Improving IEEE 802.11 power saving mechanism

This paper presents a mechanism that improves the energy efficiency of PSM (Power Saving Mechanism) specified for DCF (Distributed Coordination Function) in IEEE 802.11. In PSM, time is divided into beacon intervals. At the start of each beacon interval, every node stays awake for a duration, called the ATIM Window. During the ATIM window, nodes exchange control packets to determine whether they need to stay awake for the rest of the beacon interval. Past research results show that the size of the ATIM window has a significant impact on energy savings and throughput achieved by nodes. This paper proposes a simple mechanism that adjusts ATIM window size to improve the energy conservation of PSM. We also allow nodes to enter the doze state in the middle of beacon interval if they have completed all the transmissions that are explicitly announced during the ATIM window. Simulation results show that the proposed solution improves performance and energy savings over PSM in IEEE 802.11.