Proximity Discovery, Authentication and Link Establishment Between Mobile Devices in 3GPP LTE

The invention enables a device to discover one or more other devices within range for a device-to-device mode of communication. This proximity discovery may trigger a target device, e.g. to start listening to signals from a source device or perform any other action based on the proximity discovery like e.g. charging at a toll gate. A source device that wants to be discovered broadcasts a message including an identifier or a representation of the identifier. This identifier may be an identifier of the target device to be contacted or of the source device or a derivation thereof or a common security association used by a set of peers. The target device compares the broadcast identifier with a known identifier to establish proximity discovery.