• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.7
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• pp.1618-1626
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• 2013

Virtualization service processes all operation including the data creation, storing, and disposal in a server and transmits processed data as the streaming media form. Therefore, client can use the same environment as the traditional desktop environment without considering the type of device. Virtualization service should consider not only the video quality but also the delay bounds and continuity of video playback for improving the user perceived Quality of Service(QoS) of streaming service. In this paper, we propose a network-adaptive transmission architecture that focuses on guaranteeing QoS requirements for virtualization service. In order to provide those, the proposed architecture have the transmission rate adaptation function based on available bandwidth and the content bit-rate control function based on sender buffer state. Through each function, proposed architecture guarantee the delay bounds and continuity of virtualization contents playback. The simulation results show that proposed network-adaptive transmission architecture provides a improve performance of throughput and transmission delay.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.1A
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• pp.62-69
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• 2005

Efforts for standardization of medium access control (MAC) protocol in IEEE802.11e have been made to support quality of service (QoS) in IEEE802.11e MAC protocol. Enhanced disoibuted coordination function (EDCF) of 802.11e MAC protocol is modified to support QoS for packets that have differentiated priority. However, EDCF still has the problem of throughput optimization and priority support. Therefore, we have proposed a scheme called adaptive EDCF for both supporting priority of packets and throughput optimization. We have derived the relation between the number of nodes and contention window size for throughput optimization. Based on the analytic results, we have evaluated the performance of the proposed scheme using OPNET simulations. The simulation results show that using the proposed scheme can improve the overall throughput regardless of the number of nodes and the decrement of the throughput with increasing the number of nodes can be alleviated. Additionally, we have shown that the adaptive EDCF can support priority of packets more effectively than existing EDCF.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10c
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• pp.412-414
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• 2003

무선 이동망에서 점점 증가하는 멀티미디어 트래픽의 QoS(Quality of Service)를 위해서는 충분한 자원이 제공되어야 한다. 하지만 무선망에서의 자원은 한정적이므로 이를 효율적으로 활용해야 멀티미디어 트래픽에 대한 QoS 보장이 가능하다. 이 논문에서는 무선망에서의 멀티미디어 트래픽에 대한 QoS 보장 알고리즘을 제안하였다. 제안된 알고리즘은 이동단말이 위치한 주위 셀의 자원들을 미리 예약하는 방식을 기반으로 하는 admission control 방법이다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.7A
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• pp.620-627
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• 2005

We develop an adaptive hot-spot operating scheme(AHOS) to mitigate the negative effects from the nonuniform distribution of user location and the variation in the mixture of QoS requirements in OFDMA downlink systems. The base station in a macrocell can control the operation of picocells within the cell, and turns on or off according to the changes in the estimated user outage probability and the AHOS gain parameter. With the computer simulation, the AHOS has been proved to maximize the system throughput while maintaining the QoS outage probability very low under various system scenarios.

• Journal of Korea Multimedia Society
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• v.12 no.3
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• pp.419-426
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• 2009

The WiMedia Alliance has specified a Distributed Medium Access Control (D-MAC) protocol based on UWB for high speed wireless home networks and WPANs. The WiMedia D-MAC fundamentally removes the problems of the centralized MAC revealed at IEEE 802.15.3 MAC, by adopting a distributed architecture. However, there is no completely distributed method for allocating fair data rates to all traffic streams by considering each stream's QoS parameter. In this paper, a novel fair distributed QoS admission control method is proposed. The proposed method is a fair, adaptive QoS provisioning method, by allocating time slots to devices according to the current traffic load condition, through executing only a proposed single satisfaction of QoS (SoQ) algorithm at each device.

• Journal of Communications and Networks
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• v.14 no.4
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• pp.461-466
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• 2012

Any future heterogeneous overlay network system must be able to support ubiquitous access across multiple wireless networks. To coordinate these diverse network environments, one challenging task is a call admission decision among different types of network. In this paper, we propose a new call admission control scheme to provide quality of service (QoS) while ensuring system efficiency. Based on the interplay between network structure and dynamics, we estimate the network's QoS level and adjust the service price adaptively with the aim of maximizing the network performance. A simulation shows that the proposed scheme can approximate an optimized solution while ensuring a well-balanced network performance in widely different network environments.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.8B
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• pp.764-768
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• 2006

Over the years, the widespread proliferation of multimedia services has necessitated the development for an efficient network management. In this paper, we investigate the role of adaptive online pricing mechanism in order to manage effectively the network congestion problem. Our on-line approach is dynamic and flexible that responds to current network conditions. With a simulation study, we demonstrate that our proposed scheme enhances network performance and system efficiency simultaneously under widely diverse traffic load intensities.

• Journal of KIISE:Computing Practices and Letters
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• v.13 no.5
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• pp.260-270
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• 2007

Owing to the improved wireless communication technologies, it is possible to provide streaming service of multimedia with PDAs and mobile phones in addition to desktop PCs. Since mobile client devices have low computing power and low network bandwidth due to wireless network, the transcoding technology to adapt media for mobile client devices considering their characteristics is necessary. However, since mobile clients use wireless network and the wireless network have less stable bandwidth according to distance from AP and environments, it is hard to support stable QoS to mobile clients. In this paper, we propose a dynamic bit rate control method for transcoding in order to supprot stable QoS of streaming media service to mobile clients via wireless network. The proposed method is shown to serve seamless streaming media service with adaptive bit rate control according to state of wireless network in real time and to reduce transmission failure from experiment.

• International Journal of Contents
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• v.2 no.2
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• pp.10-16
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• 2006

In this paper, we propose a predictive resource metric region (RMR) based radio resource metric estimation (RRME) mechanism, which utilizes a resource metric mapping function (RMMF), both of which permit efficient inter-working between the physical layer and higher layers for envisaging multimedia service applications over a CDMA communication system platform. The RMR can provide the acceptable resource region where QoS and acceptable link quality can be guaranteed with an achievable resource margin to be utilized in terms of capacity margin, the degree of confidence (DCL) of user, second-order statistics of Eb/Io. With predicted capacity margin and variance, DCL can deliver decision parameters with which an adaptive QoS based admission control can perform well taking capacity and resource availability into account in a dynamic and predictive manner. Combined with advanced techniques such as adaptive modulation or rate control and power control, the proposed mechanism can adjust the conventional stringent link quality information efficiently, and deliver accurate information of the resource availability. Thus, these can guarantee the maximization of resource utilization of multimedia service applications.

• The Transactions of the Korea Information Processing Society
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• v.7 no.12
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• pp.3794-3803
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• 2000

In a Video-on-Demand system, admission control that is used to serve multimedia data efficiently has to be perfonned by an accurate grasp of the condition of surplus resources. Most of all. we need to adaptable admission control mechanism because the disk has irregular response time caused by external elements of disk, and also has high deviation of amount demanded. In previous admission control schemes, they determined whether a new user is granted or not through a theoretical value. Although they based on the measurement, they left much to be desired in dealing with the service state. Measurement ~based statistical admission control scheme, as we su~~ested in this research, perfonns 2 processes of off-line process and on-line process in real service environment. Through this processes, we can grasp the accurate resource state of system and adaptive!y detennine the admission according to circumstances. Therefore, it can guarantee both maximum resource utilization and QoS(Quality of Service). On performance evaluations, we show that the video server can utilize maximum resource utilization with QoS guarantee through precision of perfonnance by measurement and adaptable admission control according to the requested bandwidth.