“…In this modality, different devices or sensors, provided with the BLE interface and placed in a structured environment, are programmed to send broadcast messages (described in Section 2.2.1 ) so that listener devices (e.g., user’s mobile device) can receive them. In this way, it is possible to send some pieces of information about the surrounding area [ 25 ], or to detect the user position [ 26 , 27 , 28 , 29 , 30 , 31 , 32 ], or to measure the distance between sensor devices in the environment [ 33 , 34 ], or also to detect the presence of devices, and so people [ 22 , 24 , 35 , 36 , 37 , 38 ]. Moreover, thanks to its versatility and low power consumption, BLE has also been applied in Internet of Things (IoT) technologies [ 39 ], for example transmitting Internet Protocol Version 6 (IPv6) packets over Low power Wireless Personal Area Networks [ 40 , 41 , 42 ] (6LowPAN) in health monitoring application [ 43 ].…”