自IEEE 802.11草案於1997年首次獲得批准以來，無線局域網（WLAN）技術迅速發展。但是，IEEE 802.11媒體訪問控制（MAC）協議不適合支持大量設備的互聯網接入。環境。因此，IEEE標準協會（IEEE-SA）標準委員會於2014年3月批准了IEEE 802.11ax，以改進成功概率，平均成功延遲訪問等指標。 IEEE 802.11ax也稱為高效無線（HEW），如在蜂窩網絡中引入正交頻分多址（OFDMA），例如， LTE，以便同時為更多用戶服務。在IEEE 802.11ax中，信道可以劃分為更小的子信道，稱為資源單元（RU），以便可以同時進行多用戶傳輸。 IEEE 802.11ax提供了一種被接入點（AP）發送的稱為隨機接入（RA）觸發幀的方法，用於分配用於上行鏈路傳輸的資源單元而不是用於做出決定的AP。在本文中，我們提供了一個分析模型來研究IEEE 802.11ax下UL OFDMA RA的成功概率和延遲性能。

Wireless Local Area Network (WLAN) technology has grown rapidly since the draft of the IEEE 802.11 had been firstly approved in 1997. However, the IEEE 802.11 medium access control (MAC) protocol is unsuitable to support internet access for a massive number of devices in the environment. Hence, IEEE Standards Association (IEEE-SA) standards board approve IEEE 802.11ax in March 2014, to improve metrics such as success probability, average success delay access. IEEE 802.11ax also called as High-Efficiency Wireless (HEW) introduces Orthogonal Frequency-Division Multiple Access (OFDMA) as in cellular networks, e.g. LTE, in order to serve more users at the same time. In IEEE 802.11ax, channel can be partition into smaller sub-channels named Resource Units (RUs) so that simultaneous multiple-user transmission can occur. IEEE 802.11ax provides a method known as Random Access (RA) Trigger Frame sent by Access Point (AP) to allocate resource units for uplink transmission instead of AP making the decision. In this paper we provide an analytical model to study the success probability and delay performance of UL OFDMA RA under the IEEE 802.11ax.

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