CELL SELECTION FOR AIRBORNE MOBILE CELLULAR COMMUNICATIONS EQUIPMENT

• US 20170171792A1
• Filed: 12/09/2015
• Published: 06/15/2017
• Est. Priority Date: 12/09/2015
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Axmon, Joakim, Alriksson, Peter, Lindoff, Bengt, Ekelund, Bjorn
• Granted Patent: US 10,111,152 B2
• Time in Patent Office: Days
• CPC Class Codes: H04B 7/18506 Communications with or from aircraft, i.e. aeronautical mobile service
• CPC Class Codes: H04W 16/28 using beam steering
• CPC Class Codes: H04W 36/08 Reselecting an access point
• CPC Class Codes: H04W 36/30 by measured or perceived connection quality data
• CPC Class Codes: H04W 36/32 by location or mobility data, e.g. speed data
• CPC Class Codes: H04W 56/0035 detecting errors in frequency or phase
• CPC Class Codes: H04W 84/005 Moving wireless networks
• CPC Class Codes: H04W 84/06 Airborne or Satellite Networks space-based or airborne stations H04B7/185

Abstract

A network node in a cellular telecommunications system hands over responsibility for serving a wireless communication equipment from a serving cell to a target cell, wherein the wireless communication equipment is situated in a first aircraft that is in-flight. An aircraft position, an aircraft velocity, and an aircraft direction are determined. For each candidate cell of a number of candidate cells, a level of beam distortion that would result from a beam directed from the candidate cell to the first aircraft is predicted. The target cell is selected from the candidate cells by identifying which of the candidate cells has a least amount of predicted beam distortion. The target cell is then signaled to prepare for a handover of responsibility for serving the wireless communication equipment.

Claims

1. A method of handing over responsibility for serving a wireless communication equipment from a serving cell to a target cell in a cellular telecommunications system, wherein the wireless communication equipment is situated in a first aircraft that is in-flight, wherein the method is performed by a network node of the cellular telecommunications system, the method comprising:

determining an aircraft position, an aircraft velocity, and an aircraft direction;

for each candidate cell of a plurality of candidate cells, predicting a level of beam distortion through a handover that would result from a beam directed from the candidate cell to the first aircraft;

selecting the target cell from the plurality of candidate cells by identifying which of the plurality of candidate cells has a least amount of predicted beam distortion through the handover; and

signaling the target cell to prepare for a handover of responsibility for serving the wireless communication equipment.

2. The method of claim 1, wherein determining the aircraft position, the aircraft velocity, and the aircraft direction comprises:

periodically acquiring, via an aircraft navigation broadcast receiver, acquired navigation information transmitted from the first aircraft, wherein the acquired navigation information comprises;

the position of the first aircraft;

an altitude of the first aircraft; and

a time value indicating when the position of the first aircraft was determined; and

determining the velocity and the direction from the periodically acquired navigation information.

3. The method of claim 1, wherein predicting the level of beam distortion through the handover that would result from the beam directed from the candidate cell to the first aircraft comprises:

predicting a level of Doppler shift that would result from the beam directed from the candidate cell to the first aircraft.

4. The method of claim 1, wherein selecting the target cell from the plurality of candidate cells by identifying which of the plurality of candidate cells has the least amount of predicted beam distortion through the handover comprises stabilizing Doppler shift through the handover.

5. The method of claim 1, wherein:

predicting the level of beam distortion through the handover that would result from the beam directed from the candidate cell to the first aircraft comprises;

predicting for a given future moment in time, a beam angle between a first vector representing the trajectory of the first aircraft and a second vector between the first aircraft and a candidate cell antenna, wherein the first and second vectors are vectors in a Euclidean three-dimensional space; and

selecting the target cell from the plurality of candidate cells by identifying which of the plurality of candidate cells has the least amount of predicted beam distortion through the handover comprises;

determining which of the candidate cells has the beam angle that is closest to being normal to the first aircraft direction.

6. The method of claim 1, wherein:

predicting the level of beam distortion through the handover that would result from the beam directed from the candidate cell to the first aircraft comprises;

predicting for a given future moment in time, a beam angle between a first vector representing the trajectory of the first aircraft and a second vector between the first aircraft and a candidate cell antenna, wherein the first and second vectors are vectors in a Euclidean three-dimensional space; and

selecting the target cell from the plurality of candidate cells by identifying which of the plurality of candidate cells has the least amount of predicted beam distortion through the handover comprises;

determining which of the candidate cells has the beam angle that is closest to being tangential to the first aircraft direction.

7. The method of claim 1, wherein:

predicting the level of beam distortion through the handover that would result from the beam directed from the candidate cell to the first aircraft comprises;

predicting for a given future moment in time, a first angle between a first vector representing the trajectory of the first aircraft and a second vector between the first aircraft and a serving cell antenna; and

predicting for the given future moment in time, a second angle between the first vector representing the trajectory of the first aircraft and a third vector between the first aircraft and a candidate cell antenna, wherein the first, second, and third vectors are vectors in a Euclidean three-dimensional space; and

selecting the target cell from the plurality of candidate cells by identifying which of the plurality of candidate cells has the least amount of predicted beam distortion through the handover comprises;

identifying which of the plurality of candidate cells has the second angle that is most like the first angle.

8. The method of claim 1, wherein predicting the level of beam distortion through the handover that would result from the beam directed from the candidate cell to the first aircraft comprises:

predicting for a given future moment in time, an azimuth and direction of a beam from the candidate cell to the first aircraft;

predicting for the given future moment in time, an azimuth and direction of a beam from the candidate cell to a second aircraft having onboard wireless communication equipment in need of cellular communication system service;

determining a degree of similarity between the predicted azimuth and direction of the beam from the candidate cell to the first aircraft and the predicted azimuth and direction of the beam from the candidate cell to the second aircraft; and

using the degree of similarity as an indicator of the level of beam distortion.

9. The method of claim 1, wherein predicting the level of beam distortion through the handover that would result from the beam directed from the candidate cell to the first aircraft comprises:

predicting, for a future moment in time, that a second aircraft that is served by a cell other than the candidate cell will be coming into a coverage area of a beam from the candidate cell.

10. An apparatus for handing over responsibility for serving a wireless communication equipment from a serving cell to a target cell in a cellular telecommunications system, wherein the wireless communication equipment is situated in a first aircraft that is in-flight, wherein apparatus is associated with a network node of the cellular telecommunications system, the apparatus comprising:

circuitry configured to determine an aircraft position, an aircraft velocity, and an aircraft direction;

circuitry configured to predict, for each candidate cell of a plurality of candidate cells, a level of beam distortion through a handover that would result from a beam directed from the candidate cell to the first aircraft;

circuitry configured to select the target cell from the plurality of candidate cells by identifying which of the plurality of candidate cells has a least amount of predicted beam distortion through the handover; and

circuitry configured to signal the target cell to prepare for a handover of responsibility for serving the wireless communication equipment.

11. The apparatus of claim 10, wherein the circuitry configured to determine the aircraft position, the aircraft velocity, and the aircraft direction comprises:

circuitry configured to periodically acquire, via an aircraft navigation broadcast receiver, acquired navigation information transmitted from the first aircraft, wherein the acquired navigation information comprises;

the position of the first aircraft;

an altitude of the first aircraft; and

a time value indicating when the position of the first aircraft was determined; and

circuitry configured to determine the velocity and the direction from the periodically acquired navigation information.

12. The apparatus of claim 10, wherein the circuitry configured to predict the level of beam distortion through the handover that would result from the beam directed from the candidate cell to the first aircraft comprises:

circuitry configured to predict a level of Doppler shift that would result from the beam directed from the candidate cell to the first aircraft.

13. The apparatus of claim 10, wherein the circuitry configured to select the target cell from the plurality of candidate cells by identifying which of the plurality of candidate cells has the least amount of predicted beam distortion through the handover comprises circuitry configured to stabilize Doppler shift through the handover.

14. The apparatus of claim 10, wherein:

the circuitry configured to predict the level of beam distortion through the handover that would result from the beam directed from the candidate cell to the first aircraft comprises;

circuitry configured to predict for a given future moment in time, a beam angle between a first vector representing the trajectory of the first aircraft and a second vector between the first aircraft and a candidate cell antenna, wherein the first and second vectors are vectors in a Euclidean three-dimensional space; and

the circuitry configured to select the target cell from the plurality of candidate cells by identifying which of the plurality of candidate cells has the least amount of predicted beam distortion through the handover comprises;

circuitry configured to determine which of the candidate cells has the beam angle that is closest to being normal to the first aircraft direction.

15. The apparatus of claim 10, wherein:

the circuitry configured to predict the level of beam distortion through the handover that would result from the beam directed from the candidate cell to the first aircraft comprises;

circuitry configured to predict for a given future moment in time, a beam angle between a first vector representing the trajectory of the first aircraft and a second vector between the first aircraft and a candidate cell antenna, wherein the first and second vectors are vectors in a Euclidean three-dimensional space; and

the circuitry configured to select the target cell from the plurality of candidate cells by identifying which of the plurality of candidate cells has the least amount of predicted beam distortion through the handover comprises;

circuitry configured to determine which of the candidate cells has the beam angle that is closest to being tangential to the first aircraft direction.

16. The apparatus of claim 10, wherein:

the circuitry configured to predict the level of beam distortion through the handover that would result from the beam directed from the candidate cell to the first aircraft comprises;

circuitry configured to predict for a given future moment in time, a first angle between a first vector representing the trajectory of the first aircraft and a second vector between the first aircraft and a serving cell antenna; and

circuitry configured to predict for the given future moment in time, a second angle between the first vector representing the trajectory of the first aircraft and a third vector between the first aircraft and a candidate cell antenna, wherein the first, second, and third vectors are vectors in a Euclidean three-dimensional space; and

the circuitry configured to select the target cell from the plurality of candidate cells by identifying which of the plurality of candidate cells has the least amount of predicted beam distortion through the handover comprises;

circuitry configured to identify which of the plurality of candidate cells has the second angle that is most like the first angle.

17. The apparatus of claim 10, wherein the circuitry configured to predict the level of beam distortion through the handover that would result from the beam directed from the candidate cell to the first aircraft comprises:

circuitry configured to predict for a given future moment in time, an azimuth and direction of a beam from the candidate cell to the first aircraft;

circuitry configured to predict for the given future moment in time, an azimuth and direction of a beam from the candidate cell to a second aircraft having onboard wireless communication equipment in need of cellular communication system service;

circuitry configured to determine a degree of similarity between the predicted azimuth and direction of the beam from the candidate cell to the first aircraft and the predicted azimuth and direction of the beam from the candidate cell to the second aircraft; and

circuitry configured to use the degree of similarity as an indicator of the level of beam distortion.

18. The apparatus of claim 10, wherein the circuitry configured to predict the level of beam distortion through the handover that would result from the beam directed from the candidate cell to the first aircraft comprises:

circuitry configured to predict, for a future moment in time, that a second aircraft that is served by a cell other than the candidate cell will be coming into a coverage area of a beam from the candidate cell.

19. A nontransitory computer readable storage medium comprising program instructions that, when performed by one or more processors of a network node of a cellular telecommunications system, cause the network node to perform a method of handing over responsibility for serving a wireless communication equipment from a serving cell to a target cell in the cellular telecommunications system, wherein the wireless communication equipment is situated in a first aircraft that is in-flight, and wherein the method comprises:

determining an aircraft position, an aircraft velocity, and an aircraft direction;

for each candidate cell of a plurality of candidate cells, predicting a level of beam distortion through a handover that would result from a beam directed from the candidate cell to the first aircraft;

selecting the target cell from the plurality of candidate cells by identifying which of the plurality of candidate cells has a least amount of predicted beam distortion through the handover; and

signaling the target cell to prepare for a handover of responsibility for serving the wireless communication equipment.

20. The nontransitory computer readable storage medium of claim 19, wherein selecting the target cell from the plurality of candidate cells by identifying which of the plurality of candidate cells has the least amount of predicted beam distortion through the handover comprises stabilizing Doppler shift through the handover.