A system, method, and computer readable medium for processing a call setup in a network system are provided. A femtocell system receives a call origination from a user equipment located within a service area of the femtocell system and performs a service connection with the user equipment. The femtocell system creates a connection for an Internet Protocol Multimedia Subsystem core network, transmits an INVITE message to a called telephone device via the Internet Protocol Multimedia Subsystem, and completes the call setup between the user equipment and the called telephone device.