• Journal of KIISE:Information Networking
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• v.32 no.3
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• pp.327-338
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• 2005

Since the IEEE 802.11 wireless LANs were known to have several critical weaknesses in the aspect of security, a lot of works have been done to reduce such weaknesses of the wireless LAN security, Among them IEEE 802.lli may be the ultimate long-term solution that requires new security platform with new wireless LAM products. However, it might not be the best solution for small organizations due to its high cost where the cost is a critical issue. This paper proposes FR-WEP, a light-weight key management for wireless LANs that can be used with small changes of the existing Products. FR-WEP is an extension to a lightweight key management, WEP'(9), which was proposed lately. It makes up for the weak points of WEP' by providing lightweight mutual authentication with both host keys and user keys, and seamless key-refresh for authenticated users with fast re-authentication. It would be a good alternative to the heavy standards for wireless LAN security, especially to small organizations hoping for better security.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.2B
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• pp.107-118
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• 2009

In this paper, we present design and implementation for identification and location tracking techniques for vehicle information terminals in high-speed mobile environment using IEEE 802.11 wireless LAN technology. RSU be installed at a specific point. RSU recognizes it and then aware identification and location tracking for target vehicle when target vehicle that is equipped with information terminals pass near point. Issue of quick recognition using IEEE 802.11 access management frame, issue of weak wireless LAN security and tracking a range of restrictions be raised and we present solutions. Vehicle information terminal, RSU and a server-side GUI-based management program be implemented based on proposed solution. Implementation system be performed experiment at actual road environment and effectiveness be verified.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.3A
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• pp.288-292
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• 2004

Recently the application area of wireless LAN has been increased, rapidly. The application area was limited in indoor, but as the data throughput and performance of wireless LAN becomes better the application is to extend to the Internet connection and wireless bridge in outdoor. In this paper, the data throughput of wireless LAN in mobile environment is measured, and the usability of wireless LAN for ITS, Telematics, and LBS is confirmed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.6B
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• pp.338-348
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• 2005

Currently, IEEE 802.11 Wireless LAN (WLAN) is rising as the most popular means for the broadband wireless access network. In this thesis, we propose a QoS(Quality of Service)-Oriented mechanism using handshaking method of scanning phase in IEEE 802.11 handoff. In conventional process for handoff, the major criterion to select the best AP(Access Point) among candidates is normally based on the RSS(Received Signal Strength), which does not always make the selected network guarantee the maximum achievable performance. Even though the link quality with a neighboring AP is excellent, the AP may not be a good candidate to handoff to simply because MAC(Medium Access Control) protocol of IEEE 802.11 standard is contention-based such as CSMA/CA. Therefore, if we apply network level information to AP selection criteria, we can achieve better handoff efficiency rather than before. The analysis and simulation results applied to our new mechanism show clearly better performance than AP selection based on traditional handoff method.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.6
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• pp.39-47
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• 2009

This paper presents implementation of two types of the 802.11 MAC engine for the next generation WLAN, 802.11n. The first version of MAC engine consists of hardwired logic and embedded firmware. Hardwired logic includes Tx block, Rx block, Backoff block, and ChannelManage block. Embedded firmware contains Protocol Control block, MLME block, and MSDU processing block. The first version has a time-critical fault during the atomic transmission caused by software overhead, so it can not be applied to 802.11n MAC. For that reason, the second version has additional blocks with hardwired logic modules to reduce software overhead of the first version. This enhanced version has 73Mbps throughput and it is expected to be further improved up to 129 Mbps with frame aggregation which is one of the key additional features of 802.11n. As a result, the second version of MAC engine can be applied to 802.11n MAC.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.6C
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• pp.601-606
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• 2005

Recently with the high expectation of voice over WLAN service, to supped fast inter-AP security transition in WLAN AP is one of the most actively investigating issues. It is also very important to minimize inter-AP security transition latency, while maintaining constantly the secure association from old AP when a station transits to new AP. Hence, this paper first defines secure transition latency as a primary performance metric of AP system in WLAN supporting IEEE802.11i, 802.1x, and 802.11f, and then presents low latency inter-AP security transition mechanism and its security FSM whose objective is to minimize inter-AP transition latency. Experiment shows that the proposed scheme outperforms the legacy 802.1X AP up to $79\%$ with regard to the transition latency.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.219-222
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• 2010

본 논문에서는 무선 네트워크 기술인 802.11의 보안책인 802.1x의 효율성에 대해 연구한다. 무선 네트워크는 1970년대 라디오 주파수를 사용하여 컴퓨터 통신 네트워크가 구축된 이후 눈부신 발전을 거듭하여 현재 학교나 카페 등에서 쉽게 무선 랜 존을 접할 수 있다. 하지만 최근 스마트폰이나 노트북 등 많은 portable 단말기의 사용자가 급속도로 증가 하면서 무선 랜 존의 수요가 크게 늘어가고 있다. 이렇게 무선 네트워크 구축이 활발히 되면 그와 동시에 증가하는 것이 보안 문제이다. 본 논문에서는 무선 AP와 Radius(AAA) 서버를 이용한 보안 시스템 구축 시 고려해야 할 요구조건과 유지관리를 위한 효율성을 연구하여 제한된 환경에서의 효과적인 보안 시스템을 설계를 위한 방안을 제시한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.3B
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• pp.100-111
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• 2008

In this paper, to support a QoS level appropriate for the user in Wireless Home Network based Wireless LAN, we propose a QoS support architecture which includes Wired Network and Wireless Network. Actually, an important problem to support QoS in Wireless Home Network is approached not only on a MAC level in Wireless LAN but on a integrated method to combine Network layer with Datalink layer. Applying the integrated QoS support method. It is possible to provide QoS support architecture using a Wireless LAN terminal with a minimum changing, the proposed scheme has advantage of QoS support method, which is more superior than a existing scheme to support QoS in MAC level of Wireless LAN. Simulation results that overall performance of the proposed scheme can be improved.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.8
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• pp.1768-1773
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• 2005

The IEEE 802.1x standard provides an architectural framework which can be used various authentication methods. But, IEEE 802.1x also has vulnerabilities about the DoS, the session hijacking and the Man in the Middle attack due to the absence of AP authentication. In this paper, we propose a WLAN secure system which can offer a robust secure communication and a user authentications with the IEEE 802.1x framework. The user authentication on the WLAN secure system accomplishes mutual authentications between authentication severs, clients and the AP using PKI and prevents an illegal user from intervening in communication to disguise oneself as a client, the AP or authentication servers. Also, we guarantee the safety of the communication by doing secure communication between clients and the AP by the Dynamic WEP key distribution.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.3
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• pp.395-400
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• 2021

In this paper, the wideband patch antenna is simulated and manufactured for the wireless LAN of 5GHz band that is defined in IEEE 802.11a. In the 802.11a, 200 channels of 675MHz are defined. Therefore, the bandwidth is needed more than 12.3%. For the wideband characteristics, low dielectric constant is realized with the multi-layer of 2 teflon substrates and the air dielectric layer and the feeding method of the coupled-line is used. Optimized wideband patch antenna is simulated with the return loss of 38.99dB at the center frequency of 5.43GHz and the bandwidth of 12.9%. The gain of manufactured patch antenna is 4.38, 4.52, and 5.12dBi at the channel number of 46, 56, and 153, respectively.