• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.1
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• pp.64-71
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• 2009

TETRA system has been developed focusing on the supporting high-speed and high-capacity data transfer and improving the wireless technology. Hence, TETRA over IP technology became the important basis for supporting compability with various network wireless technologies and high-speed data transfer technologies. For advancing the current TETRA system based on IPv4 network, introduction of IPv6 protocol is necessary. In this paper, we propose an optimized scheme to support IP mobility to IPv6 node when IPv6 protocol is applied to the enviroment ingreated WLAN and TETRA networks. We proposed two scheme using MIPv6 protocol and HMIPv6 protocol respectively. Then, we evaluate performance of the proposed schemes and anlayze the results in order to derive the optimized scheme for the environment integrated WLAN and TETRA networks.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.1B
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• pp.1-8
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• 2006

Currently, there are many efforts underway to provide Internet service on integrated wireless and wired networks. Supporting IP mobility is one of the major issues to construct IP based wireless network. Mobile IP has been proposed to solve the IP Mobility problem. But, in processing frequent handoffs in cellular based wireless access network, Micro mobility protocols have been proposed to solve these problems. Micro mobility protocols proposed the Cellular IP, HAWII, and Hierarchical Mobile IP. Cellular IP attracts special attention for it's seamless mobility support in limited geographical areas. New BS must be known to occur begging of handoff in Cellular IP indirect handoff. Therefore during perceiving of hanoff, packet loss or packet duplication still can occur in Cellular IP indirect handoff, which results in the degradation of UDP and TCP performance. In this paper, we propose a enhanced indirect handoff scheme for Cellular IP. Proposed handoff scheme is using a crossover node to minimize the signalling procedure and using a buffering to minimize the packet loss or packet duplication.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.57-60
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• 2005

In this paper, a dynamic priority-based QoS (DPQoS) provision scheme is proposed for the required QoS from one end of the network to the other in wireless mobile networks. The DPQoS model is used to meet diversity multimedia traffic requirements. This model is come up with a framework for the wireless network of which consists of a core-IP network and also a number of wireless access networks. For the true end-to-end QoS, it is required that the core network is able to support the required QoS for the wireless users. This paper shows a solution to optimize the performance for different traffic classes according to the traffic characteristics. The performance of the proposed scheme is evaluated at delay aspects such as delay and throughput.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.6B
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• pp.563-572
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• 2003

When the Mobile IP is applied for mobility management protocol in the next-generation mobile communication networks, it can cause a serious performance degradation called micro-mobility problem. In this paper, we propose ANMM(Access Network Mobility Management) to efficiently support micro-mobility in the IP-based wireless access network. The ANMM scheme can reduce the handoff latency and signaling overhead resulting in performance enhancement by managing the mobility of mobile nodes within access network.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.2 no.4
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• pp.171-183
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• 2008

Nowadays, wireless packet data services are provided over Wireless MAN (WMAN) at a high data service rate, while 3G cellular networks provide wide-area coverage at a low data service rate. The integration of mobile WiMAX and 3G networks is essential, to serve users requiring both high-speed wireless access as well as wide-area connectivity. In this paper, we propose a cross-layer optimization scheme for a vertical handover between mobile WiMAX and 3G cellular networks. More specifically, L2 (layer 2) and L3 (layer 3) signaling messages for a vertical handover are analyzed and reordered/combined, to optimize the handover procedure. Extensive simulations using ns-2 demonstrate that the proposed scheme enhances the performance of a vertical handover between mobile WiMAX and 3G networks: low handover latency, high TCP throughput, and low UDP packet loss ratio.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.07a
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• pp.440-440
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• 2004

• Journal of information and communication convergence engineering
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• v.9 no.5
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• pp.530-538
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• 2011

Performance of TCP can be severely degraded in Mobile IP-based wireless networks where packet losses not related to network congestion occur frequently during inter-subnetwork handoffs by user mobility. To solve such a problem in the networks using Mobile IP, the packet buffering method at a base station(BS) recovers those packets dropped during handoff by forwarding the buffered packets at the old BS to the mobile users. But, when the mobile user moves to a congested BS in a new foreign subnetwork, those buffered packets forwarded by the old BS are dropped and TCP transmission performance of a mobile user degrades severely. In this paper, we propose a Modified BLUE(MBLUE) buffer required at a BS to increase TCP throughput in Mobile IP-based networks. When a queue length exceed a threshold and congestion grows, MBLUE increases its packet drop probability. But, when a TCP connection is added at new BS by a handoff, the old BS marks the buffered packets. And new BS receives the marked packets without dropping. Simulation results show that MBLUE buffer reduces congestion during handoffs and increases TCP throughputs.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.8
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• pp.1510-1518
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• 2006

As a promising technology that enables ubiquitous computing and leads IT(information Technology) industries of next generation, the exciting new field of sensor networks is attracting so much attention and considered to be the one of the hottest research topics these days. From now on, all the each node, forming a network, and even the sensor network itself will interact with the generic network and evolve dynamically according to the change of environment with the perpetual creation and extinction. In this paper, we purpose the dynamic address interworking scheme for interactive networking between sensor network and Internet(IPv6). Proposed scheme is enable to interworking dynamically between sensor network address scheme based on Zigbee and Internet address scheme based on IP. Additionally, we implement the proposed address interworking scheme using Berkeley TinyOS, mica motes, and IP protocol. And, we verify the proposed scheme by the interconnection experimental between wireless sensor networks and Internet based on IPv4/IPv6.

• Journal of the Korea Society of Computer and Information
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• v.14 no.11
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• pp.91-96
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• 2009

In this paper, interoperability in heterogeneous wireless mesh network, and mesh nodes for providing efficient IP mobility technique offers multi-hop ARP. Heterogeneous wireless mesh networks to MANETs based on a wireless mesh network backbone and non-MANET architecture is based on a client wireless mesh network and the two mobile networks, combined with a hybrid wireless mesh network are separate. In two different hybrid wireless mesh network routing protocols used to connect the two protocols in the protocol conversion at the gateway to parallel processing problems seriously overload occurs. All of the network reliability and stability are factors that reduce. Therefore, for efficient integration with L3 routing protocols, design techniques to build ARP multi-hop go through the experiment to increase the number of mesh nodes, the packet forwarding rate and an increased hop number of the node was to ensure reliability and stability.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.8B
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• pp.760-767
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• 2009

While network evolution toward all IP based wired and wireless converged network is on the move, services are being progressed into converged and complex services from simply coupled services, and telecommunication operators are developing new technologies which enable users to move between heterogeneous networks without discontinuity of a current service. In this paper, we propose a IP handover mechanism which reduces ping-pong effect during IP handover between WLAN and CDMA2000 1x EV-DO Rev.A neworks. We present stability and enhanced latency of the proposed IP handover mechanism by experimentation. The mechanism was developed under the 3rd phase of BcN project.