The reverberations of the pandemic are still rippling through society. The latest thing to be affected is Wi-Fi. It seems the way people are now using the technology has caused engineers to rethink its design. And that has positive effects on the IoT.
As more people started working from home, there was a significant shift in how traffic moved across the Internet. The ratio of downlink data—information moved to a user's computer from the cloud—to information moving the opposite way (uplink data) changed from 10:1 before the pandemic to 6:1 as COVID-19 subsided. The Wi-Fi Alliance, the group responsible for promoting the tech, expects it to decline even further, to 2:1 in the next few years.
The change in that ratio has prompted an upgrade to the Wi-Fi 6 specification (formally known as "Release 2") to enable it to cope with more significant upload usage. The original specification included a feature that allowed consumers’ network devices to simultaneously uplink on different Wi-Fi streams, effectively boosting uplink capacity. In Revision 2, this feature has been enhanced to make it easier to use and more efficient. This is a natural extension of the existing multi-user downlink feature.
While engineers were busy boosting Wi-Fi’s uplink capacity, they also looked at the technology’s battery-saving features. Wi-Fi 6 had already addressed many of the power consumption challenges of previous versions, making it better suited to energy-constrained IoT devices, but Release 2 takes this several steps further.
The first improvement adds flexibility to the synchronization of uplinks between network-connected devices (such as sensors) and access points (APs, typically the Wi-Fi routers that connect directly to the Internet). This flexibility helps to limit energy usage without compromising any downlink synchronization.
A second battery-saving measure is quite technical but in essence, allows engineers to extend the time a connected device can remain in a very low power idle state—saving power—without being disconnected from the network. An advantageous side-effect to extended “sleep” time is that because fewer “keep-alive” messages are sent, message clashes between multiple devices is decreased, and, consequently, throughput increases.
A further technical tweak that will lead to longer battery life concerns a feature called Target Wake Time (TWT). You can think of this as an alarm clock that goes off to wake up an end device when it needs to send information. For example, an engineer might set a sensor such that it sends temperature data every minute. In between it can go to sleep and save energy secure in the knowledge that TWT will wake it up in time to send some more data.
TWT was already included in the original release of Wi-Fi 6 but in the new release, it has been modified to give the connected device implementing TWT more flexibility. The connected device can now more easily update TWT and optimize its parameters. This change will improve energy efficiency, because, for example, it removes the overhead associated with repeatedly suspending and restarting old TWT agreements.
Better battery life is one thing, but IoT end devices can also benefit from extended range. That's not been forgotten in Wi-Fi 6 Release 2 with a range extension tweak that targets uplink transmissions between connected devices and APs.
The new feature enables the AP to hear connected devices at maximum range even under bad channel propagation conditions, allowing the connected devices to associate with the AP continuously. Previously, any aggressive RF environment impacted range. The new feature generally offers an increased range for connected devices that implement it.
Wi-Fi’s key advantages for the IoT are its native Internet Protocol (IP) interoperability, enabling sensors to directly connect to the cloud (without having to pay additional data subscriptions), and, because APs are already everywhere, eliminating the need for widespread new infrastructure. Those advantages will see the technology playing an increasing role as the IoT rapidly expands.