Apparatus and method for performing an interfrequency handoff in a wireless network

• US 20040121774A1
• Filed: 12/20/2002
• Published: 06/24/2004
• Est. Priority Date: 12/20/2002
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Cleveland, Joseph R., Rajkotia, Purva R., Kodali, Sanjay Kumar
• Granted Patent: US 7,512,403 B2
• Time in Patent Office: Days
• US Class Current: 455/441
• CPC Class Codes: H04W 36/32 by location or mobility data, e.g. speed data
• CPC Class Codes: H04W 36/322 by location data
• CPC Class Codes: H04W 36/324 by mobility data, e.g. speed data

Abstract

An apparatus and method is disclosed for performing an interfrequency hard handoff at a border cell in a wireless network. The apparatus comprises a handoff controller within a source base station that selects an optimal target base station using location information of at least one target base station and using one of: a location of the wireless mobile station, a velocity of the wireless mobile station, and a direction of motion of the wireless mobile station. The present invention uses the location information of at least one target base station in order to make more reliable handoff decisions.

Claims

1. For use in a source base station capable of communicating with a wireless mobile station in a wireless network, an apparatus for selecting at least one target base station for a handoff of said wireless mobile station, said apparatus comprising:

a handoff controller capable of selecting said at least one target base station based on location information of said at least one target base station and one of;

a location of said wireless mobile station;

a velocity of said wireless mobile station; and

a direction of motion of said wireless mobile station.

2. The apparatus as set forth in claim 1 wherein said handoff controller comprises:

a processor within said source base station;

a memory coupled to said processor; and

a handoff decision control program within said memory, said handoff decision control program executable by said processor to select said at least one target base station for said handoff of said wireless mobile station.

3. The apparatus as set forth in claim 2 wherein said handoff controller further comprises:

a base station location database within said memory, said base station location database containing location information of at least one target base station;

wherein said handoff controller is capable of receiving a message that contains base station location information; and

wherein said handoff controller is capable of placing said base station location information from said message in said base station location database.

4. The apparatus as set forth in claim 1 wherein said handoff controller is capable of receiving a location of said wireless mobile station and capable of calculating a distance of said wireless mobile station to at least one target base station.

5. The apparatus as set forth in claim 1 wherein said handoff controller is capable of receiving a first location of said wireless mobile station at a first time and a second location of said wireless mobile station at a second time and calculating a velocity of said wireless mobile station.

6. The apparatus as set forth in claim 1 wherein said handoff controller is capable of receiving a first location of said wireless mobile station at a first time and a second location of said wireless mobile station at a second time and calculating a direction of motion of said wireless mobile station.

7. The apparatus as set forth in claim 1 wherein said handoff controller is capable of creating a preferential order of target base stations to which to hand off said wireless mobile station, wherein a preferential ranking of said target base stations is selected by using location information of said target base stations and using one of:

a location of said wireless mobile station;

a velocity of said wireless mobile station; and

a direction of motion of said wireless mobile station.

8. A source base station comprising:

an apparatus for selecting at least one target base station for a handoff of a wireless mobile station, said apparatus comprising;

a handoff controller capable of selecting said at least one target base station based on location information of said at least one target base station and one of;

a location of said wireless mobile station;

a velocity of said wireless mobile station; and

a direction of motion of said wireless mobile station.

9. The source base station as set forth in claim 8 wherein said handoff controller comprises:

a processor within said source base station;

a memory coupled to said processor; and

a handoff decision control program within said memory, said handoff decision control program executable by said processor to select said at least one target base station for said handoff of said wireless mobile station.

10. The source base station as set forth in claim 9 wherein said handoff controller further comprises:

a base station location database within said memory, said base station location database containing location information of at least one target base station;

wherein said handoff controller is capable of receiving a message that contains base station location information; and

wherein said handoff controller is capable of placing said base station location information from said message in said base station location database.

11. The source base station as set forth in claim 8 wherein said handoff controller is capable of receiving a location of said wireless mobile station and capable of calculating a distance of said wireless mobile station to at least one interfrequency target base station.

12. The source base station as set forth in claim 8 wherein said handoff controller is capable of receiving a first location of said wireless mobile station at a first time and a second location of said wireless mobile station at a second time and calculating a velocity of said wireless mobile station.

13. The source base station as set forth in claim 8 wherein said handoff controller is capable of receiving a first location of said wireless mobile station at a first time and a second location of said wireless mobile station at a second time and calculating a direction of motion of said wireless mobile station.

14. The source base station as set forth in claim 8 wherein said handoff controller is capable of creating a preferential order of target base stations to which to hand off said wireless mobile station, wherein a preferential ranking of said target base stations is selected by using location information of said target base stations and using one of:

a location of said wireless mobile station;

a velocity of said wireless mobile station; and

a direction of motion of said wireless mobile station.

15. In a wireless network capable of communicating with wireless mobile stations located in a coverage area of the wireless network, a method for selecting at least one target base station for a handoff of a wireless mobile station, said method comprising the steps of:

receiving within a handoff controller within a source base station location information of at least one target base station;

receiving within said handoff controller one of;

a location of said wireless mobile station, a velocity of said wireless mobile station, and a direction of motion of said wireless mobile station; and

selecting said at least one target base station for said handoff of said wireless mobile station using said location information of at least one target base station and using one of;

said location of said wireless mobile station, said velocity of said wireless mobile station, and said direction of motion of said wireless mobile station.

16. The method as set forth in claim 15 further comprising the steps of:

coupling a base station location database to said handoff controller, said base station location database containing location information of at least one target base station;

receiving a message within said handoff controller that contains base station location information; and

placing said base station location information from said message in said base station location database.

17. The method as set forth in claim 15 further comprising the steps of:

receiving a location of said wireless mobile station within said handoff controller; and

calculating in said handoff controller a distance of said wireless mobile station to at least one target base station.

18. The method as set forth in claim 15 further comprising the steps of:

receiving within said handoff controller a first location of said wireless mobile station at a first time;

receiving within said handoff controller a second location of said wireless mobile station at a second time;

calculating in said handoff controller a velocity of said wireless mobile station.

19. The method as set forth in claim 15 further comprising the steps of:

receiving within said handoff controller a first location of said wireless mobile station at a first time;

receiving within said handoff controller a second location of said wireless mobile station at a second time;

calculating in said handoff controller a direction of motion of said wireless mobile station.

20. The method as set forth in claim 15 further comprising the steps of:

creating within said handoff controller a preferential order of target base stations to which to hand off said wireless mobile station, wherein a preferential ranking of said target base stations is selected by the steps of;

receiving within said handoff controller location information of said target base stations; and

selecting said preferential ranking of said target base stations using said location information of said target base stations and using one of;

said location of said wireless mobile station, said velocity of said wireless mobile station, and said direction of motion of said wireless mobile station.