  With the popularity of commercial wireless devices, the research based on RF
signal has developed rapidly in the past decade. RF signals have great
advantages in environmental perception. Wireless signals are transmitted
through the transmitter. With the propagation of these signals in the medium,
they are reflected from different objects and people in space to the receiver.
In this process, rich environmental perception information is carried. These
ubiquitous perceptual information has rich application significance and bright
prospects in the fields of indoor positioning, motion perception, behavior
recognition, human-computer interaction, fall detection, health monitoring,
smart home, search and rescue and so on. This paper will discuss and analyze
the current research results by combing some existing literature and the
research status of relevant researchers in relevant fields at this stage, so as
to understand the future development trend of RF signal based applications.
