Target Wake Time (TWT) in WiFi 6 (802.11ax) Explained

Introduction

Target Wake Time (TWT) is a revolutionary feature introduced in WiFi 6 (802.11ax) designed to improve the efficiency of wireless communication. It enables devices to schedule specific times for data transmission, minimizing unnecessary wake-ups and conserving power. This innovation is particularly beneficial for IoT devices, smartphones, and other battery-powered gadgets in dense network environments.

In this guide, we will explore what TWT is, how it works, and the key benefits it brings to modern WiFi networks.

Introduction to IEEE 802.11ax

The IEEE 802.11ax standard represents an evolution of legacy 802.11 WiFi standards such as 802.11a/g/n/ac. Previous standards primarily focused on increasing raw data rates. 802.11ax has been developed to address issues faced in those earlier standards, as well as to add new advanced features. Specifically, 802.11ax focuses on better efficiency, capacity, and performance. TWT is one of the new features introduced to increase battery life.

What is TWT (Target Wake Time) in 802.11ax?

In 802.11ax, the OFDM symbol is longer, with a duration of approximately 12.8 µs. There are three guard interval options: 0.8, 1.6, or 3.2 µs.

The figure above depicts an 802.11ax frame with an Access Point (AP) and two client devices, illustrating their wake-up and sleep times. As shown, it uses predefined uplink access, so WiFi devices don’t need to contend for uplink access. During periods when there are no transmissions, WiFi users will sleep, waking up only when they have data to transmit.

Benefits or Advantages of TWT in 802.11ax

• Reduces power consumption: By adopting sleep time, TWT increases battery life.
• Minimizes contention: By adopting scheduled uplink access, TWT minimizes contention among stations. Because there is no contention, congestion among stations can be reduced significantly.

Conclusion

Target Wake Time (TWT) is a game-changer in WiFi 6 technology, offering enhanced power efficiency, reduced network congestion, and optimized performance for connected devices. By allowing devices to schedule wake times, TWT significantly extends battery life and ensures smooth operation even in crowded networks. As WiFi 6 adoption grows, TWT will play a crucial role in advancing smart homes, IoT ecosystems, and mobile connectivity, making it an essential feature for the future of wireless communication.