• The Journal of the Korea institute of electronic communication sciences
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• v.4 no.1
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• pp.46-52
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• 2009

This paper design QHA(quadrifilar helical antenna) to receive efficiently Satellite-Digital Multimedia Broadcasting video signal. It is designed as quadrifilar structure with phase variation $0^{\circ}C$, $90^{\circ}C$, $180^{\circ}C$, $270^{\circ}C$ to obtain circular polarization. Upper gap, turn number and height of QHA are varied to obtain optimization dimensions. Optimization dimensions are gap=2.2mm, turn number=0.9, height=42mm and input reflection coefficient is approximately -5.8dB. Designed QHA can be applied to Satellite-DMB terminal.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2006.07a
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• pp.380-380
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• 2006

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.6
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• pp.17-22
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• 2010

In this paper, integral TS(Transport Stream) demultiplexer of a multi-modal receiver is proposed according to the multiple standards of European terrestrial digital broadcasting DVB-T(Digital Video Broadcasting Terrestrial), and mobile terrestrial digital broadcasting T-DMB(Terrestrial Digital Multimedia Broadcasting). This USB based integral receiver could recover the multi-modal broadcasting audios by memory sharing technique which was utilized to decrease the load by the control of streaming multi-modal broadcasting. As a result of performance analysis for a proposed integral TS demultiplexer, the CPU occupational efficiency of windows based integral demulitiplexing is improved compared with DVB-T, and T-DMB respectively.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.8
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• pp.3121-3135
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• 2015

Owing to the increase in consumption of multimedia content and the improvement of device capacity, user demand for high-quality content has increased. However, it is difficult to transport such large amounts of content over the existing broadcasting network with limited bandwidth. To provide high-definition broadcasting, some studies suggest methods of transporting multimedia over heterogeneous networks after encoding content hierarchically. MPEG Media Transport (MMT), standardized by Moving Picture Experts Group (MPEG), is a solution that enables large-volume media transport over heterogeneous networks such as digital broadcasting networks and packet-switched networks. In the case of delivering a scalable encoded video over different networks, synchronization of each stream is an important issue. MMT defines a synchronization scheme, but does not contain sufficient functions to implement it. In this paper, we propose a synchronization scheme for media streams that are encoded hierarchically, divided into layers, and transported over heterogeneous networks. We implement our scheme using MMT and HTTP, and experimented using three encapsulated video streams with different durations. As a result, we show that the proposed scheme can reduce the waiting time to display high-quality video, relative to Dynamic Adaptive Streaming over HTTP-Scalable Video Coding (DASH-SVC) by requesting segments of enhanced layers after calculating the transmission time. Additionally, we find out that the selection of durations have a relation to the characteristics of the video.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.799-800
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• 2008

An efficient intra mode selection algorithm is proposed to reduce the computational complexity of inter frames for the H.264|AVC video encoding system. We propose an adaptive thresholding algorithm based on distribution characteristics of the sum of the absolute differences (SAD) of the best inter mode. Through comparative analysis, the proposed algorithm shows better speed up ratio with a negligible quality loss.

• ETRI Journal
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• v.31 no.1
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• pp.65-67
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• 2009

We introduce an advanced terrestrial digital multimedia broadcasting (AT-DMB) system that overcomes the limitation of data transmission rates of T-DMB by doubling it with the same frequency bandwidth. In this letter, we propose an efficient algorithm which generates a scalable transport stream in AT-DMB by multiplexing certain types of elementary streams encoded using scalable video coding and an MPEG-surround audio coder for high-quality multimedia services.

• Journal of Korea Multimedia Society
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• v.20 no.6
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• pp.853-864
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• 2017

HD padding area is essential redundancy in HD broadcasting. It is possible to use this padding area for the purpose of improving DTV broadcasting services. For utilization of this area, The bit of a service data was converted to black and white $8{\times}8$ block image. Converted block images are compressed with active video and are delivered to a receiver as only DC coefficients in a video stream. video quality is not effected by the proposed method, and service data was perfectly recovered in receiver without errors by using block average and threshold. The proposed utilization of HD essential padding area can possibly overcome the limited transmission stream rate with the bandwidth of HD broadcasting. If service data in transport or video stram were transferred using this padding area, it is possible to improve video quality with expanded video stream rate. Additionally, because the proposed methods are based on well-established standards, it is also useful for world-wide HD broadcasting systems such as ATSC, DVB, and IPTV.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.11
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• pp.1019-1028
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• 2013

The BWS (broadcast website) data broadcasting service for terrestrial DMB (digital multimedia broadcasting) has a great advantage that it can provide a website like service through broadcast without web traffic to a plurality of receiving terminals. However, the value of BWS has not been recognized due to the development of mobile communication technology and changes in the environment, where mobile web services through smart devices such as smart phones and pads are common. Recently, various hybrid service technologies provided through hybrid broadcasting, a fusion of broadcasting and communications, have been developed. In this paper, we propose a scalable BWS dividing the hierarchy of BWS into transmission layers and present its application for hybrid DMB data broadcasting services.

• Proceedings of the KIEE Conference
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• 2008.10b
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• pp.530-531
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• 2008

Recently, navigation system is widely accepted for many car users for its versatile facilities. In Korea, many navigation system include DMB (digial multimedia broadcasting) which is mobile TV broadcasting system standard in Korea. However, there is little works on the navigation systems for the European market where the DVB-T can be used for the multimedia broadcasting. Thus, in this work the navigation system with DVB-T is developed and tested for European market resulting increased profits for the navigation manufacturers.

• ETRI Journal
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• v.34 no.4
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• pp.492-502
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• 2012

We consider an overlaid broadcast service, where a spread spectrum (SS)-based broadcast signal is overlaid onto the existing terrestrial Digital Multimedia Broadcasting (T-DMB) band. The system is similar to the augmented data transmission in the ATSC DTV, for which it was investigated mostly in terms of link level performance, such as bit error rate. Our focus in this paper is on the system-level performances. More specifically, utilizing both a large scale path loss and a small scale fading channel model, the primary objective is to explore the tradeoff between the coverage and the achievable rate of the overlaid service and, finally, to determine the achievable rate in the overlaid service for marginal coverage reduction in the existing broadcast service. The analytical and simulation results show that an SS-based add-on service of 10 kbps to 20 kbps can co-exist with the T-DMB service while resulting in only a marginal degradation in T-DMB coverage (for example, less than one percent reduction).