WiFi Sensing provides a noninvasive alternative to motion detection technologies that depend on cameras, sensors, and microphones. The benefit of this new concept is that it uses all connected devices like motion sensors. Therefore, you no longer need the additional equipment to make motion-sensing a possibility.

How WiFi Sensing works

The technology detects movement by measuring and interpreting changes in radio frequency signals transmitted between connected devices. It will identify signal disruptions and determine the time and location of the activity occurring. Its advanced algorithm can differentiate between various movements like pets, fans, and human motion.

An In-Depth Look at WiFi Sensing

WiFi Sensing uses WiFi signals to operate like a short-range passive radar by measuring how they interact with movement and the environment. WiFi sensing systems can easily track locations and movement based on how the signals are reflected and deflected by pinging objects around them. By analyzing these disturbances using AI-trained models, this disturbance data of the WiFi signals can be given meaning and be classified to create intelligent solutions.

WiFi sensing technologies have become quite accurate with time. The information is collected from standard data packets, and signals used for transmitting and receiving information are from regular devices connected via a WiFi network. This technology does not require any additional specialized signals, nor does it degrade network performance or the user experience when using WiFi.

Through preliminary testing, WiFi sensing performance correlated to channel bandwidth. The larger the bandwidth, the higher the resolution. Therefore, the 6 GHz band (which has the highest bandwidth of 1200 MHz) would provide the best resolution. You can learn more about WiFi 6 GHz in our article: Why you should be excited about 6 GHz WiFi

These signals are well suited for motion detection, activity detection and recognition for human bodies, breathing rate, and even heartbeat detection through a sophisticated antenna, DSP (digital signal processing), and machine learning algorithms and techniques.

WiFi sensing technology enables security, safety, and family care services in smart home and IoT applications. It supports various features and applications such as motion detection, human activity detection, recognition and vital signs detection. We wrote a whole blog about the latter, and you should take a look: Wireless Health Monitoring – A Step Towards the Future

As with any solution, WiFi Sensing has a list of its pros and cons.

Let’s break them down:

WiFi Sensing | PROs

• • No Extra Hardware
    WiFi sensing has a clear advantage over existing solutions as it does not require additional hardware. Using existing devices like cell phones, PCs, and mesh WiFi systems, the user would only need to install the necessary software to transform their setup into one capable of WiFi sensing.
  • More Security Options
    WiFi also penetrates through walls, enabling out of line-of-sight (LOS) operations, an important consideration for security monitoring applications. Additionally, since it doesn’t rely on cameras or microphones to gather data, users don’t need to worry about invasion of their privacy.
  • Independent of Device Quality
    As long as the device meets minimal baseline performance requirements, WiFi sensing can be installed in nearly any WiFi device because the quality of service doesn’t depend on the quality of the devices used.

WiFi Sensing | CONs

Strong Algorithms Needed

WiFi sensing improves as the number of connected devices increase. However, there is more competition for bandwidth with more devices on the network, resulting in higher interference. With wireless environments continuously changing and each unique home having its own complex structure, WiFi sensing will require a solid algorithm to analyze the environment while leveraging the strength of several devices linked together. Most importantly, since each device has its purpose of use, they must prioritize their primary operation and not let that be affected because of WiFi sensing taking place. 

Performance

Accuracy, precision, and latency must be considered when determining the performance of WiFi sensing:

• • Accuracy relates to detecting motion when someone is moving or present while minimizing the number of any errors the system makes.
  • Precision relates to how the system differentiates between types of movement, including speed and direction. For example, this is important if the system is being used to monitor an elderly or vulnerable person in the event of a fall.
  • Latency is the delay between detecting a movement and reporting the event. In any motion detection solution, this needs to be measured in milliseconds rather than minutes.

The issue is that WiFi signals are vulnerable to interference that decrease performance. If the WiFi equipment acting as sensors experience heavy traffic, the depleting resources will reduce service quality.

Beyond the LOS (Line of Sight)

When discussing WiFi sensing beyond the line of sight, coverage and signal strength must be considered. WiFi sensing works best with high frequency and high bandwidth transmission. However, high frequencies have more trouble penetrating walls. This solution needs to balance bandwidth and accuracy, bring more devices into the system, or reduce the sensor’s proximity to the target.

WiFi Sensing Applications

The infrastructure commonly placed for WiFi makes this technology an attractive platform for new business opportunities, and there are several use cases for sensing capable WiFi networks:

Elderly Care

Adding sensing to an existing WiFi network protects residents’ privacy since they’re not on camera and affords them greater independence. At the same time, machine learning algorithms fed by higher-resolution detection data differentiate between someone sitting down to watch TV or accidentally falling.

Automation

Connected light fixtures, multi-room audio, and climate control systems could come alive and then fade to black as family members enter and leave rooms—all without the cost or complexity of passive infrared sensors for motion detection.

Mobile Use

The wake-on-approach and lock-on-walk-away use cases are similar in concept. Consumer electronics with WiFi radios might detect a user in proximity and switch on from standby mode. The same mechanism could lock a device when a logged-in user saunters off. Enabling both features would be a boon for the battery life and security of mobile devices.

WiFi sensing is a superior alternative to keep an eye on your children after school, caring for elderly relatives remotely, and collecting biometric measurements anonymously. We wrote about other fascinating applications of this technology in our blog What is Radio Frequency Sensing, and how it improves daily lives

WiFi sensing detects environmental changes by processing signals from the countless WiFi devices transmitting and receiving all around you. Depending on the application, those changes might include motion when there shouldn’t be any, triggering a security alert. Or if there is no movement when grandma should be up and about, a notification might get pushed to her care provider.

The technology behind WiFi sensing is relatively new, and there aren’t any standards governing its implementation. While there are other up-and-coming technologies for wireless sensing like mmWave, gaps in today’s infrastructure limit the range of what WiFi sensing can do, leaving a lot of untapped value waiting for the industry to take action upon. Our was a recent step taken towards making WiFi Sensing a reality.

Want to learn more about WiFi Security? Read more about our latest partnership with BlackDice to provide best-in-class WiFi Security for home networks.

For more information about Mercku’s Connectivity Suite, our hardware and how you can partner with Mercku, please reach out to the team at connect@mercku.com

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