Peer Reviewed Journal via three different mandatory reviewing processes, since 2006, and, from September 2020, a fourth mandatory peer-editing has been added.
Indoor location systems are the key technology to provide
the location of a human or a device in indoor space. Since
WiFi technology has been spread in various spaces, WiFi is
the practical standard to realize the indoor location systems. As
a receiver can typically find some WiFi access points (APs),
indoor location systems use multiple signals from some APs to
estimate a position. Initial systems use Received Signal Strength
(RSS) as the measurement of distance because RSS decreases
according to the distance between AP and a receiver. Recently,
more practical service using indoor location systems has been
discussed. This paper proposes an occupancy detection scheme
based on a WiFi-based indoor location system. The proposed
scheme tracks users’ smartphone devices as a human location.
The location of a human in a room is useful information to
manage human resources efficiently. Therefore, some systems
track a beacon tag to estimate the location or typical location
systems use WiFi signals from several APs to estimate a
location. As a result, the conventional systems require a special
beacon tag or special tracking application to realize the human
location system. On the contrary, the proposed system uses
users’ smartphones instead of special devices or applications. In
this situation, the proposed system must track all WiFi devices
that do not associate with a WiFi access point. Therefore WiFi
APs cannot detect all users’ devices. The proposed scheme
focuses on the WiFi signaling process to detect a user’s device
and estimates the location of a user’s device. The WiFi signal
receivers detect a probe request message from a user’s device
because a probe request message should be transmitted even if
the user’s device does not associate an AP. We have developed
a prototype system to evaluate the performance.
