• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.3
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• pp.556-563
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• 2009

HMIP, an extending version of MIP, makes the signaling traffic low, thereby reducing the packet losses and delay. However, it still has the same problem in MIPv6 in the case of macro mobility, though it can reduce the out-signaling in the case of a micro mobility, a regional mobility with the MAP protocol. To overcome this problem, this paper proposes a handover which exploits an address insurance with selective buffering for the HMIP macro handover. This scheme can decrease the lost packets and the delay time and provide better performance for high QoS traffic and real-time multimedia transmission. The simulation result shows that the proposed scheme makes the transmission delay time and the lost packets smaller than the existing schemes.

• International Journal of Computer Science & Network Security
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• v.23 no.8
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• pp.121-136
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• 2023

Wireless Sensor Networks (WSNs) have many potential applications and unique challenges. Some problems of WSNs are: severe resources' constraints, low reliability and fault tolerant, low throughput, low scalability, low Quality of Service (QoS) and insecure operational environments. One significant solution against mentioned problems is hierarchical and clustering-based multipath routing. But, existent algorithms have many weaknesses such as: high overhead, security vulnerabilities, address-centric, low-scalability, permanent usage of optimal paths and severe resources' consumption. As a result, this paper is proposed an energy-aware, congestion-aware, location-based, data-centric, scalable, hierarchical and clustering-based multipath routing algorithm based on Numerical Taxonomy technique for homogenous WSNs. Finally, performance of the proposed algorithm has been compared with performance of LEACH routing algorithm; results of simulations and statistical-mathematical analysis are showing the proposed algorithm has been improved in terms of parameters like balanced resources' consumption such as energy and bandwidth, throughput, reliability and fault tolerant, accuracy, QoS such as average rate of packet delivery and WSNs' lifetime.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.8B
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• pp.1150-1158
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• 2010

At present multimedia service composed of voice, data, and video service is prevalent in the Internet. As such, wide-scale penetration of Internet service imposes tremendous pressure to the network infrastructure such as the media servers and links as well as the nodes. In addition, users from a large-scale population require broad bandwidth and high level of QoS. This requires a network with reliable and scalable services to customers, which also necessitates a realistic method for the design of the a media server. In this work, we explore the influence of user's behavior about delay on the performance of media server that takes into account the system and user attributes in a realistic manner. By incorporating user's behavior about the delay-sensitivity, we present an analytic framework for the evaluation of the performance of the media server, via which we illustrate a meaningful intuition in the provision of Internet multimedia service.

• Journal of KIISE:Information Networking
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• v.36 no.5
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• pp.425-436
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• 2009

In recent years, the user demands have increased for multimedia service of high quality over the broadband convergence network. These rising demands for high quality multimedia service led the popularization of various user terminals and large scale display equipments, which needs a variety type of QoS (Quality of Service). In order to support demands for QoS, numerous research projects are in progress both from the perspective of network as well as end system; For example, at the network perspective, QoS guaranteeing by improving of internet performance such as Active Queue Management, while at the end system perspective, SVC (Scalable Video Coding) encoding scheme to guarantee media quality. However, existing AQM algorithms have problems which do not guarantee QoS, because they did not consider the essential characteristics of video encoding schemes. In this paper, it is proposed to solve this problem by deploying the TS- AQM (Temporal Scalability Active Queue Management) which employs the differentiated packet dropping for dependency of the temporal level among the frames, based on SVC encoding characteristics by exploiting the TID (Temporal ID) field of the SVC NAL unit header. The proposed TS-AQM guarantees multimedia service quality through video decoding reliability for SVC streaming service, by differentiated packet dropping when congestion exists.

• Journal of the Korea Society for Simulation
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• v.17 no.4
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• pp.89-97
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• 2008

In wireless personal area networks (WPANs), the successful design of channel time allocation algorithm is a key factor in guaranteeing the various quality of service (QoS) requirements for the stringent real-time constraints of multimedia services. In this paper we propose a channel time allocation algorithm for achieving a high quality transmission and high channel error tolerance of MPEG stream in the IEEE 802.15.3 high-rate wireless PANs. Our algorithm exploits the characteristics of MPEG stream. When a new MPEG stream arrives, a DEV models it by the traffic envelope and delivers the traffic envelope to the piconet coordinator (PNC) along with the channel time request. The PNC performs channel time allocation according to the envelope. Performance of the proposed scheme is investigated by simulation and analysis. Our results show that compared to conventional scheme, the proposed scheme is very effective and provides a good performance under typical channel error conditions.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2013.11a
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• pp.20-23
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• 2013

Recently for the transfer of large size video file between sites for high-definition craft editing used by broadcasting company the Public Network is used a lot. In the IP Public Network with QoS(Quality-of-Service) not guaranteed, degradation of performance has several causes. In this paper, we have analyzed the causes of low performance to transfer a large size HD video file in long distance, in order to maximize the effectiveness, the high efficiency network could be implemented enabling the highspeed of HD video file using the connection with networks between hosts through packet creation and multi-session of Parallel TCP. We survey the result of high speed transfer system and verify the efficient transfer method using Public IP Network for large HD video file transfer in broadcasting cooperation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.7B
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• pp.1018-1033
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• 2010

Recently, as the use of mobile terminal is generalized, the needs of high-speed Internet mobile service is increased. Also users want to receive the multimedia contents what they want through the various terminals in anywhere, anytime via wired and wireless integrated environment. Therefore, various mechanisms that support the mobility are proposed. However, these mechanisms are difficult to support seamless mobility and QoS awareness on the mobile multicast environment. In this paper, we propose a QoS aware handover mechanism that is able to provide the high-quality and real-time services such as mobile IPTV in an integrated environment for these requests of users. Proposed mechanism manages the multicast admission control and multicast handover using the 2-layer multicast information management at the wired and wireless integrated network that extended the service guaranteed methods through the probing based admission control of the wired network to the wireless network based on PMIPv6. We present a performance evaluation results and features analyzed by the simulations using the ㎱-2.

• Journal of KIISE:Computer Systems and Theory
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• v.26 no.12
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• pp.1504-1515
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• 1999

무선 이동 통신망은 기존의 음성위주로 제공되던 단일 미디어 서비스의 제공으로부터 발전되어 2000년대 초까지 이동 사용자에게 고품질의 멀티미디어 데이타 서비스를 제공하고, 장소에 제한을 받지 않고 서비스를 제공받을 수 있도록 하는 IMT-2000을 실현을 목표로 발전하고 있다. 또한 다수의 서비스 사용자와 광대역의 데이타를 전송하기 위해서 셀의 반경은 점차로 축소되고 있다. 이에 따라서, 사용자의 위치등록과 핸드오버와 같은 처리에 대한 부하가 커지게 되었다. 그러므로 무선 이동통신에서 서비스 이용자에게 일정 수준 이상의 QoS를 보장해 주기 위해서 효율적인 핸드오버 알고리즘의 도입은 매우 중요한 문제가 되고 있다. 본 논문에서는 IMT-2000환경에서 보다 효율적인 QoS를 서비스 사용자에게 제공해 줄 수 있도록 하기 위해 다양한 이동체의 속도와 멀티미디어 트래픽 특성을 동시에 고려하여 신뢰성 있는 핸드오버를 제공하는 H-PS(Hybrid-Priority Scheme)알고리즘을 제안하고 시뮬레이션을 통해 성능을 분석한다.Abstract Wireless mobile communications is developed from the only single voice traffic sevice to multimedia sevices. And mobile communications will evolve IMT-2000, which is provide users with high quality multimedia services. A radius of cell is gradually reduced to accept many service users and transport the multimedia traffics. Therefore, a overhead of location tracking and handover processing are increased. Then to guarantee high QoS to service users in wireless mobile communications, efficient handover algorithm is very important issue.In this study, we propose a H-PS(Hybrid-Priority Scheme) handover scheme considering mobility and traffic characteristics in IMT-2000 networks. And performance evaluate using simulation.

• The KIPS Transactions:PartC
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• v.13C no.5 s.108
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• pp.651-658
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• 2006

Mobile computing environment is known to be quite difficult to provide user with a stable QoS(Qualify of Service) due to its mobility nature. In order to protect the inherent characteristics of wireless network such as low bandwidth and high transmission delay along with the user's mobility, many works are conducted to apply caching and prefetching methods. This paper presents a novel prefetching technique which is based on user's preference, that is, interest and Uuかity. It tries to improves the effectiveness of prefetching by separating and appling the interest with personal tendency of a given information, and the popularity with general tendency of the information. The proposed scheme shown relatively superior performance in terms of the utilization ratio of prefetched information and the failure ratio of information retrieval than the existing methods.

• Journal of KIISE:Information Networking
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• v.29 no.6
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• pp.595-612
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• 2002

One of the most important issues in guaranteeing the high degree of QoS on mobile computing is how to reduce hand-off drops caused by lack of available bandwidth in a new cell. Each cell can request bandwidth reservation to its adjacent cells for hand-off calls. This reserved bandwidth can be used only for hand-offs, not for new calls. It is also important to determine how much of bandwidth should be reserved for hand-off calls because reserving too much would increase the probability of a new call being blocked. Therefore, it is essential to develop a new mechanism to provide QoS guarantee on a mobile computing environment by reserving an appropriate amount of bandwidth and call admission control. In this paper. bandwidth reservation and call admission control mechanisms are proposed to guarantee a consistent QoS for multimedia traffics on a mobile computing environment. For an appropriate bandwidth reservation, we propose an adaptive bandwidth reservation mechanism based on an MPP and a 2-tier cell structure. The former is used to predict a next move of the client while the latter to apply our mechanism only to the client with a high hand-off probability. We also propose a call admission control that performs call admission test only on PNC(Predicted Next Cell) of a client and its current cell. In order to minimize a waste of bandwidth caused by an erroneous prediction of client's location, we utilize a common pool and QoS adaptation scheme. In order evaluate the performance of our call admission control mechanism, we measure the metrics such as the blocking probability of new calls, dropping probability of hand-off calls, and bandwidth utilization. The simulation results show that the performance of our mechanism is superior to that of the existing mechanisms such as NR-CAT2, FR-CAT2, and AR-CAT2.