• Proceedings of the IEEK Conference
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• 2007.07a
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• pp.189-190
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• 2007

We propose an efficient internetworking model for fast handover between UMTS and WLAN networks. Mobility anchor (MA) is provided at the boundary between GGSN and PDG, under the 3GPP-proposed internetworking reference model. Such MA can enable authentication and session initialization before L2 handover of the mobile terminal, so that seamless and fast vertical handover could be possible.

• Journal of Communications and Networks
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• v.11 no.2
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• pp.187-195
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• 2009

The application of mathematical analysis to the study of wireless ad hoc networks has met with limited success due to the complexity of mobility, traffic models and the dynamic topology. A scenario based universal mobile telecommunications system (UMTS) time division duplex (TDD) opportunistic cellular system with an ad hoc behaviour that operates over UMTS frequency division duplex (FDD) licensed cellular network is considered. In this paper, we present a new routing metric which overall improves system performance in terms of interference and routing which operate in an ad hoc network in an opportunistic manner. Therefore we develop a simulation tool that addresses the goal of analysis and assessment of UMTS TDD opportunistic radio system with ad hoc behavior in coexistence with a UMTS FDD primary cellular networks.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 2006.06a
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• pp.506-510
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• 2006

3G 이동통신기술중 하나인 UMTS(Universal Mobile Telecommunications System)에서는 무선 구간의 안전한 통신을 위해 UMTS-AKA(Authentication and Key Agreement) 프로토콜이 사용된다. 그러나 SN(Serving Network)과 HN(Home Network)의 통신량 소비 문제, SQN(SeQuence Number) 동기화 문제 등 여러 가지 문제점이 제기되었다. 본 논문에서는 기존 프로토콜의 문제점과 IMSI(International Mobile Subscriber Identity)의 노출로 인한 프라이버시 문제점을 해결하고, ECDH(Elliptic Curve Diffie Hellman) 기법으로 완전한 전방향 안전성을 제공하는 프로토콜을 제안한다.

• Korean Management Science Review
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• v.27 no.3
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• pp.1-14
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• 2010

In this paper we study the access network design problem in Universal Mobile Telecommunication Systems (UMTS) networks. Given the location of radio base stations (node-Bs), their traffic demands, and the candidate facility centers for locating radio network controllers (RNCs), the problem is to determine the configuration of access network, including the number and location of facility centers, the number of RNCs in each facility center, and the links between RNCs and node-Bs, with the objective being to design such a network at the minimum cost. We provide a mathematical formulation of the problem with constraints on RNC and node-B capacities, along with a lower bounding method. We develop a heuristic algorithm with two different initial solution methods designed to strengthen the solution quality. The computational efficacy of their procedures is then demonstrated on a number of test problems.

• Proceedings of the Korean Information Science Society Conference
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• 2001.10c
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• pp.124-126
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• 2001

GPRS/UMTS 망에서 터널링 프로토콜인 GTP(GPRS Tunneling Protocol)는 QoS를 고려하지 않는 단순한 GSN(GTP Support Node)의 터널링 기법이 적용되고 있다. 즉 모든 트래픽에 대해서 동일만 터널링 기법이 적용되고 있으므로 피부 망에서 입력되는 트래픽에 대한 QoS를 보장하기가 어렵다. 따라서, QoS 제어가 가능한 인터넷 망(RSVF, Diffserv)과 연동(interwotking)이 가능하면서 외부 망의 트래픽을 GPRS 망에 받아들여 효율적으로 처리할 수 있는 GGSN 노드의 트래픽 QoS 제어 메커니즘에 대해 이 연구되어져야 한다. 본 논문에서는 GPRS/UMTS망에서 클래스별 패킷 트래픽 처리의 성능향상을 위해서 망의 게이트웨이 역할을 담당하는 GGSN에서 I)iffserv edge function을 할 경우에 실시간 트래픽의 QoS보장을 위한 클래스별 트래픽 제어 방법에 대해 분석하였다.

• Electronics and Telecommunications Trends
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• v.16 no.1 s.67
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• pp.1-9
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• 2001

오늘날 이동통신 시대를 맞이하여 사용자에게 Anywhere, Anytime, Anybody, 그리고 Anyplace(4A) 조건을 보장해 주는 3세대인 Universal Mobile Telecommunication System/International Mobile Telecommuni-cation-2000(UMTS/IMT-2000) 비동기 시스템은 기존의 여러 종류의 서비스를 제공하기 위하여 개선된 무선 접속으로 다양한 이동 환경 하에서 여러 가입자에게 다양한 서비스를 제공하는 것을 목표로 하고 있다. 이와 같이 UMTS/IMT-2000 비동기 시스템에서는 저속의 음성에서 2Mbps까지의 전송속도를 가지는 데이터, 영상 등의 멀티미디어 서비스와 이동 가입자에게 전 세계 어디를 가든 통화할 수 있는 국제 로밍 서비스를 제공하여야 한다. 본 고에서는 UMTS/IMT-2000 기반인 Third Generation Project Partnership(3GPP)의 제3세대 이동통신망인 UMTS에 대하여 살펴 본 후 최대 2Mbps급의 트래픽 및 실시간 멀티미디어 응용을 위한 개선된 QoS를 지원하는 UMTS Terrestrial Radio Access Network (UTRAN)의 구조를 기술하였다. 특히, 기지국 및 핵심망과 접속되는 무선망 제어국의 구조, 특성, 그리고 기능에 대하여 논하였다.

• Journal of the Korea Society for Simulation
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• v.13 no.3
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• pp.31-41
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• 2004

In this paper, we consider the strategy of Universal Mobile Telecommunication System (UMTS) and Wireless Local Area Network (WLAN) internetworking that provide the seamless vertical handover for mobile nodes. We propose Mobility Anchor Points (MAP) based UMTS/WLAN internetworking architecture to support the vertical handover. Also, on integrated UMTS/WLAN networks, we propose a vertical handover scheme that avoids the call blocking caused by the network resource shortage. We provide the numerical analysis to investigate the performance evaluation to the proposed scheme and compare the proposed scheme with the existing scheme.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.187-188
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• 2006

In CDMA based mobile communication network, signaling messages are routed through Signaling Transfer Point(STP) which is responsible for MTP layer 3 switching. As WCDMA based UMTS network is considered as next generation technology allowing global roaming services, all nodes in networks have their own identity number called Global Title(GT). Therefore, it is essential to introduce Signaling Gateway(SG) responsible for SCCP layer switching to solve the problem each node has all GT tables including even all overseas nodes. In this paper, we propose the signaling network architecture in UMTS networks using SG and we show that we can reduce CAPEX and OPEX in each node. To show the validity of the proposed method some simulations are given in which the results can be expected by intuitive observation.

• The KIPS Transactions:PartC
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• v.13C no.5 s.108
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• pp.607-612
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• 2006

Universal Mobile Telecommunications System (UMTS) and Wireless Local Area Network (WLAN) have been developed independently. Then, many researchers have studied UMTS-WLAN interworking architecture for the efficiency. However, the transmission capacity difference of two networks causes the transmission quality degradation. Therefore, this paper proposes a UMTS-WLAN interworking architecture for Quality of Service (QoS). The proposed architecture is based on tight coupling and dynamically guarantees QoS by the mobility prediction method. The proposed architecture is simulated by ns-2. Performance experimental results show that the proposed architecture reduces the handover dropping probability comparing with the existing method and enhances the amount of receiving packets comparing with the method without guaranteeing QoS.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.07a
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• pp.419-419
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• 2004