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Target Wake Time (TWT) in IoT

By Shahnail Khan Last updated : November 14, 2023

Target Wake Time (TWT) is a communication scheduling mechanism designed to enhance the power efficiency of IoT devices by managing their wake-up times. In traditional IoT setups, devices often remain in an active state, consuming power even when not transmitting or receiving data. TWT introduces a more intelligent approach by allowing devices to synchronize their wake-up times with the network, thereby minimizing idle periods and maximizing energy conservation.

TWT is a key feature of the Wi-Fi 6 (802.11ax) standard, but it is also supported by some other wireless protocols, such as Bluetooth Low Energy (BLE).

How TWT Works?

TWT works by establishing a communication schedule between the IoT device and the network. The device tells the network when it will wake up to send or receive data, and the network agrees to send or receive data at that time.

The communication schedule can be negotiated dynamically, or it can be pre-configured. For example, a smart thermostat might demand a new schedule with the network each day, based on its heating and cooling schedule. A smoke detector, on the other hand, might have a pre-configured schedule to wake up every 10 minutes to send a status update.

Once the communication schedule is established, the IoT device can go to sleep until its wake time. This saves battery power because the device does not have to constantly listen for traffic from the network.

Benefits of TWT for IoT

TWT offers several benefits for IoT applications. Let's have a look at it.

• Extended battery life: TWT can significantly extend the battery life of IoT devices, especially those that are battery-powered. This is because the devices can spend more time in sleep mode, which consumes less power.
• Improved network efficiency: TWT can improve network efficiency by reducing congestion and contention. This is because devices are not all trying to communicate at the same time.
• Reduced latency: TWT can reduce latency by ensuring that devices have immediate access to the network when they wake up. This is because the network is already expecting them to communicate at that time.

Use Cases for TWT in IoT

TWT can be used in a wide range of IoT applications.

• Smart home devices: Smart thermostats, smoke detectors, door locks, and other smart home devices can benefit from TWT's extended battery life and reduced latency.
• Wearable devices: Smartwatches, fitness trackers, and other wearable devices can use TWT to conserve battery power and improve performance.
• Industrial IoT devices: Industrial IoT sensors and actuators can use TWT to reduce network congestion and improve reliability.
• Smart cities: TWT can be used to enable a variety of smart city applications, such as smart parking, smart traffic lights, and smart waste management systems.

Challenges of Deploying TWT in IoT

There are a few challenges that need to be addressed when deploying TWT in IoT environments-

• Device compatibility: Not all IoT devices support TWT. It is important to check the device specifications before deploying TWT.
• Network configuration: TWT requires the network to be configured to support it. This may require a firmware update to the network access points.
• Device management: TWT devices need to be managed to ensure that they are following the communication schedule. This can be a challenge for deployments with a large number of devices.

Conclusion

Target Wake Time (TWT) is a promising technology that can significantly improve the performance and efficiency of IoT networks. TWT is still under development, but it is already being supported by several IoT devices and network infrastructure vendors.

As TWT becomes more widely adopted, it is expected to play a major role in the next generation of IoT applications.