Patent ID: 8089956

Claim:
A method for implementing communications, comprising: A. an IP Multimedia Subsystem (IMS) Terminal Module (TM) in a Combining Circuit Switched bearer with IP multimedia subsystem (CSI) terminal indicating a Circuit Switched (CS) TM in the CSI terminal to initiate a CS bearer establishment; B. the CS TM taking the IMS TM as a called party and sending a call establish request to a CS domain call control function; C. the CS domain call control function routing the call establish request to a CS/IMS interworking gateway according to called party number information in the received request; D. the CS/IMS interworking gateway converting the received call establish request into an IMS session establish request, and then sending the IMS session establish request to the IMS TM; E. the IMS TM performing a correlated control between two sessions, wherein one is between the IMS TM and the CS/IMS interworking gateway, and the other is between the IMS TM and a peer side, so as to implement a CSI service; and allocating a Mobile Station International Integrated Services Digital Network (MSISDN) number for the CS TM in advance; wherein the step A further comprises the IMS TM obtaining the MISISDN number of the CS TM; the step D further comprises the CS/IMS interworking gateway obtaining the MSISDN number of the CS TM according to a calling party number in the received call establish request, and carrying the MSISDN number of the CS TM in a “From” header field in the IMS session establish request sent to the IMS TM; and before the IMS TM performing the correlated control process, the step E further comprises the IMS TM obtaining the MSISDN number of the CS TM from the “From” header field in the received IMS session establish request, judging whether the current obtained MSISDN number of the CS TM is identical with the MSISDN number obtained in step A, if they are identical, continuing with the correlated control process.