ACCESS GATEWAY DEVICE AND TRACKING AREA IDENTIFIER NOTIFICATION METHOD

• US 20100323705A1
• Filed: 10/29/2007
• Published: 12/23/2010
• Est. Priority Date: 10/31/2006
• Status: Active Grant

• 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
• Granted Patent: US 8,548,489 B2
• Time in Patent Office: Days
• US Class Current: 455/440
• 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 that is used in a mobile communication system in which one or more tracking areas each having one or more cells are provided 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 comprising:

a table unit configured to store 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 configured to refer to the table at a predetermined timing, detect the identifier of the tracking area in which the mobile station is located, and compares the detected identifier of the tracking area with the stored identifier; and

a tracking area identifier notification unit configured to notify 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.

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

when the mobile station moves from a cell managed by a handover source base station into a cell managed by a handover destination base station, and if the handover destination base station sends a request to switch a routing path for the mobile station, the tracking area identifier comparison unit compares the detected identifier of the tracking area with the stored identifier.

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

the stored identifier of the tracking area is updated to the notified identifier of the tracking area.

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

when the mobile station goes into an active mode from an idle mode,

the identifier of the tracking area in which the mobile station is located is stored,

a determination is made that a connection with the mobile station is to be released, and

before a process of the releasing the connection with the mobile station is performed, the tracking area identifier comparison unit detects the identifier of the tracking area in which the mobile station is located, and compares the detected identifier of the tracking area with the stored identifier.

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

the tracking area identifier notification unit notifies a release command including the identifier of the tracking area.

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 mobile station is switched from the other access gateway device to the access gateway device,

the identifier of the tracking area stored in the other access gateway device is notified to the access gateway device, and

after a relocation completion notification is sent from a home location resister, the tracking area identifier comparison unit compares the detected identifier of the tracking area with the noticed identifier of the tracking area.

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 the steps of:

a storing step of storing an identifier of the tracking area where a mobile station in communication is located;

a tracking area identifier detecting step of referring to a table at a predetermined timing, the table having a corresponding relationships between a tracking area and a base station managing a cell included in the tracking area, and detecting the identifier of the tracking area where the mobile station is located; and

a tracking area identifier comparing step of comparing the detected identifier of the tracking area with the stored identifier; and

a tracking area identifier notifying step of 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.