Method and apparatus for handover using x2 interface based on closed subscriber group in mobile communication system

Abstract

A method for handover of User Entity (UE) by a source Base Station (BS) is provided. The method includes determining whether to handover the UE using an X2 interface, transmitting a handover request message to a target BS, the handover request message including Closed Subscriber Group (CSG) information of the target BS, and receiving a handover request acknowledgement message from the target BS, wherein the determining of whether to handover the UE using the X2 interface includes, if there is the X2 interface between the source BS and the target BS, and if the target BS does not support a CSG or the target BS supports a same CSG supported by the source BS, determining to perform the handover of the UE using the X2 interface, and obtaining the CSG information of the target BS through an X2 interface set up procedure.

What is claimed is: 
     
         1 . A method for performing an X2-based handover by a first base station (BS), the method comprising:
 identifying, by the first BS, a condition to perform the X2-based handover for a user equipment (UE) from the first BS to a second BS; and   determining, by the first BS, to perform the X2-based handover based on the condition,   wherein the condition includes a first condition and a second condition to allow to perform the X2-based handover, the first condition indicating that the UE is a member of a closed subscriber group (CSG) cell, and the second condition indicating a first CSG identifier (ID) of the first BS is the same as a second CSG ID of the second BS, and   wherein the first BS is a source BS of the UE and the second BS is a target BS of the UE.   
     
     
         2 . The method of  claim 1 , wherein the condition further includes a third condition to allow to perform the X2-based handover, the third condition indicating that the first BS is an evolved node B (eNB) and the second BS is an open access home evolved node B (HeNB). 
     
     
         3 . The method of  claim 1 , wherein the second CSG ID of the second BS is obtained by performing an X2 setup procedure between the first BS and the second BS. 
     
     
         4 . The method of  claim 3 , wherein the X2 setup procedure comprises:
 transmitting, by the first BS, to the second BS, an X2 setup request message including first cell information for a first serving cell of the first BS; and   receiving, by the first BS, from the second BS, an X2 setup response message including second cell information for a second serving cell of the second BS in response the X2 setup request message,   wherein the first cell information includes a physical cell ID of the first serving cell and the first CSG ID, and   wherein the second cell information includes a physical cell ID of the second serving cell and the second CSG ID.   
     
     
         5 . A first base station (BS) for performing an X2-based handover, the first BS comprising:
 an X2 interface configured to communicate with a second BS; and   at least one processor configured to:   identify a condition to perform the X2-based handover for a user equipment (UE) from the first BS to a second BS, and   determine to perform the X2-based handover based on the condition,   wherein the condition includes a first condition and a second condition to allow to perform the X2-based handover, the first condition indicating that the UE is a member of a closed subscriber group (CSG) cell, and the second condition indicating a first CSG identifier (ID) of the first BS is the same as a second CSG ID of the second BS, and   wherein the first BS is a source BS of the UE and the second BS is a target BS of the UE.   
     
     
         6 . The first BS of  claim 5  wherein the condition further includes a third condition to allow to perform the X2-based handover, the third condition indicating that the first BS is an evolved node B (eNB) and the second BS is an open access home evolved node B (HeNB). 
     
     
         7 . The first BS of  claim 5  wherein the second CSG ID of the second BS is obtained by performing an X2 setup procedure between the first BS and the second BS. 
     
     
         8 . The first BS of  claim 7  wherein the X2 setup procedure comprises:
 transmitting, to the second BS, an X2 setup request message including first cell information for a first serving cell of the first BS, and 
 receiving, from the second BS, an X2 setup response message including second cell information for a second serving cell of the second BS in response the X2 setup request message, 
 wherein the first cell information includes a physical cell ID of the first serving cell and the first CSG ID, and 
 wherein the second cell information includes a physical cell ID of the second serving cell and the second CSG ID.