• Proceedings of the Korean Information Science Society Conference
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• 2006.06d
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• pp.7-9
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• 2006

본 논문에서는 정적인(static) 무선 애드 혹 네트워크상에서 에너지 효율적으로 broadcast하는 문제에 대한 새로운 "Broadcast by iterative Coverage sequence Adjustment with Hitch-hiking (BCAH)" 알고리즘을 제안한다. BCAH는 에너지 효율적인 broadcast알고리즘 중 가장 대표적인 Broadcast Incremental Power(BIP)와 같은 시간 복잡도를 가지면서 BIP에 비해 적은 에너지를 소모해 broadcast를 수행한다. 또한 BCAH는 각 노드의 인접한 노드들의 정보만을 이용해 동작하기 때문에 노드들의 이동성을 고려한 동적인 네트워크에 좋은 확장성을 가진다.

• Proceedings of the Korean Information Science Society Conference
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• 2006.10d
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• pp.211-216
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• 2006

본 논문에서는 정적인(static) 무선 애드 혹 네트워크(wireless ad hoc network)상에서 동작하는 에너지 효율적인 broadcast알고리즘인 "MST based Broadcast with Hitch-hiking(MBH)"알고리즘을 제안한다. MBH는 BIP[1]에 Hitch-hiking기법[2]을 적용시킨 BHH(Broadcast by Hitch-Hiking)[3]에 비해 적은 시간 복잡도를 가지면서 더 적은 에너지를 소모해 broadcast를 수행할 수 있음을 실험을 통해 확인할 수 있었다. 또한 분산(distributed) MBH는 1-hop 이웃정보만을 이용해 broadcast 트리를 구성하기 때문에 높은 확장성(scalability)을 가지며, 빠르고 효율적으로 에너지 효율적인 broadcast 트리를 구성할 수 있다. 또한 분산 MBH는 이동성을 고려한 동적 네트워크의 잦은 위상변화에 빠르게 적응할 수 있도록 쉽게 확장할 수 있다.

• Proceedings of the Korea Information Processing Society Conference
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• 2014.04a
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• pp.223-224
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• 2014

애드-혹 무선 네트워크를 구성하고 유지하기 위해서는 네트워크 내에 생존하고 있는 노드에 대한 정보가 공유되어야 한다. 본 논문에서는 영공간(null-space)을 활용하여 효율적이면서 보안을 유지할 수 있는 생존정보 전달 프로토콜을 제안한다. 이론적인 분석에서 제안하는 프로토콜은 생존 정보를 누적함으로써 전송횟수를 최소한으로 줄일 수 있고 도청과 오염 공격에 대해 강건함을 확인하였다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.6
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• pp.109-116
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• 2007

The lack of load-balancing functionality in most existing ad hoc routing protocols often causes congestion resulting in bad performance and short lifetime of participating nodes. We present an auxiliary scheme for reactive routing protocols to discover an unloaded route, thereby decreasing possibility of congestion. The scheme allows an intermediate node to determine whether to be a relaying node for a newly constructed route autonomously based on the occupancy of its queue. Thus the scheme does not require network-wide load information. Simulation results show that the proposed scheme distributes traffic load well.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.1
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• pp.35-41
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• 2017

To solve the shortage of radio spectrum and utilize spectrum resource more efficiently, cognitive radio technologies are proposed, and many studies on cognitive radio have been conducted. Multi-hop routing is one of the important technologies to enable the nodes to transmit data further with lower power in ad-hoc cognitive radio networks. In a multi-channel cognitive radio networks, each channel should be allocated to minimize interference to primary users. In the multi-hop routing, channel allocation should consider the inter-channel interference to maximize network throughput. In this paper, we propose multi-channel scheduling scheme which minimizes inter-channel interferences and avoids collision with primary users for the multi-hop multi-channel cognitive radio networks. The proposed scheduling is designed to determine both of routing path and channel selection. The performance of proposed channel allocation scheme is evaluated by the computer simulation in the aspect of capacity and collision rate.

• Proceedings of the Korean Information Science Society Conference
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• 2005.11a
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• pp.322-324
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• 2005

이질적인 노드들로 구성된 이동 애드 혹 네트워크는 상이한 전송 능력을 가진 노드들로 구성되는 특성물 가지고 있다. 이런 특성으로 인해, 이질적인 노드들 즉, 높은 전송능력을 가진 노드와 낮은 전송능력을 가진 노드간에 단방향 링크가 형성된다. 하지만 현재까지 MANET WG에서 제안되어온 애드 혹 라우팅 프로토콜들은 단방향 링크문제를 명확히 해결하지 못하고 있다. 본 논문에서는 기존 DSR 라우팅 프로토콜이 단방향 링크를 지원할 때 생기는 문제점들을 설명하고 이를 극복하기 위한 새로운 라우팅 프로토콜을 제안한다.

• Journal of the Korea Society for Simulation
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• v.15 no.1
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• pp.77-85
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• 2006

The cost of downloading content from the Internet may be costly for mobile device users using its 3G connection, because the 3G connection cost to download data from the Internet is a function of the amount of data downloaded. This paper introduces an approach in which mobile devices, called peers, form an ad hoc network and share their downloaded content with others. As an example, spectators may want to collect/share information about players and game records in a stadium. In an art gallery, visitors may want to retrieve some background information about the displayed work from the nearby ad hoc network. In an outdoor class, a teacher may download today's topic files from the Internet, and all students may share the content with minimal or no cost paid. This is possible if mobile device has both a 3G interface and a wireless LAN interface. If the peers want to improve privacy md discourage traffic analysis when sharing content, this paper describes a low-delay anonymous connection between the sending peer and the receiving peer using two additional peers. Simulation results show that the transmission time overhead of the anonymous connection may increase 50% or less as the number of peers increase or the peers are scattered over the larger area.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.07a
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• pp.51-51
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• 2004

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.4
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• pp.39-45
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• 2011

In this paper, we propose an efficient multichannel MAC protocol with idle nodes assistance to avoid the multi-channel hidden terminal problem in cognitive radio ad hoc network and further to improve the performance of the network. The proposed MAC protocol can be applied to the cognitive radio adhoc network where every node is equipped with the single transceiver and one common control channel exists for control message negotiation. In the proposed protocol, the idle nodes available in the neighbour of communication nodes are utilized because the idle nodes have the information about the channels being utilized in their transmission range. Whenever the nodes are negotiating for the channel, idle nodes can help the transmitting and receiving nodes to select the free data channel for data transfer. With the proposed scheme, we can minimize the hidden terminal problem and decrease the collision between the secondary users when selecting the channel for data transfer. As a result, the performance of the network is increased.

• Journal of Korea Multimedia Society
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• v.12 no.11
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• pp.1593-1608
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• 2009

If a certain relay node in multi-hop wireless networks might become a malicious node that does not cooperate with other nodes or a selfish node, network throughput will be dramatically decreased. Most of existing ad hoc routing protocols assuming that the nodes will fully cooperate with other nodes do not resolve the problem of network performance degradation due to malicious and selfish nodes. This paper presents the CARE (Cooperative Ad hoc routing protocol based REputation) scheme incorporating the reputation management that can achieve a multi-hop wireless network with high throughput performance. The proposed scheme provides the horizontal cross-layer approach which can identify misbehaving malicious, selfish nodes dropped out of the hop-by-hop based packet processing in the network and then set up an optimal packet routing path that will detour misbehaving nodes. And the vertical cross-layer approach contained in the CARE scheme attempts to improve the quality of routing paths by exploiting the quality of link information received from the MAC layer. Besides, it provides high TCP throughput by exploiting the reputation values of nodes acquired from the network layer into the transport layer. A case study on experiments and simulations shows that the CARE scheme incorporating vertical and horizontal cross-layer approaches yields better performance in terms of the low rate of packet loss, fast average packet delivery time, and high TCP throughput between end-to-end nodes.