How Wi-Fi 6/6E Alleviates Wireless Device Congestion in Healthcare Environments

Sep 13, 2022

Wi-Fi networks have become a nearly ubiquitous backbone for the connected devices that are now part of every facet of the way we work and live. Today, so many devices rely on Wi-Fi that those networks increasingly suffer from congestion that negatively impacts the performance of devices. That kind of network congestion is a nuisance for consumer devices like tablets streaming music or movies, but the consequences are far more serious in medical environments, where medical devices perform critical roles in patient monitoring and treatment.

As the number of Wi-Fi connected devices increases in healthcare environments, Wi-Fi networks can become overwhelmed not only by the number of devices making demands on the network but also by the RF complexity of so many networks and devices operating alongside one another in close proximity. Healthcare IT teams have unfortunately had very few tools in their toolkit to mitigate this kind of congestion, but that is changing with two new versions of Wi-Fi being released by the Wi-Fi Alliance. 

Wi-Fi 6 and 6E deliver significant advancements in performance, efficiency, latency and other key areas of performance that collectively enable far more device density without network congestion. These new versions of Wi-Fi will have an enormous impact on connected device networks in healthcare environments, where so many Wi-Fi dependent devices are packed into small, complex environments.

The first two technologies that solve these congestion challenges are MU-MIMO and OFDMA, which allow each Wi-Fi gateway to organize the spectrum temporally and physically in ways that establish stronger, higher-performing connections with each device in their domain.

MU-MIMO: Multi-User Multiple-In Multiple-Out (MU-MIMO) enables Wi-Fi gateways to create spatial streams that focus RF activity in the physical direction of each device in their domain. This is achieved by using two antennas and creating an intentional interference pattern to focus signals toward the intended device or groups of devices – creating a stronger link with each device using up to eight spatial streams. This not only boosts the strength of each device’s connection but also reduces unfocused RF noise and utilizes less power in the process. This has the added benefit of reducing the overall volume of interference in environments with many gateways and devices, preventing the physical space from becoming saturated in signals that potentially interfere with the performance of the networks, devices and applications. 

OFDMA: Orthogonal Frequency Division Multiple-Access (OFDMA) builds on MU-MIMO by enabling the gateway to talk simultaneously with multiple devices. OFDMA uses different channels to allow more devices to send and receive data than the prior version of Wi-Fi. Rather than all devices waiting in line for their turn to send or receive, they do so simultaneously, but in non-interfering channel spaces, which means they all enjoy much more immediacy to their communications. In a given segment of time for a Wi-Fi link (a frame), OFDMA allows the access point to send and receive multiple messages across different channels (frequencies) to and from different devices.

Together, MU-MIMO allows highly-focused spatial streams to more devices, and OFDMA then allows that number of devices to expand even more by allowing devices to communicate with the access point on a number of channels simultaneously. This enables Wi-Fi to achieve a previously-impossible level of coordination of devices on the network. This is enormously impactful in healthcare settings where so many devices are in close proximity and a given gateway is needed to support so many devices.

Wi-Fi 6/6E is also designed to solve another source of congestion that is common in healthcare settings: overlapping Wi-Fi networks in the same physical space. Environments like clinics and hospitals often have a high proliferation of Wi-Fi gateways whose RF ranges overlap with one another. The goal of all those gateways is to maximize coverage, but the downside is a noisy wireless environment that negatively impacts the connectivity of devices.

BSS Coloring (Basic Service Set Coloring): This technology intelligently organizes network traffic in areas where multiple gateways are overlapping. Prior versions of Wi-Fi struggled with overlapping networks, requiring devices communicating on overlapping channels to regularly pause communication, check to make sure it is safe to proceed, and only proceed if there was no competing traffic. This slowed network performance, particularly in dense environments like those in healthcare. BSS coloring alleviates this issue by allowing the access point to intelligently manage traffic occurring on the same channel by adding a prepend to their broadcast identifier in the form of a color. If a device hears a broadcast on its channel, but the broadcast is of a different color, the device can determine that it’s for another service set and go ahead and broadcast without waiting. In doing this, we can categorize devices into association or affinity with a given access point with a high degree of likelihood that they will not interfere with each other, due to proximity. This will allow devices to talk to their nearest source of connectivity without fear of interrupting another service set.

The features discussed above dramatically reduce network congestion and allow far greater device density, but there is another feature of Wi-Fi 6/6E that should also be mentioned and is impactful for medical devices. It is not focused on reducing congestion, but it dramatically improves another challenge for many medical devices: battery life. 

The centerpiece of Wi-Fi 6/6E’s low power strategy is Target Wake Time (TWT) technology. Prior technologies like PS-Poll (DTIM) and WMM (APSD) are still supported in the new version of Wi-Fi, but most engineering teams will want to take full advantage of TWT because it enables much longer sleep times for clients that preserve battery through extended inactivity while still remaining connected to the network. For devices whose role can enable sleep for long periods of time, TWT dramatically improves power scheduling, extends battery life and lowers network congestion. Additionally, TWT can be adjusted to meet individual or group device power needs rather than the whole network, providing flexibility and efficient power profiling for devices using the network.

These enhancements to Wi-Fi represent a significant step forward in strengthening Wi-Fi as a cornerstone technology for healthcare environments. These congestion-reducing and battery-extending features make it a critical technology for engineers who design connected medical devices and the teams that deploy and manage Wi-Fi networks in healthcare settings.

Contributed by

Laird Connectivity

Country: United States
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