Method and apparatus for estimating and compensating for in-phase and quadrature (IQ) mismatch in a receiver of a wireless communication device

• US 9,160,586 B1
• Filed: 07/23/2014
• Issued: 10/13/2015
• Est. Priority Date: 07/24/2013
• Status: Expired due to Fees

• Current Assignee: NXP USA, Inc. (NXP Semiconductors NV)
• Original Assignee: Marvell International Limited (Marvell Technology Group Limited)
• Inventors: Hu, Zixia, Wu, Songping
• Primary Examiner(s): DEPPE, BETSY LEE
• Application Number:
  US14/339,348
• Time in Patent Office: 447 Days
• Field of Search: 375/322, 375/324
• US Class Current: 1/1
• CPC Class Codes: H04L 2027/0016 Stabilisation of local oscillators
• CPC Class Codes: H04L 27/0014 Carrier regulation of chaotic carriers H04L27/001; for multicarrier receivers H04L27/2657
• CPC Class Codes: H04L 27/3863 Compensation for quadrature error in the received signal

Abstract

Systems and techniques relating to IQ mismatch estimation and compensation are described. A described technique includes obtaining samples of a received signal via circuitry having an IQ mismatch; determining an estimated gain imbalance parameter for the IQ mismatch based on an in-phase average value of in-phase training samples and a quadrature average value of quadrature training samples; determining an estimated phase imbalance parameter for the IQ mismatch based on a combined average value, the estimated gain imbalance parameter, and a squared average value, the combined average value being based on a pair-wise multiplication of the in-phase training samples and the quadrature training samples, the squared average value being based on squared versions of the in-phase training samples; updating the in-phase data samples based on the estimated gain imbalance parameter to produce updated in-phase data samples; and updating the quadrature data samples by respectively adding quadrature update values thereto.

Claims

1. A method comprising:

obtaining samples of a received signal via circuitry having an in-phase and quadrature (IQ) mismatch, the samples comprising (i) first samples, including in-phase first samples and quadrature first samples, of a training signal of the received signal and (ii) second samples, including in-phase second samples and quadrature second samples, of a data signal of the received signal;

determining an estimated gain imbalance parameter for the IQ mismatch based on (i) an in-phase average value and (ii) a quadrature average value, the in-phase average value being based on the in-phase first samples, and the quadrature average value being based on the quadrature first samples;

determining an estimated phase imbalance parameter for the IQ mismatch based on (i) a combined average value, (ii) the estimated gain imbalance parameter, and (iii) a squared average value, the combined average value being based on a pair-wise multiplication of the in-phase first samples and the quadrature first samples, the squared average value being based on squared versions of the in-phase first samples;

updating the in-phase second samples based on the estimated gain imbalance parameter to produce updated in-phase second samples; and

updating the quadrature second samples by respectively adding quadrature update values to the quadrature second samples to produce updated quadrature second samples, the quadrature update values being respectively based on (i) the estimated phase imbalance parameter and (ii) the updated in-phase second samples.

2. The method of claim 1, wherein determining the estimated gain imbalance parameter comprises calculating in accordance with

3. The method of claim 2, wherein determining the estimated phase imbalance parameter comprises calculating in accordance with

4. The method of claim 3, wherein updating the in-phase second samples comprises multiplicatively applying a factor based on ε

_est to each of the in-phase second samples.

5. The method of claim 4, wherein updating the quadrature second samples comprises multiplicatively applying a factor based on φ

_est to each of the updated in-phase second samples to respectively produce the quadrature update values.

6. The method of claim 2, wherein determining the estimated phase imbalance parameter comprises calculating in accordance with

7. The method of claim 1, wherein the training signal comprises a single tone signal.

8. The method of claim 1, wherein the training signal corresponds to a preamble portion of a packet, and the data signal corresponds to a data portion of the packet.

9. An apparatus, comprising:

first circuitry configured to

determine an in-phase average value based on (i) in-phase first samples of a training signal received via circuitry having an IQ mismatch, (ii) a quadrature average value based on quadrature first samples of the training signal, (iii) a squared average value based on squared versions of the in-phase first samples, and (iv) a combined average value based on a pair-wise multiplication of the in-phase first samples and the quadrature first samples,

determine an estimated gain imbalance parameter for the IQ mismatch based on the in-phase average value and the quadrature average value, and

determine an estimated phase imbalance parameter for the IQ mismatch based on (i) the combined average value, (ii) the estimated gain imbalance parameter, and (iii) the squared average value; and

second circuitry configured to

update in-phase second samples of a data signal received via the circuitry having the IQ mismatch based on the estimated gain imbalance parameter to produce updated in-phase second samples, and

update quadrature second samples of the data signal by respectively adding quadrature update values to the quadrature second samples to produce updated quadrature second samples, the quadrature update values being respectively based on (i) the estimated phase imbalance parameter and (ii) the updated in-phase second samples.

10. The apparatus of claim 9, wherein the estimated gain imbalance parameter is based on

11. The apparatus of claim 10, wherein the estimated phase imbalance parameter is based on

12. The apparatus of claim 11, wherein the second circuitry is configured to multiplicatively apply a factor based on ε

_est to each of the in-phase second samples to respectively produce the updated in-phase second samples.

13. The apparatus of claim 12, wherein the second circuitry is configured to multiplicatively apply a factor based on φ

_est to each of the updated in-phase second samples to respectively produce the quadrature update values.

14. The apparatus of claim 10, wherein the estimated phase imbalance parameter is based on

15. The apparatus of claim 9, wherein the training signal comprises a single tone signal.

16. The apparatus of claim 9, wherein the training signal corresponds to a preamble portion of a packet, and the data signal corresponds to a data portion of the packet.

17. A system, comprising:

a downconverter configured to receive signals comprising a training signal and a data signal;

an analog-to-digital convertor coupled with the downconverter, and configured to produce samples based on the receive signals, the samples comprising (i) first samples of the training signal and (ii) second samples of the data signal, the first samples comprising (i) in-phase first samples and (ii) quadrature first samples, the second samples comprising (i) in-phase second samples and (ii) quadrature second samples; and

a processor coupled with the convertor, and configured to perform operations comprising;

determining an in-phase expected value based on (i) the in-phase first samples, (ii) a quadrature expected value based on the quadrature first samples, (iii) a squared expected value based on squared versions of the in-phase first samples, and (iv) a combined expected value based on a pair-wise multiplication of the in-phase first samples and the quadrature first samples;

determining an estimated gain imbalance parameter for an IQ mismatch associated with at least the downconverter based on (i) the in-phase expected value and (ii) the quadrature expected value;

determining an estimated phase imbalance parameter for the IQ mismatch based on (i) the combined expected value, (ii) the estimated gain imbalance parameter, and (iii) the squared expected value;

updating the in-phase second samples based on the estimated gain imbalance parameter to produce updated in-phase second samples; and

updating the quadrature second samples by respectively adding thereto quadrature update values to produce updated quadrature second samples, the quadrature update values being respectively based on the estimated phase imbalance parameter and the updated in-phase second samples.

18. The system of claim 17, wherein determining the estimated gain imbalance parameter comprises calculating in accordance with

19. The system of claim 18, wherein determining the estimated phase imbalance parameter comprises calculating in accordance with

20. The system of claim 19, wherein updating the in-phase second samples comprises multiplicatively applying a factor based on ε

_est to each of the in-phase second samples.

21. The system of claim 20, wherein updating the quadrature second samples comprises multiplicatively applying a factor based on φ

_est to each of the updated in-phase second samples to respectively produce the quadrature update values.

22. The system of claim 17, wherein the training signal corresponds to a preamble portion of a packet, and the data signal corresponds to a data portion of the packet.