CROSSTALK CANCELLATION FOR DIGITAL PREDISTORTION FEEDBACK LOOP

1 - 22 . (canceled)

23 . A predistortion training system for a predistortion circuitry in a transceiver, comprising:

a separation circuitry configured to:

in a first mode, provide an amplified training signal to a receive chain of the transceiver, wherein the amplified training signal corresponds to a training signal amplified by a power amplifier in a transmit chain of the transceiver; and

in a second mode, process the amplified training signal to generate a modified amplified training signal and provide the modified amplified training signal to the receive chain of the transceiver; and

a training circuitry configured to:

receive a first feedback signal that includes the amplified training signal from the receive chain;

receive a second feedback signal that includes the modified amplified training signal from the receive chain;

determine parameters for the predistortion circuitry based at least on the first feedback signal and the second feedback signal; and

provide the determined parameters to the predistortion circuitry.

24 . The predistortion training system of claim 23 , wherein the training circuitry is configured to:

control the separation circuitry to operate in the first mode to output the amplified training signal;

receive the first feedback signal from the receive chain;

control the separation circuitry to operate in the second mode to generate the modified amplified training signal; and

receive the second feedback signal from the receive chain.

25 . The predistortion training system of claim 23 , wherein the separation circuitry comprises a phase shifter that is configured to phase shift the amplified training signal by Θ degrees to generate the modified amplified training signal, wherein Θ is other than 0.

26 . The predistortion training system of claim 25 , wherein Θ is approximately 180.

27 . The predistortion training system of claims 23 , wherein the training circuitry is configured to:

determine a power amplifier (PA) nonlinearity component and a crosstalk component based on the first feedback signal and the second feedback signal; and

determine the parameters based on either the PA nonlinearity component or the crosstalk component.

28 . The predistortion training system of claim 27 , wherein the training circuitry is configured to determine the parameters by:

determining an error between the PA nonlinearity component and the training signal; and

selecting the parameters to minimize the determined error.

29 . The predistortion training system of claim 27 , wherein the training circuitry is configured to:

in a first training iteration:

estimate model parameters of the crosstalk component; and

adapt a correction circuitry based on the estimated model parameters of the crosstalk component, wherein the correction circuitry is configured to receive the first feedback signal and generate the PA nonlinearity component; and

in a second training iteration:

determine an error between the PA nonlinearity component generated by the correction circuitry and the training signal; and

select the parameters to minimize the determined error.

30 . The predistortion training system of claim 23 , wherein the parameters comprise coefficients that are used by the predistortion circuitry to weight different components of a transmit signal.

31 . The predistortion training system of claim 23 , wherein the training circuitry comprises a baseband processor configured to execute stored instructions to determine the parameters.

32 . The predistortion training system of claim 23 , wherein the separation circuitry comprises a switch that is configured to disconnect the amplified training signal from the receive chain to generate the modified amplified training signal.

33 . A method configured to determine parameters for predistortion circuitry in a transceiver including a transmit chain and a receive chain, the method comprising:

providing a training signal to a power amplifier on the transmit chain;

controlling a separation circuitry to output the amplified training signal;

receiving a first feedback signal from the receive chain;

controlling the separation circuitry to output a modified amplified training signal;

receiving a second feedback signal from the receive chain;

determining parameters based at least on the first feedback signal and the second feedback signal; and

providing the determined parameters to the predistortion circuitry.

34 . The method of claim 33 , wherein the modified amplified training signal comprises the amplified training signal phase-shifted by Θ degrees, wherein Θ is other than 0.

35 . The method of claim 34 , wherein Θ is approximately 180.

36 . The method of claim 14 , further comprising:

determining a power amplifier (PA) nonlinearity component and a crosstalk component based on the first feedback signal and the second feedback signal; and

determining the parameters based on either the PA nonlinearity component or the crosstalk component.

37 . The method of claim 36 , further comprising:

determining an error between the PA nonlinearity component and the training signal; and

selecting the parameters to minimize the determined error.

38 . The method of claim 36 , further comprising:

in a first training iteration:

estimating model parameters of the crosstalk component; and

adapting a correction circuitry based on the estimated model parameters of the crosstalk component, wherein the correction circuitry is configured to receive the first feedback signal and generate the PA nonlinearity component; and

in a second training iteration:

determining an error between the PA nonlinearity component generated by the correction circuitry and the training signal; and

selecting the parameters that minimize the determined error.

39 . The method of claim 33 , wherein the parameters comprise coefficients that are used by the predistortion circuitry to weight different components of a transmit signal.

40 . The method of claim 33 , wherein the modified amplified training signal comprises a signal in which the amplified training signal is removed.

41 . An apparatus configured to determine parameters for predistortion circuitry in a transceiver including a transmit chain and a receive chain, the apparatus comprising:

means for receiving a first feedback signal that includes an amplified training signal from the receive chain;

means for receiving a second feedback signal that includes a modified amplified training signal from the receive chain;

means for determining parameters for the predistortion circuitry based at least on the first feedback signal and the second feedback signal; and

means for providing the determined parameters to the predistortion circuitry.

42 . The apparatus of claim 41 , further comprising means for generating the modified amplified training signal.

43 . The apparatus of claim 42 , wherein the means for generating comprises means for shifting the amplified training signal by Θ degrees, wherein Θ is other than 0.

44 . The apparatus of claim 42 , wherein the means for generating comprises means for disconnecting the amplified training signal from the receive chain.