METHOD FOR EXCHANGING INFORMATION REQUIRED FOR CSI SERVICE

摘要

A method for exchanging necessary information for a CSI(Combination of CS(Circuit Switched) and IMS(IP Multimedia Subsystems)) service is provided to prevent a waste of radio resources by exchanging radio environment information and IMS status information in setting up a CS bearer in order to prevent IMS bearer setup procedures from being unnecessarily executed. A UE comprises a communication module(101), a storage unit(102), and a controller(103). The communication module(101) transmits and receives radio environment information and IMS status information in setting up a CS bearer. In case IMS status is changed after CS bearer setup or the UE(100) moves to a dead-service area for an IMS service, the communication module(101) transmits changed IMS status and radio environment information through UUS-3 protocol. The storage unit(102) stores the other party's radio environment information and IMS status information. The controller(103) controls the communication module(101) and the storage unit(102).