SYSTEM AND METHOD OF WEIGHTED AVERAGING IN THE ESTIMATION OF ANTENNA BEAMFORMING COEFFICIENTS

• US 20090121935A1
• Filed: 05/09/2008
• Published: 05/14/2009
• Est. Priority Date: 11/12/2007
• Status: Abandoned Application

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: XIA, Pengfei, NGO, Chiu
• Application Number:
  US12/118,502
• Publication Number:
  US 20090121935A1
• Time in Patent Office: Days
• US Class Current: 342/377
• CPC Class Codes: H01Q 3/2605 Array of radiating elements provided with a feedback control over the element weights, e.g. adaptive arrays

Abstract

A system and method of training transmit or receive antenna array is disclosed. The method includes: a) entering an antenna training mode, b) receiving a training sequence to form a channel matrix (Q), c) constructing an updated receive beamforming vector (w) via a weighted averaging method, the weighted averaging comprising:

$w=\sum _{i=1}^Ka_iq_i,$

where q_i is the ith column of the matrix Q, a_i is the ith weighting coefficient, and K is the column size of the Q matrix, and d) sending another training sequence with the receive antenna array that has been beamformed with the updated w vector. The method further includes repeating b)-d) a plurality of times until the w vector is optimized. The method further includes beamforming the receive antenna array by the use of an optimized w vector.

Claims

1. A method of training transmit or receive antenna array for improving a signal-to-noise ratio performance in a beamforming wireless system, the method comprising:

iteratively constructing an optimized transmit beamforming vector (v) and an optimized receive beamforming vector (w) via an iterative antenna training algorithm in an antenna training mode, the iterative antenna training algorithm comprising;

updating a first channel matrix (P) based at least partly on a received first training sequence, the first training sequence having been processed with an updated interim v, wherein the P represents a frequency domain channel viewed from a transmit station,

updating an interim v, wherein the updating comprises estimating at least one of beamforming coefficients for the interim v by a weighted averaging of one of more elements of the updated P, the weighted averaging comprising

$v=\underset{i=1}{\overset{L}{\sum <br><br>}}<br><br>b_i<br><br>p_i,$

wherein;

p_i is the ith column of the matrix P,

b_i is the ith weighting coefficient to be designed, and

L is the column size of the P matrix; and

updating a second channel matrix (Q) based at least partly on a received second training sequence, the second training sequence having been processed with the updated interim w, wherein the Q represents a frequency domain channel viewed from a receive station, and

updating an interim w, wherein the updating comprises estimating at least one of beamforming coefficients for the interim v by a weighted averaging of one of more elements of the updated Q, the weighted averaging comprising

$w=\underset{i=1}{\overset{K}{\sum <br><br>}}<br><br>a_i<br><br>q_i,$

wherein;

q_i is the ith column of the matrix Q,

a_i is the ith weighting coefficient, and

K is the column size of the Q matrix;

terminating the iterative antenna training algorithm; and

beamforming a transmit or receive antenna array with the optimized beamforming vectors v and w.

2. The method of claim 1, further comprising storing the optimized v vector in a memory in the transmit station and storing the optimized w vector in a memory in the receive station.

3. The method of claim 1, wherein the iterative antenna training algorithm is terminated after a preset level of convergence or a beam-acquired state is achieved.

4. The method of claim 3, wherein the preset level of convergence is reached when there is less than 2% maximum difference in two consecutive estimations of beamforming coefficients.

5. The method of claim 1, wherein the iterative antenna training algorithm is terminated after a preset number of iterations.

6. The method of claim 1, further comprising providing an arbitrary initial v or w vector at the first iteration.

7. The method of claim 1, further comprising:

exiting the training mode after the iterative antenna training algorithm is terminated;

entering a data communication mode; and

processing a data signal using the optimized v vector and the optimized w vector.

8. The method of claim 1, wherein:

P;

=[H₁q, . . . H_jq, . . . , H_Kq]; and

Q;

[H₁p, . . . H_jp, . . . , H_Kp],

wherein H_j represents a multiple-input and multiple-output (MIMO) channel on the j^th subcarrier.

9. A method of training a transmit antenna array for improving a signal-to-noise ratio performance in a beamforming wireless system, the method comprising:

a) entering an antenna training mode;

b) sending a training sequence with the transmit antenna array that has been beamformed with a transmit beamforming vector (v);

c) receiving another training sequence to form an interim channel matrix (P);

d) constructing an updated v vector via a weighted averaging, the weighted averaging comprising

$v=\underset{i=1}{\overset{L}{\sum <br><br>}}<br><br>b_i<br><br>p_i,$

wherein;

p_i is the ith column of the matrix P,

b_i is the ith weighting coefficient to be designed, and

L is the column size of the P matrix;

e) repeating b)-d) a plurality of times until the v vector is optimized; and

f) beamforming the transmit antenna array with the optimized v vector.

10. The method of claim 9, wherein the construction of the updated v vector is part of an iterative antenna training algorithm for constructing the optimized v vector.

11. The method of claim 10, wherein the iterative antenna training algorithm is terminated after one of a preset level of convergence, a preset number of iterations, and a beam-acquired state.

12. The method of claim 10, further comprising:

exiting the training mode after the iterative antenna training algorithm is terminated; and

entering a data communication mode.

13. The method of claim 9, wherein the weighted averaging comprises a weighted averaging of p_i across a plurality of subcarriers.

14. The method of claim 9, wherein the weighting coefficients are predetermined at a product development stage.

15. The method of claim 9, wherein b_i=1 for all values of i ranging between 1 and L.

16. The method of claim 9, wherein b_i=1 for i=J, and b_i=0 for all other values of i ranging between 1 and L, wherein p_J, the J^th column of the P matrix, is the column with the largest vector norm compared to vector norms of other columns of the P matrix.

17. The method of claim 9, wherein b_i=1 for i=J1, J2, . . . , or JM, and b_i=0 for all other values of i ranging between 1 and L, wherein P_J1, p_J2, . . . , p_JM, the J1^th, J2^th, . . . , JM^th column of the P matrix, are the M columns with the M largest vector norm compared to vector norms of other columns of the P matrix.

18. A method of training a receive antenna array for improving a signal-to-noise ratio performance in a beamforming wireless system, the method comprising:

a) entering an antenna training mode;

b) receiving a training sequence to form a channel matrix (Q);

c) constructing an updated receive beamforming vector (w) via a weighted averaging, the weighted averaging comprising

$w=\underset{i=1}{\overset{K}{\sum <br><br>}}<br><br>a_i<br><br>q_i,$

wherein;

q_i is the ith column of the matrix Q,

a_i is the ith weighting coefficient, and

K is the column size of the Q matrix;

d) sending another training sequence with the receive antenna array that has been beamformed with the updated w vector;

e) repeating b)-d) a plurality of times until the w vector is optimized; and

f) beamforming the receive antenna array with the optimized w vector.

19. The method of claim 18, wherein the construction of the updated w vector is part of an iterative antenna training algorithm for constructing the optimized v vector.

20. The method of claim 19, wherein the iterative antenna training algorithm is terminated after one of a preset level of convergence, a preset number of iterations, and a beam-acquired state.

21. The method of claim 18, wherein the weighted averaging comprises a weighted averaging of q_i across a plurality of subcarriers.

22. The method of claim 18, wherein the weighting coefficients are predetermined at a product development stage.

23. The method of claim 18, wherein a_i=1 for all values of i ranging between 1 and K.

24. The method of claim 18, wherein a_i=1 for i=J, and b_i=0 for all other values of i ranging between 1 and L, wherein q_J, the J^th column of the Q matrix, is the column with the largest vector norm compared to vector norms of other columns of the Q matrix.

25. The method of claim 18, wherein a_i=1 for i=J1, J2, . . . , or JM, and a_i=0 for all other values of i ranging between 1 and L, wherein q_J1, q_J2, . . . , q_JM, the J1^th, J2^th, . . . , JM^th column of the Q matrix, are the M columns with the M largest vector norm compared to vector norms of other columns of the Q matrix.

26. An apparatus for data communication in a wireless network, the apparatus comprising:

one or more processors configured to;

a) send a training sequence via a transmit antenna array that has been beamformed with a transmit beamforming vector (v) in an antenna training mode,

b) receive another training sequence to form an interim channel matrix (P),

c) construct an updated v vector via a weighted averaging, the weighted averaging comprising

$v=\underset{i=1}{\overset{L}{\sum <br><br>}}<br><br>b_i<br><br>p_i,$

wherein;

p_i is the ith column of the matrix P,

b_i is the ith weighting coefficient to be designed, and

L is the column size of the P matrix,

d) repeat a)-c) a plurality of times until the v vector is optimized; and

a transmit antenna array that is configured to transmit a data signal after having been beamformed with the optimized v vector.

27. The apparatus of claim 26, further comprising a memory for storing one or more weighting coefficients for the weighted averaging.

28. An apparatus for data communication in a wireless network, the apparatus comprising:

one or more processors configured to;

a) receive a training sequence to form a channel matrix (Q) in an antenna training mode,

b) construct an updated receive beamforming vector (w) via a weighted averaging method, the weighted averaging comprising

$w=\underset{i=1}{\overset{K}{\sum <br><br>}}<br><br>a_i<br><br>q_i,$

wherein

q_i is the ith column of the matrix Q,

a_i is the ith weighting coefficient, and

K is the column size of the Q matrix, and

c) send another training sequence with the receive antenna array that has been beamformed with the updated w vector, and

d) repeat a)-c) a plurality of times until the w vector is optimized; and

a receive antenna array that is configured to receive a data signal after having been beamformed with the optimized w vector.

29. A method of training transmit or receive antenna array for improving a signal-to-noise ratio performance in a beamforming wireless system, the method comprising:

iteratively constructing optimized transmit and receive beamforming vectors by estimating interim receive and transmit beamforming vectors alternately until a preset level of convergence is achieved,

wherein estimating the interim receive and transmit beamforming vectors comprises a weighted averaging involving one or more weighting coefficients multiplied by one or more columns of receive and transmit channel matrices; and

beamforming transmit and receive antenna array by the use of the optimized transmit and receiving beamforming vectors.