• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.12B
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• pp.790-799
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• 2007

In this paper, we propose WLAN CR coexistence beacon protocol for thenext WLAN network. This method can provide WLAN with high-speed data rate in new WLAN architecture and network platform based on cognitive radio technology. WLAN CR devices that enter the CR network can know UHF channels by listening CR beacon including the coexistence parameter set and start using CR channel fast. During handover of WLAN device in UHF spectrums, WLAN device that lost their channel can change available channel by obtaining the current CR channel information from the CR beacon. In advance relaying coexistence parameter set to entire CR system, WLAN CR system can prepare own candidate channel set that is different with other CR system. In CR beacon and relay delay, we show the results that WLAN CR coexistence beacon protocol supports spectrum handover efficiently and decreases the probability of collision in candidate channel set.

• ETRI Journal
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• v.35 no.6
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• pp.1144-1147
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• 2013

Dual-mode terminals (DMTs) equipped with cellular and WLAN interfaces have become popular in recent years. Users of DMTs can enjoy high-speed WLAN Internet access and wide area Internet access to cellular networks. However, a DMT may consume power inefficiently when discovering a WLAN with inherently limited service coverage. In this letter, we propose to use smart WLAN discovery (SWD) to minimize the power consumption required for WLAN discovery. To minimize the power consumption of a DMT, an SWD DMT activates its WLAN interface only when the DMT transfers data within the WLAN coverage area. The simulation results of SWD show an improved power-saving performance compared to previous WLAN discovery schemes.

• Proceedings of the Korea Information Processing Society Conference
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• 2002.11b
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• pp.1023-1026
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• 2002

The demand for Wireless LAN (WLAN) access to use their network and the Internet is surged dramatically over the past year. Since WLAN provides users' access from anywhere in the workplace without having to plug in, it therefore leads the WLAN market to grow steadily. Unfortunately, the first WLAN implementation designed primarily for home networking did little to address these security issues. Moreover, although the 802.11b standard published by IEEE in 1999 improved WLAN connections LAN-equivalent speed and security from the 802.11 standard. However, there still are several flaws such as the weaknesses in the Authentication and WEP encryption schemes in the IEEE 802.11 WLAN standard. In this paper, we propose WLAN architecture for providing the strong centralized authentication, encryption, and dynamic key distribution on a WLAN. Additionally, this proposed architecture is able to support roaming users and is flexible and extensible to future developments in the network security.

• Journal of Satellite, Information and Communications
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• v.10 no.3
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• pp.78-83
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• 2015

In this paper, when WLAN repeater of satellite communication package system as a novel wireless disaster communication network connected to LTE D2D mobile terminal, we analyzed radio channel interference from WLAN and WPAN system of adjacent same ISM band using Monte-Carlo method. In this study, WLAN cell radius was determined using Extended Hata Model considering practical environment, and simulated physical protection distance and density in the dense-mode to minimize interference from WLAN, Bluetooth, and ZigBee. Simulation results, WLAN repeater can be operated with 15 WLAN interferer over 130m distance, 23 Bluetooth interferer over 100m distance, and with 62 ZigBee interferer over 83m distance.

• Journal of Advanced Navigation Technology
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• v.10 no.4
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• pp.306-311
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• 2006

When the WiBro/WLAN hierarchical network is structured, a dual mode access terminal should keep WLAN module with power on state for operating in WiBro network outside of WLAN hotspot zone. Power consumption of user's access terminal can be increased to maintain WLAN module power on state of dual mode access terminal in WiBro network outside of the hotspot zone. This paper focuses on power saving strategy for a dual mode access terminal in WiBro/WLAN Hierarchical network to overcome problems regarding power. We will apply information about hotspot in WiBro network to establish the efficient power saving strategy for dual mode access terminal.

• Proceedings of the Korean Information Science Society Conference
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• 2001.10c
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• pp.217-219
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• 2001

WLAN은 다양한 정보와 자원을 공유할 수 있게 하는 LAN의 장점과, 제약 없는 연결성 제공이라는 편리성을 동시에 제공하고, 신뢰성 있는 data전송뿐만 아니라 유연성과 설치의 용이성을 장점으로 갖고 있다. 그러나 WLAN 이용하여 여러 어플리케이션을 사용할 때 제기되는 문제로 WLAN은 셀룰라 폰의 soft handover와 같은 mobility가 완전하게 지원되지 않으므로 WLAN 환경에서 VoIP 서비스 같은 실시간 서비스에 제약이 있다는 단점이 있다. 본 논문에서는 WLAN의 제약을 극복하기 위해 WLAN환경에서 이동단말의 이동성을 지원하기 위한 handover 방안을 제시하였다.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.25 no.6
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• pp.1515-1523
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• 2015

It has been prevalent to be serviced through WLAN(Wireless Local Area Network) as a variety of mobile devices have been introduced. If the number of mobile devices increases rapidly for the network access in a limited range of ESS(Extended Service Set), a lengthy connection delays are induced due to the initial link setup process of the IEEE 802.11i which is WLAN security standard. In this paper, we propose a new initial link setup protocol which can be executed in the ESS area of WLAN.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.4
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• pp.213-217
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• 2014

In this paper, we designed monopole microstrip antenna for WLAN/WiMAX system. The monopole antenna is designed by FR-4 substrate with size is $30mm{\times}40mm$. The proposed antenna is based on a planar monopole design which cover WLAN and WiMAX frequency bands. To obtain the optimized parameters, we used the simulator, CST's Microwave Studio Program and found the parameters that greatly effect antenna characteristics. Using the obtained parameters, the antenna is designed. Thus the proposed antenna satisfied the -10 dB impedance bandwidth requirement while simultaneously covering the WLAN and WiMAX bands. And characteristics of gain and radiation patterns are obtained for WLAN/WiMAX frequency bands.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.14 no.3
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• pp.137-144
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• 2004

3GPP(3rd Generation Project Partnership)-WLAN(Wireless Local Area Network) interworking refers to the utilization of resources and access to services within the 3GPP system by the WLAN UE(User Equipment) and user respectively. The intent of 3GPP-WLAN Interworking is to extend 3GPP services and functionality to the WALN access environment. We propose an efficient mechanism for the setup of UE-initiated tunnels in 3GPP-WLAN interworking. The proposed mechanism is based on a secret key which is pre-distributed in the process of authentication and key agreement between UE and 3GPP AAA(Authentication, Authorization Accounting) server. Therefore it can avoid modular exponentiation and public key signature which need a large amount of computation in UE. Also the proposed scheme provides mutual authentication and session key establishment between UE and PDGW(Packet Data Gateway).

• Journal of Korea Society of Industrial Information Systems
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• v.12 no.4
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• pp.32-40
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• 2007

A mobile device accesses large-sized data in object-based IP storage as an object unit over IP network. It relies heavily on a WLAN device, which has been known as one of the major power consumers. This paper designs and implements low-power object-based IP storage for mobile devices using an efficient WLAN power control. The proposed WLAN power control exploits prefetch buffer to maximize the idleness for incoming network traffic and controls available WLAN power modes to minimize the power consumption. Our experimental results reveal that the proposed WLAN control can save the total power consumption in a PXA270-based mobile device about 9% while playing the multimedia contents through an object-based IP storage device