Influence of the Clock Drift on the Efficiency of the Power Save Mechanisms in Wi-Fi Networks

Decreasing energy consumption of devices is an important problem for modern Wi-Fi networks. To address this problem, the very first version of the Wi-Fi standard introduced a basic power saving mechanism. At the same time, the new IEEE 802.11ax and IEEE 802.11ba amendments describe modern power save mechanisms: target wake time (TWT) and wake-up radio (WUR). The main idea of these mechanisms is in periodically turning off the main radio to reduce power consumption by not listening to the channel. However, the clock drift effect, i.e., random deviation of the station’s clock, can significantly degrade the efficiency of TWT and WUR, which schedule duty cycles. The basic power save mechanism is much less affected by the clock drift effect due to periodic clock synchronization by listening to beacons, which are management frames containing network information. The paper evaluates the efficiency of the mentioned power save mechanisms with the ns-3 simulation platform. TWT and WUR mechanisms are shown to achieve lower power consumption and frame transmission delays than the basic power save mechanism even with the clock drift effect.