Method for maintaining candidate handoff list for airborne cellular system

• US 6,856,803 B1
• Filed: 06/26/2000
• Issued: 02/15/2005
• Est. Priority Date: 06/26/2000
• Status: Expired due to Fees

• Current Assignee: CDC Propriete Intellectuelle
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Tessler, Michael A., Emmons, Thomas Peter Jr., Gross, Jonathan H.
• Primary Examiner(s): Trost, William
• Assistant Examiner(s): D AGOSTA, STEPHEN M
• Application Number:
  US09/605,085
• Time in Patent Office: 1,695 Days
• Field of Search: 455/11.1, 455/12.1, 455/427, 455/432.1, 455/13.1, 455/436, 455/437, 455/438, 455/439, 455/440, 455/441, 455/492, 455/443, 455/444, 455/445, 455/517, 455/431, 455/432, 370/331
• US Class Current: 455/431
• CPC Class Codes: H04B 7/18506 Communications with or from aircraft, i.e. aeronautical mobile service
• CPC Class Codes: H04W 36/0061 of neighbour cell information
• CPC Class Codes: H04W 64/006 with additional information processing, e.g. for direction or speed determination
• CPC Class Codes: H04W 84/06 Airborne or Satellite Networks space-based or airborne stations H04B7/185

Abstract

A terrestrial cell site handoff list is dynamically maintained for an airborne cellular system. A beam pattern is maintained relative to an airborne cellular system repeater, but rotates relative to the geographic area of coverage. A location and heading of the airplane, locations of respective beams transmitted from the airplane based on airplane flight pattern data, and locations of respective cell sites within a vicinity of footprints of the respective beams transmitted from the airplane are determined. A list of viable handoff terrestrial cell site candidates is then calculated based on the beam pattern, the location and heading of the airplane, the locations of respective beams transmitted from the airplane based on airplane flight pattern data, and the locations of respective cell sites.

Claims

1. A method of maintaining a terrestrial cell site handoff list for an airborne cellular system comprising the steps of:

maintaining a fixed beam pattern of one or more communications beams transmitted from an airplane relative to terrestrial cellular system users, each of the one or more communication beams supporting cellular communications for terrestrial cellular system users, all of the one or more beans covering a footprint on the ground;

determining a location and beading of the airplane;

determining locations of each of the one or more communication beams transmitted from the airplane based on airplane flight pattern data;

determining locations of respective terrestrial cell sites within a vicinity of the footprints of each of the one or more beams transmitted from the airplane;

calculating list of viable handoff nal cell site candidates for handoffs of a terrestrial mobile user between one or more communication beams and terrestrial cell sites based on maintaining a fixed communication beam pattern, the location and heading of the airplane, the locations of each of the one or more communication beams transmitted from the airplane based on airplane flight pattern data, and the locations of respective cell sites; and

wherein the step of calculating a list of viable handoff terrestrial cell site candidates comprises mapping data generated from the steps of maintaining a fixed communication beam pattern, determining a location and heading of the airplane, determining locations of each of the one or more communication beams transmitted from the airplane based on airplane flight pattern data, and determining locations of respective cell sites to a cell site location database to determine the viable handoff terrestrial cell site candidates.

2. The method of claim 1, wherein the determining of a location and heading of the airplane comprises receiving a fight pattern location of the airplane via a telemetry link.

3. The method of claim 1, further comprising ranking each of the viable hand-off terrestrial cell site candidates based on associated probability data found during the calculating of a list of viable handoff terrestrial cell site candidates.

4. The method of claim 3, wherein a number of the viable handoff terrestrial cell site candidates found during the calculating of a list of viable handoff terrestrial cell site candidates is protocol-pendent.

5. The method of claim 1, wherein the calculating of a list of viable handoff terrestrial cell site candidates for handoffs of a terrestrial mobile user between one or more communication beams and terrestrial cell sites is performed for each of the one or more communication be transmitted from the airplane.

6. The method of claim 5, further comprising dividing up the list of viable handoff terrestrial cell site candidates into multiple candidate groups according to candidate geographic locations within each of the one or more communication beans transmitted from the airplane;

and

cycling through the multiple candidate groups to further educe the list of viable hand-off terrestrial candidates based on the multiple candidate groups.

7. The method of claim 1, further comprising updating the list of viable handoff terrestrial cell site candidates as a function of time as the airplane flight pattern data changes.

8. The method of claim 1, wherein the calculating of a list of viable handoff terrestrial cell site candidates is performed to compensate for airplane flight pattern changes caused by adverse weather conditions.

9. The method of claim 1, further comprising calculating viable airplane beams for receiving handoffs from terrestrial cell sites;

and

creating an airplane beam handoff list based on the calculating of viable airplane beams.

10. The method of claim 1, further comprising dividing the list of viable handoff terrestrial cell site candidates into time-sensitive candidates and non-time-sensitive handoff candidates.

11. A method of maintaining a terrestrial cell site handoff list for an airborne cellular system comprising the steps of:

maintaining a fixed beam pattern of one or more communications beams transmitted from an airplane relative to terrestrial cellular system users, each of the one or more communication beams supporting cellular communications for terrestrial cellular system users, all of the one or more beams covering a footprint on the ground;

determining a location and heading of the airplane;

determining locations of each of the one or more communication beams transmitted from the airplane based on airplane flight pattern data;

determining locations of respective terrestrial cell sites within a vicinity of the footprints of each of the one or more beams transmitted from the airplane;

calculating a list of viable of terrestrial cell site candidates for handoffs of a terrestrial mobile user between one or more communication beams and terrestrial cell sites based on maintaining a fixed communication beam pattern, the location and heading of the airplane, the locations of each of the one or more communication beams transmitted from the airplane based on airplane flight patter data, and the locations of respective cell sites, the calculation performed for each of tee one or more communication beams transmitted from the airplane;

dividing up the list of viable handoff terrestrial cell site candidates into multiple candidate groups according to candidate geographic locations within each of the one or more communication beams transmitted from the airplane; and

cycling through the multiple candidate groups to further reduce the list of viable hand-off terrestrial candidates based on the multiple candidate groups.

12. The method of claim 11, wherein the determining of a location and heading of the airplane comprises receiving a flight pattern location of the airplane via a telemetry links.

13. The method of claim 11, wherein the step of calculating a list of viable hand-off terrestrial cell site candidates comprises mapping data generated from the steps of maintaining a fixed communication beam pattern, determining a location and heading of the airplane, determining locations of each of the one or more communication beams transmitted from the airplane based on airplane flight pattern data, and determining locations of respective cell sites to a cell site location database to determine the viable handoff terrestrial cell site candidates.

14. The method of claim 11, further comprising ranking each of the viable handoff terrestrial cell site candidates based on associated probability data found during the calculating of a list of viable handoff terrestrial cell site candidates.

15. The method of claim 14, wherein a number of the viable handoff terrestrial cell site candidates found during the calculating of a list of viable handoff terrestrial cell site candidates is protocol dependent.

16. The method of claim 11, further comprising updating the list of viable hand-off terrestrial cell site candidates as a function of time as the airplane flight pattern data changes.

17. The method of claim 11, wherein the calculating of a list of viable hand-off terrestrial cell site candidates is performed to compensate for airplane flight patty changes caused by adverse weather conditions.

18. The method of claim 11, further comprising calculating viable airplane beams for receiving handoffs from terrestrial cell sites;

and

creating an airplane beam handoff list based on the calculating of viable airplane beams.