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Wi-Fi Sensing: The Next Big Wireless Movement

Jan. 18, 2022
Wi-Fi can do more than just communication—it has the power to improve our lives through meaningful applications. Origin Wireless CEO Dr. Ray Liu talks with Editor Bill Wong about Wi-Fi Sensing technology and its vast potential.

This article appeared in Electronic Design and has been published here with permission.

What you’ll learn:

  • How Wi-Fi Sensing technology is influencing the future of the Wi-Fi ecosystem.
  • How Wi-Fi Sensing works.
  • How the 802.11bf Wi-Fi standard could lead to broader adoption of the technology.

The applications of Wi-Fi and wireless technology are rapidly evolving, and scientists have developed new ways to make sense of Wi-Fi signals. This is called Wi-Fi Sensing. You may soon see this new functionality in your security systems, your health at home monitoring, your cars, and the IoT devices you use daily. I caught up with Dr. Ray Liu, Founder and CEO of Origin Wireless, to discuss Wi-Fi sensing technology in depth.

What is Wi-Fi Sensing?

Wi-Fi Sensing technology harnesses Wi-Fi signals to sense activities and interpret movement. The technology applies AI capabilities to make sense of Wi-Fi signals, called “channel state information (CSI),” to perform the sensing. Some sensing capabilities include basic motion detection, motion localization, presence detection, speed/velocity measurement, breathing detection, sleep monitoring, and daily activity monitoring.

How does Wi-Fi Sensing work?

Wi-Fi Sensing uses the Wi-Fi signals that exist in a home or building. Much like a pool of water waves, when a person or object crosses the pool of radio waves of a wireless device or other Wi-Fi-enabled IoT devices, Wi-Fi Sensing technology can sense the disruption and use the information to determine the size, speed, and location of the disruption.

The 802.11bf Wi-Fi standard provides a set of back-and-forth signaling protocols to set up Wi-Fi stations that, if done right, can be used to establish a Wi-Fi Sensing network. It turns out that every time a data packet is sent over the air via Wi-Fi, the Wi-Fi devices compute CSI of the wireless channel to overcome interference from the environment so as to decode the data packet properly.

While the CSI is designed primarily for data communication, in recent years we discovered that to overcome the interference due to the surrounding object movements and changes, the CSI actually captures a huge amount of information of the environment. So, in a nutshell, we perform Wi-Fi sensing by “decoding” the information hidden in the CSI. Companies like Origin apply AI on the CSI to achieve a vast array of sensing tasks.

For example, when there’s motion in the surrounding area, there will be considerable amount of “perturbation” to the CSI. So, in Wi-Fi Sensing, we detect motion by monitoring the amount of perturbation over time. A significant instantaneous fluctuation of CSI suggests an object moving over space.

While the basic idea is simple, in practical systems, we need to overcome many challenges such as what if (1) the object is very small, or (2) the motion is very slow, or (3) the object is very far away, or (4) there’s pet motion that I want to ignore, etc. All of these add to the fun and the never-ending quest for perfection in Wi-Fi Sensing. 

What are the current applications of this technology?

One application of Wi-Fi Sensing technology is in home security. Wi-Fi Sensing has revolutionized the DIY home security space by offering a highly accurate, affordable solution that covers more ground than competing security technology with far fewer false alarms.

With in-depth understanding of the many challenges in practical systems, Origin has developed a series of effective measures to contain and overcome the challenges enabling our solutions to possess extraordinary performance. In our collaboration with some professional security service providers, our home security solutions undergo long-term professional field tests and are verified to be game-changing—being highly accurate in real applications without the need of professional hardware sensors and associated tedious professional installation.

Amidst reports of security camera hacks, Wi-Fi Sensing home security products are the perfect balance of security and privacy, providing users with the peace of mind that they will not be hacked and watched.

Wi-Fi Sensing technology is most prominent when applied in the health-at-home space, with specific use in elder care. Without the use of wearables, Wi-Fi Sensing allows caregivers to monitor elderly loved ones without infringing on their privacy or sense of independence.

Although adherence to wearable health monitors can be low among those above 65, it will not be a problem for Wi-Fi Sensing. Instead, Wi-Fi Sensing provides a highly attractive alternative to detect falls, breathing rates, and abnormal behaviors, alerting caregivers of these activities, which could prevent serious injury.  

What are the potential future applications of Wi-Fi Sensing? What industries are most likely to adopt this technology?

The potential applications of Wi-Fi Sensing are vast. The health applications, which are currently limited to at-home use, are likely to expand to clinical settings and care facilities. We expect the use cases to move beyond elder care to include other types of patient monitoring within broader healthcare environments.

The automotive industry also is likely to adopt Wi-Fi Sensing technology to alert car owners when they’ve left children in the backseat, which can be an extremely dangerous problem. The building/property management industry could benefit significantly from integrating Wi-Fi Sensing technology that can be used for security purposes and energy-saving light/HVAC automation.

We also will very likely see Wi-Fi Sensing adopted by more IoT and smart-home devices, since it has broad application potential in automation triggered by human presence.

What are some common myths around Wi-Fi Sensing?

One of the most common myths around Wi-Fi Sensing is that it can’t be used for fall detection. In truth, when advanced AI technology (like that of Origin) is applied to the channel state information provided by 802.11bf, we can achieve many functionalities, including motion detection and speed/velocity measurement, which combine to accurately detect a fall.

What’s more, once a fall is detected, the AI can detect breathing, and alert caregivers and medical professionals of the urgency of the situation. And, we are especially glad to report that our fall detection accuracy can be significantly higher than the current state-of-the-art commercial fall detection systems.

Another common myth is that Wi-Fi Sensing isn’t secure because it exists in a “hackable” wireless ecosystem. Privacy and protecting personal information are top concerns of all companies in the Wi-Fi Sensing space, especially as its applications expand. The technology remains a far more secure solution than security cameras and common legacy security systems. That’s because although a hacker can watch video streams, CSIs to a hacker are simply garbage. Only Origin’s analytic algorithms can make sense of CSIs.

Lastly, there are a few misconceptions about how 802.11bf and Wi-Fi Sensing work on a technical level. 802.11bf provides raw material and Wi-Fi signal measurement information, but it doesn’t perform any of the math or motion interpretation on its own. The actual computing and machine-learning methods are carried out by Wi-Fi Sensing companies using proprietary techniques.

How can Wi-Fi Sensing be used to improve people’s lives?

Wi-Fi Sensing has the potential to transform people’s lives. The technology can provide protection through home security; it can save lives in the health sector by detecting/predicting abnormal behaviors, which could reduce injuries; it can prevent the harm that comes from leaving a child in a vehicle; it can contribute to a more sustainable future by reducing energy use in homes and buildings through automation.

What do you see for the future of Wi-Fi Sensing, and how does it impact the greater Wi-Fi ecosystem?

Origin, along with many leaders in the Wi-Fi ecosystem, views Wi-Fi Sensing as the next big movement in wireless technology. My team is working with the IEEE 802.11bf task force to ensure that the next Wi-Fi standards include Wi-Fi Sensing provisions, which would mean that all Wi-Fi -equipped devices would be developed with built-in Wi-Fi Sensing enabling technology and features, to rapidly open up application opportunities.

In the near future, Wi-Fi Sensing will influence changes in the greater Wi-Fi ecosystem and impact the way we interact with our connected devices. With the brand new dimension of Wi-Fi usage, we expect the Wi-Fi ecosystem to flourish and expand even more than what it is today.

I look forward to seeing powerful Wi-Fi Sensing make a big difference in people’s lives worldwide.

Dr. Ray Liu is a world leader in signal processing for wireless sensing and communications, both as a trailblazer and an entrepreneur. He is a Distinguished University Professor of University of Maryland, College Park, where he is Distinguished Scholar-Teacher and Christine Kim Eminent Professor of Information Technology. As the founder and President of Origin Wireless that pioneers wireless AI for wireless sensing and indoor tracking (with over 100 patents filed or granted), he led the team winning the prestigious 2017 CEATEC Grand Prix and the CES 2020 Innovation Award.

Dr. Liu is a recipient of two IEEE Technical Field Awards: the IEEE Fourier Award for Signal Processing and the IEEE Leon K. Kirchmayer Graduate Teaching Award, IEEE Signal Processing Society Technical Achievement Award, IEEE Signal Processing Society 2014 Society Award for “influential technical contributions and profound leadership impact,” and over a dozen best paper/invention awards. Recognized as a Web of Science Highly Cited Researcher, he is a Fellow of IEEE, AAAS, and the U.S. National Academy of Inventors. Dr. Liu was IEEE Vice President, Technical Activities, President of IEEE Signal Processing Society, and Editor-in-Chief of IEEE Signal Processing magazine.

About the Author

William G. Wong | Senior Content Director

I am Editor of Electronic Design focusing on embedded, software, and systems. As Senior Content Director, I also manage Microwaves & RF and I work with a great team of editors to provide engineers, programmers, developers and technical managers with interesting and useful articles and videos on a regular basis. Check out our free newsletters to see the latest content.>

You can send press releases for new products for possible coverage on the website. I am also interested in receiving contributed articles for publishing on our website. Use our template and send to me along with a signed release form. 

Check out my blog, AltEmbedded on Electronic Design, as well as his latest articles on this site that are listed below. 

You can my social media via these links:

I earned a Bachelor of Electrical Engineering at the Georgia Institute of Technology and a Masters in Computer Science from Rutgers University. I still do a bit of programming using everything from C and C++ to Rust and Ada/SPARK. I do a bit of PHP programming for Drupal websites. I have posted a few Drupal modules.  

I still get a hand on software and electronic hardware. Some of this can be found on our Kit Close-Up video series. You can also see me on many of our TechXchange Talk videos. I am interested in a range of projects from robotics to artificial intelligence. 

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