• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.591-594
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• 2005

This paper describes a design of AES-based CCM Protocol for IEEE 802.11i Wireless LAN Security. The CCMP core is designed with 128-bit data path and iterative structyre which uses 1 clock cycle per round operation. To maximize its performance, two AES cores are used, one is for counter mode for data confidentiality and the other is for CBC(Cipher Block Chaining) mode for authentication and data integrity. The S-box that requires the largest hardware in AES core is implemented using composite field arithmetic, and the gate count is reduced by about 23% compared with conventional LUT-based design. The CCMP core designed in Verilog-HDL has 35,013 gates, and the estimated throughput is about 768Mbps at 66-MHz clock frequency.

• Journal of Korea Multimedia Society
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• v.12 no.9
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• pp.1323-1332
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• 2009

In this paper, we analyze security weakness of 4-Way Handshake in IEEE 802.11i and propose fast and secure 2-Way Handshake mechanism. Compute PTK(Pairwise Transient Key) using sequence number instead of random numbers in order to protect Replay attack and DoS attack. Also, proposed 2-Way Handshake mechanism can mutual authenticate between mobile station and access point and derive PTK using modified Re-association Request and Re-association Response frames. And, compare with others which are fast and secure Handoff mechanisms.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.43 no.11 s.353
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• pp.77-82
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• 2006

Analog channel selection filter is described which is designed for a direct-conversion receiver of a IEEE 802.11a wireless LAN. The channel selection filter is an active-RC fifth-order Chebyshev filter with 10MHz cut-off frequency. Two-stage operational amplifier of the filter employs a current re-using feedforward frequency compensation scheme to minimize the power consumption. The filter has been implemented in a 0.18mm CMOS technology and the experimental results show 20mW power consumption with 1.8V supply voltage and 19dB out-of-band iIP3.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.11A
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• pp.1113-1119
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• 2007

In this paper, first, we proposed various possible candidate schemes for determining initial sleep window size and varying sleep window size in sleep mode for power saving class I of IEEE 802.16e. Then, we analyzed and compared the power saving performances of those schemes. The schemes used for the comparisons are EICV of IEEE 802.16e, and other comparable schemes such as EIED, EILD, LIED and LILD. Experimental results show that LILD and EIED outperform other comparable schemes. Especially, EIED shows the better performances for the case of high traffic intensity environments, while LILD does for the low traffic intensity case.

• Journal of Satellite, Information and Communications
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• v.11 no.1
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• pp.6-11
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• 2016

In this paper, we have analyzed the effects of co-channel, adjacent-channel, and the human shield(Body Blockage) for wideband WLAN based on the IEEE802.11n 40MHz channel bandwidth required for high speed digital signage service. Simulation results show that wideband WLAN can be operated with 78 interferers over 63m distance in co- channel, 80 interferer over 61m distance in adjacent channel. By applying the mitigation method for reducing the interference, we have confirmed that protection distance is improved to 51m using beamforming, and 40m using cognitive radio in co-channel interference. Also body blockage interference is reduced using adaptive channel bandwidth, C/I ratio, beamforming, power control mitigation methodology.

• Proceedings of the Korean Information Science Society Conference
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• 2007.06d
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• pp.243-246
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• 2007

본 논문에서는 802.11b의 네트워크 성능 측정을 통해 도출된 결과를 토대로 하여 802.11b기반의 온라인 게임을 위한 네트워크 엔진을 개발하였다. 네트워크 엔진 서버는 I/O Multiplexing 기법을 사용하였으며, 클라이언트는 .Net Compact Framework로 개발하였다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.4
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• pp.798-803
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• 2005

This paper describes a design of AES(Advanced Encryption Standard)-based CCMP core for IEEE 802.1li wireless LAN security. To maximize its performance, two AES cores ate used, one is for counter mode for data confidentiality and the other is for CBC(Cipher Block Chaining) mode for authentication and data integrity. The S-box that requires the largest hardware in AES core is implemented using composite field arithmetic, and the gate count is reduced by about $20\%$ compared with conventional LUT(Lookup Table)-based design. The CCMP core designed in Verilog-HDL has 13,360 gates, and the estimated throughput is about 168 Mbps at 54-MHz clock frequency. The functionality of the CCMP core is verified by Excalibur SoC implementation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.4
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• pp.1012-1017
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• 2008

Recently, the use of wireless fan is increased by the development of wireless communication and convenience. Moreover, it makes an issue of security threat and vulnerability of wireless tan. Therefore, the IEEE established new standard such as 802.11i in 802.11 to supplement security vulnerability of wireless tan. But the security threat that does not solve, still remains. In this paper, we proposed that the location detection algorithm, that is used Kalman-Filter, Lateration and RSSI, and the mechanism that detects security status of AP and unauthorized AP by using beacon-frame of AP in building. Finally, we confirmed performance of proposed algorithm is good in comparison of established algorithm.

• Journal of Communications and Networks
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• v.9 no.3
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• pp.282-295
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• 2007

Due to the nature that high datarate leads to shorter transmission range, the performance enhancement by high datarate 802.11 WLANs may be degraded when applying high datarate to an 802.11 based multihop ad hoc network. In this paper, we evaluate, through extensive simulations, the performance of multihop ad hoc networks at multiple transmission datarates, in terms of the number of hops between source and destination, throughput, end-to-end delay and packet loss. The study is conducted based on both stationary chain topology and mesh topologies with or without node mobility. From numerical results on network performance based on chain topology, we conclude that there is almost no benefit by applying the highest datarate when the chain length is 6 hops or more. With node mobility in mesh topology, the benefit of using high datarate diminishes at even shorter number of hops. To explore the main reasons for this behavior, analyses on multihop end-to-end throughput and network k-connectivity have been conducted later in the paper, and correspondingly an auto-rate adaptation algorithm has been proposed.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 2006.06a
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• pp.390-393
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• 2006

IEEE 802.11e 과 IEEE 802.11n에서 data의 높은 전송률을 구현하기 위해 Block Ack와 frame agegation 과 같은 새로운 mechanism이 논의 되고 있다. 이러한 mechanism은 각각의 MPDU processing 마다 짧은 응답시간을 요구한다. 본 논문에서는 위의 새로운 MAC을 지원하는 IEEE 802.11i를 위한 효율적인 CCMP 설계를 제안한다. 제안된 설계에서는 한 AES-CCM core에서 MIC calculation 과 정보 암호화가 128bit씩 순차적으로 수행되어지는 mode toggling 접근을 채택했다. 본 설계에서는 응답시간이 44 clock cycle의 짧은 짧은 시간으로 줄었다. 또한 하나의 AES-CCM core를 사용하고 낮은 주파수에서 수용할만한 data throughput과 응답시간을 얻었기 때문에 하드웨어적인 복잡성과 전력 소모를 줄일수 있었다.