• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.9B
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• pp.857-866
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• 2009

Recently, IP mobility study of infra's common elements is undergoing processes to achieve FMC based on All-IP. Existing typical mobility technology based on IP is IETF's Mobile IP. However, it faced to limitations due to packet loss, delays when MN is moving on Mobile IP, also existing network infra - routers (FA)-needed to add/change the functions to support Mobile IP. In this paper, existing mobility problems based on IP and the suggested improvements for platforms which support mobility, quality, security are proposed. It discusses the performance on the current existing IP infrastructure derived from simulation analysis on mobility packet loss and delay. From the resulting data, improvements will also be outlined for optimal performance.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.3B
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• pp.207-215
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• 2006

It has known that the handover based on MIP in mobile environments has many constraints for proving seamless service due to well hon problems. Although there has been researching for the solutions, such as MRSVP and HMRSVP etc, it is difficult to do the research related with QoS due to the issues based on MIP used as a seamless mobility. In this paper, the seamless provides in a mobility based on SCTP, which is applied by IntServ for end-to-end QoS service. The paper also proposes the path management scheme for saving reservation cost. the scheme searches a new path on the moving mobile terminal and reserves the resources on the path for providing seamless QoS service. The paper is also analyzed on the comparition between a SCTP based and MIP based solutions. the scheme is evaluated using the cost effect saved for resource reservation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.6B
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• pp.592-599
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• 2011

Proxy Mobile IPv6 (PMIPv6) is the network-based mobility management protocol that network supports the mobility of mobile node (MN) on behalf of the MN. In PMIPv6, a multi-homed MN can connect to the PMIPv6 domain by using only one interface even though it has multiple interfaces. It would be efficient when such a multi-homed MN connects to the PMIPv6 domain by using all of its interfaces. If such a multi-homed MN utilizes all of its interfaces, flow mobility can be provided that the MN handovers one or more flows from one interface to another without re-establishing session. In this paper, we propose the flow-based mobility management protocol by considering the intention of the user. The Router Advertisement (RA) message is used in order for the PMIPv6 domain to inform that the MN can utilize the flow mobility. The proposed mechanism is evaluated by analyzing signaling overhead and handover latency, and the numerical results show that the performance is affected by mobility speed of the MN and the failure probability of the wireless link.

• Journal of Information Processing Systems
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• v.8 no.4
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• pp.603-620
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• 2012

Proxy Mobile IPv6 (PMIPv6) is a network-based mobility support protocol and it does not require Mobile Nodes (MNs) to be involved in the mobility support signaling. In the case when multiple interfaces are active in an MN simultaneously, each data flow can be dynamically allocated to and redirected between different access networks to adapt to the dynamically changing network status and to balance the workload. Such a flow redistribution control is called "flow mobility". In the existing PMIPv6-based flow mobility support, although the MN's logical interface can solve the well-known problems of flow mobility in a heterogeneous network, some missing procedures, such as an MN-derived flow handover, make PMIPv6-based flow mobility incomplete. In this paper, an enhanced flow mobility support is proposed for actualizing the flow mobility support in PMIPv6. The proposed scheme is also based on the MN's logical interface, which hides the physical interfaces from the network layer and above. As new functional modules, the flow interface manager is placed at the MN's logical interface and the flow binding manager in the Local Mobility Anchor (LMA) is paired with the MN's flow interface manager. They manage the flow bindings, and select the proper access technology to send packets. In this paper, we provide the complete flow mobility procedures which begin with the following three different triggering cases: the MN's new connection/disconnection, the LMA's decision, and the MN's request. Simulation using the ns-3 network simulator is performed to verify the proposed procedures and we show the network throughput variation caused by the network offload using the proposed procedures.

• 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.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.12
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• pp.2195-2200
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• 2008

The use of WLAN technology specially 802.11 b and g has seen huge subscriber growth in a relatively short time period due to low cost and ease of installation of WLAN hardware. These technologies provide multiple data rates ranging from 1 to 54 Mbps depending on modulation used in physical layer. This paper presents the performance of 802.11b and g under different data rates in mobile IPv4 environment. OPNET is used in the study as the network simulator. The performance metrics used in this wort is data traffic received by a WLAN station roaming amongst Access Point(AP) of different ESSs. It is found that much data packets are lost during handover between mobile agents. The traffic received by the roaming station varies based on the data rates provided by two different WLAN technologies.

• Journal of the Korea Society of Computer and Information
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• v.13 no.5
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• pp.85-94
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• 2008

As a variety of wireless network services, such as WLAN, WiBro, cdma2000, and HSDPA, are provided and the range of users' choices for the wireless services are broaden, MCoA (Multiple Car-of Address) concepts that enable users to use wireless interfaces simultaneously have been presented in IETF MONAMI6 WG. Through this scheme, users can access several networks simultaneously by using multiple wireless interfaces. Such various wireless connection technologies continue to advance as they are connected and integrated to All-IP-based core network, and at the same time, heterogeneous networks are being managed overlaid according to the coverage of the wireless connection technologies. Under such circumstances, needs for an integrated architecture have arisen, and thus Wireless service framework is required that effectively manages heterogeneous networks which coexist with next generation's networks for 4G. In this paper, a wireless service framework is suggested in the consideration of current wireless service environment, and the framework covers the schemes to minimize the packet loss caused by handover, and also modified Multiple Care-of Address that helps to select most effective network by considering characteristics of various interfaces as well as users' preferences.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.19 no.1
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• pp.81-92
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• 2009

Recently, there is a drastic increase in users interested in real-time multimedia services in the WLAN environment, as the demand of IEEE 802.11 WLAN-based services increases. However, the handoff delay based on 802.11i security policy is not acceptable for the seamless real-time multimedia services provided to MS frequently moving in the WLAN environment, and there is a possibility of DoS attacks against session key derivation process and handoff mechanism. In this paper, a secure and efficient handoff mechanism in the centralized WLAN environment is introduced to solve the security problems. The 4-way Handshake for both mutual authentication and session key derivation is replaced by the 2-way Reassociation process.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.20 no.1
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• pp.51-61
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• 2010

Koinonia system is designed to fully utilize the advantage of Binary CDMA so as to guarantee QoS in wireless networks. In this paper, we propose the new network structure based on this system and refer to it as BLAN(Binary CDMA LAN). Although BLAN is similar structure to IEEE 802.11 WLAN, it will ensure the fast handover and QoS. We also propose the AKA(Authentication and Key Agreement) protocol and Reauthentication protocol to be used for communication in BLAN. These protocols are securely and efficiently designed using the user identity module to support the more powerful authentication. Hence, BLAN, including the proposed protocols, will support the high mobility and security. In conclusion, we expect that BLAN can be applied to future infrastructure on special environment, and it can be helpful showing the new network model which alternate WLAN.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.7
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• pp.1026-1031
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• 2022

Cognitive Radio Ad-Hoc Networks (CRAHNs) enable to overcome the shortage of frequency resources due to the increase of radio services. In order to avoid interference with the primary user in CRANH, channel sensing to check the idle channel is required, and when the primary user appears, the time delay due to handover should be minimized through fast idle channel selection. In this paper, throughput was improved by reducing the number of channel sensing and preferentially sensing a channel with a high probability of being idle, using reinforcement learning. In addition, we proposed a multi-channel MAC (Medium Access Control) protocol that can minimize the possibility of collision with the primary user by sensing the channel at the time of data transmission without performing periodic sensing. The performance was compared and analyzed through computer simulation.