A user equipment (UE) operable to communicate in a peer to peer (P2P) network is described. The UE can encode a proximity detection request for transmission to a ProSe server in an Evolved Packet Core (EPC). The proximity detection request can include one or more of: a time period window parameter, identification information of a second UE, or a proximity detection signal indicating when the proximity detection request is for proximity detection of the second UE. The UE can decode a proximity alert message received from the ProSe server in accordance with the time period window parameter.