Traffic-Aware Re-Grouping for Load Balance in IEEE 802.11ah IoT Network Based on the Registered Backoff Time Mechanism

Abstract

AbstractIEEE 802.11ah, which is a wireless network protocol designed for Internet of Things (IoT), devised the Restrict Access Window (RAW) mechanism to tackle the collision problem. However, some RAW’s slots may be overloaded; some RAW’s slots may be lightly loaded or have no load because no stations (STA) allocated in these slots need to access channel. This work adopted (i) the Registered Backoff Time (RBT) mechanism such that each STA can register the backoff time for its future channel access in access point (AP) and (ii) the Claiming RAW mechanism such that STAs are allowed to notify AP that they have uplinked data to transmit. In this way, AP can (1) know which STAs have uplinked data to transmit and thus (2) re-schedule those STAs from the overloaded slots to the slots that (i) are underloaded or (ii) no STAs need to access channel based on STAs’ RBTs in advance. As a result, the proposed Registration-based Regrouping for Load-Balance Channel Access (RRG-LBCA) method can achieve load balance among slots to increase the IEEE 802.11ah network’s performance. The performance evaluation results shown that the proposed RRG-LBCA method can eliminate the collision situation and increase the aggregate throughput.