• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.10
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• pp.1786-1795
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• 2006

Portable Internet extended from wireless LAN has a large cell size, similar to a wireless mobile communication. and can provide the seamless service which offers middle-low speed mobility. IEEE 802.16e, the international standard of Portable Internet, uses PKMv2 protocol for authorization and key exchange between a MSS and a BS. This paper proposes a new protocol based on PKMv2, which can provide that MSS is able to do fast authorization with a new BS when soft handover is occurred in a MSS. Our protocol can carry out fast authorization because of reducing the number of messages and parameter exchange, public key encryption and signature in wireless network more than the previous works. It also prevents eavesdropping from an external attacker and keeps the security against impersonation attacks for both a MSS and a BS.

• Journal of Korea Multimedia Society
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• v.11 no.5
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• pp.673-684
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• 2008

In this paper, we propose a signaling protocol which can support QoS for multimedia applications continuously after handover of a mobile node in the network environment where IP-based wireless access networks co-exist. Since existing RSVP-based signaling protocols can cause the waste of network resources due to double reservation and do not provide fast resource reservation/release, they are not suitable for mobile networks. The proposed QoS signaling protocol can support QoS for multimedia applications using the fast reservation of necessary resources after handover and avoid the waste of resources by resolving the double reservation problem. This paper presents design and implementation architectures of the proposed signaling protocol and analyzes its performance via a physical testbed. Based on the analysis results, it was shown that the proposed protocol is able to support seamless QoS for multimedia applications.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.981-985
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• 2006

Wibro is stand for Wireless Broadband Internet called as Portable Internet, Wireless Broadband Internet or Wireless High-Speed Internet. This provides hish-speed internet service anytime, anywhere, from anyone and device with seamless mobility and the band is located between Mobile phone and wireless LAN. Wibro service should support handover to maintain connection continuously in movement because the service is based on If system which is different from cellular system. Current Mitre Mobility system and general Mobile If system has got a problem of delayed speed and lost packets during handover. IETF protocol has been proposed for minimizing this problem and its standardization is under process, mainly focused on Mip4, Mip6 and Mipshop WG. This article studies and analyzes an effective method of minimizing handover delay to improve the problem of WiBro system and its revitalization & outlook.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.6 s.348
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• pp.39-45
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• 2006

n a hybrid ad-hoc network, wired network and a mobile ad-hoc network are connected by the internet gateway. To provide seamless service for internet users in the hybrid ad-hoc network, an efficient internet gateway selection technique and a fast handover technique are needed. In this paper, we propose a seamless handoff technique for providing mobility of mobile hosts in hybrid ad-hoc networks. The proposed internet gateway re-registration algorithm improves general handoff performance. Moreover, the handoff processing time within certain range of area is reduced by using mobility management agent(MMA). In addition the packet loss is reduced when handoff occurs out of the range of MMA by tunneling technique.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.1B
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• pp.7-20
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• 2011

Recently, Proxy Mobile IPv6(PMIPv6) networks have been studied as the mobility management protocol to effectively use limited wireless resources. And the multicasting, which is core technology of the Internet broadcast system such as mobile IPTV, has been discussed mainly based on PMIPv6 network. However, multicasting based on PMIPv6 network causes disconnection of services because it does not solve problems of packet loss during binding and group joining procedure. Hence, we propose a seamless multicast scheme which prevents packet loss in PMIPv6 networks. The proposed scheme achieves lower latency than the existing scheme because it combines binding and group joining procedure, a1so it does not cause about packet losses due to performing buffering. We proved the performance using the simulations.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.12
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• pp.45-51
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• 2010

The main issue in mobile cloud computing is how to support a seamless service to a mobile mode. Mobile IPv6 (MIPv6) is a mobility supporting protocol which is standardized by the Internet Engineering Task Force (IETF). Mobile IPv6 fast handovers (FMIPv6) is the extension of MIPv6 which is proposed to overcome shortcomings of MIPv6. Recently, fast handovers for Mobile IPv6 over IEEE 802.16e which is one of broadband wireless access systems has been proposed by the IETF. It was designed for supporting cross-layer fast handover. In this paper, we propose an enhanced cross-layering mobile IPv6 fast handover over IEEE 802.16e networks. In our scheme, a new access router generates a new address for the mobile node by using a layer 2 trigger. We utilize a layer 2 message which is sent from a new base station to the new access router in order to inform the new access router of information of the mobile node. A previous access router sends a binding update message to the mobile node's home agent when it acquires the new address of the mobile node. We evaluate the performance of the proposed scheme compared with the existing schemes in terms of the signaling cost and the handover latency. From the results, we observe that the proposed scheme can support fast handover effectively over IEEE 802.16e networks than existing schemes.

• Proceedings of the KIEE Conference
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• 2005.07d
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• pp.2780-2782
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• 2005

In this paper, we present a mobile robot localization solution by using a Ubiquitous Vision System (UVS). The collective information gathered by multiple cameras that are strategically placed has many advantages. For example, aggregation of information from multiple viewpoints reduces the uncertainty about the robots' positions. We construct UVS as a multi-agent system by regarding each vision sensor as one vision agent (VA). Each VA performs target segmentation by color and motion information as well as visual tracking for multiple objects. Our modified identified contractnet (ICN) protocol is used for communication between VAs to coordinate multitask. This protocol raises scalability and modularity of thesystem because of independent number of VAs and needless calibration. Furthermore, the handover between VAs by using ICN is seamless. Experimental results show the robustness of the solution with respect to a widespread area. The performance in indoor environments shows the feasibility of the proposed solution in real-time.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10c
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• pp.109-111
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• 2004

본 논문은 IEEE 802.11 네트워크 환경에서 MN(Mobile Node)이 핸드오버를 수행하기 전에 미리 이동 정보를 예측함으로써, 유연하게(Seamless) 서비스를 계속 받을 수 있는 예측 방법을 제안한다. 특히, MN이 속한 AP(Access Point)가 중첩된 상황에서 발생할 수 있는 여러 가지 문제점을 해결한다. MN은 이동성 패턴 레코드를 저장하고, 또한 각 이웃 AR(Access Router)은 AP의 AP-ID(BSSID, Basic Service Set ID)와 채널을 저장한다. MN이 AP의 영역의 경계를 벗어나기 전, 새로운 AP로부터 AP-lD를 획득하면, MN이 저장하는 이동성 패턴 레코드에서, AP-ID와 맞는 정보를 비교하여 확률이 높은 AP를 선택한다. 이러한 정보를 PAR(Previous Access Router)에게 정보를 보내어 신속하게 새로운 링크에서 서비스를 받을 수 있음으로써 손실.지연을 최소화 할 수 있다.

• Proceedings of the IEEK Conference
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• 2003.11c
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• pp.227-230
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• 2003

Mobile SCTP (mSCTP) is a new scheme which can be used to provide seamless handover for the mobile node. The reason that is possible is because of the SCTP extension which provides a method to reconfigure IP address on an existing SCTP association (ADDIP). While mSCTP focuses on an association originated ken mobile node (MN) toward fixed correspondent node (CN), mSCTP with Mobile IP support an association originated from CN toward MN by using the Home Agent in Mobile IP and location management. However, there are still some problems related to communication interruption. In this paper, we present a new scheme to solve these problems. The main idea of this scheme is using the home address of MN as a backup path of an SCTP association.

• 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