• Journal of KIISE:Information Networking
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• v.33 no.3
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• pp.269-276
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• 2006

This paper proposes a seamless handover scheme for high-speed trains using dual mobile routers to minimize service disruption time and packet loss during handovers. In the proposed scheme, each of the dual mobile routers is located at each end of the moving network for space diversity. One of the two mobile routers can continuously receive packets from its home agent, while the other is undergoing a handover, but they act as one logical mobile router. Analytical and simulation results showed that the proposed scheme could provide no service disruption or packet losses during handovers.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.10a
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• pp.66-69
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• 2008

As a mobility support for IP have studied, Internet Engineering Task Force(ITEF) standardized the mobile IPv6 protocol. When a mobile node moves between networks, MIPv6 maintains connectivity to network and supports seamless communication, and these processes are called a Handover. IEEE 802.21 standardized MIH(Media Independent Handover) for seamless Handover. MIH used three services for Handover between low layer and upper layer. In this paper, we designed two modes on existing MIH for seamless Handover. We implemented a dual-interface mobile host(MH) model in network simulation2 (ns2) to evaluate how it performs in comparison with single-interface MH.

• Journal of the Institute of Convergence Signal Processing
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• v.10 no.1
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• pp.66-71
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• 2009

In view of mutual complementary feature of wide coverage and high data rate, the interworking between 3G cellular network and WLAN is a global trend of wireless communications. This paper introduces the analytic result of an authentication mechanism for 3GPP-WLAN seamless mobility under the USIM-based authentication test-bed. In a handover process between heterogeneous networks, authentication is the main factor of handover delay. So authentication processing time should be firstly reduced. This paper describes an USTM-based EAP-AKA test-bed implemented for handover in UMTS and WLAN interworking systems. Experimental result has shown that the fast re-authentication mechanism during handover has reduced the handover delay by about 48.6%.

• Journal of Internet Computing and Services
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• v.13 no.3
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• pp.1-16
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• 2012

Cost-effective mobility management for the roaming mobile users is very important in the seamless services on next-generation wireless network (NGWN). MIPv6 (Mobile IPv6) is one of the mobility management schemes proposed by the IETF (The Internet Engineering Task Force) and various IPv6-based mobility management schemes have been developed. They are directly involved with data transfer from MN (Mobile Node). In this paper, two kinds of schemes in analyzing of mobility management schemes are proposed. The signaling transfer and packet delivery procedures for each mobility management schemes are analyzed, respectively. The signaling cost for mobility management schemes are calculated, and the cost of each protocol are analyzed numerically. In other word, applying the sum of signaling cost and packet delivery cost to each mobility management scheme, their costs are analyzed. Finally, our performance evaluation results that the network-based mobility management scheme shows better performance in terms of overall cost.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.589-592
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• 2007

Ubiquitous environment means the environment in which users can access the Internet at anytime and anywhere. Network mobility support is needed for seamless Internet service in ubiquitous environment. When users try to access the Internet in public transportation such as bus, train, airplane, to support network mobility by composing several sub-networks is more efficient than to support host mobility. IETF established 'Network Mobility(NEMO)' working group to research and develop network mobility technology. In this paper, we investigate the concept of network mobility, trends of research in NEMO and developed technology on the basis of 'Network Mobility Basic Support Protocol' standardized by IETF.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.6
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• pp.652-662
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• 2016

This paper proposes a user mobility management scheme which supports seamless service even if a user changes his accessing terminal in service in IP-based convergence network. Most of ongoing researches concerning mobility management as well as the existing mobility schemes have been focused to support terminal mobility. It is limited to support a variety of mobility types such as user mobility. The proposed scheme uses the mapping relationship between UID(User Identifier), user specific identifier and TID(Terminal Identifier), specific terminal identifier and forms packet address with user specific permanent 3 layer address for session continuity in case of user mobility. We numerically analyze and compare handover signaling cost between the existing user mobility scheme and the proposed scheme. The result shows that the proposed scheme has lower handover signaling cost than the existing one, [1].

• Journal of Korea Multimedia Society
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• v.19 no.11
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• pp.1871-1877
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• 2016

In this paper, a Wireless USB (WUSB) protocol is adopted for development of ASMD (Adaptive Source Multi Device) N-screen wireless services. WUSB is the USB technology merged with WiMedia PHY and Distributed-MAC (D-MAC). However, the current WUSB protocol can't provide seamless N-screen streaming services to moving WUSB devices in home network environment. Therefore, to provide the ASMD N-screen services through WUSB based on D-MAC protocol, a channel management scheme is proposed to support seamless mobility between adjacent ASMD groups for wireless IPTV N-screen services. In simulation results, proposed ASMD channel management (ACM) scheme is compared with conventional WUSB channel management scheme in view points of throughput, average path interference and energy consumption according to various numbers of nodes and elapsed simulation times. Through simulation results, it is explained that proposed ASMD channel management (ACM) scheme should be adopted in the WUSB protocol to realize ASMD N-screen wireless services.

• Proceedings of the Korea Contents Association Conference
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• 2009.05a
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• pp.677-681
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• 2009

The Smoothly Coupled Integration (SCI) proposed in this paper takes only the strength of loosely coupled integration and tightly coupled integration. Furthermore, 3G network and WiBro network, which are coupled with SCI, have independent architecture which supports mobility and seamless services by fast handoff. Computer simulation with the use of OPNET marked excellence in performance of smoothly coupled integration.

• 한국정보통신설비학회:학술대회논문집
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• 2009.08a
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• pp.211-214
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• 2009

In this paper, we present an efficient handover method avoiding ping-pong phenomenon in Wireless LAN systems. In order to provide the seamless VoIP service for terminals with mobility in Wireless LAN systems. Since the variation range of the received signal strength of the moving terminals is large, the handover procedure can be started by an instant drop of the signal strength. Then the handover procedure is repeated, which makes ping-pong phenomenon. Since the quality of service of VoIP can be lowered by ping-pong phenomenon, in this paper, we present the necessary condition to avoid the ping-pong phenomenon. Through LAB test, we show that the proposed handover method can provide an seamless service without the ping-pong phenomenon.

• Proceedings of the Korea Society for Simulation Conference
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• 2004.05a
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• pp.123-130
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• 2004

모바일 인터넷 액세스 서비스에서의 트래픽은 음성위주에서 동영상에 기반 한 멀티미디어 서비스로 급속히 전이되고 있으며 그 속도는 점차 가속되고 있다. 따라서 이러한 멀티미디어 트래픽을 보다 효율적이고 신속히 처리하기 위하여 IP에 기반 한 'Beyond IMT-2000(3G 및 그 이후 세대)' 네트워크의 필요성이 대두되고 있다. 본 논문에서는 모바일 환경에서 대용량의 멀티미디어 트래픽을 보다 효율적이고 신속히 처리하고 유비쿼터스 컴퓨팅 환경을 지원하기 위한 'Beyond IMT-2000' 네트워크의 의미를 가진 다양한 Seamless 서비스를 제공해 주는 IP에 기반하고 있는 IP$^2$네트워크의 개념 및 아키텍처에 대하여 서술한다. 나아가 본 논문은 모바일 전달매체의 역할을 수행하는 IP$^2$ 트랜스포트 네트워크의 설계 시 요구되는 필요사항을 IP-BB의 관점에서 정의하였으며 이와 같은 요구사항을 충족시킬 수 있는 방안을 설명하였다.충족시킬 수 있는 방안을 설명하였다.