Base station and communication control method

Abstract

A target base station according to one embodiment is a target base station to which a user terminal is handed over from a source base station. The target base station includes a controller configured to, when the target base station and a secondary base station perform dual connectivity communication with the user terminal accompanying the handover, notify the secondary base station of identification information related to a serving gateway connected to the target base station.

1 . A target base station to which a user terminal is handed over from a source base station, the target base station comprising
 a controller configured to, when the target base station and a secondary base station perform dual connectivity communication with the user terminal accompanying the handover, notify the secondary base station of identification information related to a serving gateway connected to the target base station.   
     
     
         2 . The target base station according to  claim 1 , wherein
 the controller is configured to perform a process of receiving a path switch response message from a mobility management device, the path switch response message indicating a data path switch from the source base station to the target base station,   the path switch response message includes the identification information, and   the controller is configured to notify the secondary base station of the identification information included in the path switch response message.   
     
     
         3 . The target base station according to  claim 1 , wherein the identification information includes at least one of an “E-RAB (Evolved-universal mobile telecommunications system terrestrial radio access network radio access bearer) ID”, a “Transport Layer Address”, and a “General packet radio service tunneling protocol-tunnel endpoint identifier (GTP-TEID)”. 
     
     
         4 . The target base station according to  claim 1 , wherein the controller is configured to, when deciding that the serving gateway connected with the target base station and a serving gateway connected to the source base station are different, notify the secondary base station of the identification information. 
     
     
         5 . The target base station according to  claim 1 , wherein the controller is configured to notify the secondary base station of information together with the identification information, the information indicating a decision result as to whether or not the serving gateway connected to the target base station is different from a serving gateway connected to the source base station. 
     
     
         6 . The target base station according to  claim 1 , wherein dual connectivity communication is dual connectivity communication of an SCG (Secondary Cell Group) bearer scheme configured to establish a bearer between the user terminal and the serving gateway without passing through the target base station. 
     
     
         7 . The target base station according to  claim 1 , wherein the handover is inter master base station handover configured to change a master base station from the source base station to the target base station without changing the secondary base station. 
     
     
         8 . A secondary base station configured to perform dual connectivity communication with a user terminal together with a target base station in a case where the user terminal is handed over from a source base station, the secondary base station comprising:
 a controller configured to perform a process of receiving, from the target base station, identification information related to a serving gateway connected with the target base station.   
     
     
         9 . The secondary base station according to  claim 8 , wherein the controller is configured to perform, based on the identification information, at least one of
 a process of establishing a data path to the serving gateway,   a process of switching a data path from a serving gateway connected to the source base station to the serving gateway connected to the target base station, and   a process of saving the identification information as context information of the user terminal.   
     
     
         10 . The secondary base station according to  claim 8 , wherein the identification information includes at least one of an “E-RAB (Evolved-universal mobile telecommunications system terrestrial radio access network radio access bearer) ID”, a “Transport Layer Address”, and a “General packet radio service tunneling protocol-tunnel endpoint identifier (GTP-TEID). 
     
     
         11 . The secondary base station according to  claim 8 , wherein the identification information is notified from the target base station when the target base station decides that the serving gateway connected to the target base station is different from a serving gateway connected to the source base station. 
     
     
         12 . The secondary base station according to  claim 8 , wherein the controller is configured to perform a process of receiving information together with the identification information from the target base station, the information indicating a decision result as to whether or not a serving gateway connected to the source base station and the serving gateway connected to the target base station are different. 
     
     
         13 . The secondary base station according to  claim 8 , wherein the dual connectivity communication is dual connectivity communication of an SCG (Secondary Cell Group) bearer scheme configured to establish a bearer between the user terminal and the serving gateway without passing through the target base station. 
     
     
         14 . The secondary base station according to  claim 8 , wherein the handover is inter master base station handover configured to change a master base station from the source base station to the target base station without changing the secondary base station. 
     
     
         15 . A communication control method comprising the steps of:
 handing over a user terminal from a source base station to a target base station; and   notifying a secondary base station of identification information from the target base station when the target base station and the secondary base station perform dual connectivity communication with the user terminal accompanying the handover, the identification information being related to a serving gateway connected to the target base station.