Ibeacon is a low-energy Bluetooth technology that works similarly to the previous Bluetooth technology. Beacon transmits signals, Bluetooth devices receive positioning, and feedback signals. When the user enters, exits, or wanders in the area, Beacon's broadcast has the ability to spread. It can calculate the distance between the user and Beacon (can be calculated by RSSI). From this, we can know that as long as there are three Beacon devices, it can be located.