A research team led by Jason Coder at the National Institute of Standards and Technology (NIST) in Gaithersburg/Maryland uses commercially available WLAN routers to monitor the breathing of a person present in the room.
For monitoring, the researchers use the exchange of Channel State Information (CSI), i.e. the channel properties, between the router and an end device such as a smartphone or laptop. The specified signal sequence serves as feedback on the transmission quality and tells the router whether changes in the room are creating new interference that the router has to compensate for.
Jason Coder sets up a WLAN router in the anechoic room. Signal fluctuations can be used to detect breathing problems demonstrated by a medical simulation manikin.
Researchers had already shown in earlier work that they can use wireless routers to detect movements in the room and the presence of people based on signal fluctuations. In their recent publication the NIST researchers demonstrated that fluctuations in the CSI signal can even reveal a person’s respiratory problems.
To do this, they developed a deep learning algorithm called BreatheSmart. They fed this with data from a test scenario with a router, a terminal device and a medical training dummy in an anechoic room. The researchers modified the WiFi router’s firmware so that it polled CSI signals up to ten times a second. The manikin simulated normal breathing and altered respiratory rates. The researchers were able to read these frequencies and conspicuous breathing patterns from the movements of the chest with around 99 percent accuracy. Further research should help to identify specific diseases in this way.
c’t 3/2023 )
In issue c’t 3/2023 we leave the wallet at home and try out how far you can get with the digital wallet. c’t shows how cards can be digitized and which apps you can use to pay without compromising on data protection. Is Paramount+ a new storm in streaming heaven? We compare subscription video streaming services and give you an overview of the current trends. Quiet 16-inch notebooks and compact LED projectors for the cinema experience or gaming on the go are also being tested. You can read all this and much more in c’t 3/2023.
(egr)
