Radio base station selection method and system and a radio base station in a mobile communication system

• US 20030017838A1
• Filed: 07/17/2002
• Published: 01/23/2003
• Est. Priority Date: 07/18/2001
• Status: Active Grant

• Current Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Original Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Inventors: Kayama, Hidetoshi, Chen, Lan, Umeda, Narumi
• Granted Patent: US 7,457,622 B2
• Time in Patent Office: Days
• US Class Current: 455/525
• CPC Class Codes: H04W 36/08 Reselecting an access point
• CPC Class Codes: H04W 36/302 due to low signal strength
• CPC Class Codes: H04W 48/20 Selecting an access point

Abstract

In a mobile communication system having a plurality of radio base stations and a mobile station, a radio base station selection method in which a radio base station to start communicating with a mobile station is selected from among adjacent radio base stations capable of communicating with the mobile station is provided. The method includes the steps of requiring, by a radio base station in service, a radio channel availability report from each of adjacent radio base stations indicated by the mobile station, in response to a signal for requesting connection to the mobile station; selecting a radio base station to be connected to the mobile station, based on the radio channel availability reports obtained from the adjacent radio base stations; and notifying the mobile station of information necessary for communicating with the selected radio base station.

Claims

1. In a mobile communication system having a plurality of radio base stations and a mobile station, a radio base station selection method in which a radio base station to start communicating with a mobile station is selected from among adjacent radio base stations capable of communicating with the mobile station, the method comprising the steps of:

requiring, by a radio base station in service, a radio channel availability report from each of adjacent radio base stations indicated by the mobile station, in response to a signal for requesting connection to the mobile station;

selecting a radio base station to be connected to the mobile station, based on the radio channel availability reports obtained from the adjacent radio base stations; and

notifying the mobile station of information necessary for communicating with the selected radio base station.

2. The radio base station selection method as claimed in claim 1, wherein the signal for requesting connection is a signal relating to sending a call to or from the mobile station.

3. The radio base station selection method as claimed in claim 1, wherein the signal for requesting connection is a signal relating to a handoff request.

4. The radio base station selection method as claimed in claim 1, wherein

the radio base station in service selects one radio base station satisfying a predetermined receiving quality, from among more than one adjacent radio base stations having radio channel availability necessary for accommodating the connection to the mobile station, based on the radio channel availability reports obtained from the adjacent radio base stations.

5. The radio base station selection method as claimed in claim 1, wherein

the radio base station in service notifies the mobile station of identification information about the selected radio base station;

and

the mobile station establishes connection to the selected radio base station identified by the identification information provided by the radio base station in service.

6. The radio base station selection method as claimed in claim 1, wherein

the radio base station in service instructs the selected radio base station to assign a radio channel to the mobile station;

the selected radio base station reports information about the radio channel assigned according to the instruction, to the radio base station in service;

the radio base station in service notifies the mobile station of the reported information about the radio channel; and

the mobile station communicates with the selected radio base station using the assigned radio channel.

7. In a mobile communication system having a plurality of radio base stations and a mobile station, a radio base station selection system in which a radio base station to start communicating with a mobile station is selected from among adjacent radio base stations capable of communicating with the mobile station, the system comprising a radio base station in service,

the radio base station in service including:

radio channel availability requiring means for requiring a radio channel availability report from each of adjacent radio base stations indicated by the mobile station, in response to a signal for requesting connection to the mobile station;

radio base station selecting means for selecting a radio base station to be connected to the mobile station, based on the radio channel availability reports obtained from the adjacent radio base stations; and

notifying means for notifying the mobile station of information necessary for communicating with the selected radio base station.

8. The radio base station selection system as claimed in claim 7, wherein the signal for requesting connection is a signal relating to sending a call to or from the mobile station.

9. The radio base station selection system as claimed in claim 7, wherein the signal for requesting connection is a signal relating to a handoff request.

10. The radio base station selection system as claimed in claim 7, wherein

the radio base station selecting means selects one radio base station satisfying a predetermined receiving quality, from among more than one adjacent radio base stations having radio channel availability necessary for accommodating the connection to the mobile station, based on the radio channel availability reports obtained from the adjacent radio base stations.

11. The radio base station selection system as claimed in claim 7, wherein

the notifying means notifies the mobile station of identification information about the selected radio base station;

and

the mobile station establishes connection to the selected radio base station identified by the identification information provided by the notifying means.

12. The radio base station selection system as claimed in claim 7, further comprising:

radio channel assignment instruction means for instructing the selected radio base station to assign a radio channel to the mobile station;

wherein

the selected radio base station includes radio channel information reporting means for reporting information about the radio channel assigned according to the instruction, to the radio base station in service;

the radio base station in service includes radio channel information notifying means for notifying the mobile station of the reported information about the radio channel; and

the mobile station communicates with the selected radio base station using the assigned radio channel.

14. The radio base station as claimed in claim 13, wherein the signal for requesting connection is a signal relating to sending a call to or from the mobile station.

15. The radio base station as claimed in claim 13, wherein the signal for requesting connection is a signal relating to a handoff request.

16. The radio base station as claimed in claim 13, wherein

the radio base station selecting means selects one radio base station satisfying a predetermined receiving quality, from among more than one adjacent radio base stations having radio channel availability necessary for accommodating the connection to the mobile station, based on the radio channel availability reports obtained from the adjacent radio base stations.

17. The radio base station as claimed in claim 13, wherein

the notifying means notifies the mobile station of identification information about the selected radio base station;

and

the mobile station establishes connection to the selected radio base station identified by the identification information provided by the notifying means.

18. The radio base station as claimed in claim 13, further comprising:

radio channel assignment instruction means for instructing the selected radio base station to assign a radio channel to the mobile station; and

radio channel information notifying means for notifying the mobile station of information about the radio channel assigned according to the instruction.

19. The radio base station as claimed in claim 18, wherein

the radio base station instructed to assign a radio channel by the radio channel assignment instruction means reports information about the assigned radio channel according to the instruction, to the in service radio base station.

13. A radio base station in service and communicating with a mobile station, comprising:

radio channel availability requiring means for requiring a radio channel availability report from each of adjacent radio base stations indicated by the mobile station, in response to a signal for requesting connection to the mobile station;

radio base station selecting means for selecting a radio base station to be connected to the mobile station, based on the radio channel availability reports obtained from the adjacent radio base stations; and

notifying means for notifying the mobile station of information necessary for communicating with the selected radio base station.