Access Point Coordination Based TWT Scheduling for the Next Generation WLAN

With the rapid development of Wireless Local Area Network (WLAN) and the trend of Internet of Everything (IoE), application scenarios have expanded to high-dense deployment scenarios which often experience serious interference and contention issues. Since many client devices in such scenario are battery-powered, energy efficiency is an important design consideration. The Target Wakeup Time (TWT) mechanism proposed in IEEE 802.11ax has attracted research interest as an energy saving technique. However, most existing studies only consider single Basic Service Set (BSS) scenario and have limited applicability to high-dense deployment scenarios. To bridge this gap, this paper proposes an Access Point (AP) Coordination based TWT Scheduling (ACTS) Algorithm tailored for next generation high-density WLANs. ACTS dynamically allocates TWT Service Periods (TWT SPs) through AP coordination based on traffic demands, energy saving requirements as well as interference relationships between client stations (STAs). It aims to minimize energy consumption while satisfying traffic needs using minimal resources. Firstly, the high-dense deployment scenarios are mapped to an interference relation matrix. Then TWT resources are allocated according to traffic load in descending order, under the constraint that interfering STAs are scheduled to different TWTs. Simulation results demonstrate that compared to other baseline schemes, the proposed ACTS algorithm has better performance in terms of throughput and energy efficiency.