Method for performing handover, user equipment, base station, and radio communication system

Abstract

Provided is a method for performing a handover from a first base station to a second base station by a user equipment that is performing a radio communication over a communication channel formed by aggregating a plurality of component carriers. The method includes a step of transmitting a handover command for a component carrier for which a handover has been approved by the second base station among the plurality of component carriers from the first base station to the user equipment and a step of trying to make an access from the user equipment to the second base station for each component carrier in response to the handover command.

1 . (canceled) 
     
     
         2 . A communication device comprising:
 a radio communication interface configured to perform radio communication over a communication channel formed by an aggregation of a plurality of component carriers, the plurality of component carriers including at least a first component carrier and a second component carrier; and   circuitry configured to:
 receive a first reference signal via the first component carrier and a second reference signal via the second component carrier; 
 transmit a first measurement report and a second measurement report to a source base station, the first measurement report being based on the first reference signal and the second measurement report being based on the second reference signal; 
 receive a first command from the source base station, the first command indicating a change of the first component carrier and the first component carrier being approved to perform handover; and 
 control handling of the plurality of component carriers according to the first command, 
   wherein the first command is sent from the source base station after a handover request with information of the plurality of component carriers, including the first component carrier and the second component carrier, is sent to a target base station.   
     
     
         3 . The communication device of  claim 2 , wherein the circuitry is further configured to perform random access to the target base station after receiving the first command. 
     
     
         4 . The communication device of  claim 2 , wherein the target base station is configured to handle component carriers in consideration of the information of the plurality of component carriers sent by the source base station. 
     
     
         5 . The communication device of  claim 4 , wherein the target base station is further configured to set component carriers in consideration of the information of the plurality of component carriers sent by the source base station. 
     
     
         6 . The communication device of  claim 2 , wherein the circuitry is further configured to:
 receive a second command from the source base station or the target base station through the radio communication interface, the second command to form one or more component carriers among the plurality of component carriers, the one or more component carriers not including the first component carrier, and   control handling the plurality of component carriers according to at least one of the first command or the second command.   
     
     
         7 . The communication device of  claim 2 , wherein the information of the plurality of component carriers includes a number of component carriers. 
     
     
         8 . The communication device of  claim 2 , wherein the information of the plurality of component carriers includes an ID of a component carrier. 
     
     
         9 . The communication device of  claim 2 , wherein the information of the plurality of component carriers includes a type of a component carrier. 
     
     
         10 . The communication device of  claim 2 , wherein the information of the plurality of component carriers includes arrangement information of a component carrier. 
     
     
         11 . The communication device of  claim 2 , wherein the information of the plurality of component carriers is a list of component carriers including the first component carrier and the second component carrier. 
     
     
         12 . A source base station comprising:
 a radio communication interface configured to perform radio communication over a communication channel formed by an aggregation of a plurality of component carriers, the plurality of component characters including at least a first component carrier and a second component carrier; and   circuitry configured to:
 transmit a first reference signal via the first component carrier and a second reference signal via the second component carrier; 
 receive a first measurement report and a second measurement report from a communication device, the first measurement report being based on the first reference signal and the second measurement report being based on the second reference signal; and 
 send a first command indicating a change of the first component carrier, the first component carrier being approved to perform handover so that the communication device can control handling of the plurality of component carriers according to the first command, after sending a handover request with information of the plurality of component carriers, including the first component carrier and the second component carrier, to a target base station. 
   
     
     
         13 . The source base station of  claim 12 , wherein the target base station is configured to handle component carriers in consideration of the information of the plurality of component carriers sent by the source base station. 
     
     
         14 . The source base station of  claim 13 , wherein the target base station is further configured to set component carriers in consideration of the information sent by the source base station. 
     
     
         15 . The source base station of  claim 12 , wherein the information of the plurality of component carriers includes a number of component carriers. 
     
     
         16 . The source base station of  claim 12 , wherein the information of the plurality of component carriers includes an ID of a component carrier. 
     
     
         17 . The source base station of  claim 12 , wherein the information of the plurality of component carriers includes a type of a component carrier. 
     
     
         18 . The source base station of  claim 12 , wherein the information of the plurality of component carriers includes arrangement information of a component carrier. 
     
     
         19 . The source base station of  claim 12 , wherein the information of the plurality of component carriers is a list of component carriers including the first component carrier and the second component carrier.