• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.11 s.353
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• pp.78-84
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• 2006

This paper proposes a method to endow the mobility to the Zigbee protocol which is a short distance wireless communication technology among the standards of wireless sensor networks. The Zigbee has a low price, long life battery, simple structure and connectivity. So it is a suitable standard for the short distance wireless communication of $10m{\sim}70m$. As the Zigbee does not support the mobility, additional factors should be studied to deal adeptly with the diverse change in the real field. By solving the problem that the previous connection and binding table of the Zigbee end device should be reset due to the Zigbee end device address variation when the Zigbee end device moves from the present router to another router, this paper presents the method to communicate without data loss or disconnection.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.8 no.5
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• pp.73-80
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• 2008

The recent trend in home network system includes intelligent home environments that remote monitoring and control service is achieved without restrictions by device types, time, and place. Also the use of a vacuum robot in homes is gradually generalized on account of the convenience of the use. In this paper, we proposed and realized new home-monitoring system with the employment of an self-movement robot as one trial for realizing an intelligent home under home network environment. The proposed system can freely monitor every where in home, because the system effectively overcame the surveillance limitations of the existing monitoring system by attaching a Wireless Router and WebCam to a commercial vacuum robot. The outdoor users of this system can readily monitor any place which they want to supervise by controlling a vacuum robot with mobile telecommunication devices such as PDA. The wireless router installed with Linux operation system "OpenWrt" made it possible for the system users to transmit images and to control a vacuum robot with RS-232 communication.

• Journal of the Korea Society of Computer and Information
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• v.14 no.5
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• pp.119-131
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• 2009

Existing proposals on route optimization for nested Network Mobility(NEMO) have a problem that it is difficult to optimize a route promptly in an environment where a MR moves frequently. Also, they have L3 handoff latency as well as route optimization latency until an optimized route is formed. In this paper, we propose a L3 handoff scheme that supports fast route optimization for nested NEMO without any additional optimization procedure. To achieve this, our proposed scheme is designed to include a procedure that an AR acquires address informations of a MR. After receiving binding update message from the MR, the AR performs the binding update procedure with the MR's HA on behalf of the MR. Packets are delivered to the AR only passing by the MR's HA after a bi-directional tunnel is formed between the AR and the HA. The result of our performance evaluation has shown that the proposed scheme could provide excellent performance compared with the RRH and the ONEMO.

• The KIPS Transactions:PartC
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• v.12C no.2 s.98
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• pp.267-280
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• 2005

In this paper, we implement and verify XMIP integrating IETF Mobile IP and the Explicit Multicast mechanism for a great number of small group multicast communications. U a source node sends Xcast packets explicitly inserting destination nodes into the headers, each Xcast router decides routes and forwards the packets toward each destination node based on unicast routing table without the support of multicast trees. n is a straightforward and simple multicast mechanism just based on a unicast routing table without maintaining multicast states because of the inheritance from the Explicit Multicast mechanism. This research modifies and extends the functionality of IETF Mobile IP's mobility agents, such as HA/FA to HA+/FA+ respectively, considering interworking with Xcast networks. Xcast packets captured by HA+ are forwarded into X-in-X tunnel interfaces for each FA+ referred to the binding table of HA.. This X-in-X tunneling mechanism can effectively solve the traffic concentration problem of IETF Mobile IP multicast services. Finally WLAN-based testbed is built and a multi-user Instant messenger system is developed as a Xcast application for finally verify the feasibility of the implemented XMIP/Xcast protocols.

• Journal of KIISE:Information Networking
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• v.32 no.6
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• pp.659-667
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• 2005

A Mobile Ad Hoc Network(MANET) is a multi hop wireless network with no prepared base stations or centralized administrations, where flocks of peer systems gather and compose a network. Each node operates as a normal end system in public networks. In addition to it, a MANET node is required to work as a router to forward traffic from a source or intermediate node to others. Each node operates as a normal end system in public networks, and further a MANET node work as a router to forward traffic from a source or intermediate node to the next node via routing path. Applications of MANET are extensively wide, such as battle field or any unwired place; however, these are exposed to critical problems related to network management, node's capability, and security because of frequent and dynamic changes in network topology, absence of centralized controls, restricted usage on network resources, and vulnerability oi mobile nodes which results from the special MANET's character, shared wireless media. These problems induce MANET to be weak from security attacks from eavesdropping to DoS. To guarantee secure authentication is the main part of security service In MANET because networks without secure authentication are exposed to exterior attacks. In this paper, a multistage authentication strategy based on CGSR is proposed to guarantee that only genuine and veritable nodes participate in communications. The proposed authentication model is composed of key manager, cluster head and common nodes. The cluster head is elected from secure nodes, and key manager is elected from cluster heads. The cluster head will verify other common nodes within its cluster range in MANET. Especially, ID of each node is used on communication, which allows digital signature and blocks non repudiation. For performance evaluation, attacks against node authentication are analyzed. Based on security parameters, strategies to resolve these attacks are drawn up.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.1A
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• pp.67-72
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• 2011

There are lots of researches for mobility of MS(mobile station) in All IP based network. Specially, NEMO(NEwork MObility) is not supporting mobility of each MS but supporting mobility of network that include group of MS. Some research try to overcome limitation of wireless with the protocol in wired state and it maintains the performance such as wire environment. There are no researches about multicast with reliability in NEMO. Therefore, this paper suggests efficient algorithm to solve problems when RMTP(Reliable Multicast Transport Protocol) apply to NEMO environment to support high reliability with multicast. And this paper shows the better performance of proposed algorithm for delay and transmission rate between AR and TLMR comparing with RMTP in NEMO.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.3
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• pp.179-186
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• 2012

Nowadays, the multihomed host equipped with multiple network interfaces has been interested research in next generation wireless network, because the mobile users expect that they can be able to access services not only anywhere, at any time and from any network but also simultaneously. This paper addresses the mobility simulation model of the multihomed node for supporting MIPv4 and MIPv6 function in an interworking of Worldwide Interoperability for Microwave Access (WiMAX) and IEEE 802.11 WLAN. The multihomed node with two air interfaces has been developed based on WiMAX and WLAN workstation node model in simulation software. The main point of the developed model is to support both MIPv4 and MIPv6 function, and provide network selection policy for the multihomed node between WiMAX and WLAN network. Based on the received Router Advertisement along with the interface number, we can manage the access interfaces in ordered list to make handover decision while the multihomed node is moving. In the end of this paper, the simulation scenarios and results are shown for testing MIPv4 and MIPv6 function.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.4A
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• pp.377-386
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• 2008

In this paper, a new handover management scheme has been proposed to reduce handover latency and to support fast handover without packet losses, so that it may be applicable to the wireless mobile Internet system such as IPv6-based WiBro system. To minimize the handover latency in processing of movement detection, we propose the handover management scheme which simplifies the handover message exchanging procedure between mobile subscriber station (MSS) and network by integrating layer 2 and layer 3 handovers efficiently based on the layer2 information. To reduce the processing delay from new care-of-address (NCoA) configuration during handover, we propose that NCoA is created, distributed and managed by new access control router (NACR). In addition, in order to minimize the packet transmission delay and eliminate the packet losses, the proposed scheme employs a crossover router (CR) which is upper network located over PACR and NACR and employs the packet buffering for MSS. The simulation study shows that the proposed scheme achieves loss-free packet delivery and low latency in the environment of narrow overlapped cell area or high velocity of the MSS, comparing the performance with the conventional schemes.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.12
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• pp.6214-6242
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• 2019

Routing in mobile ad hoc networks is performed in a distributed fashion where each node acts as host and router, such that it forwards incoming packets for others without relying on a dedicated router. Nodes are mostly resource constraint and the users are usually inclined to conserve their resources and exhibit selfish behaviour by not contributing in the routing process. The trust and reputation models have been proposed to motivate selfish nodes for cooperation in the packet forwarding process. Nodes having bad trust or reputation are detected and secluded from the network, eventually. However, due to the lack of proper identity management and use of non-persistent identities in ad hoc networks, malicious nodes can pose various threats to these methods. For example, a malicious node can discard the bad reputed identity and enter into the system with another identity afresh, called whitewashing. Similarly, a malicious node may create more than one identity, called Sybil attack, for self-promotion, defame other nodes, and broadcast fake recommendations in the network. These identity-based attacks disrupt the overall detection of the reputation systems. In this paper, we propose a reputation-based scheme that detects selfish nodes and deters identity attacks. We address the issue in such a way that, for normal selfish nodes, it will become no longer advantageous to carry out a whitewash. Sybil attackers are also discouraged (i.e., on a single battery, they may create fewer identities). We design and analyse our rationale via game theory and evaluate our proposed reputation system using NS-2 simulator. The results obtained from the simulation demonstrate that our proposed technique considerably diminishes the throughput and utility of selfish nodes with a single identity and selfish nodes with multiple identities when compared to the benchmark scheme.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.7B
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• pp.710-720
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• 2009

The Future Generation Networks(FGNs) are proposed to integrate various heterogeneous access technologies, and further expected to support both vertical and seamless handovers. In this motivation, the IEEE 802.21 specifies Media Independent Handover(Mlli) services to enhance the mobile user experience by optimizing handovers between heterogeneous access networks. Additionally, Fast handover for MIPv6(FM1Pv6) is introduced to provide transparent host mobility and to improve handover performance by reducing handover delay as well. This paper focuses on the coordination of FMIPv6 and MIH, and introduces an enhanced mobility management framework suited for FGN. This novel framework replaces handover signaling messages used in wireless networks with novel MIH messages and local primitives. Moreover, Serving Access Router(SAR) performs most of handover processes instead of Mobile Node(MN). Therefore, the proposed mobility management framework reduces handover latency, packet loss, and signaling overhead significantly. We further evaluate the performance of the proposed framework by using both numerical analysis and network simulations.