DERIVATION AND FEEDBACK OF TRANSMIT STEERING MATRIX

• US 20070268181A1
• Filed: 05/17/2007
• Published: 11/22/2007
• Est. Priority Date: 05/22/2006
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Wallace, Mark, Howard, Steven, Walton, J., Ketchum, John
• Granted Patent: US 8,290,089 B2
• Time in Patent Office: Days
• US Class Current: 342/368
• CPC Class Codes: H01Q 21/00 Antenna arrays or systems arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system H01Q3/00
• CPC Class Codes: H04B 7/0404 the mobile station comprising multiple antennas, e.g. to provide uplink diversity
• CPC Class Codes: H04B 7/0417 Feedback systems
• CPC Class Codes: H04B 7/0634 Antenna weights or vector/matrix coefficients
• CPC Class Codes: H04B 7/066 Combined feedback for a number of channels, e.g. over several subcarriers like in orthogonal frequency division multiplexing [OFDM]
• CPC Class Codes: H04L 1/0675 characterised by the signaling

Abstract

Techniques for efficiently deriving a transmit steering matrix and sending feedback for this matrix are described. A receiver determines a set of parameters defining a transmit steering matrix to be used for transmission from a transmitter to the receiver. The receiver may derive the transmit steering matrix based on a set of transformation matrices, which may be used for multiple iterations of Jacobi rotation to zero out off-diagonal elements of a channel matrix. The receiver may then determine the set of parameters based on the transformation matrices. The set of parameters may comprise at least one angle, at least one value, at least one index, etc., for each transformation matrix. The receiver sends the set of parameters defining the transmit steering matrix (instead of elements of the transmit steering matrix) to the transmitter for use by the transmitter to derive the transmit steering matrix.

Claims

1. An apparatus comprising:

at least one processor configured to determine a set of parameters defining a transmit steering matrix to be used for transmission from a transmitter to a receiver, and to send the set of parameters to the transmitter for use by the transmitter to derive the transmit steering matrix; and

a memory coupled to the at least one processor.

2. The apparatus of claim 1, wherein the at least one processor is configured to derive the transmit steering matrix based on a plurality of transformation matrices, and to determine the set of parameters based on the plurality of transformation matrices.

3. The apparatus of claim 2, wherein the at least one processor is configured to perform a plurality of iterations of Jacobi rotation on a channel matrix with the plurality of transformation matrices to zero out off-diagonal elements of the channel matrix.

4. The apparatus of claim 3, wherein for each iteration of the Jacobi rotation the at least one processor is configured to derive a transformation matrix based on the channel matrix, to update the channel matrix based on the transformation matrix, and to update the transmit steering matrix based on the transformation matrix.

5. The apparatus of claim 4, wherein for each iteration of the Jacobi rotation, the at least one processor is configured to form a submatrix of the channel matrix, to decompose the submatrix to obtain an intermediate matrix of eigenvectors of the submatrix, and to form the transformation matrix based on the intermediate matrix.

6. The apparatus of claim 4, wherein for each iteration of the Jacobi rotation, the at least one processor is configured to identify a largest off-diagonal element of the channel matrix, and to derive the transformation matrix based on row and column indices of the largest off-diagonal element.

7. The apparatus of claim 4, wherein the at least one processor is configured to select elements of the channel matrix in a predetermined order for the plurality of iterations of the Jacobi rotation, and to derive the transformation matrix for each iteration of the Jacobi rotation based on elements of the channel matrix selected for the iteration.

8. The apparatus of claim 4, wherein the at least one processor is configured to initialize the transmit steering matrix to an identity matrix, a transmit steering matrix for another subcarrier, or a transmit steering matrix for another time interval prior to the plurality of iterations of the Jacobi rotation.

9. The apparatus of claim 4, wherein the at least one processor is configured to derive the channel matrix based on a channel response estimate.

10. The apparatus of claim 4, wherein the at least one processor is configured to derive a correlation matrix for a channel response matrix and to use the correlation matrix as the channel matrix.

11. The apparatus of claim 2, wherein the set of parameters comprises at least one angle for at least one element of each of the transformation matrices.

12. The apparatus of claim 11, wherein the at least one processor is configured to obtain the at least one angle for each transformation matrix with uniform quantization.

13. The apparatus of claim 11, wherein the at least one processor is configured to obtain the at least one angle for each transformation matrix with non-uniform quantization from CORDIC computation.

14. The apparatus of claim 2, wherein the set of parameters comprises at least one value for at least one element of each transformation matrix, at least one index for the at least one element of each transmit, an indication of a form of each transformation matrix, or a combination thereof.

15. A method comprising:

determining a set of parameters defining a transmit steering matrix to be used for transmission from a transmitter to a receiver; and

sending the set of parameters to the transmitter for use by the transmitter to derive the transmit steering matrix.

16. The method of claim 15, wherein the determining the set of parameters comprises

deriving the transmit steering matrix based on a plurality of transformation matrices, and

determining the set of parameters based on the plurality of transformation matrices.

17. The method of claim 16, wherein the deriving the transmit steering matrix comprises

performing a plurality of iterations of Jacobi rotation on a channel matrix with the plurality of transformation matrices, and

for each iteration of the Jacobi rotation,

deriving a transformation matrix based on the channel matrix,

updating the channel matrix based on the transformation matrix, and

updating the transmit steering matrix based on the transformation matrix.

18. The method of claim 16, wherein the determining the set of parameters based on the plurality of transformation matrices comprises

forming the set of parameters with at least one angle for at least one element of each transformation matrix.

19. An apparatus comprising:

means for determining a set of parameters defining a transmit steering matrix to be used for transmission from a transmitter to a receiver; and

means for sending the set of parameters to the transmitter for use by the transmitter to derive the transmit steering matrix.

20. The apparatus of claim 19, wherein the means for determining the set of parameters comprises

means for deriving the transmit steering matrix based on a plurality of transformation matrices, and

means for determining the set of parameters based on the plurality of transformation matrices.

21. The apparatus of claim 20, wherein the means for deriving the transmit steering matrix comprises

means for performing a plurality of iterations of Jacobi rotation on a channel matrix with the plurality of transformation matrices, and

means for, for each iteration of the Jacobi rotation,

deriving a transformation matrix based on the channel matrix,

updating the channel matrix based on the transformation matrix, and

updating the transmit steering matrix based on the transformation matrix.

22. The apparatus of claim 20, wherein the means for determining the set of parameters based on the plurality of transformation matrices comprises

means for forming the set of parameters with at least one angle for at least one element of each transformation matrix.

23. A processor-readable medium including instructions stored thereon, comprising:

a first instruction set for determining a set of parameters defining a transmit steering matrix to be used for transmission from a transmitter to a receiver; and

a second instruction set for sending the set of parameters to the transmitter for use by the transmitter to derive the transmit steering matrix.

24. The processor-readable medium of claim 23, wherein the first instruction set comprises

a third instruction set for deriving the transmit steering matrix based on a plurality of transformation matrices, and

a fourth instruction set for determining the set of parameters based on the plurality of transformation matrices.

25. The processor-readable medium of claim 24, wherein the fourth instruction set comprises

a fifth instruction set for forming the set of parameters with at least one angle for at least one element of each transformation matrix.

26. An apparatus comprising:

at least one processor configured to receive a set of parameters defining a transmit steering matrix, to derive the transmit steering matrix based on the set of parameters, and to use the transmit steering matrix for transmission from a transmitter to a receiver; and

a memory coupled to the at least one processor.

27. The apparatus of claim 26, wherein the at least one processor is configured to initialize the transmit steering matrix, to form a plurality of transformation matrices based on the set of parameters, and to update the transmit steering matrix with each of the transformation matrices.

28. The apparatus of claim 27, wherein the at least one processor is configured to obtain at least one angle for at least one element of each transformation matrix from the set of parameters, and to form each transformation matrix based on the at least one angle for the transformation matrix.

29. The apparatus of claim 28, wherein the at least one processor is configured to derive the at least one element of each transformation matrix by performing CORDIC computation based on the at least one angle for the transformation matrix.

30. The apparatus of claim 27, wherein the at least one processor is configured to initialize the transmit steering matrix to an identity matrix, a transmit steering matrix for another subcarrier, or a transmit steering matrix for another time interval.

31. A method comprising:

receiving a set of parameters defining a transmit steering matrix;

deriving the transmit steering matrix based on the set of parameters; and

using the transmit steering matrix for transmission from a transmitter to a receiver.

32. The method of claim 31, wherein the deriving the transmit steering matrix comprises

initializing the transmit steering matrix,

forming a plurality of transformation matrices based on the set of parameters, and

updating the transmit steering matrix with each of the transformation matrices.

33. The method of claim 32, wherein the forming the plurality of transformation matrices comprises

obtaining at least one angle for at least one element of each transformation matrix from the set of parameters, and

forming each transformation matrix based on the at least one angle for the transformation matrix.

34. An apparatus comprising:

means for receiving a set of parameters defining a transmit steering matrix;

means for deriving the transmit steering matrix based on the set of parameters; and

means for using the transmit steering matrix for transmission from a transmitter to a receiver.

35. The apparatus of claim 34, wherein the means for deriving the transmit steering matrix comprises

means for initializing the transmit steering matrix,

means for forming a plurality of transformation matrices based on the set of parameters, and

means for updating the transmit steering matrix with each of the transformation matrices.

36. The apparatus of claim 35, wherein the means for forming the plurality of transformation matrices comprises

means for obtaining at least one angle for at least one element of each transformation matrix from the set of parameters, and

means for forming each transformation matrix based on the at least one angle for the transformation matrix.

37. A processor-readable medium including instructions stored thereon, comprising:

a first instruction set for receiving a set of parameters defining a transmit steering matrix;

a second instruction set for deriving the transmit steering matrix based on the set of parameters; and

a third instruction set for using the transmit steering matrix for transmission from a transmitter to a receiver.

38. The processor-readable medium of claim 37, wherein the second instruction set comprises

a fourth instruction set for initializing the transmit steering matrix,

a fifth instruction set for forming a plurality of transformation matrices based on the set of parameters, and

a sixth instruction set for updating the transmit steering matrix with each of the transformation matrices.

39. The processor-readable medium of claim 38, wherein the fifth instruction set comprises

a seventh instruction set for obtaining at least one angle for at least one element of each transformation matrix from the set of parameters, and

an eighth instruction set for forming each transformation matrix based on the at least one angle for the transformation matrix.