Access gateway device and tracking area identifier notification method

• US 8,548,489 B2
• Filed: 10/29/2007
• Issued: 10/01/2013
• Est. Priority Date: 10/31/2006
• Status: Expired due to Fees

• Current Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Original Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Inventors: Iwamura, Mikio, Ishii, Minami
• Primary Examiner(s): BEAMER, TEMICA M
• Application Number:
  US12/446,006
• Publication Number:
  US 20100323705A1
• Time in Patent Office: 2,164 Days
• Field of Search: 455/440, 455/436, 455/456.1, 455/438, 455/439, 455/422.1
• US Class Current: 455/456.1
• CPC Class Codes: H04W 60/00 Affiliation to network, e.g. registration; Terminating affiliation with the network, e.g. de-registration
• CPC Class Codes: H04W 88/16 Gateway arrangements

Abstract

An access gateway device is disclosed that is used in a mobile communication system and that is capable of storing an identifier of a tracking area in which a mobile station in communication is located. The access gateway device includes a table unit storing a table having a corresponding relationships between a tracking area and a base station managing a cell included in the tracking area; a tracking area identifier comparison unit referring to the table at a predetermined timing, detecting the identifier of the tracking area in which the mobile station is located, and comparing the detected identifier of the tracking area with the stored identifier; and a tracking area identifier notification unit notifying the mobile station of the detected identifier of the tracking area when the detected identifier of the tracking area is different from the stored identifier based on a result of the comparison.

Claims

1. An access gateway device comprising:

a storage unit configured to store an identifier of a tracking area where a mobile station is located;

a table unit configured to store a table having a corresponding relationships between the tracking area and a base station managing a cell included in the tracking area;

an acquisition unit configured to, when the mobile station in an active mode performs handover to a handover destination, acquire the identifier of the tracking area corresponding to the base station of the handover destination based on the table;

a tracking area identifier comparison unit configured to compare the identifier of the tracking area where the mobile station in the active mode is located, the identifier of the tracking area being stored in the storage unit, with the identifier of the tracking area corresponding to the base station of the handover destination, the identifier of the tracking area being acquired by the acquisition unit; and

a tracking area identifier notification unit configured to notify the mobile station in the active mode of the identifier of the tracking area corresponding to the base station of the handover destination when the identifier of the tracking area where the mobile station in the active mode is located, the identifier of the tracking area being stored in the storage unit is different from the identifier of the tracking area corresponding to the base station of the handover destination, the identifier of the tracking area being acquired by the acquisition unit, based on a comparison result by the tracking area identifier comparison unit.

2. The access gateway device according to claim 1, wherein

the tracking area identifier comparison unit is configured to compare the identifier of the tracking area where the mobile station in the active mode is located, the identifier of the tracking area being stored in the storage unit, with the identifier of the tracking area corresponding to the base station of the handover destination, the identifier of the tracking area being acquired by the acquisition unit, when the base station of the handover destination sends a request to switch a routing path for the mobile station in the active mode.

3. The access gateway device according to claim 2, further comprising:

an updating unit configured to update the identifier of the tracking area stored in the storage unit based on the identifier of the tracking area of the moving station in the active mode notified by the tracking area identifier.

4. The access gateway device according to claim 1, wherein

the storage unit is configured to store the identifier of the tracking area where the moving station in the active mode is located when a mode of the moving station is transited from an idle mode to the active mode, the acquisition unit is configured to, when a connection with the moving station in the active mode is to be released, acquire the identifier of the tracking area where the moving station in the active mode is located from the table before the connection to the moving station in the active mode is released, and

the tracking area identifier comparison unit is configured to compare the identifier of the tracking area acquired by the acquisition unit with the identifier of the tracking area where the moving station in the active mode is located, the identifier of the tracking area being stored in the storage unit.

5. The access gateway device according to claim 4, wherein

when the comparison result by the tracking area identifier comparison unit indicates that the identifier of the tracking area where the moving station in the active mode is located, the identifier of the tracking area being acquired by the acquisition unit, is different from the identifier of the tracking area where the moving station in the active mode is located, the identifier of the tracking area being stored in the storage unit, the tracking area identifier notification unit is configured to notify the moving station in the active mode of a release command including the identifier of the tracking area acquired by the acquisition unit.

6. The access gateway device according to claim 1, wherein

when each mobile station is managed by at least one access gateway device,

a determination is made that managing a first mobile station is switched from another access gateway device to the access gateway device,

the identifier of the tracking area where the first mobile station is located is notified to the access gateway device, and

based on a relocation completion notification is sent from a home location register, the acquisition unit is configured to acquire the identifier of the tracking area where the first moving station is located from the table, and

the tracking area identifier comparison unit is configured to compare the identifier of the tracking area acquired by the acquisition unit and the identifier of the tracking area notified from the other access gateway device.

7. A tracking area identifier notification method performed in an access gateway device used in a mobile communication system in which one or more tracking areas each having one or more cells are provided, the method comprising:

a storage step of storing an identifier of a tracking area where a mobile station is located;

a tracking area identifier acquisition step of, when the mobile station in an active mode performs handover to a handover destination acquiring the identifier of the tracking area corresponding to the base station of the handover destination based on a table having a corresponding relationship between the tracking area and a base station managing a cell included in the tracking area;

a tracking area identifier comparing step of comparing the identifier of the tracking area where the mobile station in the active mode is located, the identifier of the tracking area being stored in the storage unit, with the identifier of the tracking area corresponding to the base station of the handover destination, the identifier of the tracking area being acquired by the acquisition unit; and

a tracking area identifier notifying step of notifying the mobile station in the active mode of the identifier of the tracking area corresponding to the base station of the handover destination when determining that the identifier of the tracking area where the mobile station in the active mode is located, the identifier of the tracking area being stored in the storage step is different from the identifier of the tracking area corresponding to the base station of the handover destination, the identifier of the tacking area being acquired in the tracking area identifier acquisition step, based on the comparison result by the tracking area identifier comparison unit.