• 한국정보통신설비학회:학술대회논문집
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• 2008.08a
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• pp.17-20
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• 2008

A clustering scheme for ad hoc networks is aimed at managing a number of mobile devices by utilizing hierarchical structure of the networks. In order to construct and maintain an effective hierarchical structure in ad hoc networks where mobile devices may move at high mobility, the following requirements must be satisfied. The role of each mobile device for the hierarchical structure is adaptive to dynamic change of the topology of the ad hoc networks. The role of each mobile device should thus change autonomously based on the local information. The overhead for management of the hierarchical structure is small. The number of mobile devices in each cluster should thus be almost equivalent. This paper proposes an adaptive multihop clustering scheme for highly mobile ad hoc networks. The results obtained by extensive simulation experiments show that the proposed scheme does not depend on mobility and node degree of mobile devices in the ad hoc network, which satisfy the above requirements.

• Proceedings of the IEEK Conference
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• summer
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• pp.143-146
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• 2004

Differentiated services (DiffServ) has been widely accepted as the service model to adopt for providing quality-of­service (QoS) over the next-generation IP networks. There is a growing need to support QoS in mobile ad hoc networks. Supporting DiffServ in mobile ad hoc networks, however, is very difficult because of the dynamic nature of mobile ad hoc networks, which causes network congestion. The network congestion induces long transfer packet delay and low throughput which make it very difficult to support QoS in mobile ad hoc networks. We propose DiffServ module to support differentiated service in mobile ad hoc networks through congestion control. Our DiffServ module uses the periodical rate control for real time traffic and also uses the best effort bandwidth concession when network congestion occurs. Network congestion is detected by measuring the packet transfer delay or bandwidth threshold of real time traffic. We evaluate our mechanism via a simulation study. Simulation results show our mechanism may offer a low and stable delay and a stable throughput for real time traffic in mobile ad hoc networks.

• Proceedings of the Korea Information Processing Society Conference
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• 2005.05a
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• pp.1461-1464
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• 2005

In contrast with conventional networks, mobile ad hoc networks usually do not provide online access to trusted authorities or to centralized servers, and they exhibit frequent partitioning due to link and node failures and node mobility. For these reasons, traditional security solutions that require online trusted authorities or certificate repositories, but those are not well-suited for securing ad hoc networks. Moreover, a fundamental issue of securing mobile ad hoc networks is to ensure mobile nodes can authenticate each other. Because of its strength and efficiency, public key and digital signature is an ideal mechanism to construct the authentication service. Although this is already mature in the internet application, providing public key based authentication is still very challenging in mobile ad hoc networks. In this paper I propose a secure public key authentication service based on clustering model and trust model to protect nodes from getting false public keys of the others efficiently when there are malicious nodes in the network.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2007.02a
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• pp.26-31
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• 2007

An ad hoc network is a collection of mobile nodes without any Infrastructure. However, ad hoc networks are vulnerable to attacks such as routing disruption and resource consumption; thus, routing protocol security is needed This paper proposes a secure and efficient routing protocol for mobile ad hoc networks, where only one-way hash function are used to authenticate nodes in the ROUTE REQUEST, while additional public-key cryptography is used to guard against active attackers disguising a node in the ROUTE REPLY.

• Journal of information and communication convergence engineering
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• v.7 no.3
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• pp.241-246
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• 2009

Advances in mobile and wireless networking technologies have enabled mobile ad hoc networks applicable to a wide range of areas. Many cases of even such ad hoc networks demand to be accessible to the global network. Owing to be diversified in features depending on applications, however, some those networks may consist of devices or nodes which do not facilitate all the same transport protocols. This results in unreachable situations of establishing ad hoc network: such as non-existence of all required access points, faults or contention in a path of particular protocol communication. Interworking between different transport protocols can alleviate such problems. This paper proposes an interworking scheme to improve data transport performance and network accessibility, especially in such a mobile ad hoc network that is applicable to data communications among ships or user's convenient u-health services. Modeling and simulation analysis are used to verify the improvement.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.10a
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• pp.61-64
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• 2001

The concept of IPv6 stateless address autoconfiguration lends itself easily to mobile ad hoc networks. However, the Neighbor Discovery protocol (NDP)-based mechanism described in [1] does not fit well for the multi-link environments in the mobile ad hoc network. In this document, we extend the current SAA mechanism to be suitable for mobile ad hoc networks.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.3B
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• pp.224-236
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• 2003

MANET(Mobile Ad hoc networks) is a mobile, multi-hop, and wireless network which is bandwidth constrained, energy constrained, resource constrained, autonomous, and self operating systems with dynamic topology. These constraints make the routing between communicating nodes in ad hoc networks difficult. In this paper we survey several routing protocol for mobile ad hoc networks. Especially, we focus on Zone Routing Protocol, hybrid routing framework suitable for a wide of mobile ad hoc networks and analyze performance of ZRP. In the case of ZRP protocol, it is essential that the use of optimal zone radius for efficient use. Otherwise it was proved through an simulation that performance of whole network is rapidly decrease with greatly increasing overhead of ZRP traffic that need for transmission of packet by IARP or IERP traffic. Also we suggest the process of finding QoS path that use in-band signal for QoS routing in ad hoc network. This method guarantees route that make real time multimedia service for QoS enabled path.

• Proceedings of the IEEK Conference
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• 2002.06c
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• pp.67-70
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• 2002

본 논문은 IIPv6 기반의 Mobile Ad-hoc Networks 환경에서 화상회의 도구 같은 멀티캐스트 응용을 서비스하는데 이용될 수 있는 IPv6 기반의 자동네트워킹 기술을 제시한다. IPv6 유니캐스트 자동설정 기능을 이용하여 이동단말의 유니캐스트 주소를 자동으로 설정할 수 있고, 멀티캐스트 자동설정 기능을 이용하여 멀티캐스트 주소 할당을 필요로 하는 응용에게 멀티캐스트 주소를 쉽게 할당할 수 있으므로 Mobile Ad-hoc Networks 환경에서의 사용자는 이러한 자동네트워킹 기술을 통해 멀티 캐스트 서비스를 쉽게 이용할 수 있다.

• Journal of the Korea Computer Industry Society
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• v.2 no.9
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• pp.1219-1224
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• 2001

There can exist unidirectional links due to asymmetric property of mobile terminals or current wireless environments on practical mobile ad hoc networks. However, at present, the existing mobile ad hoc routing protocols are implemented to support only bidirectional links. Thus, in this paper, we extend the existing dynamic source routing protocol in order to implement a new routing protocol, which is fit to mobile ad hoc networks containing unidirectional links. For performance evaluation, we use combinations of mobility scenario files and connection pattern files from Carnegimelon Univ. We consider received data rate and average route discovery time as evaluation items, which are compared and evaluated for three suggested route discovery methods.

• Proceedings of the Korea Society for Simulation Conference
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• 2003.11a
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• pp.219-223
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• 2003

A lot of researches have been done on supporting QoS in the mobile networks and ad hoc network architectures, but most of them are not suitable in the static ad hoc environment. Most Research in mobile ad hoc networks has been devoted to routing protocol since they are fundamantal to the technology for improving QoS. In mobile ad hoc networks, QoS means not only fast speed and reliable transmission but reliable node. Needless to say, general QoS is serious question. In this paper, we enunciate the proposition to reduce network load and prevent node expire using buffer node.