• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.12
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• pp.5149-5173
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• 2016

Cooperative forwarding has shown a substantial network performance improvement compared to traditional routing in multi-hop wireless network. To further enhance the system throughput, especially in the presence of highly congested multiple cross traffic flows, a promising way is to incorporate the multi-radio multi-channel (MRMC) capability into cooperative forwarding. However, it requires to jointly address multiple issues. These include radio-channel assignment, routing metric computation, candidate relay set selection, candidate relay prioritization, data broadcasting over multi-radio multi-channel, and best relay selection using a coordination scheme. In this paper, we propose a simple and efficient cluster-based cooperative data forwarding (CCDF) which jointly addresses all these issues. We study the performance impact when the same candidate relay set is being used for multiple cross traffic flows in the network. The network simulation shows that the CCDF with MRMC not only retains the advantage of receiver diversity in cooperative forwarding but also minimizes the interference, which therefore further enhances the system throughput for the network with multiple cross traffic flows.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.11a
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• pp.459-460
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• 2009

과거 네트워크는 물리적 회선을 이용한 유선 네트워크 기반의 연구를 통하여 각 노드간의 통신을 수행하였다. 하지만 시대가 흐름에 따라 통신환경이 유선 네트워크에서 무선 네트워크 기반의 통신으로 이동하였으며 그에 관한 연구가 활발히 진행되고 있다. 특히 clustering routing 기법은 무선 네트워크 환경에서의 한계였던 에너지 소모 문제를 보완하는 기법으로서 각광받고 있다. LS2RP는 이동성이 심한 Ad Hoc 네트워크 환경에서 CH가 backup을 통해 해당 cluster를 벗어날 경우를 대비한다. 하지만 CH가 cluster를 벗어난 이후 data chunk 결합을 통한 ID database 복구와 CH 재선정을 수행하기 때문에 그동안 network의 사용이 불가능해진다는 문제점을 가지고 있다. 따라서 본 논문에서는 CH의 이동을 예측하여 미리 sub CH를 선정하여 네트워크의 안정성을 강화하는 기법을 제시한다. 시뮬레이션 수행 결과 이동성에 따른 control traffic 측면에서 기존의 LS2RP에 비해 12% 더 높은 performance를 보이고 있음을 알 수 있었다.

• Journal of Advanced Navigation Technology
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• v.15 no.6
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• pp.1015-1024
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• 2011

Mobile P2P protocols in ad-hoc networks have gained large attention recently. Although there has been much research on P2P algorithms for wired networks, existing P2P protocols are not suitable for mobile ad-hoc networks because they do not consider mobility of peers. This study proposes a new cluster-based P2P protocol for ad hoc networks which utilizes peer mobility. In typical cluster-based P2P algorithms, each cluster has a super peer and other peers of the cluster register their file list to the super peer. High mobility peers would cause a lot of file list registration traffic because they hand-off between clusters frequently. In the proposed scheme, while peers with low mobility behave in the same way as the peers of the typical cluster-based P2P schemes, peers with high mobility behave differently. They inform their entrance to the cluster region to the super peer but they do not register their file list to the super peer. When a peer wishes to find a file, it first searches the registered file list of the super peer and if fails, query message is broadcasted. We perform mathematical modeling, analysis and optimization of the proposed scheme regarding P2P traffic and associated routing traffic. Numerical results show that the proposed scheme performs much better than or similar to the typical cluster-based P2P scheme and flooding based Gnutella.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.188-194
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• 2007

We propose a new ad hoc multicast routing protocol for based on the ontology scheme called inference network. Ontology knowledge-based is one of the structure of context-aware. We will have developed an algorithm that will design multi-hierarchy Layered networks to simulate a desired system.

• 전자공학회논문지 IE
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• v.47 no.3
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• pp.41-46
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• 2010

WSN, or Wireless Sensor Network, consists of a multitude of inexpensive micro-sensors. Because the batteries in sensor nodes can not be replaced once they are deployed, the life of a WSN is absolutely determined by the batteries. So, energy efficiency of a network is a critical factor for long-life operation. LEACH protocol which divides WSN into two groups is a typical routing protocol based on the clustering scheme for the efficient use of limited energy. It is composed of round units which are separated into set-up and steady state. In this paper we propose a power saving scheme to minimize set-up phase itself and to involve a data comparison algorithm. We evaluate the performance of the proposed scheme in comparison with original LEACH protocol. Simulation results validate our scheme has better performance in terms of the number of alive nodes as time evolves and average energy dissipated.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.11A
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• pp.1064-1072
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• 2005

For the efficient operation of sensor networks, it is very important to design sensor networks for sensors to utilize their energies in very effective ways. Cluster-based routing schemes such as LEACH can achieve their energy efficiencies by delivering data between cluster heads and sensor nodes. In those cluster-based schemes, cluster reconfiguration algorithm is one of the most critical issues to achieve longer operation lifetime of sensor networks. In this paper, we propose a new energy efficient cluster reconfiguration algorithm. Proposed method does not require any location or energy information of sensors, and can configure clusters with fair cluster regions such that all the sensors in a sensor network can utilize their energies equally. The performances of the proposed scheme have been compared with LEACH and LEACH-C.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.3
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• pp.213-220
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• 2015

Wireless sensor network(WSN) is made up of a lot of battery operated inexpensive sensors that, once deployed, can not be replaced. Therefore, energy efficiency of WSN is essential. Among the methods for energy efficiency of the network, clustering algorithms, which divide a WSN into multiple smaller clusters and separate all sensors into cluster heads and their associated member nodes, are very energy efficient routing technique. The first cluster-based routing protocol, LEACH, randomly elects the cluster heads in accordance with the probability. However, if the distribution of selected cluster heads is not good, uniform energy consumption of cluster heads is not guaranteed and it is possible to decrease the number of active nodes. Here we propose a new routing scheme that, by comparing the remaining energy of all nodes in a cluster, selects the maximum remaining energy node as a cluster head. Because of decrease in energy gap of nodes, the node that was a cluster head operates as a member node much over. As a result, the network lifespan is increased and more data arrives at base station.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.27-30
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• 2012

In the Cluster-Based Routing Protocol (CBRP) a cluster header in each cluster should be elected. The cluster headers consume energy much more than other nodes because they manage and operate all of mobile nodes in their cluster. The traditional CBRP elects a cluster header without considering the remaining electric energy of each node. So, there exists problems that the cluster header has short average lifetime, and another cluster header should be elected again frequently. In this paper, we propose the improved protocol which prolongs the lifetime of the cluster header, decreases of header re-elected problem, decreases of header re-elected problem and enhances the stability of the path. In order to achieve this, when a cluster header is elected in a cluster, the remaining electric energies of all the nodes are compared with one another, and the node with the highest energy is elected as the cluster header. Also, the node with the second highest energy is elected as the second header. If the elected cluster header is unable to perform the role of the cluster header because the remaining energy level goes low, it sends a beacon message to neighbor member nodes and the second header will serve as the cluster header.

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.5
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• pp.457-461
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• 2008

Previous studies on overlay ad hoc multi-casting are mainly divided into two categories: hierarchical structure-based multicast schemes and non-hierarchical structure-based multicast schemes. They do not reflect their real-time location information for routing updates. This can be a cause of low performance on energy consumption, throughput, and latency. For improving the problems, we propose an implicit cluster based overlay ad hoc multicast scheme with analysis of related work, and then we evaluate performance through computer simulation.

• 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.