Method of determining co-location of cell sites and reducing ping-pong effect between cell sites

• US 20040224696A1
• Filed: 05/06/2003
• Published: 11/11/2004
• Est. Priority Date: 05/06/2003
• Status: Active Grant

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Korneluk, Jose E., Pichette, Robert H.
• Granted Patent: US 7,330,727 B2
• Time in Patent Office: Days
• US Class Current: 455/449
• CPC Class Codes: H04W 36/08 Reselecting an access point
• CPC Class Codes: H04W 36/32 by location or mobility data, e.g. speed data

Abstract

A method for determining the co-location of cell sites includes the steps of acquiring a neighbor cell list (602), monitoring the neighbor cell sites for longitude and latitude information (604). Te longitude and latitude information is used fo calculating the distance and bearings between the serving and neighbor cell sites (606 and 608). Neighbor cell sites having similar bearing and distances are grouped together (610), if grouped neighbors are in close proximity, the centroid of a polygon formed by the sector vertices is determined (614) and new latitude and longitude information for the centorid is determined (616). The neighbor cell list is then modified to indicate sectored versus omni-directional sites (620) and the information is then used by the communication device to make better mobility decisions. In another embodiment of the invention, the co-location information is used to minimize ping-pong effect which causes a communication device to be continually being handed back and forth between ell sites.

Claims

1. A method for determining the co-location of cell sites in a communication system by a communication device located in a serving cell site, the method comprising the steps of:

(a) acquiring a neighbor cell site list at the communication device;

(b) monitoring the neighbor cell sites for latitude and longitude information;

(c) calculating the distance and directional bearings between the serving cell site and the neighbor cells; and

(d) grouping together neighbor cell sites having similar bearings and distances from the serving cell site.

2. A method as defined in claim 1, further comprising the step of:

(e) calculate the centroid of polygon formed by the sector vertices of the neighbor cell sites that are grouped together in step (d).

3. A method as defined in claim 2, further comprising the step of:

(f) calculate the latitude and longitude for the centroid determined in step (e).

4. A method as defined in claim 3, further comprising the step of:

(g) storing the latitude and longitude and distances in the neighbor cell site list.

5. A method as defined in claim 4, further comprising the step of:

(h) modifying the neighbor cell site list to indicate omni-directional and sectored cell sites.

6. A method as defined in claim 5, wherein the modified neighbor cell site list is stored in the communication device.

7. A method as defined in claim 1, further comprising the step of:

(e) determining if the cell sites that have been grouped together in step (d) are in close proximity to each other.

8. A method as defined in claim 7, wherein in step (e) the cell sites are in close proximity if they are no more than a predetermined distance away from each other.

9. A method as defined in claim 8, wherein the predetermined distance information is stored in the communication device.

10. A method as defined in claim 5, further comprising the steps of:

(i) placing one of the sites in each of the sectored sites in the foreground and the rest in the background of the neighbor cell site list.

11. A method as defined in claim 10, wherein in step (i) the one site placed in the foreground for each of the sectored sites is the site in each of the sectored sites that is nearest the serving cell site.

12. A method as defined in claim 10, wherein in step (i) the one site placed in the foreground for each of the sectored sites is the site in each of the sectored sites that is providing the strongest signal to the communication device.

13. A method for reducing ping-pong effects in a communication device operating in a communication system having a plurality of cell sites, comprising the steps of:

(a) acquiring at the communication device a neighbor cell site list upon affiliation to one of the plurality of cell sites;

(b) determining which of the cell sites in the neighbor cell site list are omni-directional cell sites and which are sectored cell sites; and

(c) modifying the neighbor cell list to place the site of each of the sectored cell sites having the strongest signal or being nearest to the cell site the communication device is currently affiliated to at the foreground of the neighbor cell site list.

14. A method as defined in claim 13, further comprising the step of:

(d) placing the site(s) of the other site(s) of each of the sectored cell sites in the background of the neighbor cell site list.

15. A method as defined in claim 14, wherein step (b) comprises the sub-steps of:

(b1) monitoring the neighbor cell sites for latitude and longitude information;

(b2) calculating the distance and directional bearings between the serving cell site the communication device is currently affiliated to and the neighbor cells; and

(b3) grouping together neighbor cell sites having similar bearings and distances from the serving cell site.

16. A method as defined in claim 15, further comprising the substeps of:

(b4) determining if the neighbor cell sites that are grouped together are in close proximity to each other; and

(b5) if it is determined in sub-step (b4) that they are in close proximity considering the grouped cell sites as being a sectored cell site.

17. A method for determining the co-location of cell sites in a communication system by a communication device located in a serving cell site, the method comprising the steps of:

(a) acquiring a neighbor cell site list at the communication device;

(b) monitoring the neighbor cell sites for latitude and longitude information;

(c) calculating the distance and directional bearings between the serving cell site and the neighbor cells;

(d) grouping together neighbor cell sites having similar directional bearings and distances from the serving cell site;

(e) calculate the centroid of polygon formed by the sector vertices of the neighbor cell sites that are grouped together in step (d);

(f) calculate the latitude and longitude for the centroid determined in step (e); and

(g) modifying the neighbor cell site list to indicate omni-directional and sectored cell sites using the information determined in steps (b)-(f).

18. A method as defined in claim 17, wherein the communication device uses the modified neighbor cell site list to make mobility decisions.

19. A method as defined in claim 17, wherein the latitude and longitude information is provided to the communication device over a control channel.