Method and apparatus for setting up call in mobile communication system

摘要

The time required to set up a voice call in an exemplary embodiment, in which Circuit Switched Fallback (CSFB) is used, is reduced to provide a voice call service to a User Equipment (UE) in a Long Term Evolution (LTE) system. If a voice call occurs in a UE while the UE accesses the LTE system, the UE using CSFB switches to a 2G/3G legacy system, recycles system information for a 2G/3G cell that the UE has accessed before, and immediately proceeds with voice call setup without receiving system information unnecessary for a CSFB process.

主权项

1. A method for receiving a voice call by a terminal in a mobile communication system, the method comprising:
receiving, from a base station, a radio resource control (RRC) connection release message including switching information from a first communication system based on a packet switched service to a second communication system based on a circuit switched service; switching a serving cell from a first cell of the first communication system to a second cell of the second communication system based on the switching information; receiving first information from the second cell; determining that second information is stored and a value tag included in the first information indicates that the second information has not been changed; and transmitting an RRC connection request message based on the determination, wherein the second information is previously acquired in the second communication system.