Wi-Fi Sensing: Is “Big Brother” Really Watching Us?

When a person, or pet, moves through a room, they cause a measurable disturbance in the wireless signals propagating through that room. Wi-Fi Sensing simply uses algorithms (mathematical calculations) to infer presence, motion, or patterns (such as when you walk across a room) based on measurements of those disturbances.

It is important to understand that this is done without cameras or microphones - it is based purely on something affecting the wi-fi signal: something existing in a space, or something that is moving within or through an environment. 

Simple Signal Analysis

One of the biggest misunderstandings about Wi-Fi Sensing is that people believe they are being surreptitiously watched and monitored for nefarious purposes. This is not the usual case.

I’m sure you have at one time or another seen a movie where a technician is looking at a sonar or radar scanner – the thing that goes around in a circle and bleeps – “Captain, they’re coming straight at us!” The technician cannot tell who or what it is, the size of the object, its color, its markings, or any significant detail about it. They can't tell for sure that it is a giant megalodon, but an educated guess might help. The equipment can detect an entity and monitor its movement (range and direction), because that’s what sonar and/or radar does.

Simply put, this is how Wi-Fi Sensing works: it detects presence and motion, but that’s it. 

So, Why is it Being Developed?

Wi-Fi Sensing facilitates a plethora of important use cases where current technology falls short.

Some important use cases:

· Security: Monitoring a space for unauthorized movement. It’s midnight on a Saturday. If the building is supposed to be empty, why is someone moving around?

· Elder Care: Detecting falls or inactivity. Has grandma gotten up to get her breakfast like she usually does at this time of day? (Moving from one room to another.) If not, is she OK?

· Energy Efficiency: Smarter management of devices (based on occupancy). Has everyone left the building? If so, the automated system can turn down the A/C and turn off the lights.

· Home Automation: (similar to Energy Efficiency at work) Turning lights off, or on, or adjusting A/C based on who, if anyone, is in the house.

· Healthcare: Potential monitoring of breathing and heart rate without attaching sensors to the body. This information can be sent to the nurse’s station, so that they can keep an eye on the patient.

This can all happen without transmitting video or audio and, for the most part, without collecting identity-related data. (Obviously, if a patient is in a healthcare setting, the devices need an identifiable baseline with which to compare readings, so that an alert can be sent if a result falls outside of a patient’s normal parameters.)

Privacy Matters

In a world where connected devices are commonplace, sometimes, it can feel as though we no longer have any privacy. “What kind of data is being collected?" "Where is my data going?” and "Can I control my own data?" These are completely reasonable questions. For a start, Wi-Fi Sensing is an “opt IN” feature. It isn’t usually, automatically, set to “on”. You have to actively enable it.

The general recommendation is that, if you are not entirely happy with the answers to your questions, don’t enable it. As we saw earlier, there are certain use cases where it can be a great help. If grandma wants to stay in her own home, rather than entering a retirement facility, this system could give her children a level of peace of mind. If she’s up and pottering around, they don’t need to worry about her.

Many Mesh wi-fi routers and smart home hubs already possess this feature. You simply have to switch it on. Through your device’s administrator interface, you can control whether (a) it is enabled, (b) what data is logged and shared, and (c) you can disable features, review data, and set permissions. Many systems that use Wi-Fi Sensing process the data locally, so no data gets sent outside your network.