Method and system for establishing mobile station active set based on mobile station location

• US 7,092,722 B1
• Filed: 07/26/2001
• Issued: 08/15/2006
• Est. Priority Date: 07/26/2001
• Status: Expired due to Term

• Current Assignee: Sprint Spectrum LP (Deutsche Telekom AG)
• Original Assignee: Sprint Spectrum LP (Deutsche Telekom AG)
• Inventors: Oh, Dae-Sik, Anderson, Leo Ray Jr.
• Primary Examiner(s): Feild, Joseph
• Assistant Examiner(s): PEREZ, JULIO R
• Application Number:
  US09/915,731
• Time in Patent Office: 1,846 Days
• Field of Search: 455/442, 455/436, 455 332- 334, 455/51.1, 455/456, 455/437, 455/438, 455/439, 455/440, 455/444, 455/457, 455/139, 455/441, 455/443, 455/456.1, 379/60, 379/59, 370/331, 370/375, 370/342, 370/333, 370/336
• US Class Current: 455/456.1
• CPC Class Codes: H04W 36/18 for allowing seamless reselection, e.g. soft reselection
• CPC Class Codes: H04W 4/02 Services making use of location information
• CPC Class Codes: H04W 4/029 Location-based management or tracking services

Abstract

A method and system for selecting a mobile station active set based, at least in part, on the geographic location of the mobile station. A base station or other entity monitors the mobile station'"'"'s location. When the location changes, the base station refers to a predefined sector-coverage database to identify as the active set one or more sectors that each encompass the mobile station'"'"'s location. If more than one sector encompasses the location, the base station may further select as the active set a subset of one or more sectors to which the mobile station is closest.

Claims

1. A method of establishing an active set for a mobile station operating in a cellular wireless system, the method comprising:

determining a current physical position of the mobile station;

identifying a grout of sectors that each encompass the determined current physical position of the mobile station;

computing a distance respectively between the determined current physical position of the mobile station and each sector of the group; and

selecting as the active set a subset of the group of sectors, at least in part by selecting from the group one or more sectors for which the computed distance is shortest.

2. The method of claim 1, further comprising:

sending an indication of the active set to the mobile station.

3. The method of claim 2, wherein determining the current physical position of the mobile station comprises:

receiving a signal from the mobile station indicating the mobile station position.

4. The method of claim 2, wherein determining the current physical position of the mobile station comprises:

querying a mobile positioning center to obtain an indication of the current physical position of the mobile station.

5. The method of claim 2, wherein identifying the group of sectors that each encompass the determined current physical position of the mobile station comprises:

querying a sector coverage database to identify the group of sectors.

6. The method of claim 2, wherein the subset of the group of sectors consists of only one sector.

7. The method of claim 2, wherein the subset of active sectors consists of only two sectors.

8. The method of claim 2, wherein sending an indication of the active set to the mobile station comprises:

sending a Handoff Direction Message (HDM) to the mobile station, the HDM including the indication of the active set.

9. A soft handoff method comprising:

repeatedly performing the method of claim 2 as the mobile station moves from a first position to a second position,

wherein the group of sectors when the mobile station is at the first position is different than the group of sectors when the mobile station is at the second position.

10. A soft handoff method comprising:

performing the method of claim 2 when the mobile station is at a first position, thereby establishing a first active set; and

performing the method of claim 2 when the mobile station has moved from the first position to a second position, thereby establishing a second active set different than the first active set.

11. A method comprising:

periodically performing the method of claim 2.

12. A method of establishing an active set for a mobile station operating in a cellular wireless system, the method comprising:

determining a current physical position of the mobile station;

querying a sector coverage database to identify a plurality of sectors that each encompass the determined current physical position;

determining, respectively for each sector of the identified plurality of sectors, a distance between the sector and the determined current physical position of the mobile station;

selecting from the plurality of sectors at most two sectors having the shortest determined distance, the at most two sectors defining an active set; and

sending to the mobile station an indication of the active set.

13. A system for establishing an active set for a mobile station operating in a cellular wireless system, the system comprising:

means for determining current a physical position of the mobile station;

means for identifying a group of sectors that each encompass the determined current physical position of the mobile station, each sector of the group having a respective point of origin;

means for computing a distance respectively between the determined current physical position of the mobile station and the point of origin of each sector in the group;

means for selecting as the active set a subset of the group of sectors, at least in part by selecting from the group one or more sectors for which the computed distance is shortest; and

means for providing an indication of the active set for transmission to the mobile station.

14. A system for establishing an active set for a mobile station operating in a cellular wireless system, the system comprising:

a processor;

data storage;

program instructions stored in the data storage and executable by the processor to cause the processor (i) to determine a current physical position of the mobile station, (ii) to identify a group of sectors that each encompass the determined current physical position of the mobile station, each sector of the group having a respective point of origin, (iii) to compute a distance respectively between the determined current physical position of the mobile station and the point of origin of each sector in the group, (iv) to select as the active set a subset of the group of sectors, at least in part by selecting from the group one or more sectors for which the computed distance is shortest, and (v) to provide an indication of the active set for transmission to the mobile station.