Abstract: An apparatus and method for efficiently processing a dormant state in a packet service between communication networks providing the packet service using different mobile communication technologies is disclosed. This method includes disconnecting, by a multi-mode terminal, a current packet call and changing to a new serviceable mode, if a multi-mode terminal moves to a poor communication area in a dormant or preservation state occurring during a packet service. In this state, by immediately returning to a packet call reconnection state if a user performs a subsequent operation, an area in which the packet service cannot be provided can be minimized, and a communication mode in which a best communication service can be provided can be established.

Abstract: A method and apparatus for informing a plurality of terminals receiving the same Mobile Broadcast (BCAST) service of an upcoming event such as a BCAST service change in a BCAST system are provided. When receiving a notice of a notification event related to a BCAST service or an Service Guide (SG), a BCAST Subscription Management (SM), including a Notification Generation Function (NTG), creates a notification message about the notification event and sends it to a BCAST Service Distribution/Adaptation (SD/A). The BCAST SD/A sends the notification message to one terminal or a group of terminals through a Broadcast Distribution System (BDS) or an interaction network.

Abstract: A method, a terminal, and a system for establishing a Push to Talk Over Cellular (PoC) group session in a PoC network based on session initiation information, such as information regarding presence of clients to be invited or session start-up time. According to the method, Universal Resource Indicator (URI) information regarding invitation and Information Reservation Service (IRS) parameters are set up in a PoC eXtensible markup language Document Management Server (XDMS), and a PoC server is requested to provide an IRS so that a session is established.