WiFi 6 has limited potential without smart management

WiFi 6 is finally making its way into consumers’ homes. If industry predictions hold true, the technology will be one of the major trends of the decade. Just this year, the Wi-Fi Alliance expects nearly 2 billion WiFi 6 devices to ship to consumers, commercial entities, and government agencies. There’s a lot of buzz about how WiFi 6 will change the consumer experience and connectivity landscape. Hidden in all the excitement is a warning: WiFi 6 is only as good as the systems that control it.

Despite all of its breakthroughs, the technology’s new capabilities will not reach their full potential without intelligent management and optimization of home WiFi networks. To truly improve the customer experience in crowded home network environments, WiFi 6 requires additional tools, such as network optimization and control.

[[431301]]

Here’s a breakdown of some of the top WiFi features, the issues we expect to arise, and how to fix them.

160 MHz channel bandwidth

Most WiFi 6 devices are expected to support 160 MHz channels, while WiFi 5 has that capability, but few WiFi 5 devices go beyond 80 MHz. In theory, since doubling the channel width doubles the throughput, customers will experience twice the download speeds, twice the resolution, etc.

The problem is that in most countries, including the U.S., there are currently only two separate 160 MHz channels available, which are also shared by devices using smaller bandwidths. This becomes a big problem for dense environments, where overlapping channels used by many competing devices or different users will create significant interference.

Mitigating this problem requires specific network configuration. First, interference on the 80 MHz sub-channels of the 160 MHz transmission needs to be sensed and predicted, allowing for intelligent channel allocation and bandwidth selection. Additionally, it is important to consider the full interference picture in the environment so that channel allocations can be optimized in an apartment building (or neighboring homes) and allocated where they are needed most.

This configuration cannot be achieved through a locally managed network and must be handled centrally through the cloud. For example, in an apartment building, the cloud platform will analyze factors such as load and device type and take into account the historical and current client and load sets present in the network for each access point (AP). Based on this data and analysis, the platform then allocates channel bandwidth to each AP throughout the building.

Channels can also be “tiled” to minimize conflicts between neighboring units. If channel reuse cannot be avoided, the optimization platform will analyze historical activity to select apartments that can share the channel with the fewest issues.

OFDMA

This ambitious WiFi 6 feature improves efficiency and capacity by breaking down channels into smaller frequency allocations (resource units) that are transmitted in parallel from one AP so that a single transmission can communicate with a large number of devices. This eliminates 802.11 packet overhead and time wasted, especially for transmissions involving IoT and other low-data-rate devices.

The problem is that OFDMA is only efficient when a large number of IoT devices share a single AP. This is not always the case in today’s smart homes, where networks have evolved into multi-AP topologies involving mesh networks, repeaters, or multiple gateways.

If clients were simply allowed to connect to the nearest AP, each AP would not have enough devices to group into an OFDMA transmission. However, forcing clients to connect to remote APs would result in a drop in data rates. This means that OFDMA operation will require strict optimization and client steering.

The reasons behind the OFDMA-aware client turn are complex. It requires a centralized intelligent network controller to understand which APs and clients are WiFi 6 capable, take historical observations into account, and make forward-looking predictions about each client’s data needs.

The controller then needs to make an optimized choice of which AP each device should connect to based on capabilities, traffic load, signal strength, and the device’s data usage. Finally, the controller needs to be able to steer each device—using a steering mechanism specific to that device type—and keep it on the correct AP, even if it’s not the closest AP.

Target wake-up time

Target Wake Time (TWT) improves battery life for devices that transmit only occasionally or at a low duty cycle. The AP reserves a window of time for each client to wake up, communicate quickly, and return to sleep, while keeping the reserved air time free from other communications.

In a home network, multiple APs often operate on the same channel, which means that multiple APs may try to schedule the same TWT for different devices. To avoid overlap, a cloud-based central scheduler will need to coordinate the TWT cycles of co-channel APs. In order to create an optimized TWT schedule on each AP in the home network, the scheduler needs to know the transmission requirements of all TWT clients, the shared channels between APs, which clients are connected to which AP, and the signal strength between APs and clients.

In an apartment building, the optimizer can also look at all the overlapping networks it controls and plan TWT allocations and groups throughout the building. The controller takes into account data about which apartments interfere with each other, as well as the client capabilities and load requirements of each apartment.

Handling contention between nearby access points. (Source: IEEE)

6 GHz frequency

Both low-power and high-power uses of the 6 GHz spectrum present problems. Since low-power transmissions (18dBm/63mW) cannot transmit as far or at as high a data rate, optimizing the system will require a more complex multi-AP configuration to select the appropriate network topology, frequency allocation, and customer guidance options. On the other hand, to use an automatic frequency control (AFC) system (which allows for 30dBm/1 Watt), transmissions need to avoid any channels used by nearby microwave systems. This involves communication with an intelligent controller that can look up the FCC database, take into account geographic data, calculate interference levels, and then send instructions back to the AP.

For either mode, the controller must consider factors such as client type, load, and capabilities before allocating network radio resources. Depending on the capabilities of the clients in the network, putting one of the AP's radios in the 6 GHz band is not always the best choice. For example, using a 6 GHz channel for backhaul connectivity may help with backhaul, but it may take away a high-performance radio in the AP from the 5 GHz band. As a result, high-performance clients that are not 6 GHz capable may connect at lower speeds, effectively degrading the home experience.

Cautious optimism

Home networks will continue to grow more crowded and complex. The average U.S. household already has 14.5 connected devices. Global smart device shipments are expected to grow to 1.4 billion by 2023. The timing of WiFi 6 couldn’t be better.

However, without intelligent management and optimization of home networks, WiFi 6 will not be able to live up to its promise. For this new era of connectivity to live up to its promise, the limitations of the technology need to be addressed. It’s a complex task, but with the right solutions, it’s achievable.