• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.528-532
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• 2005

As the current IEEE 802.11 wireless LAN standard provides the unified channel access procedure for each traffic service without considering its own traffic characteristics, it is difficult to get its differentiated service qualities at IEEE 802.11 wireless LAN system. To solve this limit, IEEE 802.11e standard that can provide differentiated service to each traffic is under preparation. In this study, we implemented IEEE 802.11e EDCA channel access scheme with NS-2 simulator, and showed its numerical results in various system environments with using average delay and throughput as performance measures.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.5
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• pp.996-1002
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• 2009

The EDCA scheme in IEEE 802.11 MAC protocols was adopted to support QoS of each traffic. The impact of legacy DCF stations on EDCA voice service is studied using extensive simulations. The maximum number of voice sessions are obtained in cases that IEEE 802.11b and IEEE 802.11a physical layers are used.

• 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.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.535-538
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• 2005

Wireless LANs based on the IEEE 802.11 standard are widely spread for use nowadays. Traffic which are conveyed over the WLANs change rapidly from normal data such a Email and Web pages, to multimedia data of high resolution video and voice. To meet QoS (Quality of Service) required by these multimedia traffic, the IEEE 802 committee recently has developed a new standard, IEEE 802.11e. IEEe 802.11.e contains two MAC mechanisms for providing QoS: EDCA(Enhanced Distributed Channel Access) and HCCA (HCF Controlled Channel Access). Using these standardized MAC mechanisms as a building platform, various admission control mechanisms can be combined to offer QoS gurantees for multimedia traffic. This paper surveys these research efforts.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.702-704
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• 2010

Wireless LAN(Local Area Network) environment to support QoS in IEEE802.11 Working Group has standardized on the IEEE 802.11e. IEEE 802.11e EDCA channel access of the high priority traffic as by raising the probability of a chance to support QoS. This is a high priority traffic than low priority traffic, channel access is not necessarily the first. Therefore, as all traffic channels, if you have the same routing path, lower priority traffic on the performance of high priority traffic, sustainable impact. As a result, EDCA, such as voice or video to guarantee QoS for multimedia applications, follow the crowd. In this paper, to solve these problems by using Multi-Interface Multi-Path Routing Algorithm is proposed. Interface for each use in IEEE 802.11e EDCA Access Category much differently by each of the Routing Path for high priority traffic and guarantee QoS.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.40 no.12
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• pp.116-124
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• 2003

According to the convenience and efficiency, IEEE 802.11 WLAN(Wireless LAN) has became rapidly wide-spread on the market. However, QoS support is needed for various multimedia service. In this paper, we consider both MAC method of IEEE 802.11 and IEEE 802.11e and Traffic Category differentiated service by QoS support method. In addition, we study currently existing back-off algorithms in view of comparative analysis. As a result we propose a new back-off algorithm called Collision Rate Based-EDCF. The proposed back-off algorithm confirms the performance by computer simulations in terms of Throughput, and QoS support.

• Electronics and Telecommunications Trends
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• v.27 no.2
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• pp.1-10
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• 2012

최근 와이파이를 채용한 스마트폰에 대한 수요가 폭발적으로 증가함에 따라 무선랜에 기반한 새로운 신규 기술들이 활발히 연구되고 있다. Gbps 이상의 전송을 가능하게 하는 IEEE 802.11ac는 차세대 스마트폰을 위한 핵심 기술로서 기존의 IEEE 802.11n에서는 수용할 수 없었던 초고화질의 비디오 전송을 가능하게 한다. 또한 최근에는 무선랜을 사용하여 최대 수 km까지 광역으로 서비스를 지원하기 위한 광역 무선랜이 IEEE 802.11af 및 802.11ah에서 연구되고 있으며, 초기 링크 셋업 시간을 획기적으로 절감하기 위한 IEEE 802.11ai 기술도 활발히 논의되고 있다. 본고에서는 이러한 IEEE 802.11ac, IEEE 802.11af, IEEE 802.11ah, IEEE 802.11ai 무선랜 기술에 대한 표준화 추진 현황 및 주요 이슈들에 대해 기술하고자 한다.

• The KIPS Transactions:PartC
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• v.12C no.2 s.98
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• pp.217-222
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• 2005

The IEEE 802.11 based wireless local area networks are candidates to lead the broadband connectivity in the home and office scenarios. Recently IEEE proposed the 802.11e as a new standard to provide appropriate Quality of Services to a plethora of emerging real-time multimedia and high demanding applications such as high definition movie and audio distribution, video-conference and voice over IP. This paper studies the IEEE 802.11e/IEEE 802.11b interactions focusing on potential unfairness problems that might appear in networks with heterogeneous wireless LAN technologies as well as in the IEEE 802.11e deployment phase.

• 한국정보통신설비학회:학술대회논문집
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• 2005.08a
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• pp.74-84
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• 2005

In this paper, a new coexistence mechanism between IEEE 802.15.4 and IEEE 802.11, ACROS (Active Channel Reservation for coexistence), is proposed. The key idea of ACROS is to reserve the channel for IEEE 802.15.4 transmission. During the reservation, IEEE 802.11 transmissions cannot be occurred. Request-to-send/clear-to-send mechanism of IEEE 802.11 is used to reserve channel. The proposed ACROS mechanism is implemented into PC based prototype. By the experiments, the $e{\pm}ciency$ of ACROS is proved.

• Proceedings of the Korean Information Science Society Conference
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• 2007.10d
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• pp.339-342
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• 2007

무선 인터넷 사용자와 멀티미디어 서비스의 급증으로 IEEE 802.11 WG에서는 사용자에게 QoS를 지원하기 위해 기존의 MAC 프로토콜을 향상시키고 기존의 IEEE 802.11과 호환성을 가지는 IEEE 802.11e 표준을 제정하였다. 따라서 기존의 MAC 네트워크 카드를 가진 사용자도 새로운 QoS Basic Service Set(QBSS)에 문제없이 접속할 수 있다. 하지만 IEEE 802.11e가 지원되는 무선 AP가 있는 QBSS 네트워크 내에 기존의 802.11 station은 요구하는 QoS를 지원받지 못할 뿐더러 전체적인 네트워크 성능의 저하도 가져올 수 있다. 본 논문에서는 기존의 MAC을 가지고 있는 station도 Virtual Queue Middleware 통해 QoS를 보장받고 전체적인 네트워크 성능을 향상시키는 방법을 제시하고자한다.