Enhancement of IEEE 802.11ah MAC for M2M Communications

Machine-to-machine (M2M) communications is expected to be supported in the next-generation wireless LAN, IEEE 802.11ah. One of the most important issues for M2M communications is designing an effective medium access scheme to handle many devices. In this letter, we propose a new medium access control (MAC) enhancement to increase the uplink access efficiency. The proposed algorithm estimates the number of devices for the uplink access from the success probability. In the proposed algorithm, an access point (AP) determines the optimal size of the restricted access window (RAW) considering the relationship between the estimated number of devices and the size of RAW. We show that the success probability for the uplink access is improved by using our proposed algorithm through analysis and simulations.