• The KIPS Transactions:PartC
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• v.10C no.2
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• pp.163-170
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• 2003

In this paper we propose a robust clustered croup Multicast in Ad-hoc network. The proposed scheme applies to weighted clustered Algorithm. Ad-hoc network is a collection of wireless mobile hosts forming a temporary network without the aid of any centralized administration or reliable support services such as wired network and base station. In ad hoc network routing protocol because of limited bandwidth and high mobility robust, simple and energy consume minimal. WCGM method uses a base structure founded on combination weighted value and applies combination weight value to cluster header keeping data transmission by scoped flooding, which is the advantage of the exiting FGMP method. Because this method has safe and reliable data transmission, it shows the effect to decrease both overhead to preserve transmission structure and overhead for data transmission.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.9
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• pp.1665-1671
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• 2007

Mobile Ad hoc Networks (MANETs) refer to autonomous networks in which wireless data communications are established between multiple nodes in a given coverage area without a base station or centralized administration. Because of node mobility and limited battery life, the network topology may changes frequently. Selecting the most reliable path during route discovery process is important to improve performance in ad-hoc networks. In this study, we proposed an enhanced routing protocol based on AODV by monitoring variation of receiving signal strength. New metric function that consists of node mobility and hops of path is used for routing decision. From extensive experiments by using NS-2, The performance of the proposed routing scheme has been imp개ved by comparison to AODV protocol.

• Journal of Korea Society of Digital Industry and Information Management
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• v.10 no.2
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• pp.75-82
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• 2014

MANET has various types of attacks. In particular, routing attacks using characteristics of movement of nodes and wireless communication is the most threatening because all nodes which configure network perform a function of router which forwards packets. Therefore, mechanisms that detect routing attacks and defense must be applied. In this paper, we proposed hierarchical structure attack detection techniques in order to improve the detection ability against routing attacks. Black hole detection is performed using PIT for monitoring about control packets within cluster and packet information management on the cluster head. Flooding attack prevention is performed using cooperation-based distributed detection technique by member nodes. For this, member node uses NTT for information management of neighbor nodes and threshold whether attack or not receives from cluster head. The performance of attack detection could be further improved by calculating at regular intervals threshold considering the total traffic within cluster in the cluster head.

• Journal of information and communication convergence engineering
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• v.10 no.4
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• pp.329-336
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• 2012

For designing broadcast protocols in mobile ad hoc networks (MANETs), one of the important goals is to reduce the rebroadcast packets redundancy while reaching all the nodes in network. In this paper, we propose a probabilistic broadcasting mechanism based on selfishness and additional coverage in MANETs. Our approach dynamically adjusts the rebroadcast probability according to the extra covered area and number of neighbor nodes. By these two factors, mobile hosts can be classified into three groups: normal, low selfishness, and high selfishness groups. The nodes in the normal group forward packets for other nodes with high probability, whereas the nodes in the low selfishness group rebroadcast packets with low probability and the nodes in the high selfishness group do not rebroadcast packets. We compared our approach with simple flooding and the fixed probabilistic approach. The simulation results show that the proposed schemes can significantly reduce the number of retransmissions by up to 40% compared simple flooding and fixed probabilistic scheme without significant reduction in the network reachability and end-to-end packet delay.

• Journal of Communications and Networks
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• v.4 no.4
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• pp.292-301
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• 2002

Wireless LAN technology is complementary to 3G systems and could be used to provide high bandwidth hotspot coverage, for example in railway stations and offices, in order to provide the high bandwidth video and broadband services such as those emerging on DSL fixed access. The IST Projects BRAIN and MIND have investigated a number of key technical enablers for such a system beyond 3G. These include scenarios and business models, design of an all-IP access network, consideration of ad hoc network extensions, enhancing Wireless LAN efficiency and compatibility with IP and, finally, terminal middleware and signalling for rapid adaptations to network QoS changes.

• Journal of information and communication convergence engineering
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• v.11 no.3
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• pp.173-178
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• 2013

To discover objects of interest in unstructured peer-to-peer networks, the peers rely on flooding query messages which create incredible network traffic. This article evaluates the performance of an unstructured Gnutella-like protocol over mobile ad-hoc networks and proposes modifications to improve its performance. This paper offers an enhanced mechanism for an unstructured Gnutella-like network with improved peer features to better meet the mobility requirement of ad-hoc networks. The proposed system introduces a novel caching optimization technique and enhanced ultrapeer selection scheme to make communication more efficient between peers and ultrapeers. The paper also describes an enhanced query mechanism for efficient searching by applying multiple walker random walks with a jump and replication technique. According to the simulation results, the proposed system yields better performance than Gnutella, XL-Gnutella, and random walk in terms of the query success rate, query response time, network load, and overhead.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.8 no.5
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• pp.187-195
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• 2008

In MANET, it is important to efficiently manage data objects and traffic to improve network throughput and response time. This paper proposes a connection-degree based data object search and replication scheme in mobile ad-hoc networks. In this method, information about the path data object providers is stored at the cache of a cluster header at which lots of queries arrive, so that, to reduce the load of the cluster header, replicas can be created at its neighboring nodes. The method proposes an algorithm that picks up a cluster header among mobile nodes and makes it possible to search for and utilize adaptive and up-to-date information in MANET. The method is expected to be effective since it enables access to data objects in spite of broken links among mobile nodes with an enhancement in network response time of searching and a decrease in communication costs. The efficiency of this system was verified via simulation.

• The KIPS Transactions:PartC
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• v.11C no.7 s.96
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• pp.917-922
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• 2004

Mobile ad hoc networks (MANETs) are networks of mobile nodes that have no fixed network infrastructure. Since the mobile node's location changes frequently, it is an attractive area to maintain the node's location efficiently. In this paper, we present an adaptive randomized database group (ARDG) scheme to manage the mobile nodes mobility in MHANETs. The proposed scheme stores the network nodes' location in location databases to manage the nodes' mobility. When a mobile node changes its location or needs a node's location, the node randomly select some databases to update or que교 the location information. The number of the selected databases is fixed in the case of querying while the number of the databases is determined according to the node's popularity in the case of updating. We evaluated the performance of the proposed scheme using an analytical model, and compared the performance with that of the conventional randomized database group (RDG) scheme.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.8 s.350
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• pp.25-34
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• 2006

In this paper DynaMoNET is suggested as a novel IPv6-based multi-homed mobile network architecture which is composed of nested mobile ad hoc networks dynamically coming together through wireless personal area networks. Each ad hoc network has a mobile router which may work as a root mobile router instead of fixed mobile routers in a DynaMoNET. A root mobile router provides the reliable Internet connectivity for the entire mobile network. This paper includes a innovative handover protocol for multi-homed mobile networks, network switchover algorithm considering multiple decision factors, root mobile router election process based on token-based algorithm fast root mobile router discovery algorithm and fault avoidance mechanism to support reliable Internet connectivity. Finally the system architecture of a mobile router is given in detail.

• Convergence Security Journal
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• v.13 no.1
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• pp.19-24
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• 2013

MANET has a highly dynamic topology because it consists of only mobile nodes. Various attacks using these characteristics exist. Among them, damage of the attacks based flooding such as DoS or DDos is large and traceback of the attack node is not easy. It is because route information by moving of intermediate nodes which pass the data changes frequently. In this paper, we propose table-based traceback technique to perform efficient traceback although route information by moving of nodes changes frequently. Cluster head manages route management table in order to form cluster status table and network topology snapshot for storing the location information of mobile nodes when cluster member nodes change. Also, bloom filter is used to reduce the amount of storing route information. The performance of the proposed technique is confirmed through experiment.