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Why 802.11ax is Ideal for IoT

By Peter Thornycroft, Blog Contributor
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This is the sixth blog in my series about 802.11ax. The first blog explores the expected availability of 802.11ax access points and client devices. The second and subsequent blogs explore the goals and features of 802.11ax and how its new features will improve performance in different scenarios.

The next advance in Wi-Fi, 802.11ax, is fast approaching: As we seek to raise the performance bar yet again for the sixth generation of Wi-Fi (which the Wi-Fi Alliance now calls 802.11ax “Wi-Fi 6”), the traditional techniques used in 802.11n and 802.11ac – wider RF channels, more MIMO antennas, higher QAM modulation – have been pushed almost to the limit, so the new standard incorporates ideas that make it better-suited to emerging markets.

The Internet of Things (IoT) is an important new market, or markets, with new requirements. It ranges from automated factories to autonomous vehicles, smart cities and beyond, but in this blog, we will focus on in-building enterprise needs as HVAC control, environmental and occupancy sensors, security cameras, and entry and security systems become increasingly wireless. The important metrics for an IoT device in this environment are data rate, range, power consumption, security, ease of configuration, and scale. 802.11ax has new features that improve all of these performance dimensions, making Wi-Fi a more attractive choice for connecting IoT devices in enterprise environments.

More Devices, Greater Distances

Whereas the mainstream Wi-Fi application – streaming high-speed Internet signals to PCs, tablets and smartphones – requires high data rates over relatively short distances, IoT can usually use low speed connections, often in the sub-megabit range.  The new OFDMA (Orthogonal Frequency Division Multiple Access) feature allows sub-channelization to reduce the lower data rates to sub-2 Mbps, while extending the number of individual devices that can be reliably supported on an access point, into the thousands. This addresses the data rate and scale requirements of enterprise IoT.

But the connection must also work over longer distances, to ensure coverage throughout the building and beyond with good reliability. 802.11ax includes several features that extend range, both explicitly through extra redundancy in key parts of headers, and implicitly in features such as OFDMA, where range can be improved at the lower data rates.

Drive Down Power Requirements

Meanwhile, it is often impossible or inconvenient to run cabling to sensor locations, so many IoT devices are battery-powered, making power consumption a key consideration. Here, 802.11ax has several features to drive down power requirements. TWT (target wait time) allows a client device to sleep for long periods, setting a future time to wake and contact the access point. This is useful when an IoT device has few frames to send and receive at long intervals, meeting the requirement for infrequent but reliable communication.

Also, several new options in the specification are intended to drive a new product line of small-footprint, limited-function chips targeted for the IoT market, designed to achieve the lowest power consumption needed to meet the IoT performance envelope.

Since most IoT devices are headless with no keypad or display, fast, bulk configuration for connectivity and security are important requirements. While not part of the 802.11ax standard, the Wi-Fi Alliance has a new certification, “Easy Connect” that incorporates QR-code scans and other simple identifiers in a cryptographically-secure protocol.

The enterprise and smart-building IoT markets are still evolving, as sensor vendors experiment with different system approaches, seeing which are best-suited to enterprise needs. Connectivity is a small but important part of the overall IoT system, and these changes in 802.11ax are intended both to enable new IoT applications, broadening the use cases for IoT, and also to make Wi-Fi a more attractive choice when compared to the other IoT wireless protocols used in enterprise applications: BLE (Bluetooth Low-Energy) and Zigbee.

In today’s equipment, Wi-Fi already offers the highest data rates and excellent security, but with limited range and complex configuration, while the other technologies are not, in practice, as secure, but are less expensive to incorporate into sensor hardware, and – most important – have low enough power consumption to run on button cells for many months or years. 802.11ax allows Wi-Fi to narrow these gaps in the system envelope, extending its applicability in the IoT ecosystem.

 

Related 802.11ax Content

When Will We Be Able to Purchase 802.11ax Access Points and Client Devices

Goals and Key Features of 802.11ax

Why OFDMA is a Magical Feature in the 802.11ax Standard

How 802.11ax Improves the Experience for Everyone

Extending Network Capacity in Enterprise WLANs with 802.11ax

Technical Deep Dive: 802.11ax Whitepaper

Tags:

  • 11ax
  • IoT
  • Peter Thornycroft