Minimized setup time for IMS multimedia telephony using pre provisioned resources reserve according to most demanding codec

摘要

Several different methods are described herein for reducing the setup time needed to establish a media flow (e.g., packet-based voice communications) between two devices (e.g., two GPRS UEs, GPRS UE/server, GPRS UE/WLAN UE). In one embodiment, the method minimizes the setup time for establishing IMS telephony using pre-provisioned resources—reserve at INVITE. In another embodiment, the method minimizes the setup time for establishing IMS telephony using pre-provisioned radio resources—reserve at ANSWER. In yet another embodiment, the method minimizes the setup time for establishing IMS telephony using pre-provisioned radio resources—reserve according to most demanding codec properties. All of these methods and in particular a UE and PS-CN may use the network initiated ISPCA-method to reduce the setup time needed to assign packet-based bearers which are required to establish the media flow.