• Title/Summary/Keyword: IEEE 802.11a WLAN

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Optimal RTS-CTS Threshold to Maximize the Capacity of IEEE 802.11 WLAN (IEEE 802.11 무선 LAN의 최대 용량을 위한 최적의 RTS-CTS Threshold)

  • Choi, Woo-Yong
    • IE interfaces
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    • v.16 no.2
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    • pp.195-200
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    • 2003
  • In this paper, the selective use of RTS and CTS frames is considered to analyze the capacity of IEEE 802.11 WLAN (Wireless Local Area Network). The RTS and CTS frames are used to transmit the data frames longer than dot11RTSThreshold according to IEEE 802.11 specification. The analysis of the optimal RTS-CTS threshold is derived to maximize the capacity of IEEE 802.11 WLAN. And, numerical examples are also presented for IEEE 802.11 a and b WLANs.

IEEE 802.16 MAC protocol for coexistence with IEEE 802.11 in shared Frequency band (공용 주파수 대역에서 IEEE 802.11과의 공존을 위한 IEEE 802.16 MAC 프로토콜)

  • Lee, Seung-Hwan;Rhee, Seunghyong
    • Proceedings of the Korea Information Processing Society Conference
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    • 2009.04a
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    • pp.1230-1232
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    • 2009
  • 본 논문에서는 공용 주파수 대역에서 IEEE 802.11 WLAN과 IEEE 802.16 WMAN과의 효율적인 공존을 위한 MAC 프로토콜을 제안한다. 제안한 프로토콜은 IEEE 802.11 WLAN과 IEEE 802.16 WMAN이 주파수를 공유하며 지리적으로 공존하는 환경을 가정하였다. IEEE 802.16 WMAN의 BS(Base station)와 SS(Subscriber station)의 통신에서 DL(Down Link)구간에서는 SS가 자신의 DL-burst에서 IEEE 802.11의 CTS를 보내 주변의 IEEE 802.11 디바이스들의 통신을 지연시킴으로써 IEEE 802.11 WLAN 및 IEEE 802.16 WMAN이 공존하면서도 충돌을 방지해 전송 효율을 높일 수 있다. 본 논문에서 제안하는 MAC 프로토콜의 동작에 대해 설명하고 시뮬레이션을 통해 기존 방법보다 향상된 성능을 유지함을 보인다.

Performance Evaluation of RAM IEEE 802.11a Convolutional Encoder according to Puncturing Pattern (WLAN IEEE 802.11a Convolutional 부호기의 Puncturing Pattern에 따른 성능 분석)

  • 조영규;정차근
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • 2002.11a
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    • pp.21-24
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    • 2002
  • 본 논문에서는 광대역 무선 데이터 서비스용으로 표준화된 WLAN IEEE 802.11a Convolutional 부호기의 펑처링 패턴에 따른 성능을 분석하고, 간략화 된 구현 방법을 제시한다. 제한된 주파수 대역에서 Convolutional 부호기의 구조를 변경함이 없이 정보 전송율을 향상시키기 위해 부호기에서 출력되는 비트열을 일정한 비트 간격마다 1비트씩 생략하는 펑처링 기법이 주로 이용된다. IEEE 802.11a WLAN 채널코딩에서도 부호율이 l/2, 구속장 7인 Convolutional 부호기를 기반으로 2/3와 3/4과 같은 높은 부호율을 얻기 위해 펑처링 기법을 채택하고 있다. 본 논문에서는, 단일 하드웨어 구조를 사용해서 1/2의 기본 부호율로부터 전송율에 따라 WLAN IEEE 802.11a의 펑처링에 의한 부호율 2/3와 3/4에서, 부호기의 구조를 간략화하기 위해 펑처링 패턴 구조에 따른 부호화 성능을 조사하고 단일하드웨어 구조를 사용해서 이들 부호율의 시스템을 구현할 수 있도록 한다. 모의 실험에서는 부가 백색 가우시안 잡음 현상이 존재하는 채널을 모델링 해서, BPSK와 QPSK의 변조방법에 대해 WLAN IEEE 802.11a 펑처링 패턴에 따른 부호화 성능을 제시한다.

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MAC Throughput Analysis of MAC Aggregation and Block ACK in IEEE 802.11n (MAC 프레임 집합 전송과 블록 ACK 사용에 따른 IEEE 802.11n 수율 분석)

  • Moon, Kuk-Hyun;Chung, Min-Young;Cho, Kang-Yun
    • Proceedings of the KIEE Conference
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    • 2006.10c
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    • pp.467-469
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    • 2006
  • In wireless network environments, as users' demands on high-speed data communications due to increase of multi-media services, the necessity of new high-speed WLAN technologies has appeared. Nowaday, IEEE is standardizing a new WLAN protocol caned as IEEE 802.11n. To effectively use wireless resources, IEEE 802.11n introduces MAC aggregation function which is similar to that in IEEE 802.11e. In case of transmitting several frames without MAC aggregation, the frames include individual frame header and trailer, and their corresponding acknowledgement frames can appear on wireless link. However, if they are aggregated into single MAC frame, we can reduce the number of used bits due to frame headers/trailers and also remove redundant acknowledgement frames. In this paper, we explain two different MAC frame aggregation methods for IEEE 802.11e and IEEE 802.11n and evaluate their throughput by simulations.

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Performance Analysis of IEEE 802.11n System adapting Frame Aggregation Methods (Frame Aggregation 기법을 적용한 IEEE 802.11n 시스템 성능 분석)

  • Lee, Yun-Ho;Kim, Joo-Seok;Kim, Kyung-Seok
    • The Journal of the Korea Contents Association
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    • v.9 no.12
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    • pp.515-527
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    • 2009
  • IEEE 802.11n is an ongoing next-generation WLAN(Wireless Local Area Network) standard that supports a very high-speed connection with more than 100Mb/s data throughput measured at the MAC(Medium Access Control) layer. Study trends of IEEE 802.11n show two aspects, enhanced data throughput using aggregation among packets in MAC layer, and better data rates adapting MIMO(Multiple-Input Multiple-Output) in PHY(Physical) layer. But, the former doesn't consider wireless channel and the latter doesn't consider aggregation among packets for reality. Therefore, this paper analyzes data throughput for IEEE 802.11n considering MAC and PHY connection. A-MPDU(Aggregation-MAC Protocol Data Unit) and A-MSDU(Aggregation-MAC Service Unit) is adapted considering multi-service in MAC layer, WLAN MIMO TGn channel using SVD(Singular Value Decomposition) is adapted considering MIMO and wireless channel in PHY layer. Consequently, Simulation results shows throughput between A-MPDU and A-MSDU. Also, We use Ns-2(Network simulator-2) for reality.

Comparison Analysis of Packet Delay Model in IEEE 802.11 Wireless Network (IEEE 802.11 무선망에서의 패킷지연시간 모델 비교분석)

  • Lim, Seog-Ku
    • Journal of Digital Contents Society
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    • v.9 no.4
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    • pp.679-686
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    • 2008
  • Wireless LAN(WLAN) is a rather mature communication technology connecting mobile terminals. IEEE 802.11 is a representative protocol among WLAN technologies. With the rising popularity of delay-sensitive real-time multimedia applications(video, voice and data) in IEEE 802.11 wireless LAN, it is important to study the MAC layer delay performance of WLANs. In this paper, performance for packet delay model that recently have been proposed schemes is analysed in wireless LAN and proved performance results via simulation.

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Design of Dual-Band WLAN Transmitter with Frequency Doubler (주파수 체배기를 이용한 이중대역 무선 송신부 설계)

  • Roh, Hee-Jung
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.22 no.6
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    • pp.116-126
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    • 2008
  • This paper describes the Dual-band WLAN transmitter with 2.4[GHz], 5[GHz]. Dual-band WLAN transmitter was designed at 2.4[GHz] and 5[GHz]. The Dual-band WLAN transmitter has a amplifier which operate at 2.4[GHz] and 5[GHz] frequency and two VCO(Voltage Controlled Oscillator) or VCO has a wide scope of frequency. these problem cause a size and a power consumption, The Dual-band WLAN transmitter module was proposed to solve these. the transmitter was designed to get output signals of IEEE 802.11a's 5.8[GHz] band signal using frequency multiplication way or to act a amplifier about the 2.4[GHz] band signal of IEEE 802.11b/g, according to inputed frequency and bias voltage that a eve using single transmission block. The output spectrum get the improved specification of ACPR of 4[dB], 6[dB], 16[dB] at +11[MHz], +20[MHz], +30[MHz] offset of center frequency compared to no linearization, was satisfied to transmit spectrum mask of IEEE 802.11a wireless Lan.

Analysis of Packet Delay in IEEE 802.11 Wireless LAN (IEEE 802.11 WLAN에서 패킷지연시간 분석)

  • Lim, Seog-Ku
    • Proceedings of the KAIS Fall Conference
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    • 2009.12a
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    • pp.989-993
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    • 2009
  • Wireless LAN(WLAN) is a rather mature communication technology connecting mobile terminals. IEEE 802.11 is a representative protocol among WLAN technologies. With the rising popularity of delay-sensitive real-time multimedia applications(video, voice and data) in IEEE 802.11 wireless LAN, it is important to study the MAC layer delay performance of WLANs. In this paper, performance for packet delay that recently have been proposed schemes is analysed in wireless LAN and proved performance results via simulation.

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A Secure and Efficient Roaming Mechanism for Centralized WLAN Environment (중앙집중식 WLAN 환경에서의 안전하고 효율적인 로밍 메커니즘)

  • Park, Chang-Seop;Woo, Byung-Duk;Lim, Jeong-Mi
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.19 no.1
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    • pp.81-92
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    • 2009
  • Recently, there is a drastic increase in users interested in real-time multimedia services in the WLAN environment, as the demand of IEEE 802.11 WLAN-based services increases. However, the handoff delay based on 802.11i security policy is not acceptable for the seamless real-time multimedia services provided to MS frequently moving in the WLAN environment, and there is a possibility of DoS attacks against session key derivation process and handoff mechanism. In this paper, a secure and efficient handoff mechanism in the centralized WLAN environment is introduced to solve the security problems. The 4-way Handshake for both mutual authentication and session key derivation is replaced by the 2-way Reassociation process.