Target wake time: scheduled access in IEEE 802.11ax WLANs

Abstract

The increasing interest in ubiquitous networking, and the tremendous popularity gained by IEEE 802.11 WLANs in recent years, is leading to very dense deployments where high levels of channel contention may prevent meeting the increasing user demands. To mitigate the negative effects of channel contention, the TWT mechanism included in the IEEE 802.11ax amendment can have a significant role, as it provides an extremely simple but effective mechanism to schedule transmissions in time. Moreover, in addition to reducing the contention between stations, the use of TWT may also contribute to taking full advantage of other novel mechanisms in the IEEE 802.11 universe, such as multiuser transmissions, multi-AP cooperation, spatial reuse and coexistence in high-density WLAN scenarios. Overall, we believe TWT may be a first step toward a practical collision-free and deterministic access in future WLANs.