  Location information is essential to varieties of applications. It is one of
the most important context to be detected by wireless distributed sensors,
which is a key technology in Internet-of-Things. Fingerprint-based methods,
which compare location unique fingerprints collected beforehand with the
fingerprint measured from the target, have attracted much attention recently in
both of academia and industry. They have been successfully used for many
location-based applications.From the viewpoint of practical applications, in
this paper, four different typical approaches of fingerprint-based radio
emitter localization system are introduced with four different representative
applications: localization of LTE smart phone used for anti-cheating in exams,
indoor localization of Wi-Fi terminals, localized light control in BEMS using
location information of occupants, and illegal radio localization in outdoor
environments. Based on the different practical application scenarios, different
solutions, which are designed to enhance the localization performance, are
discussed in detail. To the best of the authors' knowledge, this is the first
paper to give a guideline for readers about fingerprint-based localization
system in terms of fingerprint selection, hardware architecture design and
algorithm enhancement
