Method and apparatus for enhancing mobility for 3GPP LTE-WLAN aggregation in wireless communication system

A method for a target base station in a wireless communication system, the method comprising:

• establishing an Xw interface with a wireless local area network (WLAN) termination (WT), wherein the WT is a logical node that terminates the Xw interface, and wherein the Xw interface is also established between a source base station and the WT;
• and
• performing an inter-base station handover without WT change in which a wireless device currently connected to both the source base station and the WT is to be handed over from the source base station to the target base station while keeping connection with the WT, the inter-base station handover comprising:
• receiving, from the source base station, a handover request message including a WT identifier (ID) and WT XwAP ID;
• transmitting, to the WT, a WT addition request message including the WT XwAP ID;
• receiving, from the WT, a WT addition request acknowledge message;
• and
• transmitting, to the source base station, a handover request acknowledge message informing that the WT is kept,
• wherein the WT ID identifies the WT,
• wherein the WT XwAP ID is allocated by the WT and uniquely identifies the wireless device over the Xw interface,
• wherein the handover request message further includes a mobility set of the WT,
• wherein the mobility set is a set of one or more WLAN access points (APs) identified by one or more of a BSS identifier (BSSID), a home equivalent SSID (HESSID) or an SSID.