PROCÉDÉ DE PASSAGE D'UN NGS À UN EPS DANS UN SYSTÈME DE COMMUNICATION SANS FIL ET APPAREIL ASSOCIÉ

摘要

A method for moving user equipment (UE) from a next generation system (NGS) to an evolved packet system (EPS) in a wireless communication system comprises: by the UE, a step of determining to move to the EPS; and a step of transmitting a radio resource control (RRC) connection request and an attach request to the EPS. In the method for moving from the NGS to the EPS, if the UE has an ongoing voice call when determining to move to the EPS, the UE maintains the ongoing voice call by performing at least one of an access class barring (ACB) execution or a transmission of ongoing voice call related information by using "ongoing voice call" call type information.