Method for reducing interference and increasing spectral efficiency

• US 6,088,416 A
• Filed: 04/21/1998
• Issued: 07/11/2000
• Est. Priority Date: 04/21/1998
• Status: Expired due to Term

• Current Assignee: Northrop Grumman Systems Corporation (Northrop Grumman Corporation)
• Original Assignee: TRW Inc. (Northrop Grumman Corporation)
• Inventors: Perahia, Eldad, Wilcoxson, Donald C., Saunders, Oliver W.
• Primary Examiner(s): Chin, Stephen
• Assistant Examiner(s): PARK, ALBERT C
• Application Number:
  US09/063,799
• Time in Patent Office: 812 Days
• Field of Search: 375/130, 375/377, 455/422, 455/427, 455/446, 455/447, 455/448, 455/449, 455/450, 455/451, 455/454, 455/12.1, 455/103
• US Class Current: 375/377
• CPC Class Codes: H04B 7/2041 Spot beam multiple access

Abstract

A method for reducing interference and increasing spectral efficiency in a frequency reuse pattern (600) is disclosed. The method includes the steps of generating n original communications beams (302-308) assigned to substantially non-overlapping frequency bands, with the original communications beams extending over a first set of predetermined bandwidths. The method also generates n shifted communications beams (402-408) shifted by an orthogonal frequency separation from the n original communications beams (302-308), with the n shifted communications beams (402-408) extending over a second set of predetermined bandwidths. The method projects the n original communications beams (302-308) and the n shifted communications beams (402-408) in a frequency reuse pattern (600) over a region of interest by alternating the n original communications beams (302-308) with the n shifted communications beams (402-408).

Claims

1. A method for reducing interference and increasing spectral efficiency in a frequency reuse pattern, the method comprising the steps of:

a. generating n original communications beams assigned to substantially non-overlapping frequency bands, said original communications beams extending over a first set of predetermined bandwidths;

b. generating n shifted communications beams shifted by an orthogonal frequency separation from said n original communications beams, said n shifted communications beams extending over a second set of predetermined bandwidths; and

c. projecting said n original communications beams and said n shifted communications beams in a frequency reuse pattern over a region of interest by alternating said n original communications beams with said n shifted communications beams.

2. The method of claim 1, wherein said orthogonal frequency separation is a minimum orthogonal frequency separation.

3. The method of claim 1, wherein said n shifted communications beams are shifted up in frequency by said orthogonal frequency separation.

4. The method of claim 3, wherein said orthogonal frequency separation is a minimum orthogonal frequency separation.

5. The method of claim 1, wherein said n shifted communications beams are shifted down in frequency by said orthogonal frequency separation.

6. The method of claim 5, wherein said orthogonal frequency separation is a minimum orthogonal frequency separation.

7. The method of claim 1, wherein n=(i² +ij+j²) for integer i,j.

8. The method of claim 7, wherein n=3.

9. The method of claim 7, wherein n =4.

10. The method of claim 7, wherein n=7.

11. The method of claim 7, wherein n=21.

12. A satellite communications method for reducing interference and increasing spectral efficiency in a frequency reuse pattern, the method comprising the steps of:

a. providing at least one transmitting antenna on-board a satellite.

b. generating n original communications beams assigned to substantially non-overlapping frequency bands, each of said original communications beams extending over a first set of predetermined bandwidths;

c. generating n shifted communications beams shifted by an orthogonal frequency separation from said n original communications beams, each of said n shifted communications beams extending over a second set of predetermined bandwidths; and

d. projecting, with said at least one transmitting antenna, said n original communications beams and said n shifted communications beams in a frequency reuse pattern over a region of interest by alternating said n original communications beams with said n shifted communications beams.

13. The method of claim 12, wherein said orthogonal frequency separation is a minimum orthogonal frequency separation.

14. The method of claim 12, wherein said n shifted communications beams are shifted up in frequency by said orthogonal frequency separation.

15. The method of claim 14, wherein said orthogonal frequency separation is a minimum orthogonal frequency separation.

16. The method of claim 12, wherein said n shifted communications beams are shifted down in frequency by said orthogonal frequency separation.

17. The method of claim 16, wherein said orthogonal frequency separation is a minimum orthogonal frequency separation.

18. The method of claim 12, wherein n=(i² +ij+j²) for integer i,j.

19. The method of claim 18, wherein n=3.

20. The method of claim 18, wherein n=4.

21. The method of claim 18, wherein n=7.

22. The method of claim 18, wherein n=21.