Patent ID: 7904103

Claim:
In a Push-to-Talk (PTT)-over-Cellular (PoC) system comprising a transmitting-side PoC client, a transmitting-side PoC server, a receiving-side PoC client, and a receiving-side PoC server, a method for establishing, at the receiving-side PoC client, a group session requested by the transmitting-side PoC client, the method comprising the steps of: requesting register of a service setting for receiving invitee information in the receiving-side PoC server, the invitee information comprising a list of at least one user invited to the group session; receiving a Real-Time Control Protocol (RTCP) connection message, which has been created considering the service setting, from the receiving-side PoC server; identifying the invitee information in the RTCP connection message and providing the invitee information to a user; receiving an input of whether or not establishment of the group session has been accepted from the user; and creating an RTCP response comprising the input of whether or not establishment of the group session has been accepted, and transmitting the RTCP response to the receiving-side PoC server.