Passive Indoor Localization Using Ambient Radio Signals

[immi]

Reading http://popleteev.com/static/pdf/2012/Investigation%20of%20indoor%20localization%20with%20ambient%20FM%20radio%20stations_PerCom-2012.pdf and http://www.ubicomp.org/ubicomp2013/adjunct/adjunct/p549.pdf,
I got curious over the feasibility.

You detect scattered FM signals (on several frequencies) with a rtl-sdr every 5 minutes, and recognize which room in your house is empty.
Any hint on the topic is appreciated.