• Proceedings of the Korean Information Science Society Conference
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• 2005.07a
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• pp.145-147
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• 2005

IEEE 802.11 기술이 상용화된 이후 여러 가지 보안에 관련된 취약점들이 드러났다. 이를 보완하기 위하여 802.1li 그룹이 802.11보안 관련 표준안을 제시하였다. 그러나 802.11에서 문제가 되었던 여러 종류의 DoS 공격들 중 몇 개의 공격들은 802.11i에서 아직 유효하다. Deauthe-ntication, Disassociation 메시지를 이용한 공격이 802.1li에서도 유효한 대표적인 공격 중 하나이다. 이 공격은 802.1li에서의 관리 프레임에 802.11과 같은 수준의 데이터 암호화가 적용되기 때문에 가능한 것이다. 본 논문에서는 이러한 취약점을 TKIP를 이용해 제안된 state value를 암호화하여 이를 예상 값과 비교한 후 Deauthentication, Disassociation 공격을 판단하는 메커니즘을 제시 하였다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.11
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• pp.1554-1557
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• 2020

Looking at the direction of the recent amendments of 802.11 family, there are two major trends. One is to enable the wireless transceivers to support the extremely high-speed wireless transmissions, which has been the mainstream so far. Another big trend is providing a high-performance wireless application platform that meets the demands of the market. This paper summarizes the brand-new IEEE 802.11 amendments from 11ax to 11bf under development by analyzing the innovative features and use cases on them. We provide the vision and direction for the research on the revolutionary data-hungry Wi-Fi 6 and the IEEE 802.11be, alias Wi-Fi 7.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.12A
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• pp.1367-1374
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• 2004

Efforts for standardization of medium access control (MAC) protocol in IEEE802.11e have been made to support quality of service (QoS) in IEEE802.11 MAC protocol. Enhanced distributed coordination function (EDCF) of 802.11e MAC protocol is modified to support QoS for packets that have differentiated priority. However, EDCF still has e problem of throughput optimization and priority support. Therefore, we have proposed a scheme called adaptive EDCF for both supporting priority of packets and throughput optimization. We have derived the relation between the number of nodes and contention window size for throughput optimization. Based on the analytic results, we have evaluated the performance of the proposed scheme using OPNET simulations. The simulation results show that using the proposed scheme can Improve the overall throughput regardless of the number of nodes and the decrement of the throughput with increasing the number of nodes can be alleviated. Additionally, we have shown that the adaptive EDCF can support priority of packets more effectively than existing EDCF.

• Information and Communications Magazine
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• v.24 no.6
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• pp.58-66
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• 2007

IEEE 802.11 무선랜 기술은 가장 성공한 무선 통신 기술 중 하나이다. 주로 가정이나 사무실, 공공 장소에서 소규모 무선 네트워크를 형성하여 무선 인터넷 환경을 제공한다 고속통신이 가능하며 사용자의 이동성을 함께 제공하는 무선 통신 기술에 대한 요구가 증가하면서 새로운 기술 표준도 함께 도입되었다. 이에 따라 IEEE 802.11 무선랜은 크고 복잡한 형태로 발전하고 있으며, 이에 상응하는 무선랜 환경을 관리하기 위한 기술 표준이 필요하게 되었다. 이러한 요구를 충족하기 위해서 IEEE 802.11v Task Group (TG)이 발족하여 새로운 기술 표준을 만들고 있다. 본고는 현재 진행중인 IEEE 802.11v TG에서 발행한 초안을 바탕으로 무선네트워크 관리 기술에 대한 내용을 소개한다.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10c
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• pp.226-228
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• 2003

무선통신과 관련된 대표적인 프로토콜로써 Bluetooth, IEEE 802.11, HomeRF등이 있다. 이러한 프로토콜들을 이용한 제품들이 생산되면서, 동일한 환경에서 어느 프로토콜이 더 적합한지를 결정할 필요가 있다. 본 논문에서는 Bluetooth와 IEEE 802.11의 표준을 기반으로 무선 노트북이나 이동전화에서의 성능을 평가하고 그 결과를 보여준다.

• The KIPS Transactions:PartC
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• v.11C no.4
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• pp.497-508
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• 2004

The existing wireless LAN standard IEEE802.11b has many vulnerabilities from security point of view. The authentication mechanisms in IEEE802.11b have many vulnerabilities. As a result to complement the weak of IEEE802.11b authentication, the IEEE802.1x had been developed in the sense of providing strong user authentication with appropriate mechanism. But this mechanism does not perform AP authentication and there are also some weak points. And in confidentiality and message Integrity case, WEP is weak from key stream reuse attack, IV reuse attack and so on. For that reason, in this paper we propose secure wireless LAN system. Our system provides strong user authentication, confidentiality, and message integrity based on existing IEEE802.1x framework and TLS.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.6
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• pp.1386-1390
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• 2011

The IEEE 802.11 MAC uses DCF for media access among the participating network nodes. But DCF alone is neither capable nor suitable for fulfilling the QoS requirements of realtime applications. There are many ways in which QoS is provided by modifying DCF based MAC. This paper proposes (m,k)-collision scheme which is based on IEEE 802.11 and (m,k)-firm scheme tries to improve DCF functionality. The proposed scheme uses different Contention Window according to the number of collision in the node. The simulation result shows that the proposed scheme helps improve the throughput of the DCF.

• Proceedings of the Korea Contents Association Conference
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• 2007.11a
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• pp.611-614
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• 2007

The IEEE 802.11 Task Group E has worked to enhance the legacy 802.11 MAC to expand support for applications with QoS requirements. EDCF(Enhanced Distributed Coordination Function) of IEEE 802.11e is enhanced from DCF(Distributed Coordination Function) of 802.11 and It has differential AC(Access Category). In this paper, we change parameters(AIFS, CWmax) and make an analysis of network performance. We use NS-2 to verify change of network performance.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.05a
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• pp.796-798
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• 2011

The IEEE 802.11 MAC uses DCF for media access among the participating network nodes. But DCF alone is neither capable nor suitable for fulfilling the QoS requirements of realtime applications. There are many ways in which QoS is provided by modifying DCF based MAC. This paper proposes (m,k)-collision scheme which is based on IEEE 802.11 and (m,k)-firm scheme tries to improve DCF functionality. The proposed scheme uses different Contention Window according to the number of collision in the node. The simulation result shows that the proposed scheme helps improve the throughput of the DCF.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.5
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• pp.21-29
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• 2008

This paper proposes a carrier frequency of set estimation algorithm for IEEE802.11n system. As IEEE802.11n is a multiple input multiple output(MIMO) system, so there are several combining techniques which are used in multiple receive antenna system. In this paper, we propose hybrid carrier frequency offset estimation algorithms using combining techniques in multiple receive antenna systems, and show that the proposed selection combining carrier frequency offset (CFO) estimation algorithm can estimate carrier frequency offset within 1/10 MSE error at SNR 10 dB in channel B and within 1/2 MSE error at SNR 10 dB in channel D rather than the conventional MIMO CFO one.