Patent ID: 7920864

Claim:
A mobile communication system including an IP (Internet Protocol) core network, a mobile communication network, a switching center server and a mobile terminal, comprising: processing means of providing a plurality of services in each of said IP network and said mobile communication network for said mobile terminal, wherein said switching center server includes a function for converting a signal protocol from said mobile terminal to a SIP (Session Initiation Protocol), and said IP core network is an IMS (IP Multimedia Subsystem) network, and an SIP sequence adds a response signal for mapping a signal protocol of a service in said mobile communication network to be provided for said mobile terminal and an SIP signal of said IMS network, wherein in order to map said signal protocol and said SIP signal, if said SIP signal is determined to be a normal sequence, said response signal is added, and the switching center server that has received said response signal sends a Call Proceeding signal to said mobile terminal and confirms said normal-sequence signal.