IEEE 802.11ah，也被稱作為WiFi Halow，其被認為是物聯網(IoT)中最有前景的協定。傳統的802.11ah提出了諸多分群機制，其為分層式的架構以緩解通道存取的碰撞，解決物聯網溝通環境中的以下四個主要問題：(1)能源受限(2)傳送距離長(3)傳送數據小而不頻繁(4)傳輸速率低。然而在擁擠的環境下依然無法有效避免碰撞。本文提出了兩種新的機制以改善802.11ah的性能。基於註冊的衝突避免(RCA)機制用於避免碰撞產生並減少了backoff時的等待時間。基於註冊的情境感知存取擴展(RSAE)機制用於改善時隙利用率，以便充分利用具有較輕負載的時隙。與傳統的802.11ah相比，所提出的兩種機制在每個時隙中的裝置數量較高的環境下，能獲得較低的碰撞率及較高的產能。

IEEE 802.11ah, which is also known as Wi Fi HaLow, is considered to be a promising protocol for Internet of Things (IoT). The legacy 802.11ah proposes a number of grouping mechanisms, which are based on the hierarchical organization to relieve channel access’s collision, to resolve the following four main issues in the IOT’s communication environment, i.e., (1) power-constrained, (2) long transmission distance, (3) small and infrequent transmission data and (4) low transmission rate. However, collisions still cannot be effectively avoided in the legacy 802.11ah in a crowded environment. Two novel mechanisms were proposed in this work to improve the performance of 802.11ah. The Registration-based Collision Avoidance (RCA) mechanism is used to avoid collisions, and furthermore reduce the waiting time of backoff. The Registration-based Situation-aware Access Extension (RSAE) mechanism is used to improve slot utilization so that slots with light load can be fully utilized. Comparing with the legacy 802.11ah, experimental results for these two proposed control schemes shown that they have the lower collision rate and better throughput when the number of stations in a slot is high.

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