“…With the popularity of mobile devices, such as smartphones, smartwatches, tablets, as well as some wearable devices, wireless localization has spawned numerous location-based services (LBS) to facilitate our daily life in the fields of emergency services, navigation, healthcare, geofence, social networking, entertainment/gaming, asset tracking, etc. [ 1 , 2 , 3 , 4 , 5 , 6 ]. For example, smartphone users can easily plan their trips using Google Maps and order a nearby taxi.…”