• Journal of Advanced Navigation Technology
• /
• v.22 no.4
• /
• pp.302-310
• /
• 2018

To realize the self-driving technology, there have been various system designs based on the related V2X standards, especially the IEEE 802.11p and WAVE standard supporting the WLAN V2X communication. On the other hand, the new standard IEEE 802.11ba defining supplementary wake-up radio operation is now under standardization targeting the low power operation, and it includes the V2P operation in use cases. However, if IEEE 802.11ba is used with the IEEE 802.11ba for V2X operation, the additional transmission procedure of wake-up frame in IEEE 802.11ba may cause the congestion problem and fails to meet the delay requirement. In this paper, the system structure of the combination of IEEE 802.11ba with the 802.11p is studied. In addition, based on the analysis and simulation, the considerations and improvements for effective low-power V2P communication in future self-driving technology using IEEE 802.11ba are proposed.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2009.04a
• /
• pp.1230-1232
• /
• 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.

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

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• v.9 no.1
• /
• pp.528-532
• /
• 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 Institute of Convergence Signal Processing
• /
• v.12 no.2
• /
• pp.119-127
• /
• 2011

The paper surveys various analytical models for IEEE 802.11 medium access control protocols and critically discusses recent issues developing in wireless mobile ad hoc networks and their MACs. The surveyed MAC protocols include the standard IEEE 802.11 MAC suites such as IEEE 802.11 DCF, IEEE 802.11 PCF, IEEE 802.11e EDCA, and IEEE 802.11 ad hoc mode; and also the newer, de facto MAC protocols. We study the analytic models of the standard MAC suites followed by the newer analytic models that have been published in recent years. Also, the paper tries to include most of current literatures discussing analytic modeling of MAC in conjunction to some critical issues such as contention among ad hoc nodes, hidden terminal problems, and real-time service support.

• IE interfaces
• /
• v.16 no.2
• /
• pp.195-200
• /
• 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.

• 한국정보통신설비학회:학술대회논문집
• /
• 2005.08a
• /
• pp.74-84
• /
• 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 KIEE Conference
• /
• 2006.10c
• /
• pp.467-469
• /
• 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.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.40 no.8
• /
• pp.1613-1621
• /
• 2015

This paper analyzes the rate adaptation scheme and suggests applicable strategy of the MCS(Modulation and Coding Scheme) for improving DCF throughput in the IEEE 802.11ad and 802.11ad wireless LAN. IEEE 802.11ac and 802.11ad wireless LAN provide MCS technique that dynamically adjusts modulation level and code rate to the time-varying channel conditions in order to obtain considerably high data rates. But these standards did not provide rate adaptation algorithm, so this paper surveyes rate adaptation algorithm and suggests MCS scheme applied to IEEE 802.11ac and 802.11ad wireless LAN. Specially A MAC(Medium Access Control) layer throughput is evaluated over error-prone channel in the IEEE 802.11ac-based wireless LAN. In this evaluation, DCF (Distributed Coordination Function) protocol and A-MPDU (MAC Protocol Data Unit Aggregation) scheme are used. Using theoretical analysis method, the MAC saturation throughput is evaluated with the PER (Packet Error Rate) on the condition that the number of station, transmission probability, the number of parallel beams and the number of frames in each A-MPDU are variables.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.13 no.6
• /
• pp.107-112
• /
• 2003

Handover in IEEE 802.11 requires repeated authentication and key exchange procedures, which are an obstacle to seamless services of wireless LAM. We propose a fast authentication and key exchange mechanism using IEEE 802.11f. Especially, by proposing a modified version of the 4-way handshake of IEEE 802.11i, we solve the perfect forward secrecy problem that arises when the pre-authentication is adopted. The scheme can be implemented only using the Context Block of IEEE 802.11f and the 4-way handshake of IEEE 802.11i without involving authentications server's interaction or non-standard behavior between access points. Our scheme is applicable to devices not supporting the us-authentication of IEEE 802.11i and also, it can substitute the pre-authentication when the pre-authentication is failed.