The First Measurement Study of Target Wake Time Mechanism in 802.11ax on COTS Devices

Nowadays, the 802.11ax protocol is widely adopted in the local area networks. Compared with the former version of 802.11 standards, 802.11ax brings a new power-saving mechanism named TWT (Target Wake Time). In this paper, we conduct a comprehensive measurement study on how TWT mechanism performs on the commercial-off-the-shelf devices in our daily life. To me more specific, we focus on the impact on power consumption, network performance and stability of TWT mechanism on the smartphones. Counterintuitively, we find that TWT mechanism is not as power-saving as we thought in the experimental setup we built, and it also poses nagative impacts on the network stability. We further perform a root-cause analysis to find the rationale behind the measurement results and we also summarized the implications and suggestions to the stakeholders of 802.11ax.