AP-initiated multi-user transmissions in IEEE 802.11ax WLANs
AP-initiated multi-user transmissions in IEEE 802.11ax WLANs
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DOI：
10.1016/j.adhoc.2018.10.021
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发表时间：
2019-03-15
期刊：
影响因子：
4.8
通讯作者：
Kosek-Szott, Katarzyna
中科院分区：
文献类型：
--
作者：
Bellalta, Boris;Kosek-Szott, Katarzyna
下一代 IEEE 802.11ax 无线局域网 (WLAN) 将在下行链路 (DL) 和上行链路 (UL) 方向广泛使用多用户通信，以在每个接入点有多个用户站的场景中实现高效的频谱利用率。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 引入的用于在 DL 和 UL 方向上实现 AP 发起的 OFDMA 和多用户 MIMO (MU-MIMO) 传输的新颖特性。也就是说，我们描述了在物理 (PHY) 层和媒体访问控制 (MAC) 层所做的更改，以支持 OFDMA、使用触发帧来调度上行链路多用户传输，以及新的多用户 RTS/CTS 机制来保护大型多用户传输免受冲突。然后，为了研究 IEEE 802.11ax WLAN 可实现的吞吐量，我们使用数学分析和仿真来数值量化 MU 传输的增益以及 IEEE 802.11ax 开销对 WLAN 饱和吞吐量的影响。结果显示了在具有许多用户站的场景中使用 MU 传输的优势。此外，我们还对 IEEE 802.11ax WLAN 能够最大化其性能的条件提供了新颖的见解，例如需要为 AP 发起的 MU 传输提供严格的优先级，以避免与用户站的传输发生冲突。 (C) 2018 Elsevier B.V. 保留所有权利。
Next-generation IEEE 802.11ax Wireless Local Area Networks (WLANs) will make extensive use of multiuser 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 Multiuser (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 multiuser MIMO (MU-MIMO) transmissions in both DL and UL directions. Namely, we describe the changes made at the Physical (PHY) layer and at the Medium Access Control (MAC) layer to support OFDMA, the use of trigger frames to schedule uplink multi-user transmissions, and the new multiuser RTS/CTS mechanism to protect large multi-user transmissions from collisions. Then, in order to study the achievable throughput of an IEEE 802.11ax WLAN, we use both mathematical analysis and simulations to numerically quantify the gains of MU transmissions and the impact of IEEE 802.11ax overheads on the WLAN saturation throughput. Results show the advantages of using MU transmissions in scenarios with many user stations. Additionally, we provide novel insights on the conditions in which IEEE 802.11ax WLANs are able to maximize their performance, such as the need to provide strict prioritization to AP-initiated MU transmissions to avoid collisions with transmissions from user stations. (C) 2018 Elsevier B.V. All rights reserved.