• Journal of the Korean Professional Engineers Association
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• v.34 no.5
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• pp.69-72
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• 2001

The national 2G-3G roaming is emerging as one of essential and important issues In Korea in connection with the recent granting of 3G licenses. Accustomed to the current seamless coverage and superb quality of 2G networks, many subscribers have very high expectations of an equal or better service provisioning by 3G networks. However, it is very unlikely for 3G operators to successfully build their networks as comprehensive as the current 2G networks in the beginning of network implementation and commercial launch. Therefore,3G operators are seriously considering the national 2G-3G roaming in Korea. In this paper. 1 would like to discuss and present a technical implementation scheme and problems that need to be solved fer successfully realizing the national 2G-3G roaming.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.3
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• pp.1373-1379
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• 2011

The SLA (Service Level Agreement) is once determined between service provider and users in B3G networks so that the network service must be provided as QoS management. Here, the network situation is changed as the time flow, and the service environment is also altered. Hence, dynamic QoS management scheme should be considered. In this paper, we propose a handover scheme for dyanamic QoS as the network situation in B3G networks. The heterogeneous networks can be used for dynamic QoS management in B3G networks.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.2 no.4
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• pp.171-183
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• 2008

Nowadays, wireless packet data services are provided over Wireless MAN (WMAN) at a high data service rate, while 3G cellular networks provide wide-area coverage at a low data service rate. The integration of mobile WiMAX and 3G networks is essential, to serve users requiring both high-speed wireless access as well as wide-area connectivity. In this paper, we propose a cross-layer optimization scheme for a vertical handover between mobile WiMAX and 3G cellular networks. More specifically, L2 (layer 2) and L3 (layer 3) signaling messages for a vertical handover are analyzed and reordered/combined, to optimize the handover procedure. Extensive simulations using ns-2 demonstrate that the proposed scheme enhances the performance of a vertical handover between mobile WiMAX and 3G networks: low handover latency, high TCP throughput, and low UDP packet loss ratio.

• Journal of the Korea Society for Simulation
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• v.14 no.1
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• pp.33-42
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• 2005

Service Level Agreement (SLA) is a service providing scheme by a service class agreement between a user and a service provider SLA allows that a user can select an expected service class in various service classes provided from a service provider. Recently, SLA management is adapted to support the end-to-end Qos for service users in Beyond 3 Generation (B3G) networks. In B3G networks, SLA provides multiple service classes on access networks so that service classes should be managed to assure the service satisfaction for users. In this paper, we propose a dynamic Qos management scheme by IP traffic class controlling based on SLA in B3G networks. Also, to manage dynamic traffic service, we consider Differentiated services (Diffserv) mechanism for the resource management by SLA. An If service traffic class on SLA can be dynamically changed by Diffserv traffic management to support dynamic end-to-end Qos. Hence, in this paper, we consider the buffer threshold scheme for controlling traffic loads and the traffic level control scheme for implementing the dynamic traffic management by the SLA.

• Journal of Communications and Networks
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• v.7 no.2
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• pp.207-221
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• 2005

The proliferation of wireless local area networks (WLANs) offering high data rate in hot spot area have spurred the demand for possible WLANs and third-generation (3G) cellular network integration solutions as the initiative step towards 4G systems. This paper provides a novel architecture for seamless location-aware integration of WLANs into 3G cellular networks and also an analysis for the efficient handover techniques. We introduce location as a key context in secure roaming mechanism for context-aware interworking in 4G systems. The fast secure roaming with location-aware authentication is implemented at an entity called location-aware service (LAS) broker that utilizes the concepts of direction of user and pre-warming zone. The location-ware interworking architecture supports seamless roaming services among heterogeneous wireless networks including WLANs, wireless metropolitan area networks (WMANs), and 3G cellular networks. This paper also includes a description of procedures needed to implement efficient mobility and location management. We show how the LAS broker with pre-warming and context transfer can obtain significant lower latency in the vertical handover.

• Journal of the Korea Society of Computer and Information
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• v.17 no.11
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• pp.93-99
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• 2012

The B3G networks that provide the internetworking techniques of heterogeneous network systems and services are constructed to support various service requirements of mobile users. In this paper, we represent the internetworking scheme of heterogeneous networks systems such like UMTS and WLAN which can be used as access networks, and illustrate the service providing of each network system and the internetworking service based on heterogeneous access networks. UMTS and WLAN can provide each proper service to mobile users, and is included to B3G networks to increase the service usage effectiveness by using complementary service for mobile users.

• Proceedings of the IEEK Conference
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• 2002.06c
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• pp.47-50
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• 2002

In this paper, the efficient transmission technique of real time video data over 3G wireless networks is presented. To understand the transmission characteristic of 3G networks on real time video data, we implemented the data transport structure of 3G wireless networks. Also this research is based on current 3G wireless network specification of 3GPP, 3GPP2 standard organization to evaluate the result over real 3G wireless network environment. The retransmission by radio link layer results in the delay factor. To implement video data transmission efficiently, we Propose to use both no-retransmission and forward error correction method.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.677-678
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• 2012

The B3G network architecture by the connection of access network is divided into two forms:tightly-coupled networks and loosely-coupled networks. In this paper, we consider the tightly-coupled networks in the internetworking architecture of mobile network.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.679-680
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• 2012

The B3G network architecture by the connection of access network is divided into two forms:tightly-coupled networks and loosely-coupled networks. In this paper, we consider the loosely-coupled networks in the internetworking architecture of mobile network.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.6
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• pp.1016-1021
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• 2008

A number of wireless technologies have been implemented, but each technology has its limitation in terms of coverage and bandwidth. WLAN and 3G cellular network has emerged to be a complementary platform for wireless data communications. However, the mobility of roaming terminals in heterogeneous networks poses several risks. To maintain secure communications in universal roaming, the effective authentication must be implemented. The focus of this paper is on analysis of authentication architecture involved in integrated WLAN/3G networks.