Patent ID: 8817778

Claim:
A session processing method, comprising: when a first User Equipment (UE) is to set up an IP Multimedia Subsystem (IMS) session with a second UE, triggering setup of an unstructured supplementary service data (USSD) transaction between a Circuit Switched (CS) network and the first UE; and sending, by using the USSD transaction, an I1 protocol (IMS Centralized Services (ICS) protocol) message used to bear IMS session control signaling; wherein the sending, by using the USSD transaction, an I1 protocol message used to bear IMS session control signaling further comprises: sending, by the first UE, a specific I1 protocol message to a SCC-AS (Service Centralization and Continuity (SCC) Application Server (AS)) by using the USSD transaction to transfer a turn of data transmission to the SCC-AS; or sending, by the SCC-AS, a specific I1 protocol message to the first UE by using the USSD transaction to transfer a turn of data transmission to the first UE.