1. A method for generating a virtual bearer by a mobility management entity (MME) in a wireless communication system, the method comprising:obtaining context information from any one of a home subscriber server (HSS), an evolved packet data gateway (ePDG), or a trusted wireless local area network (WLAN) access network (TWAN), wherein the context information, which includes at least one of an access point name (APN), a PDN gateway (PDN GW) identity (ID), and a quality of service (QoS) parameter, is used for a packet data network (PDN) connection generated through a Wi-Fi network;
transmitting a create session request to a serving gateway (S-GW) or a PDN gateway (P-GW) when there is no PDN connection in a cellular network mapped to the PDN connection, and there is no default bearer in the cellular network, wherein the create session request includes the context information;
generating a virtual bearer in the cellular network based on the create session request; and
transmitting establishment information for the virtual bearer to a user equipment (UE), wherein an uplink/downlink (UL/DL) bearer between the UE and the P-GW, for data to be transmitted, is generated based on the establishment information.