Patent ID: 7853258

Claim:
A method for fast call setup for originating User Equipment and a receiving User Equipment, comprising: when the originating UE starts a service sensitive to call setup delays, NAS (Non-access Stratum) of the UE informing a RRC layer whether to start fast call setup procedure, If not, the RRC (Radio Resource Control) starting RRC connection request directly, and transferring the Service Request to the CN via the air interface (UU) Initial Direct Transfer (IDT) message and interface uplink (IU) message after RRC connection is successful; otherwise, non-critically extending the RRC Connection Request message; disposing a NAS Service Request Message and Access Stratum (AS) information into the extended portion; and RNC, after receiving the extended RRC Connection Request, encapsulating the Service Request of Non-Access Stratum into IU message, and sending IU message to CN, wherein the method further comprises a connection establishment process for an originating UE and a receiving UE: for the originating UE: 1) modifying the RRC connection Request message by encapsulating the NAS Service Request message therein, and transmitting the NAS Service Request message to the CN via the RNC; 2) modifying the RRC Connection Setup message by adding RB parameters corresponding to the requested service, and the RNC then maps from RAB (Radio Access Bearer) to RB (Radio Bearer) parameters after receiving the RAB Assignment Request message, and then informs the UE to establish both the signaling channel and the service channel via the extended RRC/RB Connection Setup message; 3) after receiving the extended RRC/RB Connection Setup message, the UE configures the signaling channel and the service channel at the same time and after completing physical layer synchronization, the UE transmits a RRC Connection Setup Complete message via the dedicated signaling channel, indicating that signaling and service channel setup is successful; for the receiving UE: the connection establishment process is similar to that of the originating UE except the addition of a paging process.