• Journal of Advanced Navigation Technology
• /
• v.12 no.3
• /
• pp.233-238
• /
• 2008

Recently, network component become to follow wireless and mobile network from wired network proposed that many TCP algorithm optimized in variety environment. When TCP was created, however as it was design based on wired link, wireless link made more transmission error than wired link. Transmission errors are more frequent and may be incorrectly regarded as indications of network congestion. In this paper, it conduct how effect congestion control algorithm in Mobile ad-hoc network and compare traffic of TCP-Tahoe, TCP-Reno, TCP-New-Reno and TCP-Vegas in Mobile ad-hoc environment.

• Journal of Satellite, Information and Communications
• /
• v.6 no.1
• /
• pp.75-79
• /
• 2011

Wireless devices can communicate between each other without existing infrastructure in mobile Ad-hod network. Ad hoc networks can be used under difficult conditions, where it is difficult to construct infrastructures, such as shadowing areas, disaster areas, war area, and so on. In order to support to considerable and various wireless services, more spectrum resources are needed. However, efficient utilization of the frequency resource is difficult because of spectrum scarcity and the conventional frequency regulation. Ad-hoc networks employing cognitive radio (CR) system that guarantee high spectrum utilization provide effective way to increase the network capacity. In this paper, we simulate and compare the performance of conventional single and cooperative spectrum sensing with CR system using ad-hoc networks in additive white Gaussian noise (AWGN) and Rayleigh channel model. And we demonstrate performance improvement by analyzing the system performance.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.43 no.7 s.349
• /
• pp.41-49
• /
• 2006

Wireless AD-hoc network can construct a network itself without any arbitrator. Therefore, it is difficult to make preparation for disguised assault from an illegal node, and because lots of packets from disguised assault spread over whole network, it influences the network usability and livability. This thesis proposed a safe IPv6 tunnel broker (TB) based on TSP (Tunnel Setup Protocol) to improve safety of the wireless Ad-hoc network, and to solve security problem of a tunnel broker that makes a linkage IPv4 and IPv6. To communicate between client and the tunnel broker, proposed method does not base on HTTP, but S-HTTP (Secure-HTTP) and it uses encryption/decryption to send and receive XML document. Finally, this method encrypts (decrypts) important information by applying IPSec between client and TS (Tunnel Server).

• Convergence Security Journal
• /
• v.13 no.1
• /
• pp.59-70
• /
• 2013

Along with the rapid development of the wireless network (Wireless Network) technology for secure wireless communications, security problems have emerged as an important issue. In order to operate the wireless network intrusion detection system detects the agent installed on each wireless node should be. Ad-hoc network structures scattered in the AP over a wireless network without the node is a structure that makes it possible to communicate to connect. Intrusion detection agent to be installed on the node, and the corresponding energy consumption occurs when the survival time is reduced. On a node that can monitor a lot of traffic in order to increase the effect of intrusion detection, an intrusion detection agent should be placed. Therefore, in this paper, by taking advantage of the structure of Ad-hoc wireless network, considering the maximum living time of the network, while at the same time, the effectiveness of intrusion detection and intrusion detection by proposing a plan for installing the agent. Also improve the system performance by reducing the network load on each network, a system designed for data aggregation to reduce data redundancy, network energy consumption by reducing.

• Journal of information and communication convergence engineering
• /
• v.7 no.3
• /
• pp.241-246
• /
• 2009

Advances in mobile and wireless networking technologies have enabled mobile ad hoc networks applicable to a wide range of areas. Many cases of even such ad hoc networks demand to be accessible to the global network. Owing to be diversified in features depending on applications, however, some those networks may consist of devices or nodes which do not facilitate all the same transport protocols. This results in unreachable situations of establishing ad hoc network: such as non-existence of all required access points, faults or contention in a path of particular protocol communication. Interworking between different transport protocols can alleviate such problems. This paper proposes an interworking scheme to improve data transport performance and network accessibility, especially in such a mobile ad hoc network that is applicable to data communications among ships or user's convenient u-health services. Modeling and simulation analysis are used to verify the improvement.

• Journal of Ubiquitous Convergence Technology
• /
• v.1 no.1
• /
• pp.35-41
• /
• 2007

In mobile ad-hoc wireless networks, one of the most important challenging issues is how to conserve energy, maximizing the lifetime of route(networks) in the view points of both power and mobility of nodes. However, many transmission methods presented in the previous works can not satisfy these two objectives simultaneously. To obtain these two goals, in this paper we propose an architecture to support power saving transmission services with route stability in mobile ad-hoc wireless networks. The proposed architecture consists of two parts, the underlying route stability method to support route(network) lifetime and the power saving transmission methods. The performance evaluation of the proposed architecture is achieved via simulation and analysis.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.31 no.11A
• /
• pp.1120-1129
• /
• 2006

It is very important to maximize the battery durability of mobile host in wireless ad-hoc network environments, because it extends the durability and Performance of the system. Since mobile hosts play a routing role, the network structure and the location of mobile hosts create a difference of energy consumption of mobile hosts. In this paper, each mobile host maintains energy tree and evaluates the amount of the energy of the neighboring mobile hosts by using message tree packet by periods. When mobile host sets up a routing path to send a packet, it selects the most proper path in order to consume energy effectively by using energy tree and breadth first search. In this paper, we suggest that, in wireless ad-hoc network environments, if each mobile host consumes balanced energy, mobile hosts of which energy capacity is limited can work as long as it can. Therefore, the durability and performance of the system can be extended.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.23 no.8
• /
• pp.976-984
• /
• 2012

Ad hoc networks can be used under difficult conditions, where it is difficult to construct infrastructures, such as shadowing areas, disaster areas, war area, and so on. In order to support to considerable and various wireless services, more spectrum resources are needed. However, efficient utilization of the frequency resource is difficult because of spectrum scarcity and the conventional frequency regulation. Ad-hoc networks employing cognitive radio(CR) system that guarantee high spectrum utilization provide effective way to increase the network capacity. However, there is a problem that all CR user do not fairly use the primary user's idle bandwidth which has been sensed. In this paper, to solve this problem, we propose the spectrum sharing algorithm which uses the multiple orthogonal sequences based on the code division multiple access(CDMA). From the proposed algorithm, it is expected that system performance of CR based ad-hoc network is improved significantly and it can be applied to the implementation of CR based ad-hoc network system.

• Journal of KIISE:Information Networking
• /
• v.34 no.4
• /
• pp.269-275
• /
• 2007

Since being constructed without any infrastructure-based network, ad hoc network has been received much attention as a key technology for ubiquitous networks. Due to high bit error rate and dynamically changing network topology in ad hoc network, the routing protocol that provides stable multi-hop communication path is the one of the key issues to address. The previously proposed ad hoc routing protocols have their limitations on network overhead, stability, and scalability. In this paper, we consider hybrid wireless network, which can overcome shortcomings of ad hoc network, and propose a novel routing protocol called zone master-based routing protocol. We verify with computer simulations that the proposed routing protocol outperforms other existing routing protocols in the various wireless environments.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.8 no.4 s.23
• /
• pp.68-76
• /
• 2005

In this paper, Ad-hoc network is a collection of mobile nodes without any wired infrastructure. Design of efficient routing protocols in ad-hoc network is a challenging issue. An AODV routing protocol for wireless ad hoc networks one that searches for and attempts to discover a route to some destination node. We propose a technique that reduce the number of Routing packet. Our technique use variable values reflecting the condition of network. This also contributes to improve throughput.