Blind signal separation using array deflection

• US 7,098,849 B2
• Filed: 09/22/2005
• Issued: 08/29/2006
• Est. Priority Date: 09/23/2004
• Status: Expired due to Fees

• Current Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Original Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Inventors: Goldberg, Steven J.
• Primary Examiner(s): Tarcza, Thomas H.
• Assistant Examiner(s): Mull, Fred H
• Application Number:
  US11/233,160
• Publication Number:
  US 20060069530A1
• Time in Patent Office: 341 Days
• Field of Search: 342/373, 342377-378, 342/380, 342382-383
• US Class Current: 342/383
• CPC Class Codes: H04B 7/08 at the receiving station

Abstract

A communications device for separating source signals provided by M signal sources includes an antenna array comprising N antenna elements for generating N initial antenna patterns for receiving N different summations of the M source signals, with N being less than M. The antenna array includes an elevation controller for selectively changing an elevation of at least one of the N initial antenna patterns for generating at least one additional antenna pattern so that at least one additional different summation of the M source signals is received thereby. A blind signal separation processor forms a mixing matrix comprising the N different summations of the M source signals, and the at least one additional different summation of the M source signals. The mixing matrix has a rank equal to N plus the number of additional different summations of the M source signals received using the additional antenna patterns. The blind signal separation processor separates desired source signals from the mixing matrix.

Claims

1. A communications device for separating source signals provided by M signal sources, the communications device comprising:

an antenna array comprising N antenna elements for generating N initial antenna patterns for receiving N different summations of the M source signals, with N being less than M;

said antenna array comprising an elevation controller for selectively changing an elevation of at least one of the N initial antenna patterns for generating at least one additional antenna pattern so that at least one additional different summation of the M source signals is received thereby;

a receiver connected to said antenna array for receiving the N different summations of the M source signals using the N initial antenna patterns, and for receiving the at least one additional different summation of the M source signals using the at least one additional antenna pattern; and

a blind signal separation processor connected to said receiver for forming a mixing matrix comprising the N different summations of the M source signals and the at least one additional different summation of the M source signals, the mixing matrix having a rank equal to N plus the number of additional different summations of the M source signals received using the additional antenna patterns, said blind signal separation processor for separating desired source signals from the mixing matrix.

2. A communications device according to claim 1 wherein N=1 so that the rank of the mixing matrix is equal to 2.

3. A communications device according to claim 1 wherein said elevation controller selectively changes the elevation of the N initial antenna patterns so that N additional antenna patterns are generated for receiving N additional different summations of the M source signals, with the rank of the mixing matrix now being equal to 2N.

4. A communications device according to claim 1 wherein said elevation controller is segmented into k regions relative to said N antenna elements, each region being independently controlled for changing the elevation of the N initial antenna patterns so that N additional antenna patterns are generated for receiving N additional different summations of the M source signals, with the rank of the mixing matrix now being equal to 2 kN.

5. A communications device according to claim 1 wherein at least two of said N antenna elements are paired for different polarizations.

6. A communications device according to claim 1 wherein at least two of said N antenna elements are uncorrelated.

7. A communications device according to claim 1 wherein said N antenna elements are correlated.

8. A communications device according to claim 7 wherein said N correlated antenna elements comprise N active antenna elements so that said antenna array forms a phased array.

9. A communications device according to claim 7 wherein said N correlated antenna elements comprise at least one active antenna element, and up to N-1 passive antenna elements so that said antenna array forms a switched beam antenna.

10. A communications device according to claim 1 wherein said antenna array comprises a ground plane;

and wherein said N antenna elements comprise;

an active antenna element adjacent said ground plane;

a plurality of passive antenna elements adjacent said ground plane, each passive antenna element comprising

an upper half and a corresponding lower half,

an upper variable reactive load connecting said upper half to said ground plane for changing an antenna pattern in azimuth;

said elevation controller comprising a respective lower variable reactive load for each passive antenna element for connecting said lower half to said ground plane, the N antenna patterns being moved in elevation by adjusting at least one of the lower variable reactive loads.

11. A communications device according to claim 1 wherein said antenna array comprises a ground plane adjacent said N antenna elements;

and wherein said elevation controller comprises a controllable RF choke coupled to said ground plane, the N antenna beams being moved in elevation by controlling said RF choke.

12. A communications device according to claim 1 wherein said antenna array forms at least N antenna beams for receiving the at least N different summations of the M source signals, each antenna beam having 3 db points down from a maximum gain point thereof providing for signal rejection in at least one direction of an approaching signal.

13. A communications device according to claim 1 wherein said antenna array forms at least one antenna pattern for receiving at least one of the N different summations of the M source signals, the at least one antenna pattern having substantially no 3 db points down from a maximum gain point thereof resulting in no signal rejection in any direction of an approaching signal.

14. A communications device according to claim 1 wherein each summation of the M source signals is linear.

15. A communications device according to claim 1 wherein said blind signal separation processor separates the desired source signals from the mixing matrix based on principal component analysis (PCA).

16. A communications device according to claim 1 wherein said blind signal separation processor separates the desired source signals from the mixing matrix based on independent component analysis (ICA).

17. A communications device according to claim 1 wherein said blind signal separation processor separates the desired source signals from the mixing matrix based on single value decomposition (SVD).

18. A method for operating a communications device for separating source signals provided by M signal sources, the communications device comprising an antenna array comprising N elements and an elevation controller connected thereto, a receiver connected to the antenna array, and a blind signal separation processor connected to the receiver, the method comprising:

generating at the antenna array N initial antenna patterns for receiving N different summations of the M source signals, with N being less than M;

operating the elevation controller for selectively changing an elevation of at least one of the N initial antenna patterns for generating at least one additional antenna pattern so that at least one additional different summation of the M source signals is received thereby;

providing the N different summations of the M source signals using the N initial antenna patterns to the receiver, and providing the at least one additional different summation of the M source signals using the at least one additional antenna pattern to the receiver; and

processing by the blind signal separation (BSS) processor the N different summations of the M source signals and the at least one additional different summation of the M source signals, the processing comprising

forming a mixing matrix comprising the N different summations of the M source signals and the at least one additional different summation of the M source signals, the mixing matrix having a rank equal to N plus the number of additional different summations of the M source signals received using the additional antenna patterns, and

separating desired source signals from the mixing matrix.

19. A method according to claim 18 wherein N=1 so that the rank of the mixing matrix is equal to 2.

20. A method according to claim 18 wherein the elevation controller selectively changes the elevation of the N initial antenna patterns so that N additional antenna patterns are generated for receiving N additional different summations of the M source signals, with the rank of the mixing matrix now being equal to 2N.

21. A method according to claim 18 wherein the elevation controller is segmented into k regions relative to the N antenna elements, each region being independently controlled for changing the elevation of the N initial antenna patterns so that N additional antenna patterns are generated for receiving N additional different summations of the M source signals, with the rank of the mixing matrix now being equal to 2 kN.

22. A method according to claim 18 wherein at least two of the N antenna elements are paired for different polarizations.

23. A method according to claim 18 wherein at least two of the N antenna elements are uncorrelated.

24. A method according to claim 18 wherein the N antenna elements are correlated.

25. A method according to claim 24 wherein the N correlated antenna elements comprise N active antenna elements so that the antenna array forms a phased array.

26. A method according to claim 24 wherein the N correlated antenna elements comprise at least one active antenna element, and up to N-1 passive antenna elements so that the antenna array forms a switched beam antenna.

27. A method according to claim 18 wherein the antenna array forms at least N antenna beams for receiving the at least N different summations of the M source signals, each antenna beam having 3 db points down from a maximum gain point thereof providing for signal rejection in at least one direction of an approaching signal.

28. A method according to claim 18 wherein the antenna array forms at least one antenna pattern for receiving at least one of the N different summations of the M source signals, the at least one antenna pattern having substantially no 3 db points down from a maximum gain point thereof resulting in no signal rejection in any direction of an approaching signal.

29. A method according to claim 18 wherein the blind signal separation processor separates the desired source signals from the mixing matrix based on principal component analysis (PCA).

30. A method according to claim 18 wherein the blind signal separation processor separates the desired source signals from the mixing matrix based on independent component analysis (ICA).

31. A method according to claim 18 wherein the blind signal separation processor separates the desired source signals from the mixing matrix based on single value decomposition (SVD).