Patent attributes
Beacon devices transmit beacon messages that may be used to alert an application on a user device, e.g., a mobile phone, of the beacon device's proximity. Some embodiments contemplate a beacon device configured to transmit a pattern of successive beacon messages and/or Bluetooth Low Energy broadcast messages at one or more different power levels. The pattern of power levels may securely identify the beacon device. For example, the mobile phone application may confirm with a network server that the pattern agrees with the beacon device's identity. The pattern may also serve a calibration function. Where the mobile device application has knowledge of the expected power levels in the pattern, the application can infer from weaker transmissions that the beacon device is further from the mobile device. The weaker power levels may also indicate the character of the transmission environment.