• Proceedings of the Korea Information Processing Society Conference
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• 2008.11a
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• pp.1340-1343
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• 2008

최근 인터넷기반의 멀티미디어 서비스의 발전에 힘입어 기존의 IP망을 코어 네트워크로 사용하는 이종망간의 통합서비스가 주를 이루고 있다. 이에 따른 사용자들의 요구로 고품질 멀티미디어 데이터 서비스 지원의 QoS와 멀티미디어 서비스를 끊김없는 이동성(Seamless Mobility)에 대해서 지원할 수 있는 핸드오버기법이 필수적이게 되었다. 이중 끊김없는 이동성 지원하기 위해 MIP(Mobile IP)기법이 제안되었고, 이를 향상시킨 FMIP(Fast Handover for. MIP), HMIP(Hierarchical MIP) 그리고 PMIP(Proxy MIP)까지 제안되었다. 본 논문에서는 IMS망의 P-CSCF의 SIP프로토콜과 PMIP핸드오버 기법을 연동하는 PTSA(PMIP To SIP Agent)를 두어 IMS망에서 적용할 수 있는 향상된 PMIP 핸드오버 기법을 제안한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.11
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• pp.1997-2015
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• 2011

In this paper, we propose the enhanced network-based mobility management protocol, called enhanced proxy mobile ipv6 (E-PMIPv6), which can provide mobile nodes (MNs) with a fast and efficient mobility service in PMIPv6 domain. The proposed scheme can provide a fast and efficient mobility service to MNs and also the strength of network scalability and stability to an access network by proposing the dynamic virtual hierarchical network architecture. In addition, the pre-authentication procedure for an MN, based on the information of neighbor mobile access gateway (MAG) list in the enhanced-policy server (E-PS), is proposed to support seamless handover by reducing MN's handover latency. Through performance evaluations of numerical analyses and simulations, we have confirmed and verified the superiority of the proposed scheme compared to the conventional proxy mobile ipv6 (PMIPv6).

• The Journal of the Korea Contents Association
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• v.11 no.9
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• pp.54-62
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• 2011

This paper proposes both global and local mobility management (MM) scheme improved from Multi Protocol Label Switching (MPLS)-based Mobility Management scheme (MPLS-MOB) for seamless service in Next Generation Network (NGN). The proposed scheme adds local MM on the existing MPLS-MOB which supports global MM by processing handover signaling by 2.5 layer switching via Label Switch Path (LSP) of MPLS. We numerically analyze and verify that the proposed scheme has lower handover latency time than the existing ones, such as micro-MM methods using MPLS as well as MIP and an interworking scenario between PMIP and MIP.

• Proceedings of the Korea Information Processing Society Conference
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• 2005.05a
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• pp.1339-1342
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• 2005

이기종 네트워크들이 계층적인 구조로 결합되어 있는 오버레이 네트워크 환경에서 이동 단말(Mobile Terminal:MT)의 끊김없는 이동성 지원을 위해서는, 패킷 손실 및 호 단절 현상을 최소화할 수 있는 최적의 핸드오버 시점을 결정할 수 있어야 한다. 기존의 수직적 핸드오버 기법은, 단순히 MT의 위치 정보를 바탕으로 핸드오버 수행을 예측하고 결정하였다. 하지만 이 기법은, MT의 위치와 관계없이 네트워크의 과부하로 인한 패킷 손실 및 호 단절 현상이 발생할 수 있기 때문에, 네트워크의 과부하에 따른 핸드오버 시점을 간과하는 문제점을 노출하였다. 하루가 다르게 인터넷 트래픽이 급증하는 현실에서, 네트워크의 과부하를 고려하는 핸드오버 기법이 필요한 때이다. 따라서 본 논문에서는 MT의 위치와 네트워크의 부하를 모두 고려하여 핸드오버 시점을 결정할 수 있는 핸드오버 맵(Handover-Map:H-Map)의 개념을 제안한다. 그리고 핸드오버 동기화 현상을 최소화하기 위해 향상된 H-Map을 기반으로 차별화된 핸드오버 시점을 부여하는 VAH(Vertical handover on Advanced H-Map) 기법을 소개하고, 이의 성능을 기존기법과 비교한다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.2
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• pp.127-134
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• 2017

In this paper, we try to solve the frequency shortage due to the increase of LTE terminals and the traffic jam caused by the inefficient WiFi connection method. The proposed LTE-WIFI Vertical Handover method uses a pre-authentication method of the AP through LTE and a method of controlling the access AP of the terminal using the RADIUS server. Through the simulation, the proposed method shows that the access speed of the AP is improved by about 95% compared to the conventional connection method, and the connection speed is improved by about 18% compared to the conventional method. Providing seamless AP through pre-authentication system and improving wireless network speed through AP access distribution can solve LTE frequency shortage problem and improve wireless network usage satisfaction.

• Journal of KIISE:Information Networking
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• v.35 no.5
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• pp.437-452
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• 2008

IEEE 802.16j MR networks introduce RSs (Relay Stations) within the IEEE 802.16 system in order to enhance the data throughput and extend the coverage. However, the current standardization defines that the BS (Base Station) controls MS's (Mobile Station's) handover, not only it induces the large signaling overhead but also handover latency could increase. In this paper, we propose a handover protocol in the MR networks where the high capability RSs that can process the MS's control functions are deployed. First, we classify the handover scenarios for the MR networks with the high capability RSs. Then, we define the MAC handover procedure, corresponding MAC management messages and the transmission routes for the proposed messages so that an 802.16e MS can perform seamless handover without noticing it is attached to an MR network. The simulation results show that the proposed handover protocol not only reduces the MAC management message overhead transferred through the wireless links compared to IEEE 802.16j/D1, which is the current standard for MR networks, but also performs the rapider and more secure MS handover than IEEE 802.16e and IEEE 802.16j/D1.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.12
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• pp.17-27
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• 2011

Most of the previous mobility management protocols such as IETF MIPv4/6 and its variants standardized by the IETF do not support global seamless handover because they require partially changes of the existing network infrastructure. In this article, we propose a simple mobility management protocol (SMMP) which can support global seamless handover between homogeneous or heterogeneous wireless networks. To do this, the SMMP employs separate location management function as DMMS to support global user and service mobility and the bidirectional tunnels are dynamically constructed to support seamless IP mobility by using the IEEE MIH extension server, which is extended the IEEE 802.21 MIH standards. The detailed architecture and functions of the SMMP have been designed. Finally, the mathematical analysis and the simulation have been done. The performance results show the proposed SMMP outperforms the existing MIPv6 and HMIPv6 in terms of handover latency, packet loss, pear signal noise ratio (PSNR).

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.7
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• pp.2389-2413
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• 2015

High data rates in long-term evolution (LTE) networks can affect the mobility of networks and their performance. The speed and motion of user equipment (UE) can compromise seamless connectivity. However, a proper handover (HO) decision can maintain quality of service (QoS) and increase system throughput. While this may lead to an increase in complexity and operational costs, self-optimization can enhance network performance by improving resource utilization and user experience and by reducing operational and capital expenditure. In this study, we propose the self-optimization of HO parameters based on fuzzy logic control (FLC) and multiple preparation (MP), which we name FuzAMP. Fuzzy logic control can be used to control self-optimized HO parameters, such as the HO margin and time-to-trigger (TTT) based on multiple criteria, viz HO ping pong (HOPP), HO failure (HOF) and UE speeds. A MP approach is adopted to overcome the hard HO (HHO) drawbacks, such as the large delay and unreliable procedures caused by the break-before-make process. The results of this study show that the proposed method significantly reduces HOF, HOPP, and packet loss ratio (PLR) at various UE speeds compared to the HHO and the enhanced weighted performance HO parameter optimization (EWPHPO) algorithms.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.87-90
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• 2007

Many moderncommunication technologies are developing based on internet protocol (IP) and there is many work to archive seamless mobility service. IETF proposed MIPv6 protocol that uses IPv6 to provide mobility services to mobile node however it has some limits like sending and receiving too many messages during binding update (BU) procedure. So, now a day it makes HMIPv6(Hierarchical Mobile IPv6). HMIPv6 solves overhead and transmission delay problem in MAP(Mobile Anchor Pointer), but it can't accomplish effectively Macro handover between MAPs. This paper introduces use of FMIPv6 and Selective handover mechanisms based on hierarchical MAP information in HMIPv6 for improvement of handover efficiency.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.21 no.3
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• pp.57-66
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• 2011

The current trend of the handover authentication delay time is gradually increased according to the interworking between 3G cellular network and WLANs. Therefore, authentication mechanism minimized in delay is required to perform the seamless handover and support the inter-subnet and inter-domain handover. In this paper, we propose a novel pre-authentication scheme based on the fast channel switching which directly performs the authentication with the next access point in advance. In addition, the proposed scheme is efficient in the inter-domain handover and can be easily implemented in current WLANs since it just modifies the client side of user. To analysis and evaluate our scheme, we compare the packet loss ratio and the delay time with the two standard 802.11 authentication schemes. The analytical results show that our scheme is approximate 10 times more effective than the standard schemes in packet loss and the delay time is minimized down to 0.16 msec.