Antenna array calibration for wireless communication systems

• US 8,498,669 B2
• Filed: 04/04/2006
• Issued: 07/30/2013
• Est. Priority Date: 06/16/2005
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Naguib, Ayman Fawzy, Agrawal, Avneesh, Gorokhov, Alexei
• Primary Examiner(s): Doan, Kiet
• Assistant Examiner(s): Vu, Michael T
• Application Number:
  US11/398,077
• Publication Number:
  US 20060284725A1
• Time in Patent Office: 2,674 Days
• Field of Search: 455/562, 455/562.1, 455/509, 455/550.1, 455/445, 455/522, 455/423, 340/7.39, 343/729, 702/107
• US Class Current: 455/562.1
• CPC Class Codes: H01Q 3/267 Phased-array testing or checking devices

Abstract

Calibration for a transmit chain of a device transmitting information to multiple devices over wireless links and receive chains of the multiple devices receiving information over one of the wireless links utilizing a plurality of forward link channel estimates received from at least some of the plurality of devices and a plurality of reverse link channel estimates from the plurality of devices.

Claims

1. A method of calibrating an antenna array in a wireless network, comprising:

receiving first channel estimate information corresponding to transmissions to a first access terminal;

determining second channel estimate information corresponding to transmissions from the first access terminal;

receiving third channel estimate information corresponding to transmissions to a second access terminal;

determining fourth channel estimate information corresponding to transmissions from the second access terminal; and

determining a calibration ratio based upon the first, second, third, and fourth channel estimate information for at least the first and second access terminals,

wherein determining the calibration ratio comprises;

determining a first calibration ratio based upon the first and second channel estimate information;

determining second calibration ratio based upon the third and fourth channel estimate information; and

determining the calibration ratio based upon combining the first and second calibration ratios.

2. The method of claim 1, wherein combining comprises averaging the first and second calibration ratios.

3. The method of claim 1, wherein the first and second calibration ratios comprise a plurality of elements each corresponding to at least one antenna of an access point in communication with the first and second access terminals, and wherein combining comprises:

normalizing the first calibration ratio;

normalizing the second calibration ratio; and

determining the calibration ratio based upon a matrix including the first and second calibration ratio.

4. The method of claim 3, wherein determining the calibration ratio based upon the matrix comprises decomposing the matrix utilizing singular value decomposition.

5. A method of calibrating an antenna array in a wireless network, comprising:

receiving first channel estimate information corresponding to transmissions to a first access terminal;

determining second channel estimate information corresponding to transmissions from the first access terminal;

receiving third channel estimate information corresponding to transmissions to a second access terminal;

determining fourth channel estimate information corresponding to transmissions from the second access terminal; and

determining a calibration ratio based upon the first, second, third, and fourth channel estimate information for at least the first and second access terminals

wherein determining the calibration ratio comprises solving the equation;

6. The method of claim 5, wherein solving comprising using an MMSE technique to solve the equation.

7. A method of calibrating an antenna array in a wireless network, comprising:

receiving first channel estimate information corresponding to transmissions to a first access terminal;

determining second channel estimate information corresponding to transmissions from the first access terminal;

receiving third channel estimate information corresponding to transmissions to a second access terminal;

determining fourth channel estimate information corresponding to transmissions from the second access terminal; and

determining a calibration ratio based upon the first, second, third, and fourth channel estimate information for at least the first and second access terminals;

receiving fifth channel estimate information corresponding to transmissions to a third access terminal;

determining sixth channel estimate information corresponding to transmissions from the third access terminal; and

determining calibration ratio based upon the first, second, third, fourth, fifth, and sixth channel estimate information for at least the first, second, and third access terminals.

8. A wireless communication apparatus comprising:

at least two antennas; and

a processor coupled with the at least two antennas, the processor configured to determine a calibration ratio for communication with each of the plurality of access terminals, the processor operative to

receive first channel estimate information corresponding to transmissions to a first access terminal;

determine second channel estimate information corresponding to transmissions from the first access terminal;

receive third channel estimate information corresponding to transmissions to a second access terminal;

determine fourth channel estimate information corresponding to transmissions from the second access terminal; and

determine a calibration ratio based upon the first, second, third, and fourth channel estimate information for at least the first and second access terminals,

wherein determining the calibration ratio comprises;

determine a first calibration ratio based upon the first and second channel estimate information;

determine second calibration ratio based upon the third and fourth channel estimate information; and

determine the calibration ratio based upon combining the first and second calibration ratios.

9. The wireless communication apparatus of claim 8, wherein the processor is configured to combine the ratios by averaging the first and second the calibration ratios.

10. The wireless communication apparatus of claim 8, wherein the first and second calibration ratios comprise a plurality of elements each corresponding to at least one of said antennas, and wherein the processor is configured to combine the ratios by normalizing the first calibration ratio, normalizing the second calibration ratio, and to determine the calibration ratio based upon a matrix including the first and second calibration ratios.

11. The wireless communication apparatus of claim 10, wherein the processor is configured utilize singular value decomposition to decompose the matrix to obtain the calibration ratio.

12. An wireless communication apparatus comprising:

at least two antennas; and

a processor coupled with the at least two antennas, the processor configured to determine a calibration ratio, based upon a plurality of forward link channel estimates and reverse link channel estimates from a plurality of access terminals, for communication with each of the plurality of access terminals,

wherein the processor is configured to determine the calibration ratio by solving the equation;

13. The wireless communication apparatus of claim 12, wherein the processor is configured to solve the equation by using an MMSE technique.

14. An apparatus comprising:

means for receiving first channel estimate information corresponding to transmissions to a first access terminal;

means for determining second channel estimate information corresponding to transmissions from the first access terminal;

means for receiving third channel estimate information corresponding to transmissions to a second access terminal;

means for determining fourth channel estimate information corresponding to transmissions from the second access terminal;

means for determining a calibration ratio based upon the first, second, third, and fourth channel estimate information for at the least first and second access terminals,

means for determining a first calibration ratio based upon the first and second channel estimate information;

means for determining second calibration ratio based upon the third and fourth channel estimate information; and

means for determining the calibration ratio based upon combining the first and second calibration ratios.

15. The apparatus of claim 14, wherein the means for combining comprises means for averaging the different calibration ratios.

16. The apparatus of claim 14, wherein the first and second calibration ratios comprise a plurality of elements each corresponding to at least one antenna of an access point in communication with the first and second access terminals, and wherein means for determining comprises:

means for normalizing the first calibration ratios;

means normalizing the second calibration ratio; and

means for determining the calibration ratio based upon a matrix including the first and second calibration ratio.

17. A processor-readable medium having stored thereon instructions for use by a processor, the instructions comprise instructions to:

receive first channel estimate information corresponding to transmissions to a first access terminal;

determine second channel estimate information corresponding to transmissions from the first access terminal;

receive third channel estimate information corresponding to transmissions to a second access terminal;

determine fourth channel estimate information corresponding to transmissions from the second access terminal;

determine a calibration ratio based upon the first, second, third, and fourth channel estimate information, for at the least first and second access terminals,

determine a first calibration ratio based upon the first and second channel estimate information;

determine second calibration ratio based upon the third and fourth channel estimate information; and

determine the calibration ratio based upon combining the first and second calibration ratios.

18. The processor-readable medium of claim 17, further comprising instructions to:

average the first and second calibration ratios.

19. The processor-readable medium of claim 17, wherein the first and second calibration ratios comprise a plurality of elements each corresponding to at least one antenna of an access point in communication with the first and second access terminals, and wherein the instructions to combine the calibration ratios comprises instructions to:

normalize the first calibration ratio;

normalize the second calibration ratio; and

determine the calibration ratio based upon a matrix including the first and second calibration ratio.

20. The processor-readable medium of claim 19, wherein the instructions to determine the calibration ratio based upon the matrix comprises instructions to decompose the matrix utilizing singular value decomposition.

21. A wireless communication apparatus comprising:

at least two antennas; and

a processor coupled with the at least two antennas, the processor configured to determine a calibration ratio for communication with each of the plurality of access terminals, the processor operative to

receive first channel estimate information corresponding to transmissions to a first access terminal;

determine second channel estimate information corresponding to transmissions from the first access terminal;

receive third channel estimate information corresponding to transmissions to a second access terminal;

determine fourth channel estimate information corresponding to transmissions from the second access terminal; and

determine a calibration ratio based upon the first, second, third, and fourth channel estimate information for at least the first and second access terminals,

receive fifth channel estimate information corresponding to transmissions to a third access terminal;

determine sixth channel estimate information corresponding to transmissions from the third access terminal; and

determine a calibration ratio based upon the first, second, third, fourth, fifth, and sixth channel estimate information for at least the first, second, and third access terminals.

22. An apparatus comprising:

means for receiving first channel estimate information corresponding to transmissions to a first access terminal;

means for determining second channel estimate information corresponding to transmissions from the first access terminal;

means for receiving third channel estimate information corresponding to transmissions to a second access terminal;

means for determining fourth channel estimate information corresponding to transmissions from the second access terminal; and

means for determining a calibration ratio based upon the first, second, third, and fourth channel estimate information for at least the first and second access terminals,

wherein determining the calibration ratio comprises means for solving the equation;

23. The apparatus of claim 22, wherein said means for solving comprise means for using an MMSE technique to solve the equation.

24. An apparatus comprising:

means for receiving first channel estimate information corresponding to transmissions to a first access terminal;

means for determining second channel estimate information corresponding to transmissions from the first access terminal;

means for receiving third channel estimate information corresponding to transmissions to a second access terminal;

means for determining fourth channel estimate information corresponding to transmissions from the second access terminal; and

means for determining a calibration ratio based upon the first, second, third, and fourth channel estimate information for at least the first and second access terminals;

means for receiving fifth channel estimate information corresponding to transmissions to a third access terminal;

means for determining sixth channel estimate information corresponding to transmissions from the third access terminal; and

means for determining a calibration ratio based upon the first, second, third, fourth, fifth, and sixth channel estimate information for at least the first, second, and third access terminals.

25. A processor-readable medium having stored thereon instructions for use by a processor, the instructions comprise instructions to:

receive first channel estimate information corresponding to transmissions to a first access terminal;

determine second channel estimate information corresponding to transmissions from the first access terminal;

receive third channel estimate information corresponding to transmissions to a second access terminal;

determine fourth channel estimate in formation corresponding to transmissions from the second access terminal; and

determine a calibration ratio based upon the first, second, third, and fourth channel estimate information for at least the first and second access terminals,

wherein determining the calibration ratio comprises solving the equation;

26. The processor-readable medium of claim 25, wherein the instructions for solving comprise instructions to use an MMSE technique to solve the equation.

27. A processor-readable medium having stored thereon instructions for use by a processor, the instructions comprise instructions to:

receive first channel estimate information corresponding to transmissions to a first access terminal;

determine second channel estimate information corresponding to transmissions from the first access terminal;

receive third channel estimate information corresponding to transmissions to a second access terminal;

determine fourth channel estimate information corresponding to transmissions from the second access terminal; and

determine a calibration ratio based upon the first, second, third, and fourth channel estimate information for at least the first and second access terminals;

receive fifth channel estimate information corresponding to transmissions to a third access terminal;

determine sixth channel estimate information corresponding to transmissions from the third access terminal; and

determine a calibration ratio based upon the first, second, third, fourth, fifth, and sixth channel estimate information for at least the first, second, and third access terminals.