Push-to-talk wireless telecommunications system utilizing a voice-over-IP network

摘要

System and method for enabling push-to-talk (PTT) private calls in a wireless communications network are described. One embodiment includes selecting a called party private identification for a private call by a calling party on a mobile device; pressing a PTT button on the mobile device; transmitting a SIP SUBSCRIBE including the calling and called parties private identifications to request a speech token; redirecting the SIP SUBSCRIBE to the PTT Server for purposes of removing the calling party and the called party from a multicast group; receiving an acknowledge message that includes a speech token; transmitting calling party information from the PTT Server to the called party; communicating speech packets from the calling party to the called party in a half-duplex manner; releasing the PTT button on the mobile device; transmitting a SIP SUBSCRIBE to release the speech token; and notifying the calling and called parties that the group's speech token is available.