Call setup method and system for push-to-talk service in a cellular mobile communication system

摘要

A method and system for setting up a call for a Push-to-Talk (PTT) service in a cellular mobile communication system including at least two user agents, each of the user agents serving as a talker or a listener. A talker transmits a first PTT request message for starting a PTT call to a PTT server over a reverse common channel, and sets up a traffic channel to a corresponding radio access network. The PTT server transmits a second PTT request message to a listener in a dormant state over a forward common channel, and the listener sets up a traffic channel to a corresponding radio access network in response to the second PTT request message. The listener sets up the traffic channel, and transmits a PTT confirm message to the PTT server over a reverse common channel in response to the second PTT request message. The talker transmits voice packets to the listener over the set traffic channel via the PTT server.