MOBILE CONTROL DEVICE AND HANDOVER CONTROL METHOD

• US 20100232394A1
• Filed: 05/26/2010
• Published: 09/16/2010
• Est. Priority Date: 12/27/2005
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Tajima, Yoshiharu, Ohta, Yoshiaki, Kawabata, Kazuo
• Granted Patent: US 9,055,494 B2
• Time in Patent Office: Days
• US Class Current: 370/331
• CPC Class Codes: H04W 36/0072 of resource information of target access point
• CPC Class Codes: H04W 36/02 Buffering or recovering information during reselection ; Modification of the traffic flow during hand-off
• CPC Class Codes: H04W 36/026 Multicasting of data during hand-off
• CPC Class Codes: H04W 36/08 Reselecting an access point
• CPC Class Codes: H04W 36/18 for allowing seamless reselection, e.g. soft reselection
• CPC Class Codes: H04W 36/28 involving a plurality of connections, e.g. multi-call or multi-bearer connections
• CPC Class Codes: H04W 80/04 Network layer protocols, e.g. mobile IP [Internet Protocol]
• CPC Class Codes: H04W 88/14 Backbone network devices
• CPC Class Codes: H04W 92/12 between access points and access point controllers

Abstract

The present invention is a handover control method in a mobile communication system that performs handover control by switching base stations that communicate with a mobile terminal as the mobile terminal moves. In this handover control method, a mobile control device selects one or more handover base station candidates based on the communication state, and based on the communication capabilities of the handover base station candidates, decides a transmission rate for multicasting communication data, and transmits communication data to each of the handover base station candidates at the decided transmission rate, and a handover base station candidate that is decided as a handover base station sends the saved multicast communication data to the mobile terminal.

Claims

1. A base station in a mobile communication system that performs handover control by changing base station that communicates with a mobile terminal as the mobile terminal moves, and comprising:

a handover base station candidate decision unit that selects one or more handover base station candidates based on the communication state during communication with a mobile terminal;

a multicast unit that transmits communication data that is to be transmitted from its own base station to the mobile terminal, to the handover base station candidates under respective transmission conditions of the handover base station candidates; and

a handover base station decision unit that decides one of the plurality of handover base station candidates as a handover base station.

2. The base station according to claim 1, wherein the multicast unit transmits the communication data to each of the handover base station candidates by way of a host device.

3. The base station according to claim 1, wherein said respective transmission conditions include transmission rates at which the communication data is respectively transmitted to the handover base station candidates.

4. The base station according to claim 1, further comprising:

a transmission rate decision unit that decides said respective transmission conditions of the handover base station candidates based on the respective communication capabilities.

5. The base station according to claim 4, wherein said communication capability for each handover base station candidate includes at least one among a buffer capacity of the handover base station candidate, availability state of radio communication resources of the handover base station candidate and level of QoS (quality of service) that is executable by the handover base station candidate.

6. The base station according to claim 1, further comprising:

a transmission rate decision unit that acquires the communication capability of each of the handover base station candidates by making an inquiry to each handover base station candidate for the communication capability, and decides said respective transmission conditions of the handover base station candidates based on the acquired respective communication capabilities.

7. The base station according to claim 1, wherein the multicast unit acquires the transmission condition of each of the handover base station candidates by making an inquiry to each handover base station candidate for the transmission condition, and transmits the communication data to the handover base station candidates under the respective transmission conditions.

8. The base station according to claim 1, wherein each of the handover base station candidates saves the transmitted communication data, and a handover base station candidate that is decided as the handover base station sends the saved communication data to the mobile terminal.

9. A handover control method in a mobile communication system that performs handover control by changing base station that communicates with a mobile terminal as the mobile terminal moves, and comprising:

selecting in a base station that is communicating with a mobile terminal, one or more handover base station candidates based on the communication state;

transmitting communication data that is to be transmitted from the communicating base station to the mobile terminal, to the handover base station candidates under respective transmission conditions from the communicating base station; and

sending the communication data from a handover base station candidate that has been decided as a handover base station to the mobile terminal.

10. A mobile communication system that comprises a mobile terminal and a base station which communicates with the mobile station, and performs handover control by changing base station that communicates with the mobile terminal as the mobile terminal moves, wherein

said base station includes:

a handover base station candidate decision unit that selects one or more handover base station candidates based on the communication state during communication with a mobile terminal;

a multicast unit that transmits communication data that is to be transmitted from its own base station to the mobile terminal, to the handover base station candidates under respective transmission conditions of the handover base station candidates; and

a handover base station decision unit that decides one of the plurality of handover base station candidates as a handover base station, and

said mobile terminal includes a receiver that receives the communication data that is transmitted from a handover base station candidate that has been decided as the handover base station.