Enhanced interactive services for end users in IMS

The user interaction (UI) function is enhanced to the IMS service architecture by defining the data model between the UI client and the UI server, introducing the user behavior trace function (UBTF), enhancing the interface between a CSCF and a PDFE. Unlike traditional services such as Call Forwarding, Ring Back Tone, etc., which are based on an end user status and/or a pre-provisioned user profile, the services built on this extended architecture enables end users to actively and instantly intervene in session control. The user preferences will be statistically collected into the network by the UBTF based on historical user behavior, and used for future sessions. And the UBTF can also improve the user experience by changing the UI function of a service and cut down the network resource usage.