• Journal of the Korea Society of Computer and Information
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• v.11 no.5 s.43
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• pp.165-173
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• 2006

Network Mobility Basic Support protocol enables mobile network to change their point of attachment to the Internet, but causes some problems such as suboptimal muting and multiple encapsulations. The proposed scheme, combining Prefix Delegation protocol with HMIPv6 concept can provide more effective route optimization and reduce the amount of packet losses and the burden of location registration for handoff. It also uses hierarchical mobile network prefix (HMNP) assignment and provides tree-based routing mechanism to allocate the location address of mobile network nodes (MNNs) and support micro-mobility. In this scheme, Mobility Management Router (MMR) not only maintains the binding informations for all MNNs in nested mobile networks, but also supports binding procedures to reduce the volume of handoff signals oyer the mobile network. The performance is evaluated using NS-2.

• Journal of the Korea Society of Computer and Information
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• v.12 no.6
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• pp.235-242
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• 2007

Network Mobility Basic Support protocol reduces location-update signaling by making network movements transparent to the mobile nodes (MNs) behind the mobile router (MR), but causes some problems such as sub-optimal routing and multiple encapsulations. This paper proposes an Route Optimization Employing HMIP Extension for Mobile Networks (ROHMIP) scheme for nested nubile networks support which introduces HMIP concept with relation information between MNNs behind a MR and the MR in order to localize handoff, to optimize routing and especially reduce handoff signal overhead. With ROHMIP, a mobile network node (MNN) behind a MR performs route optimization with a correspondent node (CN) as the MR sends a binding update message (BU) to mobility anchor point (MAP) via root-MR on behalf of all active MNNs when the mobile network moves. This paper describes the new mechanisms and provides simulation results which indicate that our proposal reduces transmission delay, handoff latency and signaling overhead.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.10A
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• pp.796-806
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• 2003

Mobile Node usually communicate with CN bia only it's own HA but Nested Mobile Networks correspond with CN bia all HA involved with them. when Mobile Network of a MR moves from its home link to a foreign link in the stationary network. then Mobile Network of another MR moves from its home link in stationary network to foreign link in previous mobile network. CN send Packet destined to the latter MR via both Home Agent of the former MR and the latter MR. There are two problem in this scenario. One is inefficient routing path that bypass via several HA. the other is waste of transmission resource and delay of Registration process which change of Nested Mobile Network Architecture cause Mobile Router. so We propose MRA(Mobile Relay Agent) to support effective routing by local mobility management.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.8 no.5
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• pp.95-103
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• 2008

The Network Mobility (NEMO) basic support protocol extends the operation of Mobile IPv6 to provide uninterrupted Internet connectivity to the communicating nodes of mobile networks. The protocol is not efficient to offer delays in data delivery and higher overheads in the case of nested mobile networks because it uses fairly sub-optimal routing and multiple encapsulation of data packets. In this paper, our scheme combining Hierarchical Mobile IPv6 (HMIPv6) functionality and Hierarchical Prefix Delegation (HPD) protocol for IPv6, which provide more effective route optimization and reduce packet header overhead and the burden of location registration for handoff. The scheme also uses hierarchical mobile network prefix (HMNP) assignment and tree-based routing mechanism to allocate the location address of mobile network nodes (MNNs) and support micro-mobility and intra-domain data communication. The performance is evaluated using NS-2.

• Journal of the Korea Society of Computer and Information
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• v.19 no.12
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• pp.81-89
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• 2014

The heterogeneous LTE-Advanced networks comprising a macrocell and femtocells can provide an efficient solution not only to extend macrocell coverage but also to deal with packet traffics increasing explosively within macrocells. Efficient resource management schemes are necessary to maintain the QoS requirements of versatile multimedia applications in LTE-Advanced networks because their service-continuity may be defected by some delay and information loss. In this paper, we propose a resource allocation method for the heterogeneous LTE-Advancedl networks overlaid with femtocells. Performances are analyzed by simulation.

• Proceedings of the Korea Information Processing Society Conference
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• 2008.05a
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• pp.1080-1083
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• 2008

유비쿼터스 사회에는 도서관, 커피숍과 같은 공공장소와 자동차, 전철, 비행기등과 같은 대중교통에도 인터넷에 접근할 수 있게 될 것이다. 또한 모든 통신은 끊임없는 인터넷이 지원되어야 하고, 세션이 유지되어야 하며, 이동 중에 통신이 끊어지지 않고, 라우팅이 효율적으로 이루어져야 한다. 이러한 요구를 반영할 수 있는 네트워크 이동성 기술은 이동 IPv6이 가지고 있는 근본적이고, 비효율적인 삼각 라우팅 문제와 중첩된 환경에서 삼각라우팅 문제가 반복되는 핀볼 라우팅 문제를 가지고 있다. 본 논문은 중첩환경의 라우팅 문제를 조사하고, 해결하기 위해 이미 제안된 내용들을 분석하고, 효율성과 안전성을 만족할 수 있는 프로토콜을 제안한다.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.10
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• pp.83-98
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• 2007

The handover between different radio access networks, especially where their coverage overlaps, suffers various complications since the different access networks provide different service characteristics. One way to reduce service interruptions and QoS (i.e., bandwidth, throughput, delay) degradations during the inter-technology handover is to reserve the required resource in advance. The resource reservation algorithm should minimize the handover latency and maximize the resource utilization based on the accurate estimation on mobile's location, velocity, movement pattern and service requirements. In this paper, we propose a resource reservation algorithm based on the mobile terminal velocity and the cell selection probability, which maximizes resource utilization ana reduces network overhead. We compare the proposed algorithm with PMS(Predictive Mobility Support) and VCDS(Velocity and Call Duration Support scheme) based on 3-layer network model under various scenarios.

• Journal of Internet Computing and Services
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• v.11 no.1
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• pp.35-48
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• 2010

For the next generation mobile communication system, diverse wireless network techniques such as beyond 3G LTE, WiMAX/WiBro, and next generation WLAN etc. are proceeding to the form integrated into the All-IP core network. According to this development, Beyond 3G integrated into heterogeneous wireless access technologies must support the vertical handover and network to be used of several radio networks. However, unified management of each network is demanded since it is individually serviced. Therefore, in order to solve this problem this study is introducing the theory of Common Radio Resource Management (CRRM) based on Generic Link Layer (GLL). This study designs the structure and functions to support the vertical handover and propose the vertical handover algorithm of which policy-based and MCDM are composed between LTE and WLAN systems using GLL and CRRM. Finally, simulation results are presented to show the improved performance over the data throughput, handover success rate and the system service cost.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.1
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• pp.35-42
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• 2010

Geo-location using a cellular network is a core technology for LBS together with GPS. With preamble symbols broadcasted in each frame, geo-location using WiBro network can be easily implemented. Because the WiBro network has a cellular structure, it is difficult for a mobile station to detect signals from multiple base stations. In order to get user position using trilateration, long integration techniques for sensitivity enhancement should be employed. This paper presents hybrid integration scheme for WiBro network. By analyzing coherent and non-coherent integration loss according to frequency residual and SNR respectively, optimal combination of the hybrid integration is proposed. Simulation results show that the hybrid integration method is profitable in WiBro network when the frequency residual is estimated and compensated accurately.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.20 no.3
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• pp.293-301
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• 2007

We present a new global-local analysis with the aid of MLS(Moving Least Square) variable-node finite elements which can possess an arbitrary number of nodes on element master domain. It enables us to connect one finite element with a few finite elements without complex remeshing. Compared to other type global-local analysis, it does not require any superimposed mesh or need not solve the equilibrium equation twice. To demonstrate the performance of the proposed scheme, we will show several examples in relation to capturing highly local stress field using global-local analysis.