• Journal of Information Processing Systems
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• v.3 no.1
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• pp.1-7
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• 2007

In mobile ad hoc networks, an application scenario requires mostly collaborative mobility behavior. The key problem of those applications is scalability with regard to the number of multicast members as well as the number of the multicast group. To enhance scalability with group mobility, we have proposed a multicast protocol based on a new framework for hierarchical multicasting that is suitable for the group mobility model in MANET. The key design goal of this protocol is to solve the problem of reflecting the node's mobility in the overlay multicast tree, the efficient data delivery within the sub-group with group mobility support, and the scalability problem for the large multicast group size. The results obtained through simulations show that our approach supports scalability and efficient data transmission utilizing the characteristic of group mobility.

• Journal of information and communication convergence engineering
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• v.17 no.2
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• pp.97-104
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• 2019

Distributed mobility management (DMM) does not use a centralized device. Its mobility functions are distributed among routers; therefore, the mobility services are not limited to the performance and reliability of specific mobility management equipment. The DMM scheme has been studied as a partially distributed architecture, which distributes only a packet delivery domain in combination with the software defined network (SDN) technology that separates the packet delivery and control areas. Particularly, a separated control area is advantageous in introducing a new service, thereby optimizing the network by recognizing the entire network situation and taking an optimal decision. The SDN-based mobility management scheme is studied as a method to optimize the packet delivery path whenever a mobile node moves; however, it results in excessive signaling processing cost. To reduce the high signaling cost, we propose a hybrid distributed mobility management method and analyze its performance mathematically.

• Journal of KIISE:Information Networking
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• v.31 no.5
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• pp.482-489
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• 2004

Paging extensions for Mobile IP was proposed to avoid unnecessary registration signaling overhead of Mobile IP. In order to support the paging function in Mobile IP, the slates of a mobile node arc divided into active on, active off, idle. The active on state means when any incoming or outgoing data session arrives to a mobile node. After data session is completed, the state of the motile node is changed into active off from active on. At this moment, the active timer starts to be operated. If the active timer expires, the mobile node moves to idle state. If a mobile node has very frequently data sessions at the same cell, the mobile node is better to move slowly into idle state. The other way, if the mobile node very frequently moves into new cell area and receives or sends little data, the mobile node is better to move earlier into idle state. In this raper, the active timer is adaptively set by the mobile nodes traffic and mobility characteristics and the paging scheme using this active timer is proposed to reduce the location registration cost.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.7A
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• pp.662-668
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• 2011

This paper analyzes the performance of the Ad hoc On-demand Distance Vector (AODV) routing protocol and Optimized Link State Routing (OLSR) for Mobile Ad hoc Networks (MANETs) using node mobility models. Mobility affects the performance of a routing protocol as it causes changes to network topology. Thus, evaluating the performance of a MANET routing protocol requires mobility models that can accurately represent the movements of mobile nodes. Therefore, this paper evaluates the performance of the AODV and OLSR routing protocols using the random way point model and the Levy walk model by the ns-2 simulations.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.04a
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• pp.1178-1181
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• 2009

Geographic forwarding algorithms을 사용하는 Georouting protocol에서는 route maintenance을 위해서 고정된 주기마다 beacon message을 이웃노드에 전송하는 fixed periodical beacon based route algorithm을 사용하여 mobile node 정보를 습득한다. Fixed periodical beacon scheme에서의 기존 연구 이슈는 이웃노드 정보의 신뢰성을 유지하기 위해서 다양한 mobility environment 환경에 맞도록 beacon 전송주기를 적절히 결정하는 연구가 진행되어 왔다. 이와 같은 연구에서는 long periodical interval 사용 시 이웃노드의 위치정보 error을 발생시킬 확률이 높으며 또한 short periodical interval 의 경우 네트워크 내에 high route overhead 을 유발시키는 단점을 가지고 있다. 따라서 고정된 주기 방법은 다양한 mobility environment에 잘 적용되지 못하며 또한 mobility environment 에서 발생하는 route maintenance 내에 이웃노드 정보에 대한 불확실성 문제가 빈번이 발생하여 경로 설정에 잘못된 정보를 제공하여 경로 신뢰성(path reliability)과 낮은 전송률 (transmission rate)을 야기한다. 본 논문에서는 이런 이웃노드 정보의 불확실성 문제를 극복하기 위해서 mobile node가 스스로 자신의 위치를 체크하여 routing table을 능동적으로 갱신하는 방법을 이용하여 이 문제를 극복할 수 있도록 하였다. 모의 실험은 ns2를 이용하여 실시하였으며 결과는 low/high mobility scenario에서는 기존 방법 보다 routing overhead 을 줄이면서 높은 전송률 (transmission rate)을 보인다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.3
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• pp.99-114
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• 2012

Proxy Mobile IPv6 (PMIPv6) has received considerable attention between telecommunications and the Internet communities and does not require active participation of the Mobile Node (MN) by way of network-based mobility management. The PMIPv6 domain is studying establishment in progress to support extensively a number of MN by using a low handover latency. In this research, we are propose a novel 3S scheme for building Scalable and Secure and Seamless PMIPv6 domains. In the proposed scheme, all of Mobility Access Gateway (MAG) are acting as the Local Mobility Anchor (LMA) and composing a virtual ring with another MAG. General hashing is used in the efficient distribution-mapping between each MN and the MN's LMA of all MAGs. And, MAG and MN are authenticated using the symmetric key. Through mathematical analysis, we verifies the safety, scalability, and seamless service for 3S. Also, we're propose a handover procedure of 3S and show better than the existing schemes in terms of handover latency.

• Proceedings of the Korea Information Processing Society Conference
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• 2004.05a
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• pp.1529-1532
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• 2004

A Mobile Ad Hoc NETwork (MANET) is a collection of wireless mobile nodes that forms a temporary network without the need for any existing network infrastructure or centralized administration. Therefore, such a network is designed to operate in a highly dynamic environment due to node mobility. In mobile ad hoc network, frequent topological changes cause routing a challenging problem and without the complete view of the network topology, establishing the shortest path from the source node to the destination node is difficult. In this paper, we suggest a routing approach which utilizes location information to setup the shortest possible path between the source node and the destination node. Location information is obtained through Global Positioning System (GPS) and this geographical coordinate information of the destination node is used by the source node and intermediate nodes receiving route request messages to determine the shortest path to the destination from current node.

• Proceedings of the Korean Information Science Society Conference
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• 2004.04a
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• pp.577-579
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• 2004

Mobile IP는 이동노드(Mobile node)들에게 이동성 서비스를 지원하기 위해 제안된 것으로 이동노드가 자신의 IP주소를 이용하여 현재 위치에 관계없이 이동성 에이전트(mobility Agent)메 등록함으로 인터넷에 접근 할 수 있는 프로토콜이다. 애드 혹 네트워크는 하부구조 없이 이동노드들 끼리 패킷을 교환 할 수 있는 네트워크이다. 본 논문에서는 Mobile IP의 에이전트가 주기적으로 에이전트 광고 메시지를 전달하여 자신의 서비스 영역 내부에 있는 애드 혹 네트워크의 이동노드들에게 인터넷에 접속할 수 있는 MAAM (Mobility Agent Advertisement Mechanism) 및 AMAAM(Aggregation based Mobility Agent Advertisement Mechanism)을 제안한다.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10c
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• pp.334-336
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• 2004

If Network에서 mobility의 보장은 효과적인 network 동작을 위해 중요하다. Mobile IP와 SIP를 사용할 경우 MH가 위치변경 시 마다 MH로부터 먼 곳에 위치할 가능성이 있는 MH의 Home network내 Home Agent나 Redirect Server에 registration을 수행해야 하는데 이 경우 이전 subnet에서 새로운 subnet으로의 registration이 완료되기 전까지는 correspondent node에 대한 연결성을 잃어 버리게 되어 이로 인해 발생되는 Packet 손실과 delay 생기게 된다. 이런 Registration Problem을 효과적으로 해결하기 위해 Presence System을 이용한 효율적인 network architecture를 제안한다.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.209-210
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• 2006

Hierachical Mobile IPv6 (HMIPv6) solves Micro-mobility protocol problem about Handover. Mobility Anchor Point(MAP) helps reducing the handover, but this makes a load on the MAP. Besides the MAP operates this work everytime, and every Nodes. In this paper, we propose the algorithm that reduces the amount of Map working.