Performance of Centralized Authentication Control in IEEE 802.11ah with Multirate Registration

IEEE 802.11ah Wireless Local Area Network (WLAN) is a new wireless network technology standard used for Internet of Things (IoT) applications. Under IEEE 802.11ah, up to 8,191 IoT devices can connect to the same access point (AP) from a range of up to 1 km, and multirate connections are possible with speeds ranging from 150 Kbps to 346.6 Mbps. Before transmitting data frames, each IoT device must register with the AP using the centralized authentication control method. One problem with this is that simultaneous registration by many devices can result in registration taking a long time. Some papers have proposed algorithms to reduce registration time by dynamically adjusting the number of devices allowed to register in each time period. However, these proposed algorithms assume a constant rate is used when transmitting authentication and association frames. In our study, we evaluated the effect on registration speed of allowing multiple transmission speeds to be used. In our evaluation, we used the multirate Minstrel algorithm. The results from extensive simulation with an NS-3 network simulator show that the use of multirate capabilities during registration can improve IoT-device registration speed by 5-15% relative to registration at a constant transmission rate.