• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.7 s.361
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• pp.70-80
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• 2007

For supporting various mobile networks, this paper proposes a framework of distributed connection admission control, named SmartCAC. Especially, intelligent CAC operations are adopted in terms of interoperation between mobile nodes and mobile networks. This scheme does not need to correct information between networks. Basically vertical handover call can use guard channel that was reserved for handoff, because SmartCAC addresses the identification between vertical handover call and new call, delay and reliability as requirement of QoS for efficient connection control. The scheme also uses mobile terminal speed for network filtering. Especially an extended protocol is proposed to give different network states information to mobile nodes because there have been no ways for mobile nodes to compare the states of different networks. Sophisticated simulation study is performed in order to evaluate SmartCAC in terms of signaling cost. As a result, signaling cost of ours is up to 96% better than that of the existing scheme.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.153-155
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• 2010

Internet phone (VoIP) services in Korea have achieved noticeable growth year after year since the service launching, and the growth still coninues. The market of mobile internet phone also expands sharply. Therefore, it is crucial to deploy networks which can support mobile internet phone services with excellent quality. For mobile internet phone services, it will be necessary to build and use networks with good mobility and high transmission rate. Current wireless networks for Internet services include 3G, Wi-Fi, and mobile WiMAX networks. 3G provides good mobility but lower transmission rate, whereas Wi-Fi exhibits excellent transmission rate but less mobility. Mobile WiMAX networks taking the merits of both, high mobility and transmission rate, are being deployed widely in recent years. This article examines the recent standardization efforts of WiMAX Forum for VoIP service in WiMAX networks.

• Journal of information and communication convergence engineering
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• v.7 no.2
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• pp.141-147
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• 2009

To initialize and maintain self-organizing networks such as mobile ad hoc networks, address allocation protocol is essentially required. However, centralized approaches that pervasively used in traditional networks are not recommended in this kind of networks since they cannot handle with mobility efficiently. In addition, previous distributed approaches suffer from inefficiency with control overhead caused by duplicated address detection and management of available address pool. In this paper, we propose a new dynamic address allocation scheme, which is based on adaptive partition. An available address is managed in distributed way by multiple agents and partitioned adaptively according to current network environments. Finally, simulation results reveal that a proposed scheme is superior to previous approach in term of address acquisition delay under diverse simulation scenarios.

• Journal of the Korea Society for Simulation
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• v.14 no.2
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• pp.83-92
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• 2005

Access networks connected in B3G networks provide its property network service. Hence, though mobile users may utilize only a network service from an access network, they can also use variety of network services from several access networks for their service satisfaction. To support heterogeneous changeable network service in access networks, the mobile terminal must implement heterogeneous system techniques so that it is able to change the network service by ISHO (Inter-System Handover) In this paper, we present the ISHO condition by the policy-based framework in B3G networks. Also, we propose an ISHO scheme to control network resources for the QoS management of a mobile session between UMTS and WLAN access networks. To support the QoS management, the proposed scheme is that it will be implemented before the resource exhaustion occurs to effect network performances.

• Journal of the Korea Society of Computer and Information
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• v.15 no.11
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• pp.117-124
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• 2010

Appling centralized network management architecture SNMP(Simple Network Management Protocol) to wireless networks causes the network overhead, NAT(Network Address Translation) problem on AP, and performance degradation of mobile nodes. In this paper, we propose an integrated management scheme for wired and wireless networks using mobile agents in order to solve above problems. In our proposed scheme, SNMP is applied to manage wired networks and MAs of SNMP are implemented in APs or wireless nodes to manage wireless networks. In addition, we propose a method to reduce the redundant OID information within SNMP response messages. Through the analysis, we show that our proposal resolves the given problems and reduces the processing delay of the wireless nodes.

• Smart Media Journal
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• v.5 no.1
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• pp.55-60
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• 2016

Mobility of the sensor networks proposed a new way to the efficient design of sensor networks and improvement of network system performance. Mobility results in a number of functional changes in the MAC protocol and routing protocol. Especially, the mobility of the nodes may occur the increase of the overhead of transmission or disconnection of the link. Therefore, the study of the energy efficient transmission is very important in mobile sensor networks. This paper proposed adaptive transmission mechanism on the distance-based power control. The proposed mechanism was analyzed better than conventional method in the average energy consumption and network life by simulation results.

• Proceedings of the Korea Information Processing Society Conference
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• 2007.05a
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• pp.1096-1097
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• 2007

We address the data confidentiality for wireless broadband (WiBro) networks. In WiBro, as the channel is wireless in nature, it suffers from passive and active attack. Passive attack, for example is to decrypt traffic based on statistical analysis and active attack is to modify traffic or inject new traffic from unauthorized mobile stations. Due to high mobility, frequent session key distribution is a bottleneck for the mobile stations. In aspect of WiBro, there is a communication between mobile station to base station, and also in mobile station to mobile station. It is expected to ensure data confidentiality while maintaining minimum overhead for the resource constrained mobile stations. In this paper, we proposed a security framework based on the concept of hyper-encryption to provide data confidentiality for wireless broadband networks.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.23 no.6
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• pp.1191-1197
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• 2013

In large-scale distributed sensor networks, it is often recommended to employ mobile sinks, instead of fixed base stations, for data collection to prolong network lifetime and enhance security. Mobile sinks may also be used, e.g., for network repair, identification and isolation of compromised sensor nodes and localized reprogramming, etc. In such circumstances, mobile sinks should be able to securely interact with neighbor sensor nodes while traversing the network. This paper presents a secure and efficient mobile query protocol that can be used for such purposes.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.699-700
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• 2008

In this paper, we implement Mobile AP system, which has Multihoming function providing vertical handover between WiBro and HSDPA networks. We monitor packet drop in networks during binding updates(BU) and acknowledgement(BA) and analyze handover latency. We propose methodology to reduce handover latency and describe the further development direction of Mobile AP system.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2007.02a
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• pp.26-31
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• 2007

An ad hoc network is a collection of mobile nodes without any Infrastructure. However, ad hoc networks are vulnerable to attacks such as routing disruption and resource consumption; thus, routing protocol security is needed This paper proposes a secure and efficient routing protocol for mobile ad hoc networks, where only one-way hash function are used to authenticate nodes in the ROUTE REQUEST, while additional public-key cryptography is used to guard against active attackers disguising a node in the ROUTE REPLY.