Proximity discovery, authentication and link establishment between communication mobile devices in 3GPP LTE

The present invention allows a device to discover one or more devices that are within range for a diverse communication mode. This proximity discovery may trigger the target device to begin listening to the signal from, for example, the source device or to perform any other action based on proximity discovery such as, for example, a request at the toll gate. The source device wishing to be discovered broadcasts a message containing an identifier or a representation of the identifier. This identifier may be an identifier of the target device or source device to which it is intended to be connected, its derived type, or a common security association used by the set of peers. The target device compares the broadcast identifier with a known identifier to establish proximity discovery.