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

• US 7,457,622 B2
• Filed: 07/17/2002
• Issued: 11/25/2008
• Est. Priority Date: 07/18/2001
• Status: Expired due to Fees

• 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
• Primary Examiner(s): Nguyen; Duc
• Assistant Examiner(s): THIER, MICHAEL
• Application Number:
  US10/196,196
• Publication Number:
  US 20030017838A1
• Time in Patent Office: 2,323 Days
• Field of Search: 455/425, 455436-439, 455442-453
• US Class Current: 455/437
• 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:

measuring, by a mobile station, a reception quality of each of a plurality of adjacent radio base stations;

receiving, by a radio base station in service, a signal including a connection request and the measured reception quality of each of the plurality of adjacent radio base stations from the mobile station;

transmitting, by the radio base station in service, to each adjacent radio base station, but not to the mobile station, a message requesting a radio channel available capacity report;

making the radio channel available capacity report by each adjacent radio base station, but not by the mobile station;

sending the radio channel available capacity report directly from said each adjacent radio base station, but not from the mobile station, to the radio base station in service, each radio channel available capacity report including an available bandwidth of the respective adjacent radio base station;

making, by the radio base station in service, a table including the reception qualities measured by the mobile station and the radio channel available capacity reports directly obtained from the adjacent radio base stations;

selecting, by the radio base station in service, but not by a radio base station control station or an adjacent radio base station, a radio base station to be connected to the mobile station, based on the table; 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 from the mobile station 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 from the mobile station 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 available capacity necessary for accommodating the connection to the mobile station, based on the radio channel available capacity reports directly 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 mobile station including means for measuring a reception quality of each of a plurality of adjacent radio base stations;

the radio base station in service including;

radio channel available capacity requiring means for requiring a radio channel available capacity report from each adjacent radio base station, but not from the mobile station, when receiving a signal for requesting connection and including the measured reception quality from the mobile station;

means for receiving the radio channel available capacity reports directly from said each adjacent radio base station, but not from the mobile station, each radio channel available capacity report including an available bandwidth of the respective adjacent radio base station;

means for making, by the radio base station in service, a table including the reception qualities measured by the mobile station and the radio channel available capacity reports directly obtained from the adjacent radio base stations;

radio base station selecting means for selecting by the radio base station in service, but not by a radio base station control station or an adjacent radio base station, a radio base station to be connected to the mobile station, based on the table; 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 from the mobile station 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 from the mobile station 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 available capacity necessary for accommodating the connection to the mobile station, based on the radio channel available capacity reports directly 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.

13. A radio base station in service and communicating with a mobile station capable of measuring a reception quality of each of a plurality of adjacent radio base stations, comprising:

radio channel available capacity requiring means for receiving a signal including a connection request and the measured reception quality from the mobile station, and for requesting a radio channel available capacity report from each adjacent radio base station, but not from the mobile station;

means for receiving the radio channel available capacity reports directly from said each adjacent radio base station, but not from the mobile station, each radio channel available capacity report including an available bandwidth of the respective adjacent radio base station;

means for making, by the radio base station in service, a table including the reception qualities measured by the mobile station and the radio channel available capacity reports directly obtained from the adjacent radio base stations;

radio base station selecting means for selecting, by the radio base station in service, but not by a radio base station control station or an adjacent radio base station, a radio base station to be connected to the mobile station, based on the table; and

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

14. The radio base station as claimed in claim 13, wherein the signal for requesting connection from the mobile station 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 from the mobile station 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 available capacity necessary for accommodating the connection to the mobile station, based on the radio channel available capacity reports directly 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.