-show through decoding the PAD within the received audio bitstream and demonstrates their validity through experiments.

• Journal of Broadcast Engineering
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• v.15 no.6
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• pp.731-741
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• 2010

In this paper, we propose the methodology of prediction of field strength for a digital television (DTV) receiver by virtue of Recommendation ITU-R P.1546. The curves shown in this recommendation represent the point-to area field strength for 1.0 kW effective radiated power in the 30 MHz ~ 3000 MHz. Based upon the procedures described in this Recommendation, computation results are presented here from the derived formulation of field strength for DTV receiver. To show the validity of this method, some results are compared with the analysis by Okumura-Hata model and it was shown that the error of field strength is in the range of 6.9 ~ 11.5 %. The presented method provides not only the predicted values of field strength for DTV receiving area to check the quality of transmitted signal, but also an appropriate site selection for obtaining good propagation environment. In addition, it can be directly used for analyzing the protection ratio or separated distance for frequency sharing in the same band.

• Journal of Broadcast Engineering
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• v.14 no.3
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• pp.332-341
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• 2009

Terrestrial digital multimedia broadcasting(T-DMB) is one of mobile broadcasting services, and the commercial service was started in December 2005 in Korea. The performance targets of T-DMB are providing VCD(video CD) quality video and FM radio quality audio. In recent years, the researches for providing high quality video or audio service on T-DMB environments have been being carried out. To provide high-quality video or audio service, some additional data should be transmitted to the receiver as well as T-DMB video and audio data. Since the data rate for one T-DMB program is low, it is important to transmit the additional data at a low bit rate. In this paper, we propose a packetizing method for efficient transmission of the additional data to provide multichannel audio service on T-DMB environment.

• Journal of Broadcast Engineering
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• v.16 no.5
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• pp.693-704
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• 2011

As mobile devices become multi-functional, and converge into a single platform, there is a strong need for a codec that is able to provide consistent quality for speech and music contents. MPEG-D USAC standardization activities started at the 82nd MPEG meeting with a CfP and approved Study on DIS at the 96th MPEG meeting. MPEG-D USAC is converged technology of AMR-WB+ and HE-AAC V2. Specifically, USAC utilizes three core codecs (AAC, ACELP, and TCX) for low frequency regions, SBR for high frequency regions, the MPEG Surround for stereo information, and window transition technology for smoothing transition between various core coder. USAC can provide consistent sound quality for both speech and music contents and can be applied to various applications such as multi-media download to mobile devices, digital radio, mobile TV and audio books.

• Journal of Broadcast Engineering
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• v.21 no.5
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• pp.662-671
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• 2016

In this paper, we propose a wireless video transmission system, providing medium and long communication distance in the 5.8GHz band to decrease the loss of video data. Beamforming with multiple antennas in a radio environment to enable more than 10km communication distance and an image transmission method that combines the retransmission to MCS(modulation and coding scheme) are applied. By applying the proposed method in the indoor environment of 80dB attenuation using the payload size of 1000 bytes, the packet loss rate of at least 0.92% is achieved through the FPING with the time-out of 10ms. The transmission distance of 21.2Km is achieved with the transmission rate of 13Mbps in the outdoor environment.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2011.11a
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• pp.251-254
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• 2011

와이브로(Wibro) 또는 WiFI 망에서 동일한 멀티캐스트 그룹에 속한 이동 단말기들은 동일한 MBS(멀티캐스트/브로드캐스트 방송 서비스) 콘텐츠를 수신한다. 동일한 MBS 존 내의 기지국(RAS: Radio Access Station) 들이 MBS 콘텐츠 소스로부터 수신된 MBS 콘텐츠에 대한 전송 시간을 동기화할 수 있도록 기지국들은 전송 동기화 정보와 신뢰성 있는 데이터 패킷 수신을 동기 시간을 결정하기 이전에 보장받을 수 있어야 한다. 만약에 동일한 MBS 존에 속하는 다수의 기지국 중에 전송 동기화 정보를 수신하지 못하거나 패킷 데이터 일부 또는 전부를 수신하지 못한다면, 동기 전송 시간을 결정하기 전에 이미 손실된 정보와 패킷 데이터를 이동 단말기로 전송하게 됨으로써 이동 단말기가 MBS 콘텐츠를 수신하면서 동일 MBS 존 내의 다른 기지국으로 핸드오버하게 되면 MBS 콘텐츠에 대한 끊김없는 수신을 보장할 수 없을 뿐만 아니라 매크로 다이버시티(macro diversity) 이득을 얻기 위한 동일한 MBS 존에서 이동 단말기들에게 전송되는 MBS 콘텐츠들의 동기를 보장 할 수 없다. 따라서, 본 논문에서는 동기 전송 시간을 결정하기 앞서서 다수의 RAS가 전송 동기화 정보와 신뢰성 있는 패킷 데이터 콘텐츠 수신을 보장받을 수 있는 장치를 보완한 멀티캐스트/브로드캐스트 서비스 데이터 전송 동기화 방법을 제안한다.

• Journal of Broadcast Engineering
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• v.10 no.3
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• pp.261-269
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• 2005

Throughout the history of digital communication, the digital speech coder is used as speech compression tool. Nowadays, the speech coder has been rapidly developed in the area of mobile communication system to overcome severe channel error and limitation of radio frequency resources. Due to the development of high performance communication system, high quality of speech coder is needed. This kind of speech coder can be used not only in communication services but also in digital multimedia services. In this paper, we describe the technologies of digital speech coder which are used in wire and wireless communication. We also present a summary of recent speech coding standards for narrowband and wideband applications. Finally we introduce the technical trends of next generation speech coder.

• KIPS Transactions on Computer and Communication Systems
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• v.5 no.3
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• pp.55-70
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• 2016

The most critical research issue in MANET environment is on supporting reliable communication between various devices. Various Multi-Hop Routing Protocol studies have proceeded. However, some problems you might have found when you use the existing link state routing technique are that it increases Control Message Overhead and it is unstable when node moves in CR circumstance which has transformation of using channel and MIMC circumstance which uses a number of interfaces. This essay offers a technique which is based on On-Demand Hello and the other technique which used Broadcast Interface of optimization as a solution to decrease Control Message Overhead. Also it proposes Quick Route Restoration technique which is utilized by GPS and MPR Selection technique which consider mobility as a solution of stable communication when node moves. Those offered Routing Protocol and OPNET based simulator result will be expected to be an excellent comparison in related research fields.

• Journal of Broadcast Engineering
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• v.24 no.2
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• pp.341-352
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• 2019

The inconvenience of using the product weakens the competitiveness of the product and makes it difficult to obtain various users. This study proposes a 5-step evaluation method that is derived from a formal usability evaluation to suggest improvement directions for easier and more convenient manipulation of complex or inconvenient user interface. The 5-step usability evaluation method can not be applied to all broadcasting equipments, but it is expected to improve the user interface of broadcasting equipments. In addition, it is expected to provide an opportunity to more flexible access to user interface development to be applied to new application services in a variety of telecommunication convergence equipment industry, while leading the era of convergence of broadcasting industry throughout broadcasting equipment industry.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.9 s.351
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• pp.60-68
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• 2006

Using the wireless communication among unacquainted vehicles, an intelligent vehicle safety system can be constructed to exchange vehicle safety-related information, such as urgency stop, traffic accident and road obstacles. In the majority of vehicle safety applications, vehicle safety messages are propagated in the form of broadcast. However, this approach causes some effectiveness and performance problems with massive radio collision, multi-hop propagation. This paper presents a priority based relay node selection method for propagating vehicle safety messages of traffic accident protection system. With this method, vehicle safety messages are relayed by a node that locates in proper distance out of the nodes that are included in the radio transmission range. By decreasing the number of duplicated messages, the packet overhead is lessened while the communication performance is raised. The proposed method was proven to be better than other schemes through network simulations.