Method for pointing high-gain antennas to reduce interference in mobile networks

• US 8,254,843 B2
• Filed: 12/11/2006
• Issued: 08/28/2012
• Est. Priority Date: 12/11/2006
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Tillotson, Brian J.
• Primary Examiner(s): Le, Lana N
• Assistant Examiner(s): LIAO, HSINCHUN
• Application Number:
  US11/609,076
• Publication Number:
  US 20080139124A1
• Time in Patent Office: 2,087 Days
• Field of Search: 455/63.4, 455/431, 455/562.1, 343/705
• US Class Current: 455/63.4
• CPC Class Codes: H01Q 1/246 specially adapted for base stations
• CPC Class Codes: H01Q 3/08 for varying two co-ordinates of the orientation
• CPC Class Codes: H01Q 3/2605 Array of radiating elements provided with a feedback control over the element weights, e.g. adaptive arrays
• CPC Class Codes: H04W 16/28 using beam steering

Abstract

A method for reducing interference in a mobile network is provided. The method includes determining locations of a plurality of nodes in the mobile network; steering at least one antenna at a node in the plurality of nodes in the mobile network; estimating intensity of signals from the at least one antenna at each of the plurality of nodes; determining optimal direction to steer the at least one antenna to reduce interference; and steering the at least one antenna in the optimal direction.

Claims

1. A method for reducing interference in a mobile network, comprising:

determining locations of a plurality of nodes in the mobile network;

steering at least one antenna at a first node in the plurality of nodes in the mobile network;

estimating intensity of signals from the at least one antenna at each of the plurality of nodes;

determining a direction to steer the at least one antenna to reduce interference in which a second node in the plurality of nodes is located at a null in the signals; and

steering the at least one antenna in the direction;

wherein the step of determining the direction further comprises;

computing a first primary-to-secondary ratio when the at least one antenna is pointed at a first node in the plurality of nodes with a highest interference level to form a first direction;

responsive to the first primary-to-secondary ratio meeting a specified level, determining that the optimal direction is the first direction;

responsive to the first primary-to-secondary ratio not meeting the specified level, computing a second primary-to-secondary ratio when the at least one antenna is pointed such that a second node is in the null in the signals to form a second direction, wherein the second node received a most interference when the at least one antenna was pointed in the first direction;

responsive to the second primary-to-secondary ratio meeting the specified level, determining that the optimal direction is the second direction;

responsive to the second primary-to-secondary ratio not meeting the specified level, computing a third primary-to-secondary ratio when the at least one antenna is pointed at the second direction and a beam for the signals is incrementally widened to form a third direction;

responsive to the third primary-to-secondary ratio meeting the specified level, determining that the optimal direction is the third direction.

2. The method of claim 1, wherein a series of heuristics are used to determine the direction to minimize the interference when the plurality of nodes are too close to each other.

3. The method of claim 2, wherein each heuristic in the series of heuristics employs a primary-secondary ratio as part of applying the heuristic.

4. The method of claim 3, wherein a parameter in optimizing the primary-secondary ratio is varying antenna beam width.

5. The method of claim 3, wherein a parameter in optimizing the primary-secondary ratio is varying antenna beam'"'"'s rotation angle about beam axis.

6. The method of claim 1, wherein the locations are determined by reports from radars, by navigation data embedded in messages from each node, or by conical scans.

7. The method of claim 1, wherein the step of steering the at least one antenna in the direction further comprises:

mechanically pointing the at least one antenna in the direction.

8. The method of claim 7, wherein azimuth, elevation and antenna gain are used to determine the direction to point the antenna.

9. The method of claim 7, wherein the range to each node and the signal'"'"'s attenuation with distance are used to determine the direction to point the at least one antenna.

10. The method of claim 1, wherein an automated tracking system keeps the at least one antenna pointed in a correct location when the plurality of nodes are moving.

11. The method of claim 1, wherein the at least one antenna is pointed off-center relative to the first node in the plurality of nodes.

12. The method of claim 10, wherein the automated tracking system measures signal power in a plurality of directions.

13. The method of claim 12, wherein coefficients for each signal power measurement location are computed;

and wherein the coefficients correspond to relative signal power at the direction; and

wherein the coefficients are used by the autotracker to steer the antenna.

14. The method of claim 1, wherein the null is a first null, the signals have at least two nulls separated by an area where the signals may be received, and the first null and a second null are areas of zero gain in the signals.

15. The method of claim 1, wherein the second node being located at the null in the signals comprises the second node receiving less of the signals than the first node.

16. The method of claim 1, wherein the null is a first null, and a third node in the plurality of nodes is located at a second null in the signals, wherein the second null is separated from the first null by at least a portion of the signals.