User equipment, base station, connection establishment method, and context information retrieval method

A base station of a mobile communication system supporting a function for establishing a connection by reusing context information retained in each of user equipment and the base station, the base station comprising:

• a receiver that receives, from the user equipment that retains user equipment side context information, first identifying information for identifying a retaining base station that retains base station side context information for the user equipment and second identifying information for identifying the base station side context information;
• and
• a context retriever that transmits, to the retaining base station identified by the first identifying information, a context request message including the second identifying information, and that obtains the base station side context information that is transmitted from the retaining base station in response to the context request message.

A connection establishment method to be executed by user equipment of a mobile communication system supporting a function for establishing a connection by reusing context information retained in each of the user equipment and a base station, the connection establishment method comprising:

• a transmission step of transmitting, to the base station, first identifying information for identifying a retaining base station that retains base station side context information for the user equipment and second identifying information for identifying the base station side context information when the user equipment retains user equipment side context information;
• and
• a connection step of establishing the connection with the base station by using the user equipment side context information after the base station obtains the base station side context information from the retaining base station.

A content information retrieval method to be executed by a base station of a mobile communication system supporting a function for establishing a connection by reusing context information retained by each of user equipment and the base station, the content information retrieval method comprising:

• a reception step of receiving, from the user equipment that retains user equipment side context information, first identifying information for identifying a retaining base station that retains base station side context information for the user equipment and second identifying information for identifying the base station side context information;
• and
• a context retrieval step of transmitting, to the retaining base station identified by the first identifying information, a context request message including the second identifying information, and obtaining the base station side context information that is transmitted from the retaining base station in response to the context request message.