Handover processing system in mobile communication system

• US 20090086675A1
• Filed: 02/21/2008
• Published: 04/02/2009
• Est. Priority Date: 07/07/2005
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Kishino, Fuminori, Yamamoto, Keiji
• Granted Patent: US 8,068,480 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

1-12. -12. (canceled)

13. A gateway device which is connected to a subscriber network including a base station in a mobile communication system, a public network and an internet protocol (IP) network, the gateway device comprising:

a handover processing unit executing a handover operation when a radio terminal, in communication with a communication partner, moves between cells in the mobile communication system;

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 voice data to/from the IP network to carry out communication and call control functions for VoIP communications;

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 a handover source call is present in the same gateway or whether it is originated in another gateway device or the public network;

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

a handover source call retrieval unit retrieving the handover source call from another gateway device via the IP network;

whereby, when the handover source call originates in another gateway device the handover source call retrieval unit acquires information relating to the communication partner of the source call from said other gateway device through the IP network rather than the public network.

14. The gateway device according to claim 13, 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.

15. The gateway device according to claim 13, 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.

16. The gateway device according to claim 13, 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.

17. The gateway device according to claim 13, 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.

18. The gateway device according to claim 13, 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.

19. The gateway device according to claim 13, 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.

20. The gateway device according to claim 13, 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.

21. The gateway device according to claim 13, 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.

22. The gateway device according to claim 13, 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.