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

• US 7,330,727 B2
• Filed: 05/06/2003
• Issued: 02/12/2008
• Est. Priority Date: 05/06/2003
• Status: Expired due to Fees

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Pichette, Robert H., Korneluk, Jose E.
• Primary Examiner(s): Taylor; Barry
• Application Number:
  US10/430,245
• Publication Number:
  US 20040224696A1
• Time in Patent Office: 1,743 Days
• Field of Search: 455/446, 455/449, 455/422.1, 455/456.1, 455/457, 455/562.1, 455/442, 455/439, 455/440, 455/444, 455/437, 455/438, 455/436
• US Class Current: 455/438
• 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 of 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, the neighbor cell site list identifying neighbor cell sites of the serving cell site;

(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 cell sites;

(d) grouping together neighbor cell sites having similar bearings and distances from the serving cell site together in the neighbor cell site list, where the similar bearings and distances indicate that the grouped cell sites are sectors of a single base site; and

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

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

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

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

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

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

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

5. A method as defined in claim 4, wherein the modified neighbor cell site list is stored in the communication device.

6. A method as defined in claim 4, further comprising the steps of:

placing one of the sites in each of the grouped sites in the foreground and the rest in the background of the neighbor cell site list.

7. A method as defined in claim 6, wherein in step (i) the one site placed in the foreground for each of the grouped sites is the site in each of the grouped sites that is nearest the serving cell site.

8. A method as defined in claim 6, wherein in step (i) the one site placed in the foreground for each of the grouped sites is the site in each of the grouped sites that is providing the strongest signal to the communication device.

9. A method as defined in claim 1, wherein in step (d) the cell sites are grouped together if they are no more than a predetermined distance away from each other.

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

11. 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 as sectored cells of a single site;

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

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

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

12. A method as defined in claim 11, wherein the communication device uses the modified neighbor cell site list to make mobility decisions.

13. A method as defined in claim 11, wherein the latitude and longitude information is provided to the communication device over a control channel.