Handover processing system in mobile communication system

• US 20070008931A1
• Filed: 07/07/2006
• Published: 01/11/2007
• Est. Priority Date: 07/07/2005
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Yamamoto, Keiji, Kishino, Fuminori
• Granted Patent: US 8,144,659 B2
• Time in Patent Office: Days
• US Class Current: 370/331
• CPC Class Codes: H04W 36/0011 for data sessions of end-to-end connection
• CPC Class Codes: H04W 36/14 Reselecting a network or an air interface
• CPC Class Codes: H04W 8/08 Mobility data transfer
• CPC Class Codes: H04W 88/16 Gateway arrangements

Abstract

A handover processing system in mobile communication system, implemented in gateway connected to subscriber network including base station in the mobile communication system, public network and IP network and accompanied by movement of radio terminal in the mobile communication system, wherein the gateway comprises line exchanger performing line exchange processing, VoIP connection unit controlling communication function to transmit/receive IP-packetized data to make communication and call control function for the VoIP communication function, handover detector determining whether or not call originating request from the base station is handover call, communication call detector determining whether or not communication source call of handover is present, call information storage unit storing call information, handover source call retriever retrieving handover source call in IP network, and handover processor taking over communication call from communication partner to continue the communication, and performing handover processing of VoIP communication call.

Claims

1. A handover processing system in a mobile communication system, which is implemented in a gateway device connected to a subscriber network including a base station in the mobile communication system, a public network and an internet protocol (IP) network and is accompanied by a movement of a radio terminal in the mobile communication system, wherein the gateway device comprises:

a line exchange connection unit performing line exchange processing;

a voice over IP (VoIP) connection unit controlling a communication function to transmit/receive IP-packetized sound data to/from the IP network to make a communication and a call control function for the VoIP communication function;

a handover detection unit determining whether or not a call originating request from the base station is a handover call;

a communication call detection unit determining whether or not a communication source call of handover is present in its own device;

a call information storage unit storing call information including caller information, recipient information, call references and call types;

a handover source call retrieval unit retrieving a handover source call in the IP network; and

a handover processing unit taking over a communication call from a communication partner to continue the communication, and performing handover processing of a VoIP communication call by shutting it into the IP network.

2. The handover processing system in the mobile communication system according to claim 1, wherein the handover source call retrieval unit includes an adjacent gateway information storage unit managing information to determine a gateway device designated as a retrieval partner of the handover source call and determining the gateway device that is the retrieval partner on the basis of information in the information storage unit.

3. The handover processing system in the mobile communication system according to claim 1, being applied to a mobile communication system in which adjacent and potential handover sections are identical networks, wherein the handover source call retrieval unit retrieves the communication source call by a broadcast message by designating all gateway devices in the IP network as retrieval objects.

4. The handover processing system in the mobile communication system according to claim 1, wherein the handover source call retrieval unit retrieves the communication source call by designating gateway devices on a multicast network as retrieval objects and inquiring to the gateway devices of the retrieval objects by a multicast message.

5. The handover processing system in the mobile communication system according to claim 1, wherein the handover source call retrieval unit retrieves the communication source call by designating all gateway devices as retrieval objects and the gateway devices as regards the retrieval objects by a broadcast message.

6. The handover processing system in the mobile communication system according to claim 1, wherein the handover source call retrieval unit retrieves the communication source call by acquiring position information of the radio terminal from a server storing position information of the radio terminal and interrogating gateway devices that are designated as retrieval objects and cover a call area of the radio terminal.

7. The handover processing system in the mobile communication system according to claim 1, assigning IP addresses to gateway devices adjacent to each other in accordance with a prescribed assigning rule, wherein

the handover source call retrieval unit retrieves the communication source call by interrogating adjacent gateway devices that are designated as retrieval objects in accordance with the assigning rule.

8. The handover processing system in the mobile communication system according to claim 1, wherein the handover processing unit reconstructs connections to communication partners between gateway devices by acquiring partner information of the source call from the gateway device having the source call retrieved by the handover source call retrieval unit and by directly communicating in relation to call control with a retrieved partner gateway device by a protocol on the IP network.

9. The handover processing system in the mobile communication system according to claim 1, wherein The handover processing unit of a gateway device having the source call retrieved by the handover source call retrieval unit transfers a call in accordance with a call control procedure to a communication partner gateway device of the handover source call and a gateway device of a handover destination

the gateway device having the source call initiatively performs transfer processing of the call.

10. The handover processing system in the mobile communication system according to claim 1, wherein the handover processing unit provides a new link for call control by a protocol on the IP network to and from a gateway device having the source call retrieved by the handover source call retrieval unit, and performs a handover connection by directly communicating voice communications between a gateway device of a handover destination and a communication partner gateway of the source call, and the retrieved gateway device is designated as an anchor to transmit/receive call control information.

11. The handover processing system in the mobile communication system according to claim 1, wherein the handover processing unit shuts a communication partner into its own device to perform switching when it is determined by the communication call detection unit that the source call of handover is present in its own gateway device.

12. The handover processing system in the mobile communication system capable of selectively implementing the method according to any one of claims 2-7 when the handover source call retrieval unit determines that a gateway device is a retrieval partner.