Performance Analysis of the TXOP Sharing Mechanism in the VHT IEEE 802.11ac WLANs

Abstract

International audienceThe 802.11ac amendment of the IEEE 802.11 standard, known as a very high-throughput wireless local area network (WLAN), has attracted extensive attention for achieving a maximum transmission rate up to 7 Gb/s. This is mainly possible by adopting the DownLink MultiUser Multiple-Input-Multiple-Output (DL MU-MIMO) technology, which allows multiple frames to be simultaneously transmitted from the access point (AP) to different receivers via multiple spatial streams. To support the DL MU-MIMO technology at medium access control level, a technique called transmission opportunity (TXOP) sharing has been proposed to extend the mandatory TXOP of the WLAN standard. In this letter, we propose an analytical model based on Markov chains to evaluate the performance of an IEEE 802.11ac AP enabling the TXOP sharing mechanism. Based on this model, we are able to derive the achievable throughput of a given access category (AC), namely, voice (VO), video (VI), best effort (BE), and background (BK). The ultimate goal of this letter is to analyze how the TXOP sharing mechanism could improve the utilization of the scarce wireless bandwidth while achieving channel access fairness among the different ACs. Note that the obtained theoretical results are also validated by computer simulatio

Integration Application Technologies and Performance Analysis of Very High Throughput Wi-Fi in Dense Deployment Networks

“…Each AP is equipped with multi-antenna, using beam forming and multiuser diversity techniques, which are used to support the simultaneous data transmission of multiple UEs. 802.11ac defines a new type of transmitting opportunity sharing mechanism, in which a downlink data frame based on the traffic types is divided into different access categories (ACs) of the transmission queue [8]. Different transmission queues allow simultaneous data transmission.…”

Modeling the TXOP Sharing Mechanism of IEEE 802.11ac Enhanced Distributed Channel Access in Non-Saturated Conditions

“…We propose a two-dimensional discrete Markov chain, which is similar to that in [5], to characterize the EDCA TXOP sharing mechanism. Given data types of the data frames, four type of the ACs are arranged in order of increasing priority identified by the index h ∈ {1, 2, 3, 4}.…”

“…Mohand et al [5] present a Morkov chain based analysis model of the 802.11ac TXOP sharing mechanism under a saturated traffic assumption. Shanshan et al [6] propose an analytical model based on Markov chain to characterize the saturation throughput for multi-user MIMO wireless LANs.…”

“…Only when the backoff counter is equal to zero and the queue is not empty, the transmission can occur. It is According to [5], probability p h c means the collision occurs in the case that at least one of the higher priority class AC, j (j > h), transmits. At steady state, each class AC j transmits a packet with probability τ (j).…”

Mathematical Model of Variable-Length Payloads for EDCA and Multi-User MIMO Based Wireless LAN

“…서 론 기존 대부분의 무선랜 medium access point (MAC) 분석 모델은 고정 길이의 프레임을 가정한다 [1,2] . 그러나 무선랜을 통해 전송되는 대부분의 트래픽 은 가변 길이 특성을 보인다 [3] .…”