• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.9
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• pp.1873-1882
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• 2009

In the ad-hoc mode of IEEE 802.11 standard, beacon is used for power control and network alarming between each node, and also it is for the synchronization in controlling network as PCF. However beacon is also used to inform the neighbor nodes of itself except for original purpose in the environment of IEEE 802.11s. For this, the existing beacon's transmission mechanism can't perform a function in full. In this paper, we suggest much faster neighbor discovery reducing network congestion caused by beacon through modification of beacon transmission mechanism. And we will show that suggesting algorithm more faster full neighbor discovery than traditional neighbor discovery using for IEEE 802.11 through simulation and test in real ad-hoc network.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.2
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• pp.336-342
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• 2008

We proposed a simple power allocation scheme to maximize network lifetime for "amplify and forward(AF)" and "decode and forward(DF)". To maximize network lifetime, it is important to allocate power fairly among nodes in a network as well as to minimize total transmitted power. In the proposed scheme, the allocated power is proportional to the residual power and also satisfies the required SNR at destination node. In this paper, we calculate power allocation in model of AF and DF. We evaluated the proposed power allocation scheme using extensive simulation and simulation results show that proposed power allocation obtains much longer network lifetime than the equal power allocation.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.05a
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• pp.421-424
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• 2013

차량 애드 혹 네트워크는 도심 교차로에서 도로의 특성과 차량의 높은 이동성으로 인해 네트워크의 단절이 자주 일어난다. 향상된 지리기반 라우팅 프로토콜인 GBSR(Greedy Border Superiority Routing)은 V2V(Vehicle-to-Vehicle)에 적합하다. 그러나 탐욕모드에서 stale노드가 로컬최대에 직면하는 문제를 가지고 있다. EGBSR(Enhanced GBSR)은 반대 방향의 차량과 같은 방향의 차량에게 보내는 비콘 메시지와 도로 정보를 관리하는 테이블을 이용하여 경로를 탐색하고 설정된 경로를 통해 패킷을 보낸다. 이를 통해 소스노드가 목적지노드에 빠르고 안전하게 패킷을 전달할 수 있는 양방향 라우팅 기법 제안한다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.431-435
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• 2005

Mobile Ad-Hoc network is the network(MANET) of mobile nodes which has no fixed infrastructure, and mobile node in MANET can move and communicate freely each other. Recently, many researches for mobility management of mobile nodes are actively carried out by using the location information of mobile nodes. The location management is an important issue in MANET because location information of mobile node is frequently changed in MANET. In this paper, an adaptive mobility management scheme using fuzzy-logic based GQS by considering the mobile locality is proposed in order to manage location information of mobile nodes in MANET efficiently. The proposed scheme selects mobility databases adaptively from GQS by considering the locality of mobile node. The performance of the mobility management scheme proposed in this paper is evaluated by an analytic model and compared with that of existing UQS based mobility management scheme.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.3
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• pp.48-58
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• 2009

Geo-graphical routing protocols as GPSR are known to be very suitable and useful for vehicular ad-hoc networks. However, a corresponding node can include some stale neighbor nodes being out of a transmission range, and the stale nodes are pone to get a high priority to be a next relay node in the greedy mode. In addition, some useful redundant information can be eliminated during planarization in the recovery mode. This paper deals with a new recovery mode, the Greedy Border Superiority Routing(GBSR), along with an Adaptive Neighbor list Management(ANM) scheme. Each node can easily treat stale nodes on its neighbor list by means of comparing previous and current Position of a neighbor. When a node meets the local maximum, it makes use of a border superior graph to recover from it. This approach improve the packet delivery ratio while it decreases the time to recover from the local maximum. We evaluate the performance of the proposed methods using a network simulator. The results shown that the proposed protocol reveals much better performance than GPSR protocol. Please Put the of paper here.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.5
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• pp.40-52
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• 2010

A mobile ad hoc network is instant and heuristic, and it is also vulnerable and volatile. Since topology and route changes are frequent, no single routing protocol designed for a conventional network performs well. Some protocols suffer from significant performance degradation when the number of nodes increases, or when nodes become highly mobile. In this paper we investigate a way to adaptively select a routing protocol that fits to the real-time network conditions. The first phase of our study is to analyze the performances of two classes of routing protocols under various network scenarios. The second phase consists of constructing a routing protocol selection reference. All nodes continue to monitor the status of neighbor nodes and control packets exchanged. Then, the aggregated information is periodically compared against the protocol selection reference. The selected routing protocol is maintained throughout the network until the network property changes substantially. The performance of the proposed algorithm is verified by a set of computer simulations using the OPNET modeler. The experimental results show that selectively changing routing protocol adaptive to the network conditions greatly improves the efficacy of bandwidth utilization.

• Journal of the Korea Society of Computer and Information
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• v.16 no.6
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• pp.131-142
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• 2011

In this paper, we propose a new multipath routing protocol and compare it with other multipath routing protocols in mobile ad hoc network (MANET) environments. The new multipath routing establishes the main route using a mechanism based on Ad Hoc On-demand Distance Vector(AODV), after which data transmission starts immediately. The backup route search process takes place while data are transmitted, to reduce the transmission delay. The protocol can also operate in a hybrid node-disjoint/link-disjoint mode, where the protocol finds the node-disjoint backup route first; if the node-disjoint does not exist, the protocol discovers the link-disjoint backup route from the main route. When either of the main route or the backup route is broken, data are transmitted continuously through the other route and the broken route is recovered by the route maintenance process. The results of simulations, based on the Qualnet simulator, show that the proposed multipath routing protocol increases the packet transmission success rate and reduces end-to-end delays, when compared with AODV and AOMDV protocols.