Wi-Fi Motion Sensing: Transforming healthcare assistance and home security

Market Expertz   |     January 02, 2020


Since it was introduced in 1999, Wi-Fi has become omnipresent. As per the Wi-Fi Alliance, the 40 billion devices were shipped in the year 2019, just 20 years after the first. Not unpredictably, Wi-Fi is now found almost everywhere, with the latest applications being developed to serve new use cases across every market division, including enterprise, residential, and the IoT. One mainly innovative application of Wi-Fi technology, which may not be instantly apparent but has become possible, all thanks to developments in the way the technology is utilized, is motion detection.

At the same time, disturbances in the field of most forms of radio frequency (RF) technologies are likely to be utilized to detect motion, implementing it would usually need dedicated hardware. On the other hand, in most cases, no specialized or additional hardware is required in order to support motion detection with the use of Wi-Fi. Additionally, the widespread use of Wi-Fi makes it the ultimate platform for incorporating motion detection as an ‘over the top’ service. Wi-Fi motion detection works owing to the way that 5GHz RF and 2.4GHz radio waves spread and react to stationary and moving objects in their operating surroundings. Every signal path exhibits an exclusive signature as it travels through the medium (or channel), changing a little as it is reflected or absorbed by objects. Equipment that receives a Wi-Fi signal offers feedback to the source of the signal, router, or gateway (GW) and the access point (AP). This feedback has information about the channel’s aspects, in wireless communications, this is usually referred to as the Channel State Information (CSI), and it has information that let the transmitter to optimize its operation based on what the receiver ‘sees.’

The AP, GW, or router analyzes the CSI data, to recognize patterns that explain changes in the channel. More developed algorithms can then establish if the reported disruptions are caused by someone moving or entering within a Wi-Fi field. Significantly, RF propagation delays and angles can also be measured from this information, which offers the means to locate the location of the object or person.