[debbiedowner]

The link to the wivi research is to a 2013 article, so that took a while!

I had a HW assignment in 2017 to do this, specifically we were given raw wifi signals and told to determine how many people were in the room. We did it by detecting breath rate of each person with the MUSIC spectral algorithm. For that challenge there ended up being 6 people in the room, all with slightly different breath rate (attenuating the signal as their chest expanded).