Technique for setting up calls in mobile network

Abstract

In a technique for setting up calls in IP mobile networks, when an application level in a mobile station sends a setup message to set up a multimedia call, before sending such a message over the radio interface, the mobile station performs the appropriate procedures to setup the appropriate bearers over the radio interface and in the network to satisfy the call requirements specified by the application level in the setup message. The technique applies to both mobile originated calls and mobile terminated calls, the called mobile station performing the transport level procedures after having received a setup message and before sending a confirmation/call acceptance message back to the calling party. Furthermore, the allocation of radio resources for PDP contexts that will be used to carry the media of a multimedia IP called is delayed so that no radio resources are allocated to the PDP contexts activated before the call control signaling is exchanged. The radio resources are allocated only when the call signaling has been completed and the called party has accepted the call and indicated the call characteristics that it can support. An indication is forwarded from the SGSN to the GGSN advising that no packets are to be sent on the PDP context because there are no radio resources for the PDP context.