• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.9
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• pp.1829-1836
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• 2009

A wireless Ad-hoc network is willing to send and receive data and for other nodes, and it is a temporal network where the nodes with mobility are automatically constituted. This network has been studied to construct networks in the state where there is no infrastructure. The limited nodes and its frequent moving in a wireless Ad-hoc network have resulted in frequent network disconnection. Therefore, the data transmission rate should be secured in a wireless Ad-hoc network. This study proposes the method to improve QoS of data transmission considering the mobility of nodes that respond to path searching by means of AOMDV routing protocol. By applying the suggested method, it is possible to raise the transmission rate by improving the reliability of transmission path.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.6
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• pp.43-48
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• 2009

Wireless mesh networks, unlike Ad-hoc network, has low mobility and multi-path communication between terminals and other networks because it has the backbone structures. Most studies are advanced on finding the optimal routing path in multi-hop wireless mesh network environment. Various routing metric, minimum number of hops(Hop_count) and ETX, ETT metric, are proposed to wireless mesh networks. However, most metrics cannot identify the high throughput routing paths because this metric uses a different measurement parameters in each direction. So actual delivery rate does not provide to this metric. This paper describes the metric and implementation of IETC as a metric. This paper shows the improvement in performance.

• Journal of the Korea Computer Industry Society
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• v.2 no.9
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• pp.1219-1224
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• 2001

There can exist unidirectional links due to asymmetric property of mobile terminals or current wireless environments on practical mobile ad hoc networks. However, at present, the existing mobile ad hoc routing protocols are implemented to support only bidirectional links. Thus, in this paper, we extend the existing dynamic source routing protocol in order to implement a new routing protocol, which is fit to mobile ad hoc networks containing unidirectional links. For performance evaluation, we use combinations of mobility scenario files and connection pattern files from Carnegimelon Univ. We consider received data rate and average route discovery time as evaluation items, which are compared and evaluated for three suggested route discovery methods.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.6
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• pp.89-94
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• 2009

In wireless mesh network, nodes are communicates as like as Ad-Hoc. Nodes of Wireless Mesh Network must have a good QoS and a algorithm for good path. ETX, ETT and WCETT are proposed Wireless Mesh Network routing methods. But these have Interference problem. This paper propose ETI(Expected Transmission Interference) based on ETT for good path selection. This paper show the algorithm and improved performance in simulation than other algorithms.

• Proceedings of the Korea Information Processing Society Conference
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• 2006.05a
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• pp.1179-1182
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• 2006

Ad Hoc 무선망은 기존 인프라에 영향을 받지 않으면서, 노드들이 네트워크를 구성하기 때문에 TCP의 혼잡(Congestion) 제어가 나쁜 영향을 미친다. 기존의 TCP에 무선망의 요소와 거리에 따른 노드 홉수의 영향을 반영해서 새로운 환경에 적합한 TCP를 개선해야한다. 본 논문에서는 혼잡의 원인을 구별하여, 패킷 손실을 최소화할 수 있는 알고리즘을 제안한다.

• Journal of Information Technology Services
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• v.3 no.2
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• pp.119-127
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• 2004

A mobile ad hoc network(MANET) is a network where a set of mobile devices communicate among themselves using wireless transmission without the support of a fixed network infrastructure. The use of wireless links makes MANET susceptible to attack. Eavesdroppers can access secret information, violating network confidentiality, and compromised nodes can launch attack from within a network. Therefore, the security for MANET depends on using the cryptographic key, which can make the network reliable. In addition, because MANET has a lot of mobile devices, the authentication scheme utilizing only the symmetric key cryptography can not support a wide range of device authentication. Thereby, PKI based device authentication technique in the Ad Hoc network is essential and the paper will utilize the concept of PKI. Especially, this paper is focused on the key management technique of PKI technologies that can offer the advantage of the key distribution, authentication, and non-reputation, and the issuing and managing technique of certificates based on clustering using Threshold Cryptography for secure communication in MANET.

• Journal of Multimedia Information System
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• v.6 no.2
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• pp.61-66
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• 2019

VANET (Vehicular Ad-hoc Network) is a mobile Ad-hoc Network which deals with the moving vehicles. VANET supports Intelligent Transport Systems (ITS) which is related to different modes of transport and traffic management techniques. VANETs enabled users to be informed and make them safer. VANET uses IEEE 802.11p standard wireless access protocol for communication. An important and necessary issue of VANET is to design routing protocols. In a network, communication takes place by the use of the routing protocols. There are mainly two types of communications used such as Vehicle to Vehicle (V2V) and Vehicle to Infrastructure (V2I) in VANET. Vehicles can send and receive messages among them and also to and from infrastructure used. In this paper, AODV, DSR and DSDV are compared by analysing the results of simulation on various metrics such as average throughput, instant throughput, packet delivery ratio and residual energy. Findings indicates utilization of AODV and DSR is more applicable for these metrics as compared to DSDV. A network simulator (NS2) is used for simulation.

• Proceedings of the Korea Society for Simulation Conference
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• 2000.11a
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• pp.97-101
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• 2000

Energy consumption is considered as a principal ingredient in mobile wireless ad-hoc networks. In such a network, most of mobile nodes takes a role in forwarding messages received from neighbor nodes. Energy of these nodes is consumed in different rates depending on message traffic routes. This paper proposes a scheme to balance routing energy consumption by transferring routing function from node with small residual energy to node with enough residual energy. This scheme requires additional local message transfer, increasing the energy consumption of nodes to transfer routing function, and increasing total energy consumption of ad-hoc network. But balancing of energy consumption make the system lifetime the longer and increase the average node lifetime.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.4
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• pp.627-635
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• 2008

Using directional antenna in wireless network can offer many advantages including significant decrease of interference, increase of spatial reuse and possibility of improving network capacity. However, existing 802.11 MAC is designed for use of omni-directional antenna then those advantages can not be shown in that MAC protocol when it uses directional antenna. In this paper, we present a MAC protocol specifically designed for directional antenna to achieve spatial reuse and improve capacity of MAC protocol. Simulation result shows the advantages of our proposal in comparison with existing MAC in terms of end-to-end delay and network throughput.

• Journal of Industrial Technology
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• v.27 no.B
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• pp.37-42
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• 2007

A mobile ad hoc network (MANET) is a kind of wireless ad hoc network. It is a self-configuring network of mobile nodes connected by wireless links. Infostation is a lower cost and low power system that provides very high bit rate with limited coverage. In this study, we propose search and rescue system that combines MANET of climbers with Infostations. A climber shares location information of climbers with other climbers while climbing, and delivers the information to Infostations. This system is an intermittent network due to the mobility of nodes. From the system, we can track the locations of missing climbers. Ultimately, proposed system achieves low cost and reduces memory requirement using Infestations. We also analyze the performance of the proposed system by simulation. From the performance analysis results, we expect that the proposed system will be very useful to early detect climbers' locations in emergency situations in Korea mountain areas.