  The Internet has grown into a large cyber-physical system centered that
connects not just computer systems but a plethora of systems, devices, and
objects, collectively referred to as "Things", giving rise to the term
"Internet of Things" (IoT). It encompasses technologies for identification and
tracking, sensing and actuation, both wired and wireless communications, and
also, intelligence and cognition. Wireless communications, which is an integral
part of IoT, suffers from radio irregularity -- a phenomenon referring to radio
waves being selectively absorbed, reflected or scattered by objects in their
paths, e.g., human bodies that comprises liquid, bone and flesh. Radio
irregularity is often regarded as a problem in wireless communications but,
with the envisioned pervasiveness of IoT, we aim to exploit radio irregularity
as a means to detect and estimate the number of people. We demonstrate how
radio signal fluctuations arising from radio irregularity, combined with
discriminant analysis, can be used to provide a simple low-cost alternative to
dedicated sensing systems for indoor people counting.
