• The KIPS Transactions:PartC
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• v.13C no.2 s.105
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• pp.171-176
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• 2006

Bandwidth is an extremely valuable and scarce resource in a wireless network. Therefore, efficient bandwidth management is necessary in order to provide high qualify service to users with different requirements in a multimedia wireless/mobile network. In this paper, we propose an on-line bandwidth reservation algorithm that adjusts bandwidth reservations adaptively based on existing network conditions. The most important contribution of our work is an adaptive algorithm that is able to resolve conflicting performance criteria - bandwidth utilization, call dropping and call blocking probabilities. Our algorithm is quite flexible, is responsive to current traffic conditions in cellular networks, and tries to strike the appropriate performance balance between contradictory requirements for QoS sensitive multimedia services.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.9
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• pp.4287-4306
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• 2016

Network resilience provides an effective way to overcome the problem of network failure and is crucial to Internet protocol (IP) network management. As one of the main challenges in network resilience, recovering from link failure is important to maintain the constancy of packets being transmitted. However, existing failure recovery approaches do not handle the traffic engineering problem (e.g., tuning the routing-protocol parameters to optimize the rerouting traffic flow), which may cause serious congestions. Moreover, as the lack of QoS (quality of service) restrictions may lead to invalid rerouting traffic, the QoS requirements (e.g., bandwidth and delay) should also be taken into account when recovering the failed links. In this paper, we first develop a probabilistically correlated failure model that can accurately reflect the correlation between link failures, with which we can choose reliable backup paths (BPs). Then we construct a mathematical model for the failure recovery problem, which takes maximum rerouting traffic as the optimizing objective and the QoS requirements as the constraints. Moreover, we propose a heuristic algorithm for link failure recovery, which adopts the improved k shortest path algorithm to splice the single BP and supplies more protection resources for the links with higher priority. We also prove the correctness of the proposed algorithm. Moreover, the time and space complexity are also analyzed. Simulation results under NS2 show that the proposed algorithm improves the link failure recovery rate and increases the QoS satisfaction rate significantly.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.11a
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• pp.239-240
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• 2012

When users access to use the computing resources in the cloud, they expect specific quality of service (QoS) which should be guaranteed by the service provider. Meanwhile, the service provider should adopt proper schemes to enhance the resource utilization. In this thesis, we propose the MapChem-Broker which aims to satisfy users' QoS requirements as well as enhance the resource utilization by controlling the provision of VM resources in the cloud. On the experimental cloud testbed, we compare the proposed scheme with an existing one for VM resource provisioning. Results show that the proposed scheme outperforms the existing one.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.4
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• pp.84-91
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• 2011

Recently, WBAN(Wireless Body Area Network) which has progressed standardization based on IEEE 802.15.6 standardization is a network for the purpose of the short-range wireless communications within around 3 meters from the inner or outer human body. Effective QoS control technique and data efficient management in limited bandwidth such as audio and video are important elements in terms of users and loads in short-range wireless networks. In this paper, for high-speed WBAN IEEE 802.15.6 standard, the dynamic allocation to give an efficient bandwidth management and weighted fair queueing algorithm have been proposed through the adjustment of the super-frame about limited data and Quality of Service (QoS) based on the queuing algorithm. Weighted Fair Queueing(WFQ) Algorithm represents the robust performance about elements to qualitative aspects as well as maintaining fairness and maximization of system performance. The performance results show that the dynamic allocation expanded transmission bandwidth five times and the weighted fair queueing increased maximum 24.3 % throughput and also resolved delay bound problem.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.7
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• pp.3175-3181
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• 2012

The need of multimedia based application service is increasing as the number of smart mobile devices such as smart phone, tablet PC, and netbook is increasing rapidly and the development of application service like IPTV. There are various proposed policies to control the limited network resources. The IMS is used to control wired and wireless aggregation network to support multimedia services that are suitable to the user's need and the policy based models using the PDF of the IMS have emerged. In this paper, we propose the QoS adaption model using various protocols with the PDF of the IMS and the user scenario.

• Journal of Digital Contents Society
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• v.9 no.1
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• pp.101-107
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• 2008

The level of transference of NGN is beginning as the operation of Access Gateway in korea at present, but NGN will keep developing continuously to the NGN integrated network until 2010. This research is finding the meaning and assignment of NGN QoS to deduct how to manage the control system and presenting the QoS control process and trial framework. The trial framework is the modeling of the QoS measurement metrics, the measurement time schedule, the section, hierarchy, instrument, equipment and method of measurement and the series of cycle & the methodology about analysis of the result of measurement. The objective standard of quality in communication service is guaranteed not by itself but by controlling and measuring continuously. Especially it's very important time to maintain the research about NGN QoS measurement and control because the big conversion of new network technology paradigm is now spreading.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.11
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• pp.44-52
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• 2011

In this article, we present a QoS-guaranteed IP mobility management scheme of Internet service for fast moving vehicles with multiple wireless network interfaces. The idea of the proposed mechanism consists of two things. One is that new wireless connections are established to available wireless channels whenever the measured data rate at the vehicle equipped with mobile gateway drops below to the required data rate of the user requirement. The other is that parallel distribution packet tunnels between an access router and the mobile gateway are dynamically constructed using multiple wireless network interfaces in order to guarantee the required data rate during the mobile gateway's movement. By doing these methods, the required data rate of the mobile gateway can be preserved while eliminating the possible delay and packet loss during handover operation, thus resulting in the guaranteed QoS. The architecture of the IETF standard HMIPv6 has been extended to realize the proposed scheme, and detailed algorithms for the extension of HMIPv6 has been designed. Finally, simulation has been done for performance evaluation, and the simulation results show that the proposed mechanism demonstrates guaranteed QoS during the handover with regard to the handover delay, packet loss and throughput.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.54.5-54
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• 2002

1. Introduction II. Internet Telephony III. Proposed method for quality of service IV. Simulation V. Conclusion

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.6A
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• pp.458-467
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• 2009

Long Tenn Evolution (LTE) is the next generation mobile phone technology which has being standardized by the Third Generation Partnership Project (3GPP). In the existing mobile communication networks, voice traffic is delivered through circuit switched networks. In LTE, however, all kinds of traffic are transferred through IP based packet switched networks which has best-effort characteristic. Therefore, providing QoS in LTE system is difficult. In order to provide QoS in LTE, RRM is very important. Especially, in part of RRM, call admission control (CAC) performs an important function to reduce network congestion and guarantee a certain level of QoS for on-going calls. In this paper, we propose a CAC algorithm in order to provide QoS for various kinds of services in LTE system. The performance of the proposed algorithm is evaluated with various simulation environments. The results show that the proposed algorithm provides QoS through rejections of requested calls. Especially, the proposed CAC algorithm can be satisfied with packet delay requirement defined in LTE specification.

• Electronics and Telecommunications Trends
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• v.29 no.3
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• pp.107-117
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• 2014

최근 스마트폰의 보급에 따라 모바일 관련 서비스의 급격한 시장성장으로 인한 무선랜 사용이 급속하게 증가하고 있다. 이로 인한 사용자의 증가는 사용기기의 고밀도화를 야기하였고, 이에 따른 전송신호에 대한 심각한 간섭증가 및 서비스 품질 저하를 초래했다. 본고에서는 현재 무선랜 네트워크의 성능저하의 주요 문제점인, 간섭증가에 대한 해결책으로 고려되고 있는 간섭회피기술과 간섭정렬기술에 대해 살펴본다. 또한 이동통신시스템의 트래픽 분산망으로, 무선랜 네트워크가 제공할 수 있는 성능측면에서 중요하게 고려되고 있는 QoS(Quality of Service) 관리기술에 대해 무선랜 표준그룹의 최근 기술에 대해 살펴보고자 한다. 이들 세 분야에 대한 종합적인 기술개발이 진행될 때 차세대 무선랜 네트워크의 요구되는 성능이 확보될 것이다.