The same fingerprinting strategy was used for both BLE and WiFi signals.  Offline data was gathered by measuring RSSI values obtained from Android devices placed at predetermined and measured locations.  At these locations, the smartphones monitored the signal strength of the iBeacons and WiFi access points.  After 10 seconds, the data was saved for fingerprint processing.  In this experiment, a fingerprint is determined by the median value of RSSI at each location for each BLE beacon and WiFi access point the device can hear.