• ETRI Journal
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• v.30 no.2
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• pp.238-248
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• 2008

At the extremes of the complexity-performance plane, there are two exemplary QoS management architectures: Integrated Services (IntServ) and Differentiated Services (DiffServ). IntServ performs ideally but is not scalable. DiffServ is simple enough to be adopted in today' core networks, but without any performance guarantee. Many compromise solutions have been proposed. These schemes, called quasi-stateful IntServ or stateful DiffServ, however, have not attracted much attention due to their inherently compromising natures. Two disruptive flow-based architectures have been recently introduced: the flow-aware network (FAN) and the flow-state-aware network (FSA). FAN's control is implicit without any signaling. FSA's control is even more sophisticated than that of IntServ. In this paper, we survey established QoS architectures, review disruptive architectures, discuss their rationales, and points out their disadvantages. A new QoS management architecture, flow-aggregate-based services (FAbS), is then proposed. The FAbS architecture has two novel building blocks: inter-domain flow aggregation and endpoint implicit admission control.

• ETRI Journal
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• v.30 no.6
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• pp.871-873
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• 2008

In this letter, we investigate the spectral efficiency of IEEE 802.22 wireless regional area network (WRAN) spectrum overlay when it is used in TV white space. Since 2004, when the FCC published the notice of proposed rule making 04-186 to make use of unused TV spectrum, the IEEE 802.22 working group has been standardizing specifications for WRAN operations. There have been a few papers investigating the spectral efficiency of this, but their analyses were limited to the cases for various guard distances between WRAN base stations. Since WRAN base station (BS) power for WRAN service may differ from country to country, it is important to analyze the spectral efficiency for various WRAN BS powers. In this letter, we analyze the spectral efficiency of WRAN spectrum overlay as a function of the power of WRAN BSs. The simulation results show that spectral efficiency decreases as the power of WRAN BSs and guard distances increase.

• ETRI Journal
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• v.31 no.5
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• pp.481-488
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• 2009

This paper proposes a new multiuser scheduling algorithm that can simultaneously support a variety of different quality-of-service (QoS) user groups while satisfying fairness among users in the same QoS group in MIMO broadcast channels. Toward this goal, the proposed algorithm consists of two parts: a QoS-aware fair (QF) scheduling within a QoS group and an antenna trade-off scheme between different QoS groups. The proposed QF scheduling algorithm finds a user set from a certain QoS group which can satisfy the fairness among users in terms of throughput or delay. The antenna trade-off scheme can minimize the QoS violations of a higher priority user group by trading off the number of transmit antennas allocated to different QoS groups. Numerical results demonstrate that the proposed QF scheduling method satisfies different types of fairness among users and can adjust the degree of fairness among them. The antenna trade-off scheme combined with QF scheduling can improve the probability of QoS-guaranteed transmission when supporting different QoS groups.

• Journal of Broadcast Engineering
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• v.23 no.6
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• pp.790-799
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• 2018

UHD broadcasting based on ATSC 3.0 is being implemented in Korea, and discussion on mobile broadcasting based on ATSC 3.0 is underway. The ATSC 3.0 standard introduces internet protocol based standards in order to facilitate the implementation of conventional broadcasting services as well as broadcasting and communication convergence services interlocking with communication services. In this process, various requirements for the receiver have been derived, and factors to consider for developing the receiver product have also increased. ATSC 3.0 broadcasting is currently in the introduction stage of the service, and additional technology development and product implementation related to the receiver should proceed until the full-scale market is formed. In this regard, this paper describes the considerations for developing UHD receiver based on ATSC 3.0 and the test procedure for verifying developed receiver.

• ETRI Journal
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• v.28 no.5
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• pp.561-573
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• 2006

In this paper, we present a practical implementation of the MPEG-21 multimedia framework for broadcasting and communication convergent services. MPEG-21 standard technology was exploited to build a convergent service framework. Using this framework, a service model and several scenarios have been successfully designed and implemented. In addition, interoperability, which is the main objective of a multimedia framework, especially in a convergent environment consisting of heterogeneous networks and various types of devices, has been addressed in detail. The experimental results show that the implemented test bed provides a next-generation multimedia service; that is, universal multimedia access (UMA), meeting the requirements of a broadcasting and communication convergent environment.

• ETRI Journal
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• v.31 no.4
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• pp.466-468
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• 2009

In this letter, we propose a one-way ranging algorithm that is based on wireless synchronization with measured timestamps and clock frequency offsets. In our proposed algorithm, an active mobile node initiates a ranging procedure by transmitting a ranging frame, and the anchor nodes report their timestamps for the received ranging frame to a reference anchor node. The synchronization of a pair of nodes is provided with instantaneous time information, and the corresponding difference of distances can be calculated.

• ETRI Journal
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• v.34 no.1
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• pp.17-23
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• 2012

This paper analyzes the feasibility of a new 3DTV broadcasting service scenario via Advanced Television Systems Committee Mobile/Handheld (ATSC-M/H). We suggest a dual-channel system in which a left-view image is encoded by MPEG-2 with HD quality and a small-sized right-view image is encoded by AVC. Also, the left view is transmitted through ATSC main channel and the right view is transmitted through ATSC-M/H channel. Although the transport stream formats of two channels are different from each other, we demonstrate that it is possible for the ATSC 2.0 decoder to synchronize the display of the left and right views when both encoders use a common wall clock and time stamp. We also propose a program specific information descriptor which guarantees full compatibility with the conventional 2D HDTV and emerging mobile TV services. Finally, we provide the results of subjective visual quality assessment of the proposed system in support of its 3DTV service quality.

• ETRI Journal
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• v.38 no.1
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• pp.195-205
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• 2016

This paper presents a novel follicular unit (FU) classification method based on an angle variation of a boundary vector according to the number of hairs in several FU images. The recently developed robotic FU harvest system, ARTAS, classifies through digital imaging the FU type based on the number of hairs with defects in the contour and outline profile of the FU of interest. However, this method has a drawback in that the FU classification is inaccurate because it causes unintended defects in the outline profile of the FU. To overcome this drawback, the proposed method classifies the FU's type by the number of variation points that are calculated using an angle variation a boundary vector. The experimental results show that the proposed method is robust and accurate for various FU shapes, compared to the contour-outline profile FU classification method of the ARTAS system.

• Journal of Broadcast Engineering
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• v.19 no.5
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• pp.687-698
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• 2014

ATSC is currently working on standardization of hybrid 3DTV broadcasting service in heterogenous network environment after completion of service-compatible 3DTV broadcasting service standard based on broadcasting channel. This paper proposes a convergence 3D video broadcasting method on broadcasting and IP network while guaranteeing a Full-HD 3D quality without degrading the image quality of legacy DTV. Specifically, this paper describes transmission of the 3D additional video using the ISO/IEC 23009-1 DASH, robust synchronization method under heterogenous network environments and system target decoder model for hybrid 3DTV receiver. Based on experimental results, we confirm that proposed technologies can be used as a core technology in the hybrid 3DTV standardization and a reference model for a development of hybrid 3DTV encoder and receiver.

• Journal of Broadcast Engineering
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• v.15 no.2
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• pp.248-264
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• 2010

In this paper, we presents an efficient rich media framework based on MPEG-4 LASeR PMSI. Rich media provides distinctive features such as dynamic updates and object-based interactivity over the conventional AV centric media service. It rapidly gains its popularity as the convergent multimedia services between broadcasting and telecommunication. MPEG-4 LASeR is an international standard which provides specifications for such rich media services. Recently MPEG added an extension to LASeR called PMSI. It provides an efficient technique to present SI on a scene by referencing specific portions of SI from PI. The presented rich media application is using PMSI of MPEG-4 LASeR standard to provide users a widget-like rich media application. This application utilizes MPEG-4 LASeR with PMSI technique as PI, and this PI references SI to present information that resides in SI on a scene. In this paper, we provide descriptions of technical ingredients used to build the presented application. The framework is presented followed by the implementation result. Possible impacts and applicable services are described in the conclusion.