• Journal of Communications and Networks
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• 제4권4호
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• pp.282-291
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• 2002

3GPP (Third Generation Partnership Project) is defining UMTS (Universal Mobile Telecommunication System) releases which span the transition from GSM/UMTS coexistence to All-IP UMTS networks. The deployment of an UMTS network depends, in the first place, on the intended service offerings and the release an operator chooses to start service with. Other key decisions in-fluencing UMTS deployment relate to the timing of the functional enhancements and capacity increases along the economic life of the network. This paper gives an overview on the architectural and technical options for UMTS deployment. It also outlines the methodology underlying the business plan aimed at estimating the returns from investments in the UMTS infrastructure, thus helping to tune operators’ strategies for UMTS deployment.

• 한국통신학회논문지
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• 제32권8B호
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• pp.492-501
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• 2007

UMTS-WLAN 망 연동을 통해 두 서비스가 가진 장점을 극대화 하고자 하는 연구에 관심이 집중되고 있다. 연동망을 통해 사업자는 망 구축 및 운용 비용을 절감할 수 있으며, 사용자는 지역에 따라 최적의 서비스를 제공받을 수 있다. 현재 연구되고 있는 UMTS-WLAN 연동 방식은 크게 MIP(Mobile IP) 기반의 Loose coupling 방식과 Telecom Emulation 기반의 Tight coupling 방식이 있다. 본 논문에서는 이 두 방식의 결합된 형태의 새로운 연동망 구조 및 빠른 수직적 핸드오버를 위한 절차를 제안하였다. 제안된 방식은 3GPP에서 제시한 연동망 참조 모델의 기반 위에 MIP를 통해 단말의 이동성 관리가 가능하며, GGSN과 PDG 경계구간에 MA(Mobility Anchor)를 제안하여 단말의 L2 핸드오버 이전에 네트워크 측에서 사전 인증 및 세션을 미리 확립함으로써 Seamless한 서비스 제공이 가능하도록 하였다. 제안된 방식의 성능을 검증하기 위해 OPNET을 이용한 시뮬레이션을 수행하였으며 이를 통해 제안 방안의 우수성을 검증하였다.

• 대한전자공학회논문지TC
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• 제41권4호
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• pp.25-34
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• 2004

GSM에서 발전한 UMTS 망의 경우 SGSN(Serving GPRS Support Node)과 GGSN(Gateway GPRS Support Node)을 중심으로 한 패킷 핵심 망을 포함하고 있다. 이러한 UMTS 망에서는 가입자 이동성, 위치 등록, 가입자 분포 등을 고려하여 망을 설계하고 장비의 제원을 정하여야 한다. 또한 향후 IMT-2000의 주요 트래픽이 데이터이기 때문에 인터넷 데이터 트래픽의 특성인 burstiness를 반영한 SGSN과 GGSN의 설계 기준이 마련되어야 하고 제약적인 시스템 조건 하에서 성능의 변화를 살펴보아야 한다. 이에 본 논문에서는 먼저 패킷 호 가입자의 신호 트래픽을 분석하며 이에 따른 망 성능 변화를 살펴보고, burstiness 특성을 가지는 패킷 데이터가 패킷 코아 망에 미치는 영향을 다양한 환경 하에서 시뮬레이션으로 분석한 뒤 UMTS 망에 새로이 추가하는 두개의 주요 망 요소인 SGSN과 GGSN의 요구 성능을 구하여 그 결과를 바탕으로 새로운 패킷 모드 핵심 망의 설계 기준을 제시하도록 한다.

• Journal of Communications and Networks
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• 제2권1호
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• pp.46-57
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• 2000

Ongoing standardization effort on 3G cellular system in 3GPP (UNTS) is based on GPRS core network and promises a global standard for systems capable of offering ubiquitous access to internet for mobile users. Considered radio access systems(FDD CDMA, TDD CDMA, and EDGE) are optimized for robust mobile use. However, there are alternative relatively high-rate radio interfaces being standardized for WLAN (IEEE802.11 and HIPER-LAN/2) which are capable of delivering significantly higher data rates to static or semi-static terminals with much less overhead. Also WPANs(BLUETOOTH, IEEE802.15), which will be present in virtually every mobile handset in the near future, are offering low cast and considerable access data rate and thus are very attractive for interworking scenarios. The prospect of using these interfaces as alternative RANs inthe modular UMTS architecture is very promising. Additionally, the recent inclusion of M-IP in the UMTS R99 standard opens the way for IP-level interfacing to the core network. This article offers an overview into WLAN-Cellular interworking. A brief overview of GPRS, UMTS cellular architectures and relevant WLAN standards is given. Possible interworking architectures are presented.

• Journal of Communications and Networks
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• 제11권2호
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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.

• 경영과학
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• 제27권3호
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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.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2006년도 하계종합학술대회
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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.

• 정보와 통신
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• 제14권11호
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• pp.22-28
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• 1997

ETSI SMG plays a key role at the development of standards for the UMTS Universal Mobile Telecommunications System, a set of standards aimed at the global market. It will be a real Third Generation Global System for Mobile CommunlcaUons adding new features and Introducing relevant technological InnovaUons while evolving from both GSM and ISDN networks. UMTS Is based on the carefully selected market requirements and belongs to the IMT-2000 family. UMTS standardlsaUon Is a market driven process being developed In a close co-operatlon with the UMTS Forum and GSM MoU.

• Journal of Communications and Networks
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• 제6권4호
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• pp.295-306
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• 2004

In this paper, a novel air-interface is presented for Fleet-Net1, a self-organizing network for inter-vehicle and vehicle-toroadsidecommunication. The air-interface is based upon the lowchip-rate version of UMTS/TDD. To adapt the cellular UMTS standard to an air-interface for ad hoc networks, changes of the physical layer, medium access control sub-layer and radio resource management are required. An overview of the required modifications is given here. Particularly, a decentralized synchronization mechanism is presented and analyzed by means of simulations. Furthermore, changes for the medium access control are explained in detail, which allow for an efficient operation in partly meshed networks and prioritization. Performance results of the overall system considering throughput and delay are derived by means of analytical evaluations and event-driven simulations. Based on realistic mobility models, it is shown that the presented solution provides a robust communication platform even in vehicular environments. The proposed air-interface is a cost-effective solution not only for inter-vehicle communication, but also for ad hoc networking in general, benefiting from the mass-market of UMTS.

• 한국시뮬레이션학회논문지
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• 제13권3호
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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.