• Journal of Digital Contents Society
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• v.14 no.4
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• pp.471-479
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• 2013

WiBro technology provide mobile devices with a transmission speed of more than 1 Mbps even under the condition of high mobility (120 km/h). In a building, however, there is more demand for high bandwidth for various activities, and WiBro services may not be available. In order to guaranteeing a seamless service continuity and high transmission capability for mobile users within a specific establishment that has deployed WiBro network, we should secure an internetworking platform for WiBro and WiFi networks. This paper introduces WiMax forum and 3GPP standards, proposes WiBro-WiFi Interworking (WWI) architecture, its implementation details, and finally verifies validity of the proposal by using OPNet simulations.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.1
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• pp.51-56
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• 2011

WiBro network technologies developed mainly by Korea are one of very promising 4G technologies. WiBro has been standardized as international standard called Mobile WiMAX, and has been deployed in many countries. Emergency Services in WiBro networks are infrastructure services and will be very essential to induce subscribers from other types of networks. This paper proposes a network architecture for supporting emergency services for WiBro mobile VoIP networks. The proposed architecture is based on WMF's architecture for international compatibilities, and reflects national considerations on interfacing PSAP for domestic compatibilities.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.10
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• pp.2247-2253
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• 2010

WiBro(Wireless Broadband Internet) is the standard of high-speed portable internet based on OFDMA/TDD (Orthogonal frequency division multiple access / Time division duplexing) techniques, and the subset of consolidated version of IEEE802.16e Wireless MAN standard. In this paper, we propose performance improvements of WiBro system using the LVQ(Learning Vector Quantization) blind equalization. Proposed method used the prefiltering LVQ neural network blind equalization in the Broadband WiBro system receiver. The prefiltering LVQ neural network constellates 16QAM that is transmitter data shape and the blind equalization removes ICI(Inter Carrier Interference). To verificate the proposed method usability, the MSE(Mean Square Error) and the BER(Bit Error Rate) are simulated. The simulation results shown that is improved the performances of the proposed WiBro system using the LVQ blind equalization than the existing WiBro system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.5
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• pp.1125-1132
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• 2010

WiBro(Wireless Broadband Internet) is the standard of high-speed portable internet based on OFDMA/TDD (Orthogonal frequency division multiple access / Time division duplexing) techniques, and the subset of consolidated version of IEEE802.16e Wireless MAN standard. In this paper, we propose performance improvements of WiBro system using the 64QAM SOFM(Self-Organizing Feature Maps)prefiltering. Proposed method used the prefiltering SOFM neural network blind equalization in the Broadband 64 QAM WiBro system receiver. The prefiltering SOFM neural network constellates 64QAM that is transmitter data shape and the blind equalization removes ICI(Inter Carrier Interference). To verificate the proposed method usability, the MSE and the BER are simulated. The simulation results shown that is improved the performances of the proposed WiBro system using the 64QAM SOFM Prefiltering than the existing WiBro system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.5B
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• pp.264-273
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• 2005

Nowadays the integration of heterogeneous wireless networks become a hot issue in communications research area. Especiall,y, 3G and WiBro interworking will be introduced soon as users can be offered the most suitable service according to service area and service providers can reduce network construction and operation expenses. In this paper, we propose an interworking scheme for fast handoff between 3G and WiBro networks. The SCI (Smoothly Coupled Integration) scheme proposed in this paper takes advantages of the existing LCI (Loosely Coupled Integration) and TCI (Tightly Coupled Integration) scheme and can offer seamless services by providing fast handoff between 3G and WiBro although each network may work independently. Through extensive computer simulations using OPNET, the efficiency of the proposed scheme has been validated.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.283-284
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• 2008

A cross-layer optimization is becoming a popular design methodology for the IP based next generation wireless network. We begin by investigating a cross-layer optimization scheme to enhance the system performance in wireless networks. By applying cross-layer optimization methodology to WiBro distributed network, the WiBro systems are expected to gain significant performance improvement and resource utilization enhanced. For further study we highlight some open challenges and new opportunities for cross-layer design.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.335-336
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• 2008

By using DM(Diagnostic Monitoring) data measured at WiBro network, automatic optimization function of WiBro network is implemented in this paper. The optimization function mentioned is able to be run on PC with 2GHz CPU and 1 GB memory. Automatic optimization function is one module of CellTREK that is a wireless network planning and optimization software developed by Infra Lab., KT.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.6B
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• pp.334-341
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• 2007

A Mobile IP is considered for the efficient mobility function in IEEE 802.16/WiBro environment. However, during the deployment of WiBro, only some of the ACRs(Access Control Router) can support the Mobile IP function. Therefore, a WiBro network can not support the mobility function for the mobile node. In this paper, we implement an overlay-based Mobile IP function and measure the performance through a field trial. Moreover, we evaluate the possibility of commercial deployment and suggest areas that need to be improved.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.11A
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• pp.1101-1112
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• 2006

With the recent growth in demand for high-data rate multimedia services in the wireless environments, the Mobile Broadband Wireless Access (MBWA) technologies, such as WiBro (Wireless Broadband internet) system, are gradually coming into the spotlight. Unlike the conventional mobile communication networks based on cellular system, the WiBro system basically consists of IP based backbone networks that will be ultimately deployed by Ipv6 (IP version six) based backbone networks according to the All-IP trend for the network evolution. In such wireless mobile environments, it is needed to support the mobility management protocol on network layer as well as physical layer and Medium Access Control (MAC) layer in WiBro system. Accordingly, in this paper, we propose a fast handover scheme for improving the handover performance in IPv6 based WiBro system and show that the proposed scheme achieves loss-free and low handover latency during inter-subnet movement of the mobile stations through the simulation.

• The KIPS Transactions:PartC
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• v.13C no.7 s.110
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• pp.873-880
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• 2006

Since various networks are deployed and the most of users request higher mobility, there are many researches about the interworking between widely deployed 3G network and rapidly boarded WLAN. On the other side, WiBro is focused on as a next generation network, because many people expect that WiBro gives satisfaction about the enough mobility and mass data transmission. So the study of the integration between WiBro and cdma2000 will show better effects than the present study of the integration between WLAN and cdma2000. The L2 handoff proposed in this paper takes advantages over the existing L3 handoff scheme because it does not require the L3 procedure for the mobility unlike the L3 handoff. Through extensive computer simulations, the efficiency of the proposed scheme has been validated.