• Proceedings of the Korean Information Science Society Conference
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• 2005.07a
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• pp.286-288
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• 2005

최근 기지국(Base Station)의 도움 없이 이동 단말기 간의 다중 무선 홉을 사용하여 송,수신자 간의 데이터 전송을 가능하게 하는 Ad-hoc 통신망에 관한 연구가 활발히 진행되고 있다. 유선망과 달리 Ad-hoc 통신망은 무선 전송 매체를 사용하기 때문에 신호의 페이딩(Fading), 간섭(Interference), 잡음(Noise) 등에 의해 높은 BER(Bit Error Rate)이 발생하는 특징을 가지고 있다. 하지만, 현재 인터넷 상에서 광범위하게 사용되고 있는 전송 규약인 TCP(Transmission Control Protocol)는 유선망의 신뢰적인 전송 매체를 고려하여 개발된 프로토콜이기 때문에 TCP를 수정 없이 Ad-hoc 통신망에 적용할 경우 전송 성능이 저하되는 문제를 가지고 있다. 전송 성능이 저하되는 문제는 기존 TCP가 에러 발생의 원인을 혼잡에 의한 것으로 인식하고 불필요한 혼잡 제어를 하기 때문이다. 본 논문에서는 송신자가 에러 발생 원인을 구별하고, 그에 따라 전송률을 조절함으로써 Ad-hoc 망에서의 TCP성능 향상을 위한 방법을 제시하였다. 또한 ns-2 시뮬레이터를 이용한 실험을 통해 TCP의 성능이 제안된 알고리즘에 의해 향상되었음을 확인하였다

• Journal of Korea Multimedia Society
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• v.13 no.8
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• pp.1202-1211
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• 2010

The connection between devices in Ad-hoc network a network based on trust. Because a temporary device frequently join or leave, the authentication and security technology should be prepared for malicious device of a third-party attacks. The authentication scheme with the existing certification and ID, and the security technology using symmetric key and the public key is used. Therefore, in this paper we proposed two devices not having shared information use to generate each other's authentication ID. The use of authentication ID can establish the mutual trust and, provide security and efficiency for communication uses to generate a symmetric key.

• Journal of Korea Multimedia Society
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• v.13 no.2
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• pp.258-264
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• 2010

In the Ad-hoc networks, the limitation on the availability of power for operation is a significant bottleneck, given the requirements of portability, weight, and size of mobile devices. Hence, the use of routing metrics that consider the capabilities of the power sources of the network nodes contributes to the efficient utilization of energy. This paper presents a QoS routing protocol that minimize the power consumed by a packet in traversing from source node to the destination node. Results obtained of simulation show that, with our approach we can reduce the power consumption of nodes and increases the life time of the network.

• Journal of KIISE:Information Networking
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• v.29 no.5
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• pp.459-465
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• 2002

Ad-hoc networks have the dynamic topology characteristics and most of the applications on ad-hoc networks require the group communication capability. Previously proposed multicast mechanisms on mobile ad-hoc networks build multicast-infrastructures like the tree or mesh for the group communication and these infrastructures nay cause significant overhead especially in a highly dynamic mobile ad-hoc network environment. Therefore, in this paper, we propose a new multicast mechanism supporting multicast services based on only the underlying unicast routing tables, hence any multicast-related infrastructures like trees and meshes are not required to be constructed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.11B
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• pp.1413-1421
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• 2011

A next generation military communication system called Tactical Information Communication Network(TICN) is designed to advance into large capacity, high speed, and long distance wireless relay transmission. To support mobility in battlefield, the application of Ad-hoc networking technology to its wireless communication is being considered. In Ad-hoc network, the key management technique is very important to ensure the confidentiality, integrity, and authentication. In this paper, we propose a new hybrid key management scheme considering the hierarchical characteristics of the tactical ad-hoc such as TICN. For upper layer with sufficient energy and computation capability, we apply PKI based key management scheme. For lower layer with restricted resources, we propose a new key management scheme using the location-based authentication to ensure the energy efficiency.

• The Journal of Korean Association of Computer Education
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• v.7 no.1
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• pp.45-53
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• 2004

Ad-Hoc network is wireless network architecture without infrastructure. We encounter new types of security problems in Ad-Hoc networks because such networks have little or no support from infrastructure. Thus, wireless communications need security mechanisms in order to guarantee the integrity and the privacy of the communication, as well as the authentication of the entities involved. Many practical systems have been proposed. The most familiar system is the Diffie-Hellman key distribution system. This algorithm allows the establishment of a cryptographic secret key between two entities. If more than two users want to compute a common key, then a group key agreement system is used. This paper discusses several group key agreement systems and presents two efficient fault tolerant methods to perform successful group key agreement.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.12B
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• pp.800-808
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• 2007

With the development of wireless data communication technology, all IP-based network will become compositions of wired and wireless networks. TCP is a connection-oriented, reliable transport protocol and has been used as de facto standard in most wired networks. Because TCP's congestion control algorithm could not distinguish congestion from BER, link failure and frequent route changes, TCP shows a poor performance over mobile ad-hoc networks. In this paper, the theoretical feature of TCP was studied and the performance of TCP over mobile ad-hoc networks was analyzed with ns2.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.49 no.1
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• pp.92-101
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• 2012

Security support is a significant factor in ad hoc networks. Especially in dynamic topologies, key agreement with private key updating is essential in providing a secure system. And it is also necessary to protect the identities of individual nodes in wireless environments to avoid personal privacy problems. However, many of the existing key agreement schemes for ad hoc networks do not consider these issues concurrently. This paper proposes an anonymous ID-based private key update scheme and a key agreement scheme for mobile ad hoc networks. We also suggest a method of rekeying between different domains using service-coordinators. These schemes are secure against various attacks and are suitable for service-oriented mobile ad hoc networks.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.12C
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• pp.1188-1193
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• 2007

This paper proposes a secure data forwarding scheme on source routing-based ad-hoc networks. The scheme uses two hash-key chains generated from a trusted third party to generate Message Authentication Codes for data integrity The selected MAC keys are delivered to the ad-hoc node using a pre-shared secret between the trusted third party and a node. The proposed scheme does not require the PKI, or the provisioning of the pre-shared secrets among the ad-hoc nodes.

• Journal of the Korea Society of Computer and Information
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• v.12 no.2 s.46
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• pp.189-196
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• 2007

In this paper, we proposed a mobile ad hoc routing protocol based on AODV(Ad hoc On demand Distance Vector) with QoS(Quality of Service) support and evaluated the performance through simulation. The waste of communication resources is reduced by establishing the shortest route suitable to QoS support, considering in advance the usable communication resources at each node. For performance evaluation, we analyzed the average data reception rate, considering the node mobility and the number of best effort/QoS data flows. We found that in the mobile Ad Hoc networks the QoS service for some specific data flows increased the average data reception rate for the QoS data flows.