• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.2B
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• pp.143-150
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• 2009

In this paper, we propose a novel shadow clustering mechanism including a mobility estimation algorithm based on Gauss-Markov mobility model which analyses patterns of moving direction and speed of a mobile terminal respectively and a selection algorithm of the most suitable network for the requirements of mobile terminals. The proposed mechanism makes much less shadow cluster area than that of the legacy methods, and reduces unnecessary resource reservation. It is compared the proposed algorithm with traditional methods under various scenarios.

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.110-113
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• 1999

In this paper. we propose an adaptive handover scheme in wireless network The proposed handover scheme is a hybrid type of virtual path extension and rerouting. The proposed handover scheme chooses the virtual path management scheme according to the service QoS instead of the network topology which is used in the previous hybrid handover schemes. The proposed scheme supports the seamless service and small buffering during virtual path rerouting handover through the multicasting service. To evaluate the performance of the proposed scheme. we compute the number of signaling message used for handover and perform computer simulation. The simulation results show that the proposed scheme provides more efficiency in the handover delay and seamless service than the previous methods.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.11a
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• pp.453-453
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• 2004

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.2
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• pp.1-7
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• 2019

Recently, multimedia streaming service has been activated, and the demand for high-quality multimedia convergence contents services is predicted to increase significantly in the future. The issues of the increasing network load due to the rise of multimedia streaming traffic must be addressed in order to provide QoS guaranteed services. To do this, an efficient network resource management and mobility support technologies are needed through seamless mobility support for heterogeneous networks. Therefore, in this paper, an MIH technology was used to recognize the network situation information in advance and reduce packet loss due to handover delays, and an ACLMIH-FHPMIPv6 is designed that can provide an intelligent interface through introducing a hierarchical mobility management technique in FPMIPv6 integrated network.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.3
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• pp.101-108
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• 2009

Since the use of wireless communication instruments was standardized, users expect to be provided with seamless information whenever and wherever they use the instruments. Also, some technology is required to satisfy the users' needs which will cover their mobility. To support the mobility of host, the Internet Engineering Task Force (lETF) Mobile IP Working Group proposed a protocol called MIPv6 (Mobile IPv6). But in the case of the existing MIPv6, sometimes Mobile Node cannot receive data packet if Handover occurs although it is a temporal phenomenon. For solving these Handover problems, there are many methods like FMIPv6 (Fast Handover for Mobile IPv6) and HMIPv6 (Hierarchical Mobile IPv6) have been suggested. This paper suggested the use of Dual Buffer of Access Point and an effective way of registration as a way of reducing delayed time caused by Handover. Also, it analyzed and compare the existing MIPv6 with a proposed scheme concerning delayed time of Handover. Finally, the main objective of this paper is to proposed scheme that can reduce the delayed time of Handover compare to the existing MIPv6.

• The Journal of the Korea Contents Association
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• v.6 no.3
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• pp.46-54
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• 2006

Various schemes for mobility are currently studied in ITU-T, 3GPP, IETF, and so on. Mobility support in NGN for seamless service is necessarily required. Currently proposed mechanisms are MIPV6,0, Q.MMF, and IMS. However the performance comparison of all existing schemes is not examined as yet. That is, the existing methods need to be compared according to each performance parameter. So, in this paper, we investigate and compare the performances of MIPv6,0, Q.MMF, IMS to location registration. In addition, this paper presents the performance comparison of handover latency times. For this, we use NS-2 simulator. As a result of analysis, Q.MMF shown the best performance as it is measured the minimum time and cost. And it has low handover latency time in comparison with other mechanisms.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.05a
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• pp.577-580
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• 2012

Communication environment has rapidly evolved into All-IP based core network, which is centered on a variety of access network, and develops into ubiquitous environment for each user due to the development of multiple interface terminals and the spread of contents usage. Especially, mobile streaming technologies and integrated authentication technologies are needed for mobile users to provide seamless mobility. The technology for seamless mobility services is an important issue. In this paper, the IEEE 802.21 MIH information server is based on the network offering handover technology between heterogeneous network.

• Journal of Internet Computing and Services
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• v.9 no.1
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• pp.1-8
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• 2008

IETF has proposed Fast Handovers for Mobile IPv6 (FMIPv6) for efficient mobility management, FMIPv6 has no solutions to protect binding updates. Previous researches have mainly concentrated on using AAA, public cerificates or cryptographic algorithms to secure binding updates. However the approaches need a particular infrastructure or a heavy processing cost to setup secure associations for handovers. Proposed scheem provides authentication for FMIPv6 without infrasturcture and costly cryptographic algorithms by extending Return Routability Protocol. Also proposed scheme is oble to be used for various existing handover mechanisms in IPv6 network.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.2
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• pp.127-134
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• 2017

In this paper, we try to solve the frequency shortage due to the increase of LTE terminals and the traffic jam caused by the inefficient WiFi connection method. The proposed LTE-WIFI Vertical Handover method uses a pre-authentication method of the AP through LTE and a method of controlling the access AP of the terminal using the RADIUS server. Through the simulation, the proposed method shows that the access speed of the AP is improved by about 95% compared to the conventional connection method, and the connection speed is improved by about 18% compared to the conventional method. Providing seamless AP through pre-authentication system and improving wireless network speed through AP access distribution can solve LTE frequency shortage problem and improve wireless network usage satisfaction.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2011.11a
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• pp.251-254
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• 2011

와이브로(Wibro) 또는 WiFI 망에서 동일한 멀티캐스트 그룹에 속한 이동 단말기들은 동일한 MBS(멀티캐스트/브로드캐스트 방송 서비스) 콘텐츠를 수신한다. 동일한 MBS 존 내의 기지국(RAS: Radio Access Station) 들이 MBS 콘텐츠 소스로부터 수신된 MBS 콘텐츠에 대한 전송 시간을 동기화할 수 있도록 기지국들은 전송 동기화 정보와 신뢰성 있는 데이터 패킷 수신을 동기 시간을 결정하기 이전에 보장받을 수 있어야 한다. 만약에 동일한 MBS 존에 속하는 다수의 기지국 중에 전송 동기화 정보를 수신하지 못하거나 패킷 데이터 일부 또는 전부를 수신하지 못한다면, 동기 전송 시간을 결정하기 전에 이미 손실된 정보와 패킷 데이터를 이동 단말기로 전송하게 됨으로써 이동 단말기가 MBS 콘텐츠를 수신하면서 동일 MBS 존 내의 다른 기지국으로 핸드오버하게 되면 MBS 콘텐츠에 대한 끊김없는 수신을 보장할 수 없을 뿐만 아니라 매크로 다이버시티(macro diversity) 이득을 얻기 위한 동일한 MBS 존에서 이동 단말기들에게 전송되는 MBS 콘텐츠들의 동기를 보장 할 수 없다. 따라서, 본 논문에서는 동기 전송 시간을 결정하기 앞서서 다수의 RAS가 전송 동기화 정보와 신뢰성 있는 패킷 데이터 콘텐츠 수신을 보장받을 수 있는 장치를 보완한 멀티캐스트/브로드캐스트 서비스 데이터 전송 동기화 방법을 제안한다.