• 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.

• Proceedings of the Korean Information Science Society Conference
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• 2010.06d
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• pp.278-282
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• 2010

모바일 애드혹 네트워크에서의 멀티패스 라우팅 프로토콜은 기존의 단일패스 라우팅 프로토콜에 비하여 대역폭을 효율적으로 사용할 수 있고 혼잡을 완화시킬 수 있으며, 데이터 전달의 신뢰성을 제공할 수 있다. 하지만 멀티패스 라우팅 프로토콜에서의 경로 탐색 과정은 오버헤드가 크고 계산의 복잡도 또한 높다. 본 논문에서는 무선 애드혹 네트워크에서의 멀티패스 라우팅을 위한 효율적인 노드디스조인트 경로 탐색 알고리즘을 제안한다. 제안하는 알고리즘은 지연된 RREP(Route Reply) 패킷을 사용하여 최적의 노드 디스조인트 경로를 탐색하고 그중 간섭 및 충돌의 영향이 적은 경로 집합을 선택한다. 이를 통해 빠르게 트래픽을 분산시킬 수 있고 충돌로 인한 오류의 발생을 낮추어 신뢰성을 높일 수 있다. 실험을 통하여 제안하는 경로 탐색 알고리즘이 최적의 멀티패스를 선택함을 확인하였다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.8
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• pp.1196-1204
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• 2022

In this paper, we propose an optimization algorithm that maximizes the network lifetime in wireless ad-hoc networks using the broadcast transmission method. The optimization algorithm proposed in this paper applies tabu search algorithm, a metaheuristic method that improves the local search method using the memory structure. The proposed tabu search algorithm proposes efficient encoding and neighborhood search method to the network lifetime maximization problem. By applying the proposed method to design efficient broadcast routing, we maximize the lifetime of the entire network. The proposed tabu search algorithm was evaluated in terms of the energy consumption of all nodes in the broadcast transmission occurring in the network, the time of the first lost node, and the algorithm execution time. From the performance evaluation results under various conditions, it was confirmed that the proposed tabu search algorithm was superior to the previously proposed metaheuristic algorithm.

• Annual Conference of KIPS
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• 2011.04a
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• pp.643-646
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• 2011

스마트 폰의 보급과 함께, 무선 네트워크에서의 데이터 사용량이 급격하게 증가하고 있다. 이로 인해 발생하는 서버의 과부하와 그로 인한 속도 저하를 해결하기 위하여, 본 논문에서는 Wi-Fi 에드혹 네트워크를 이용한 통신을 3G 통신망에 효율적으로 접목하는 기법을 제안한다. 본 논문에서는 하나의 파일을 다수의 파일 블록으로 나누어 받는 방식을 이용하며, Wi-Fi 애드혹 네트워크를 이용해 주변에 있는 다른 이용자에게 파일 블록을 요청함과 동시에 자신이 가진 파일 블록 테이블을 다른 이용자에게 전달해주는 기법을 제안한다. 이를 이용하여 상대가 가지고 있을 것이라고 추측되는 파일 블록을 알아내어, 요청할 수 있다. 그 결과, 제안된 알고리즘이 3G와 Wi-Fi 에드혹 네트워크를 랜덤으로 이용하는 방법 대비 73%의 속도 향상과 43%의 3G 사용량 감소 효과를 보임을 확인할 수 있었다.

• Journal of KIISE:Information Networking
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• v.32 no.1
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• pp.100-109
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• 2005

A Mobile Ad-Hoc Network (MANET) supports a multi-hop wireless network without any prepared base station (BS). The MANET is capable of building a mobile network automatically without any help from DHCP servers for address allocation or routers to forward or route messages. Many routing protocols have been proposed for the MANET, but these specify the most optimized or shortest path from a source to a destination, and they assume that nodes are pre-configured before communication. To make up for this, address allocation algorithms, such as MANETConf [1] and prophet address allocation algorithm [2], have been proposed. Especially, MANETConf proposes address allocation algorithm with duplication address check. In this paper, we present a dynamic node configuration protocol based on 2-tierd hierarchical network architecture for mobile ad-hoc network, modified from [1]. Especially, it reduces the number of broadcast message exchange between nodes when a new node somes into a network, which lessens network overhead, remarkably. This protocol is based on two-tired structure, and it ensures address allocation with simple duplication address defection mechanism.

• Journal of Advanced Navigation Technology
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• v.11 no.1
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• pp.118-126
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• 2007

An ad hoc network is a system of wireless mobile nodes that dynamically self-organize in arbitrary and temporary network topologies allowing people and devices to internetwork without any preexisting communication infrastructure. Although ad hoc network is attractive solution, there are still some major flaws that prevent commercial growth. Security is one of these main barriers; ad hoc networks are known to be particularly vulnerable to security attack. It is difficult to establish a centralized key distribution center and a trusted certification authority to provide cryptographic keys and digital certificates to nodes. To prevent attacks in ad hoc routing protocols, many algorithms have been used. In this paper, we have depicted a secure framework for multipath routing in wireless multihop network, which is comprehensive solution for secure data forwarding in wireless multihop networks. With the simulation results, the proposed scheme is compared with existing source routing scheme.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.3A
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• pp.290-296
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• 2007

We propose new routing scheme, Cooperative Diversity-based Routing (CDR) which utilizes the cooperative space diversity for power saving and performance enhancement of wireless ad-hoc networks. The improved performance is compared with Multi-hop Relay Routing (NRR) by analytical methods. When the required outage probability is $1\times10^{-3}$ at the destination node in ad-hoc networks with 7 nodes, we noticed that each node can save power consumption by 15.5 dB in average, by using our proposed CDR compared to MRR.

• Journal of Korea Multimedia Society
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• v.11 no.10
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• pp.1446-1459
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• 2008

In an infrastructure-based wireless network, an access point is used for all communications among mobile devices. However, when a mobile device moves into a dead Bone, a connectivity disruption between the mobile device and the access point occurs. Such connectivity disruption consequently leads to another connectivity disruption between the mobile device moving toward the dead zone and other wireless-enabled devices located within the area of the infrastructure-based wireless network. To cope with the connectivity disruption in the infrastructure-based wireless network the ad hoc network that dynamically forms a network without any preexisting communication infrastructure needs to be set up to provide seamless connections among mobile devices. In this paper, we propose the DNSQ-MAC (Dynamic Network State aware QoS-Medium Access Control) technique that meets the deadlines of MAC frames forwarded over hop-by-hop multipaths and guarantees the QoS performance of an ad hoc-based wireless network. Mobile devices incorporating the DNSQ-MAC technique are capable of adjusting to the new dynamic network status in order to enhance the QoS performance in the ad hoc-based wireless network. A case study which exploits the Qualnet simulator shows that the proposed DNSQ-MAC technique can guarantee the deadlines of MAC frames forwarded over hop-by-hop multipaths and enhance the QoS performance of various routing protocols and packet schedulers running on the network layer above the MAC layer.

• KIPS Transactions on Computer and Communication Systems
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• v.6 no.11
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• pp.463-468
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• 2017

To sense a wide area with mobile nodes, the uniformity of node deployment is a very important issue. In this paper, we consider the coverage problem to sense big data in sparse mobile ad hoc networks. In most existing works on the coverage problem, it has been assumed that the number of nodes is large enough to cover the area in the network. However, the coverage problem in sparse mobile ad hoc networks differs in the sense that a long-distance between nodes should be formed to avoid the overlapping coverage areas. We formulate the sensor coverage problem in sparse mobile ad hoc networks and provide the solution to the problem by a self-organized approach without a central authority. The experimental results show that our approach is more efficient than the existing ones, subject to both of coverage areas and energy consumption.

• Journal of Korea Society of Industrial Information Systems
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• v.14 no.2
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• pp.16-22
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• 2009

The most efficient method to reduce duplicated messages is a partial dominant pruning for receiving and forwarding messages by in-fly format on the mobile ad hoc network. In this paper, we propose directional partial dominant pruning method by expanding partial dominant pruning for reducing not only number of forwarding nodes but number of antenna elements on the ad hoc network with directional antennas. by simulation, we prove superiority that average number of forwarding nodes for each antenna element and the ratio of duplicated messages for each nodes rather than existing partial dominant pruning method though the number of antenna elements are increasing rather than in case of using omni antennas.