PMSA: Power Mode Selection Algorithm in IEEE 802.11 WLANs operating TWT

Target Wake Time (TWT) is a key energy-saving mechanism in IEEE 802.11 WLANs, allowing stations (STAs) to reduce power consumption by restricting transmissions to scheduled service periods (SPs). Despite its potential, TWT remains underutilized due to concerns over performance degradation, especially under congested network conditions. In this paper, we address this limitation by proposing the Power Mode Selection Algorithm (PMSA), a lightweight and standard-compliant mechanism implemented at the Access Point (AP). PMSA operates on top of existing TWT schedulers and dynamically determines whether each STA should operate in power save (PS) mode or temporarily switch to active mode (and disable TWT) based on current network congestion. Our simulation results demonstrate that PMSA enhances the robustness of TWT scheduling by adapting to traffic conditions, maintaining low delays and avoiding packet losses even under heavy load, while preserving energy savings when feasible.