• 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.

• Journal of the Korea Society for Simulation
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• v.8 no.4
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• pp.33-51
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• 1999

In this study, the system level network simulation is considered with adaptive array antenna in CDMA mobile communication system. A network simulation framework is implemented based on IS-95A/B system to consider dynamic handoff, system level network behavior, and deploying strategy into the overall CDMA mobile communication network under adaptive array algorithm. Its simulation model, such as vector channel model, adaptive beam forming antenna model, handoff model, and power control model, are described in detail with simulation block. In order to maximize SINR of received signal at antenna, Maximin algorithm is particularly considered, and it is computed at each simulation snap shot with SINR based power control and handoff algorithm. Graphic user interface in this system level network simulator is also implemented to define the simulation environments and to represent simulation results on real mapping system. This paper also shows some features of simulation framework and simulation results.

• Journal of the Korea Society of Computer and Information
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• v.21 no.10
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• pp.99-105
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• 2016

The active rule system is a key element of the rule-based mobile agent middleware system for activeness and autonomy of the sensor network. The rule manager, which is the main components of active rule based mobile agent framework and active rule system, performs the control and management of the rule-related processes. In this paper, we design and implement the roles and functions of the rule manager in detail. The proposed rule manager plays an important role in the sensor network environment. The sensor data server loads the active rule on the mobile agent by the rule manager according to the situations, and the mobile agent migrates to the destination node and performs the designated action. This active rule-based mobile agent middleware system presents the usefulness for the various sensor network applications. Through the rule execution experiment using the rule-based mobile agent, we show the adaptability and applicability of rule-based mobile agent middleware system to the dynamic environmental changes in sensor networks.

• 전자공학회논문지 IE
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• v.47 no.4
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• pp.48-52
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• 2010

Recently, WiBro service as a mobile internet has been being extended. The market of wireless data communication has been being extended rapidly due to the increase of mobile data communication service supply such as smart-phone, WiBro service and so on. As the result, security is also emphasized in the mobile Internet In this paper, we propose the methods that tighten up security in the upcoming Enterprise Mobile-VPN service on WiBro network.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.3
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• pp.93-99
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• 2009

The Internet Engineering Task Force (lETF)proposed the Mobile IPv6 protocol to provide host mobility in IPv6-based network and to offer a standardized technology. However, Mobile IPv6 (MIPv6) is not applied in actual network because of long handover latency and packet loss problems. Therefore, to compensate these drawbacks, many studies are in progress and FMIPv6 (Fast handover for Mobile IPv6) is one of the studies that has been proposed to supplement the shortcomings of MIPv6. But there are problems occurred in using router tunneling which causes packet loss and out of sequence problems. In this paper, we propose an Advanced Mobile IPv6 (AMIPv6) protocol to minimize the handover latency when Mobile Node frequently moves in each subnet. We compared the performance analysis of AMIPv6 handover latency with MIPv6 handover latency in the same network environment to prove that AMIPv6 is more efficient.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.7 no.2
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• pp.43-54
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• 1997

In this paper, we introduce a secure and minimal protocol for authenticated key distribution over the CDMA mobile communication network. The CDMA mobile communication network has been developed the security protocol that provides a means for user authentication and subsequent protection of user traffic. However, this model has no security assumptions for the intermediate, fixed networks. To avoiding these drawbacks, we introduce a minimal authenticated key distribution protocol. This protocol provides the security of the intermediate and fixed network in mobile environment, and maintains the confidentiality of user identification and the minimum size of information flow compared with the existing protocols.

• Journal of Communications and Networks
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• v.2 no.1
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• pp.35-45
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• 2000

this paper presents the concept of "mobile ATM', a proposal for third-generation (3G) mobile communication network infrastructure capable of supporting flexible evolution of radio technologies from today's cellular and data services towards future wireless multimedia services. Mobile ATM provides generic mobility management and QoS-based transport capabilities suitable for integration of multiple radio access technologies including cellular voice. wireless data, and future broadband wireless services. The architecture of a mobile ATM network is outlined in terms of the newly-defined "W-UNI" interface at the radio link and "M-UNI"and "M-UNI" interface which supports unified access for WATM and non-ATM mobile terminals through corresponding interworking functions (IWF) is explained. leading to an understanding of how different radio access technologies are supported by the same ATM-based core network infrastructure. Generic mechanisms for handoff and location management within the core mobile network are discussed. and related protocol extensions over the "W-UNI" and "M-UNI/NNI"interfaces are proposed. the issue of "crossover switch (COS)" selection in mobile ATM is considered, and a unified handoff signaling syntax which supports flexibility in COS selection is described. Typical signaling sequences for call connection and handoff using the proposed protocols are outlined. Experimental results form a proof-of-concept mobile ATM network prototype are presented in conclusion.

• Electronics and Telecommunications Trends
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• v.39 no.2
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• pp.77-92
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• 2024

The 3GPP (3rd Generation Partnership Project) mobile communication standard has emerged as a leading standard in the market over the past 20 years, driving continuous development in protocol stacks and libraries that support the standard within simulation software for communication network research. We summarize and analyze seven communication network simulators that support the 3GPP standard specifications related to core network technologies. Through comparisons, we aim to offer valuable insights for researchers and engineers engaged into research and development related to mobile communication networks based on 3GPP standards. Our findings can provide assistance for making informed decisions on simulator selection.

• Journal of the Korea Society of Computer and Information
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• v.9 no.1
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• pp.87-93
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• 2004

In the design of mobile wireless communication network, BSC(Base Station Location), BSC(Base Station Controller) and MSC(Mobile Switching Center) are the most important parameters. Designing base station location, the cost must be minimized by combining various, complex parameters. We can solve this Problem by combining optimization algorithm, such as Simulated Annealing, Tabu Search, Genetic Algorithm, Random Walk Algorithm that have been used extensively for global optimization. This paper shows the 4 kinds of algorithm to be applied to the optimization of base station location for communication system and then compares, analyzes the results and shows optimization process of algorithm.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.8
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• pp.50-58
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• 2009

Fourth generation mobile communication network have the technology of extensive form include basic service technology and it has been developed from the radio access technology and network topology. Not only fourth generation mobile communication network have basically done new highspeed radio access technology which is suitable to high and low speed environment of transfer, but also it is possible that they have been made for freely vertical handover. ETRI also has made fourth generation mobile communication network which is WiNGS(Wireless Initiative for Next Generation Service) satisfied that demand. This paper is made by lossless handover method through the local retransmission ARQ agent that is one of the main technology of fourth generation mobile communication network. Lossless handover method through local retransmission ARQ agent has been basically made by WiNGS and it was better than original local retransmission of layer by simulation.