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arXiv 1702.05397cs.NI
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IEEE 802.11ax无线局域网中AP发起的多用户传输

AP-initiated Multi-User Transmissions in IEEE 802.11ax WLANs

Boris Bellalta, Katarzyna Kosek-Szott

摘要:

下一代802.11ax WLAN将在下行链路(DL)和上行链路(UL)两个方向上广泛使用多用户通信,以在每个接入点具有许多用户站的场景中实现高且高效的频谱利用。在多用户(MU)多输入多输出(MIMO)和正交频分多址(OFDMA)传输的支持下,这将成为可能。在本文中,我们首先概述了IEEE 802.11ax引入的新特性,以实现AP发起的OFDMA和MU-MIMO传输在下行链路和上行链路方向。也就是说,我们描述了在物理层和媒体访问控制层进行的更改以支持OFDMA,使用\emph{trigger frames}来调度上行链路多用户传输,以及使用新的\emph{multi-user RTS/CTS mechanism}来保护大型多用户传输免受冲突。然后,为了研究802.11ax网络的可实现吞吐量,我们使用数学分析和仿真来量化MU传输的好处和802.11ax开销对WLAN饱和吞吐量的影响。结果显示了MU传输在有许多用户站的场景中的优势,还提供了一些关于802.11ax WLAN能够最大化其性能的条件的新见解,例如在吞吐量方面存在最佳数量的活动用户站,或者需要为AP发起的MU传输提供严格的优先级,以避免与用户站发生冲突。

英文摘要:

Next-generation 802.11ax WLANs will make extensive use of multi-user communications in both downlink (DL) and uplink (UL) directions to achieve high and efficient spectrum utilization in scenarios with many user stations per access point. It will become possible with the support of multi-user (MU) multiple input, multiple output (MIMO) and orthogonal frequency division multiple access (OFDMA) transmissions. In this paper, we first overview the novel characteristics introduced by IEEE 802.11ax to implement AP-initiated OFDMA and MU-MIMO transmissions in both downlink and uplink directions. Namely, we describe the changes made at the physical layer and at the medium access control layer to support OFDMA, the use of \emph{trigger frames} to schedule uplink multi-user transmissions, and the new \emph{multi-user RTS/CTS mechanism} to protect large multi-user transmissions from collisions. Then, in order to study the achievable throughput of an 802.11ax network, we use both mathematical analysis and simulations to numerically quantify the benefits of MU transmissions and the impact of 802.11ax overheads on the WLAN saturation throughput. Results show the advantages of MU transmissions in scenarios with many user stations, also providing some novel insights on the conditions in which 802.11ax WLANs are able to maximize their performance, such as the existence of an optimal number of active user stations in terms of throughput, or the need to provide strict prioritization to AP-initiated MU transmissions to avoid collisions with user stations.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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