Transceiver capable of IQ mismatch compensation on the fly and method thereof

• US 9,479,203 B2
• Filed: 12/29/2011
• Issued: 10/25/2016
• Est. Priority Date: 04/14/2011
• Status: Active Grant

• Current Assignee: MediaTek, Inc.
• Original Assignee: MediaTek, Inc.
• Inventors: Peng, Chun-Hsien
• Primary Examiner(s): TAYONG, HELENE E
• Application Number:
  US13/339,666
• Publication Number:
  US 20120263215A1
• Time in Patent Office: 1,762 Days
• Field of Search: 375/221, 375/222, 375/296, 375/316, 455/552.1, 455/127.4, 455/132
• US Class Current: 1/1
• CPC Class Codes: H04B 1/0475 with means for limiting noise, interference or distortion H04B1/0483 takes precedence
• CPC Class Codes: H04B 1/40 Circuits

Abstract

A transceiver capable of IQ mismatch compensation on the fly and a method thereof. The transceiver comprises a transmitter circuit and a loop-back circuit. The transmitter circuit is configured to up-convert a modulation signal on the fly to generate a first RF signal. The loop-back circuit is configured to down-convert the first RF signal and then digitize the down-converted first RF signal to determine a first IQ mismatch parameter based on a first statistical measure of the digitized down-converted RF signal. The transmitter circuit is further configured to compensate for first IQ mismatch in the transmitter circuit according to the first IQ mismatch parameter to generate an IQ compensated modulation signal.

Claims

1. A transceiver capable of IQ mismatch compensation, comprising:

a transmitter circuit, configured to up-convert a modulation signal on the fly to generate a first RF signal for both radio transmission and IQ mismatch determination, wherein the first RF signal is passed to an antenna for radio transmission; and

a loop-back circuit, configured to receive the first RF signal generated by the transmitter circuit, down-convert the first RF signal, and then digitize the down-converted first RF signal, the loop-back circuit comprising an IQ mismatch detector configured to receive both the modulation signal and the down-converted first RF signal, the IQ mismatch detector further configured to determine a first IQ mismatch parameter based on a first statistical measure of the digitized down-converted first RF signal in relation to the modulation signal,

wherein the transmitter circuit further comprises a transmitter IQ mismatch compensator that receives the modulation signal and is configured to compensate for first IQ mismatch in the transmitter circuit according to the first IQ mismatch parameter determined by the IQ mismatch detector to generate an IQ compensated modulation signal.

2. The transceiver of claim 1, wherein the transmitter circuit is configured to up-convert the modulation signal by a first oscillation signal with a first oscillation frequency that is substantially identical to a second oscillation frequency of a second oscillation signal, which is used to down-convert the first RF signal in the loop-back circuit.

3. The transceiver of claim 1, wherein the loop-back circuit is further configured to receive a second RF signal from an air interface, down-convert the second RF signal and then digitize the down-converted second RF signal to determine a receiver IQ mismatch parameter based on a second statistical measure of the digitized down-converted second RF signal, and compensate for IQ mismatch of a receiver path therein according to the receiver IQ mismatch parameter.

4. The transceiver of claim 1, wherein the transmitter circuit is configured to up-convert the modulation signal with a first oscillation signal comprising a first frequency, and the loop-back circuit is configured to down-convert the first RF signal with a second oscillation signal comprising a second frequency, and the first oscillation frequency is different from the second oscillation signal by a frequency difference.

5. The transceiver of claim 4, wherein the loop-back circuit is further configured to compensate for second IQ mismatch in the loop-back circuit according to the first IQ mismatch parameter to generate a receiver IQ compensated signal, and down-convert the receiver IQ compensated signal with the frequency difference to determine the first IQ mismatch parameter based on a second statistical measure of the down-converted receiver IQ compensated signal, and the transmitter is configured to compensate for the first IQ mismatch in the transmitter circuit according to the second IQ mismatch parameter to generate the IQ compensated modulation signal.

6. The transceiver of claim 1, wherein the transmitter circuit is further configured to determine a scale factor according to the modulation signal and the IQ compensated modulation signal, and scale the IQ compensated modulation signal with the scale factor.

7. The transceiver of claim 1, wherein the transmitter circuit comprises:

a complex conjugate unit, for receiving the modulation signal to generate a conjugate thereof;

a complex multiplier, for multiplying the conjugate of the modulation signal by the first IQ mismatch parameter to generate an IQ compensation signal; and

a complex adder, for adding the modulation signal and the IQ compensation signal together to generate the IQ compensated modulation signal.

8. The transceiver of claim 1, wherein the first IQ mismatch parameter comprises a first parameter and a second parameter, and the transmitter circuit comprises

a first complex multiplier, for multiplying the modulation signal by the first parameter to generate a first IQ compensation signal;

a complex conjugate unit, for receiving the modulation signal to generate a conjugate thereof;

a second complex multiplier, for multiplying the conjugate of the modulation signal by the second parameter to generate a second IQ compensation signal; and

a complex adder, for adding the first IQ compensation signal and the second IQ compensation signal together to generate the IQ compensated modulation signal.

9. The transceiver of claim 1, wherein the transmitter circuit is further configured to up-convert a single tone signal during startup of the transceiver for initial compensation of the first IQ mismatch in the transmitter circuit.

10. A compensation method, performed by a transceiver to compensate for IQ mismatch thereof, comprising:

up-converting a modulation signal to generate a first RF signal for both radio transmission and IQ mismatch determination;

passing the first RF signal to an antenna for radio transmission;

down-converting and digitizing the first RF signal;

directing the first RF signal to a loop-back circuit comprising an IQ mismatch detector configured to receive both the modulation signal and the down-converted first RF signal, the IQ mismatch detector further configured to determine a first IQ mismatch parameter based on a first statistical measure of the digitized down-converted first RF signal in relation to the modulation signal; and

compensating for first IQ mismatch in the transmitter circuit comprises a transmitter IQ mismatch compensator that receives the modulation signal according to the first IQ mismatch parameter to generate an IQ compensated modulation signal.

11. The compensation method of claim 10, further comprising up-converting the modulation signal on the fly by a first oscillation signal with a first oscillation frequency that is substantially identical to a second oscillation frequency of a second oscillation signal, which is used to perform the step of down-converting the first RF signal.

12. The compensation method of claim 10, further comprising:

receiving a second RF signal from an air interface;

down-converting and digitizing the second RF signal;

determining a receiver IQ mismatch parameter based on a second statistical measure of the digitized down-converted second RF signal; and

compensating for IQ mismatch of a receiver path therein according to the receiver IQ mismatch parameter.

13. The compensation method of claim 10, further comprising:

up-converting the modulation signal with a first oscillation signal comprising a first frequency; and

down-converting the first RF signal with a second oscillation signal comprising a second frequency,

wherein the first oscillation frequency is different from the second oscillation signal by a frequency difference.

14. The compensation method of claim 13, further comprising:

compensating for a second IQ mismatch in the loop-back circuit according to the first IQ mismatch parameter to generate a receiver IQ compensated signal;

down-converting the receiver IQ compensated signal with the frequency difference to determine the first IQ mismatch parameter based on a second statistical measure of the down-converted receiver IQ compensated signal; and

compensating for the first IQ mismatch in the transmitter circuit according to the second IQ mismatch parameter to generate the IQ compensated modulation signal.

15. The compensation method of claim 10, wherein the compensating for the first IQ mismatch further comprises determining a scale factor according to the modulation signal and the IQ compensated modulation signal, and scaling the IQ compensated modulation signal with the scale factor.

16. The compensation method of claim 10, further comprising:

receiving the modulation signal to generate a conjugate thereof;

multiplying the conjugate of the modulation signal by the first IQ mismatch parameter to generate an IQ compensation signal; and

adding the modulation signal and the IQ compensation signal together to generate the IQ compensated modulation signal.

17. The compensation method of claim 10, wherein the first IQ mismatch parameter comprises a first parameter and a second parameter, and the compensation method further comprises:

multiplying the modulation signal by the first parameter to generate a first IQ compensation signal;

receiving the modulation signal to generate a conjugate thereof;

multiplying the conjugate of the modulation signal by the second parameter to generate a second IQ compensation signal; and

adding the first IQ compensation signal and the second IQ compensation signal together to generate the IQ compensated modulation signal.

18. The compensation method of claim 10, further comprising up-converting a single tone signal during startup of the circuitry for initial compensation of the first IQ mismatch in the transmitter circuit.

19. A transceiver capable of IQ mismatch compensation, comprising:

a transmitter circuit comprising a transmitter IQ mismatch compensator that receives a modulation signal, the transmitter circuit configured to up-convert the modulation signal to generate a first RF signal for both radio transmission and IQ mismatch determination, wherein the first RF signal is passed to an antenna for radio transmission and passed to a loop-back circuit for IQ mismatch determination concurrently, the loop-back circuit, configured to receive the first RF signal generated by the transmitter circuit, down-convert the first RF signal, and then digitize the down-converted first RF signal, the loop-back circuit comprising an IQ mismatch detector configured to receive both the modulation signal and the down-converted first RF signal, the IQ mismatch detector further configured to determine a first IQ mismatch parameter based on a first statistical measure of the digitized down-converted first RF signal in relation to the modulation signal;

wherein the transmitter circuit is further configured to compensate for IQ mismatch in the transmitter circuit according to the IQ mismatch parameter determined by the loop-back circuit, and normal operation of the transceiver needs not to be hindered, interrupted or stopped when performing the IQ mismatch determination and compensation.