Abstract
Traditional IEEE 802.11 network is designed for the use of small scale local wireless networks. However, the emergence of the Internet of Things (IoT) has changed the scene of wireless communications. Thus, recently, the IEEE task group ah (TGah) is dedicated to the standardization of a new protocol, called IEEE 802.11ah, which is customized for this type of large-scale networks. IEEE 802.11ah adopts the grouping-based MAC protocol to reduce the contention overhead for each group of devices. However, most existing designs simply randomly distribute devices to groups, and less attention has been paid to the problem of forming efficient groups. Therefore, in this paper, we argue that the performance of grouping is closely related to heterogeneity in traffic demands of devices, and further build a traffic model with consideration of transmission probability. Then a traffic-aware grouping algorithm is proposed to improve channel utilization of each group. The evaluation shows that our traffic-aware grouping outperforms the other methods, especially when the network is almost saturated.