Patent ID: 8401004
Filing Date: 2013-03-19
Classification: H04L,H04W

Abstract:
1. A terminal capable of providing a circuit switched (CS) service, a session initiation protocol (SIP)-based service, or a CSI service which is a combination of the CS service and an IP multimedia subsystem (IMS), the terminal comprising: a controller configured to receive a terminal capability version of at least one target terminal, to compare the received terminal capability version with a previously stored terminal capability version of the at least one target terminal, and to determine whether to request for terminal capability information of the at least one target terminal based on the comparison result, wherein the terminal capability version identifies a version of capabilities of the at least one target terminal, wherein the controller receives the terminal capability version of the at least one target terminal from the at least one target terminal during a CS call set-up or an IMS session set-up, wherein if the received terminal capability version of the at least one target terminal is different from the previously stored terminal capability version of the at least one target terminal, then the controller requests for terminal capability information of the at least one target terminal, wherein the controller requests for the terminal capability information of the at least one target terminal by using a SIP (Session Initiation Protocol) OPTIONS message, wherein if the received terminal capability version of the at least one target terminal is the same as the previously stored terminal capability version of the at least one target terminal, then the controller does not request the terminal capability information of the at least one target terminal from the at least one target terminal, and proceeds with a CS or IMS process, wherein the terminal capability version of the at least one target terminal has a value in a UCV-XX (UE capability version-XX) form where XX is a 2-digit hexadecimal number, wherein the at least one target terminal includes a second terminal and a third terminal for selectively exchanging their terminal capability information with the controller, and the third terminal is designated by the second terminal to communicate directly with the terminal based on forward function setting information, wherein when the controller transmits a setup request message intended for the second terminal based on the forward function setting information, the third terminal receives the setup request and transmits a terminal capability version of the third terminal to the controller, wherein the controller compares the received terminal capability version of the third terminal with a stored terminal capability version of the third terminal, and determines whether to request for terminal capability information of the third terminal based on the comparison result, wherein the controller requests for the terminal capability information of the third terminal, if the received terminal capability version of the third terminal is different from the stored terminal capability version of the third terminal, and wherein the controller does not request the terminal capability information and proceeds with carrying out a requested service, if the received terminal capability version of the third terminal is the same as the stored terminal capability version of the third terminal.