Adaptive taper selection for beamforming

1. A satellite communication system, comprising:

a planar phased antenna array having a field of view (FoV) and configured to communicate with a plurality of cells in the FoV via a plurality of uplink beams, each of the plurality of uplink beams being associated with one of the plurality of cells; and

a control satellite having a processing device configured for the plurality of uplink beams that adaptively determine an uplink beam taper for each uplink beam of the plurality of uplink beams and distribute, to the phased array, the uplink beam taper for each uplink beam of the plurality of uplink beams.

2. The satellite communication system of claim 1 , wherein the uplink beam taper is adapted based on a distance between a target cell and a source of interference.

3. The satellite communication system of claim 2 , wherein the source of interference is a network of terrestrial cells.

4. The satellite communication system of claim 2 , wherein the uplink beam taper is a Chebyshev taper in response to the target cell being nearby the network of terrestrial cells.

5. The satellite communication system of claim 1 , wherein the processing device of the control satellite determines a first interference from a Chebyshev taper and a second interference from a Kaiser taper, and apply the Chebyshev taper if the first interference is lower than the second interference, and apply the Kaiser taper if the first interference is equal to or higher than the second interference.

6. The satellite communication system of claim 1 , wherein the processing device of the control satellite determines a first interference from a Chebyshev taper and a second interference from a Kaiser taper, and select the Chebyshev taper or the Kaiser taper based on which one of the first interference and the second interference is lower.

7. The satellite communication system of claim 1 , wherein the processing device of the control satellite determines a first interference from a Chebyshev taper and a second interference from a rectangular taper, and apply the Chebyshev taper if the first interference is lower than the second interference, and apply the rectangular taper if the first interference is equal to or higher than the second interference.

8. The satellite communication system of claim 1 , wherein the processing device of the control satellite determines a first interference from a Chebyshev taper, a second interference from a Kaiser taper, and a third interference from a rectangular taper, and applies the Chebyshev taper if the first interference is lower than the second interference and the third interference, applies the Kaiser taper if the second interference is lower than the first interference and the third interference, and applies the rectangular taper if the third interference is lower than the first interference and the second interference.

9. The satellite communication system of claim 1 , wherein the processing device of the control satellite determines a first interference from a Chebyshev taper, a second interference from a Kaiser taper, and a third interference from a rectangular taper, and selects the Chebyshev taper or the Kaiser taper or the rectangular interference based on which one of the first interference, second interference, and third interference is lowest.

10. The satellite communication system of claim 2 , wherein when the target is at or near a nadir in the FoV and when the target cell is nearby to the source of interference, the processing device of the control satellite applies a Chebyshev taper.

11. The satellite communication system of claim 2 , wherein when the target is at or near a nadir in the FoV and when the target cell is remote from the source of interference, the processing device of the control satellite applies a Kaiser taper.

12. The satellite communication system of claim 2 , wherein when the target is at or near an edge of the FoV and when the target cell is nearby to the source of interference, the processing device of the control satellite applies a Chebyshev taper.

13. The satellite communication system of claim 2 , wherein when the target is at or near an edge of the FoV and when the target cell is remote from the source of interference, the processing device of the control satellite applies a rectangular taper.

14. The satellite communication system of claim 2 , wherein the processing device of the control satellite applies a full aperture for each uplink beam of the plurality of uplink beams.

15. The communication system of claim 13 , wherein:

the phased antenna array includes a plurality of antenna elements; and

the phased antenna array is configured to apply the determined downlink sub-aperture to reduce peak-to-average-power (PAPR) of the plurality of antenna elements.

16. A satellite communication system, comprising:

a planar phased antenna array having a plurality of antenna elements, a field of view (FoV) and an aperture, and configured to communicate with a plurality of cells in the FoV via a plurality of downlink beams, each of the plurality of downlink beams being associated with one of the plurality of cells; and

a control satellite having a processing device configured to:

select a downlink sub-aperture for each of the plurality of downlink beams, each selected downlink sub-aperture being a collection of contiguous antenna elements of the plurality of antenna elements in the planar phased antenna array;

determine a downlink beam taper for each downlink beam of the plurality of downlink beams; and

distribute, to the phased array, the selected downlink sub-aperture and the downlink beam taper for each downlink beam of the plurality of downlink beams.

17. The communication system of claim 16 , wherein:

the processing device is configured to select the downlink sub-aperture substantially tangential to the overall aperture, substantially orthogonal to the direction of the target cell, in order to reduce peak-to-average-power (PAPR) of the plurality of elements;

for arbitrary-shape overall aperture, this PAPR reduction employs a search procedure to select each downlink beam's sub-aperture;

when the peak power is associated with the antenna element at a centroid of the overall aperture, the search procedure may be done on a beam-by-beam basis; and

the search procedure involves determining a sub-aperture position in the overall aperture that has a lowest contribution to peak power.