Handover processing system in mobile communication system

• US 8,144,659 B2
• Filed: 07/07/2006
• Issued: 03/27/2012
• Est. Priority Date: 07/07/2005
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Yamamoto, Keiji, Kishino, Fuminori
• Primary Examiner(s): Corsaro, Nick
• Assistant Examiner(s): Patel, Mahendra
• Application Number:
  US11/482,070
• Publication Number:
  US 20070008931A1
• Time in Patent Office: 2,090 Days
• Field of Search: 455/436, 455/439, 455/445, 455/168, 455/522, 370/331, 370/401, 370/338, 370/329, 370/352
• 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 method performed by a first gateway connected to a PSTN, an IP network, and a mobile communications network including a base station arranged to receive a communication source call from a mobile terminal in the mobile communications network, in which the communication source code is retrieved in the IP network without use of the PSTN, the method comprising:

receiving at the first gateway, from the base station, a communication request relating to the communication source call, which communication source call is either a voice over Internet (VoIP) or a line exchange type and determining whether the communication request is a handover call, and

a1) on determination that the communication request is not a handover call, performing at the first gateway, without use of the PSTN, either a line exchange connection through the PSTN or a VoIP connection through the IP network depending upon the type of the communication source call;

or

a2) on determination that the communication source call is a handover call, determining, without use of the PSTN, whether the first gateway is managing the communication source call, and

b1) on determination that the first gateway is managing the communication source call, retrieving the communication source call from the first gateway wholly within the IP network and performing at the first gateway, without use of the PSTN, handover through the PSTN or the IP network depending upon the type of the communication source call, the handover being performed by the gateway itself;

or

b2) on determination that the first gateway is not managing the communication source call, determining, without use of the PSTN, whether the communication source call is being managed by another gateway connected to the gateway via the IP network, and

c1) on determination that the communication source call is not being managed by the other gateway, performing at the first gateway, without use of the PSTN, handover itself through the PSTN;

or

c2) on determination that the other gateway is managing the communication source call, retrieving the communication source call from the other gateway wholly within the IP network and performing handover at the first gateway without use of the PSTN and through the IP network by taking over management of the communication source call from the other gateway.

2. The method according to claim 1, in which adjacent and potential handover sections are identical networks, wherein:

the communication source call is retrieved by a broadcast message by designating all gateways in the IP networks as retrieval objects.

3. The method according to claim 1, further comprising:

inquiring to the gateways by a multicast message; and

wherein the communication source call is retrieved by designating gateways on a multicast network as retrieval objects.

4. The method according to claim 1, further comprising:

interrogating gateways in the IP network that are designated as retrieval objects and that cover a call area of the terminal and wherein;

the communication source call is retired by acquiring position information of the mobile terminal from a server storing position information of the terminal.

5. The method according to claim 1, further comprising:

assigning IP addresses to gateways in the IP network that are adjacent to each other in accordance with a prescribed assigning rule; and

wherein

the communication source call is retrieved by interrogating adjacent gateways that are designated as retrieval objects in accordance with the assigning rule.

6. The method according to claim 1, further comprising:

reconstructing connections to communication partners between gateways by acquiring partner information of the communication source call from the other gateway and by directly communicating in relation to call control with the other gateway by a protocol on the IP network.

7. The method according to claim 1, further comprising:

when a gateway having the communication source call, transferring a call in accordance with a call control procedure to a communication partner gateway of the handover call and a gateway of a handover destination, wherein the gateway having the communication source call is arranged preliminarily to perform transfer processing of the call.

8. The method according to claim 1, further comprising:

providing a new link for call control by a protocol on the IP network to and from a gateway having the communication source call; and

performing a handover connection by directly communicating voice communications between a gateway of a handover destination and a communication partner gateway of the other gateway is designated as an anchor to transmit/receive call control information.