• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.12A
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• pp.1349-1355
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• 2004

In tile wireless communication networks although the modulation and demodulation structure with proposed BOWLIS algorithm is a little confusing but we certified that it is fit structure in fast operation processing and high speed wireless LAM system that is more strong on frequence and electro magnetic interference because it process the inputted data within 2.8Us that is faster 0.4Us than 3.2Us in standard form. Also we certified that in the sigtlt of consuming power it is better than pipe-lined structure because of reducing the processing step to 4.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.11a
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• pp.683-684
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• 2009

최근 IEEE 802.11n 표준의 상용화와 함께 무선랜 환경에서 실시간 멀티미디어 서비스를 이용하려는 수요가 증가하고 있다. 그러나 IEEE 802.11i 보안표준에서 정의한 IEEE 802.1x 인증과정은 끊김 없는 실시간 멀티미디어 서비스를 제공하기에는 핸드오프 지연시간이 너무 길다. 본 논문은 Ticket이라는 새로운 인증 기법을 도입하여 고속의 로밍을 지원하는 핸드오프 메커니즘을 소개한다.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.7
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• pp.15-21
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• 2015

Due to the appearance of various mobile terminals like smartphone, smartpad, and smartwatch and tremendous development of WiFi technology, data utilization rate on WiFi network is significantly increasing. As a result, users are wanting to use WiFi network using only a simple identification at a visited place as if they are at their home institute. In this paper, we review the domestic status of eduroam service which supports global extension of wireless network access environment and present the future development perspective of the service in Korea. Besides, we shed light on the current status of WiFi sharing service between domestic universities and propose some methods to facilitate the join of domestic universities in eduroam service.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.13 no.3
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• pp.45-55
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• 2003

Wireless LAM has the advantage of extension, flexibility and easiness of installation and maintenance. However, due to the characteristics of wireless media, it is vulnerable to security attacks. PKI(Public Key Infrastructure) is estimated to be a good solution offering security function to wireless LAM including global roaming. It offers high security functions as authentication confidentiality and digital signature while it generates big overheads such as CRL search and certificate verification. The overheads can not be avoided during the initial authentication. However, when we consider the case of handoff, it can be minimized through the fast handoff. In this paper, we design a fast handoff authentication mechanism based on PKI in the wireless LAM and analyze the performance of the scheme.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.10 no.6
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• pp.98-107
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• 2011

In this paper, we propose the location determination system of an agent mobile device using the information provided by the WLAN(Wireless LAN) infrastructure. This system is configured as a typical ESS(Extended Service Set)-type WLAN structure with real-time location positioning engine and thru AP(Access Point) controller. The positioning engine collects the information of agent devices using SNMP(Small Network Management Protocol) thru AP controller and utilize those information as Cell ID. for LBS(Location Based Service). In the result of a real office environment implementation, the average success rate of inter-AP roaming is measured to 62.5% and the duration time of the device information update within the AP is average of 11 second of time, which means this system is adaptable to the location based service of above average accuracy but somewhat less urgency.

• Proceedings of the Korea Information Processing Society Conference
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• 2004.05a
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• pp.1201-1204
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• 2004

Mobile IPv6는 IP기반 3계층에서 하부 기술에 독립적으로 이동성을 제공하여 차세대 망에서 글로벌 로밍을 쉽게 지원 할 수 있다. 그러나 핸드오프 과정 중에 각 계층마다 생기는 지연은 피할 수 없는 부분 요소 이다. 본 연구에서는 2계층의 IEEE 802.11 기술을 기반으로 하는 Mobile IPv6 환경에서 이동 인터넷 사용자들에게 끊김 없는 서비스의 제공, 핸드오프 지연의 최소화, 신뢰성 있는 보안성의 제공을 위하여 Mobile IPv6를 위한 핸드오프와 AAA서비스 인증 절차의 성능 향상 방안을 제시하였다.

• The KIPS Transactions:PartC
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• v.14C no.1 s.111
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• pp.7-16
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• 2007

3G telecommunication and wireless LAN provide various wireless communication services with their own native advantages and disadvantages. Currently WiBro service was developed to make up for the disadvantages of those services, and 3G-WLAN-WiBro underworking system which enables a user who uses triple-mode terminals to use those three networks was proposed. Even though each network adopts mutual authentication process between users and networks to provide security and accounting, they use different authentication protocols. In this paper, integrated authentication and key management protocol is proposed which makes use of previously used authentication information and supports safe roaming when a user moves from one network to another one under a same service provider on the 3G-WLAN-WiBro interworking network.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2011.07a
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• pp.272-274
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• 2011

최근 들어 케이블 방송망을 기반으로 한 디지털 방송, VoIP(Voice over Internet Protocol), VOD(Video on Demand), 영상전화, 이동전화, 무선 랜 로밍 등의 다양한 멀티미디어 서비스의 출현과 향후 도입될 새로운 융합형 멀티미디어 서비스의 수용을 위해 케이블 망의 고도화에 대한 요구가 제기되었다. 특히 유럽을 중심으로 이러한 요구를 만족시키기 위해 DVB(Digital Video Broadcasting)-C2 규격의 개발이 진행되었다. DVB-C2 규격에서는 기존의 게이블 전송 규격인 DVB-C에 대해 30% 이상의 전송 효율을 높이고자 새로운 변조 방식과 채널 오류정정 부호 방식을 도입하였다. 이에 본 논문은 본 논문에서는 DVB-C2 규격에서 도입된 채널 오류정정 부호인 BCH(Bose, Chaudhuri, and Hocquenghem) 부호와 LDPC(Low Density Parity Check) 부호의 연접 방식에 대한 성능을 검증하고자 한다. 이를 위해 개발된 시뮬레이터의 소개와 이를 통한 시험결과를 제시한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.3B
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• pp.235-246
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• 2009

The number of industry wireless networks based on IEEE 802.11 WLAN technology deployed in large outdoor work sites, such as freight container terminal, is increasing these days. Wider service coverage, frequent movements of stations and high requirement on service reliability are main characteristics of these networks compared to the conventional IEEE 802.11 networks used in home, office and school. While the importance of these networks Bets higher, we can hardly find previous studies including concrete analysis on these networks based on actual experiments. We carried out several field experiments at a freight container terminal to analyze its IEEE 802.11 network and found out some problematic situations, such as over 50% retransmission rates and frequent disruption of communication link while a station is moving. We explain why these problematic situations happen and suggest some solutions, such as application of mesh technology, smart handoff based on location and movement pattern and adjustment of signal strength and channel allocation. Methods and tools used in the experiments are also detailed in the paper which may be helpful for similar future studies.