Forwarding performance information of the user equipment methods and systems

Discloses a method for simultaneous calls for a PS service of IMS services in the circuit switched (CS) voice communications may be used for the CS and IMS services (CSI) UE using for both voice communication and PS service between the IMS UE IMS session, exchanged UE capability information method and system for communication. MGCF performs interworking of capability information between a CS message and an IMS message so that the IMS UE by an IMS session request / response to process UE capability information. When the UE capability exchange does not support the creation of a call does not include the capability information request message, CSI AS UE capability information can be transmitted after the estimated UE to the call request message into a call to the peer request message, and the UE stores each other performance information of the UE.