Blue Planet Studio - stock.adobe

Guest Post

Top 5 considerations of IoT Wi-Fi interoperability testing

Wi-Fi interoperability is an essential component of successful IoT device design. Avoid operational errors and test security modes, radio options and 802.11 functionality.

Jason WallsGuest Contributor

Published: 01 Mar 2022

Wi-Fi interoperability is critical given the technology's use in IoT devices. Connectivity issues are among the most cited problems when consumers complain about their IoT and smart home devices.

Wireless technology is essential for IoT realization. Many smart home products can be -- and are -- hard-wired into a home or utility's network infrastructure, but the vast majority use wireless connectivity in one form or another. Wireless connectivity for the IoT includes different options such as ZigBee/Thread, Zwave, Bluetooth, 5G and Wi-Fi; a smart home may simultaneously use many of these wireless standards.

Wi-Fi is probably the most ubiquitous wireless technology available in the home and the business. More offerings are turning towards all-IP networks for IoT and smart home device communication, regardless of wireless technology.

Wi-Fi is designed to be flexible and adaptable to IoT configuration demands. Because of this, however, the number of any Wi-Fi deployment options and features are vast, which requires devices to support almost any operation mode and creates a high chance of interoperability issues.

With home networks, IoT manufacturers need assurance that their products will work reliably in as many different scenarios as possible. Consumers are not networking experts, and home network composition and performance is unpredictable.

If a customer buys a product and it does not work with their 802.11g network with poor coverage and outdated security, odds are that the customer blames the manufacturer. This is bad for IoT manufacturers and the industry overall and is why testing is so important.

Ensure quality Wi-Fi connectivity in IoT products through testing

It can get complex very quickly to test for these issues across the spectrum of Wi-Fi types and deployment options; testing automation is the best way to ensure a quality product and a successful end-user experience.

Here are five things to consider during product testing, development and lifecycle management.

1. Test over different security modes

Wi-Fi supports many security suites, such as WEP and WPA/2/3, that have evolved over time. When you add mixed modes, this creates complex interoperability scenarios that can affect all connectivity layers.

The Wi-Fi network devices that IoT products interact with could realistically be from any Wi-Fi generation, so it's important to make sure that the devices work using any or all these security modes. Even Wired Equivalent Privacy (WEP), a weak form of Wi-Fi security, is found in legacy deployments.

Since security suites affect product performance at all layers, consider security mode as the baseline variable for automated testing iterations. Exercise API calls and system stability over all security modes provide a comprehensive picture of the product's performance.

2. Test all radio options

Wi-Fi routers and access points can operate in the 2.4, 5 and 6 GHz (with Wi-Fi 6E) spectrum range. With band steering, 802.11 radios dynamically select which frequency band provides the best connectivity, which can be a source of interoperability issues.

Wi-Fi radios select a given channel for transmission within a given radio frequency band. This involves many options, including channel width in Mhz (20, 40, 80, 160, 80+80) and the number of spatial streams used. This also depends on regional regulations, spectrum availability and allowed transmission power.

The unpredictability of how a product interacts with Wi-Fi routers and access points in the field means that the quality assurance process should test every radio option.

3. Test 802.11 association and disassociation

IoT device designs are mobile and move around a network where they might disconnect and connect to different access points. They also can go into a low power mode when they are not needed.

This all means that a device's ability to go through the 802.11 association and disassociation processes quickly and successfully is critical to overall performance. Ultimately, testing association/disassociation helps prove that a device can come back after losing connectivity and become fully capable, functioning and secure.

4. Test your product's long-term stability

Basic connectivity and application performance are important to IoT product quality. The problems that can affect user experience the most are also the hardest to catch. This makes it important to test how well a device handles being active and on a Wi-Fi connection for long periods of time.

Association and dissociation are some of the most useful features to exercise long-term stability. To test these features, engineers can automatically perform many on/off flaps of the connection in a short period of time. This can illustrate memory leaks or fragmentation that builds up and causes devices to significantly decrease performance or become unusable altogether.

Additionally, physical tests that frequently power a device off and on over long periods stress the device and uncover stability issues.

5. Prepare for legacy technologies

Consumer or enterprise IoT products must contend with legacy Wi-Fi routers and access points that still exist in the field. Many of them only support older Wi-Fi versions as well as outdated and insecure security modes. Testers should ensure products still work when they connect to legacy products.

Automation is key

With so many possible connectivity and security combinations, the number of Wi-Fi tests teams should run against IoT products can become very large, very quickly. Moreover, problems that are uncovered in real-world deployment are difficult to replicate in a short period of time without automated testing abilities.

Building these tests into the overall development process with automation will allow teams to exercise all aspects of Wi-Fi connectivity and build greater confidence in IoT products.

About the author

Jason Walls is director of technical marketing at QA Cafe, developers of quality test and analysis solutions for networks and networking products. A protocol geek at heart, he's been involved with computer networking technologies for over 20 years and helps drive industry standards and open source projects for broadband, enterprise and consumer networks.