• Journal of the Korea Society of Computer and Information
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• v.12 no.6
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• pp.235-242
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• 2007

Network Mobility Basic Support protocol reduces location-update signaling by making network movements transparent to the mobile nodes (MNs) behind the mobile router (MR), but causes some problems such as sub-optimal routing and multiple encapsulations. This paper proposes an Route Optimization Employing HMIP Extension for Mobile Networks (ROHMIP) scheme for nested nubile networks support which introduces HMIP concept with relation information between MNNs behind a MR and the MR in order to localize handoff, to optimize routing and especially reduce handoff signal overhead. With ROHMIP, a mobile network node (MNN) behind a MR performs route optimization with a correspondent node (CN) as the MR sends a binding update message (BU) to mobility anchor point (MAP) via root-MR on behalf of all active MNNs when the mobile network moves. This paper describes the new mechanisms and provides simulation results which indicate that our proposal reduces transmission delay, handoff latency and signaling overhead.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.11A
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• pp.1085-1091
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• 2006

For an experiment in this paper, designed test bed to secure confidentiality of data and safe transmission that Mobile node exchanges in Mobile network. And, For IPsec use that support basically in MIPv6, modeling and experimented IKEv2 protocol that is used for reliable authentication key management and distribution between End Point. When Mobile node handoff in Mobile network, analyzed effect that authentication key re-exchange and limited bandwidth that happen often get in key exchange. And studied about Performance and latency about authentication setting and exchange process that use multi interface. To conclusion, when Mobile node transmits using IPSec, re-authentication of key confirmed that re-setting by limit of bandwidth that existent Mobile network has can be impossible. According to other result, proposed MN's multi interface is expected to minimise key exchange latency by hand-off when transmit IPSec.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.5A
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• pp.509-516
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• 2008

The Fast Handover in Hierarchical Mobile IPv6(F-HMIPv6) scheme provides a seamless handover in mobile IP networks effectively. However, there is a problem that the mobile node can lose its connectivity to the previous access router because of a sudden degradation of the link quality during fast handover procedure. Additionally, in many cases, the mobile node does not have enough time to exchange messages during the fast handover procedure, especially in case of movement with high speed during handover. In this paper, we propose a modification to F-HMIPv6 that significantly reduces the time to exchange messages during fast handover procedure and thereby increases the probability which the F-HMIPv6 can perform the fast handover in predictive mode.

• Journal of KIISE:Information Networking
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• v.36 no.3
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• pp.204-211
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• 2009

Proxy Mobile IPv6(PMIPv6) is that network-based mobility management protocol that network supports mobile node's mobility on behalf of the Mobile Node(MN). In PMIPv6 network, data packets from a Correspondent Node(CN) to a MN will always traverse the MN's Local Mobility Anchor(LMA). Even though, CN and MN might be located close to each other or within the same PMIPv6 domain. To solve this problem, several PMIPv6 Route Optimization(RO) schemes have been proposed. However, these RO schemes may result in a high signaling cost when MN moves frequently between MAGs. For this reason, we propose an adaptive route optimization(ARO) scheme. We analyze the performance of the ARO. Analytical results indicate that the ARO outperforms previous schemes in terms of signaling overhead.

• The KIPS Transactions:PartC
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• v.18C no.2
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• pp.111-118
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• 2011

Recently, with the popularity of smartphones, an interest in multi-networking service through wireless multi-interface of a mobile node is increased. Also, wireless networking technology for using wireless multi-interface has been studied. As the related work, in the IETF Netext WG, the extension of PMIPv6 protocol for multi-interface support is being discussed. Existing PMIPv6 protocol includes the functions for simultaneous access over multi-interfaces of a mobile node and inter-technology handover between multi-interfaces of the mobile node. However, in case of the existing protocol, the problem occurs when inter-technology handover is performed after simultaneous access on the PMIPv6 domain, this problem is the discontinuous of simultaneous connections. Therefore, the PMIPv6 Protocol cannot support flow based multi-homing service. In this paper, as a way to solve the problem, Hybrid Home Network Prefix scheme is proposed.

• Proceedings of the Korea Contents Association Conference
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• 2005.05a
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• pp.507-513
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• 2005

This paper proposes a fast handoff scheme between PDSNs in 3GPPs network for a mobile node. It introduces a method by which handoff can be performed without reestablishing PPP connection that may occur in the process of performing handoff between PDSNs. The method for handoff between PDSNs which provide packet services to a mobile node, requires that the PDSNs should receive subscribers information about mobile nodes from their neighbor PDSNs forming a communication network. When the PDSN recognizes the mobile node moving into its coverage area, it can quickly establish a communication channel with the mobile node based on the already received subscriber information. As a result, handoff is performed without reestablishing PPP. Accordingly, handoff between PDSNs can be performed faster, removing time needed for establishing a PPP session with a terminal and for terminating a previously set up PPP session.

• Journal of the Korea Society of Computer and Information
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• v.20 no.2
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• pp.89-97
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• 2015

In this paper, we propose a handoff method supporting LBS (Location Based Services) Information in mobile clouding environment. In mobile clouding computing, handoff delay and re-authentication is occurred. A mobile node needs re-authentication procedure from cloud server whenever it arrives new AP. But Using of location information of node enables to reduce delay time due to re-authentication. To reduce re-authentication delay time, proposed method stores location information of APs on WiFi based location server to complement. GPS-based technology which can't receive satellite signal in indoor and then node collects location information of AP at handoff time. And also enables to process LBS without increasing handoff delay by splitting the process of handoff from process of requesting location information. For analysis of proposed method, We analyze handoff delay and location information process time and have compared previous handoff method in cloud environment. We confirmed that proposed method shows lower delay time without increasing LBS process time than previous method because node receives location information from location information server when handoff is occurred.

• Journal of the Korea Society of Computer and Information
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• v.14 no.1
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• pp.107-115
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• 2009

The cryptological key which is used in WiMAX environment is used at regular intervals by mobile nodes (laptop computer, PDA, cell-phone) which is in the range of base station coverage. But it is very weak at local attack like man-in-the-middle when the mobile node is off the range of base station or enters into the range to communicate with base station because the communication section is activated wirelessly. This paper proposes a distribution key building protocol which can reuse security key used by nodes to reduce cryptological security attack danger and communication overhead which occurs when mobile node tries to communicate with base station. The proposed distribution key establishing protocol can reduce overhead which occurs between base station and mobile node through key reusing which occurs during the communication process and also, makes security better than IEEE 802.16 standard by creating shared key which is required for inter-certification through the random number which node itself creates.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.7B
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• pp.991-1000
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• 2010

The Hierarchical Mobile IPv6 (HMIPv6) has been proposed to accommodate frequent mobility of the Mobile Node. HMIPv6 can effectively reduce the signaling overhead and latency. However, it has a problem that the registration of a mobile node concentrates on the furthest MAP(Mobility Anchor Point) when the mobile node enters into a new domain. This paper proposes a new load distribution mechanism by using the concept of Nash Bargaining Solution. The main advantage of the proposed scheme can prevent load concentration from being registered to the specified MAP based on the weight value according to the available resource-ratio of a MAP. With a simulation study, the proposed scheme can improve network performance under widely diverse traffic load intensities.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.3
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• pp.872-885
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• 2015

The rapid increase of smart mobile devices and mobile applications has led to explosive growth of data traffic in cellular network. Offloading data traffic becomes one of the most urgent technical problems. Recent work has proposed to exploit opportunistic communications to offload cellular traffic for mobile data dissemination services, especially for accepting large delayed data. The basic idea is to deliver the data to only part of subscribers (called target-nodes) via the cellular network, and allow target-nodes to disseminate the data through opportunistic communications. Human mobility shows temporal and spatial characteristics and predictability, which can be used as effective guidance efficient opportunistic communication. Therefore, based on the regularity of human mobility we propose NodeRank algorithm which uses the encounter characteristics between nodes to choose target nodes. Different from the existing work which only using encounter frequency, NodeRank algorithm combined the contact time and inter-contact time meanwhile to ensure integrity and availability of message delivery. The simulation results based on real-world mobility traces show the performance advantages of NodeRank in offloading efficiency and network redundant copies.