Optimizing M2M Energy Efficiency in IEEE 802.11ah

In order to efficiently support the Machine-to- Machine (M2M) applications, a new amendment of Wi-Fi standard known as IEEE 802.11ah is introduced. In 802.11ah, several enhanced MAC features are added so as to provide scalability for a large number of stations as well as to reduce the energy consumption compared with the existing Wi-Fi technologies. In this paper, a selected set of 802.11ah MAC features are discussed and optimized mainly from the perspective of energy utilization. Moreover, a new energy-saving mode, FESM, is proposed and analyzed. The evaluations are carried out with a system-level MAC simulator assuming an uplink scenario with sporadic data traffic; and complemented with an in- depth analysis for a selected M2M use case, the farming scenario, along with the energy harvesting potential.