A method performed by a wireless transmit/receive unit (WTRU) may include sending, to a network, a registration message indicating the WTRU is capable of device-to-device (D2D) communication and sending a request for assistance in discovering at least one other WTRU in proximity to the WTRU. The method may include receiving, from the network, in response to the request for assistance in discovering the at least one other WTRU, assistance information including one or more of a unique identifier or filtering information. The method may include performing, using the assistance information, a device discovery procedure to discover the at least one other WTRU, wherein the device discovery procedure comprises at least one of: monitoring for signals from the at least one other WTRU using the assistance information, or sending a discovery announcement based on the assistance information and transmitting application data directly to the at least one other WTRU.