Low complexity MIMO digital pre-distortion

1. A method for cancelling crosstalk and correcting power amplifier (PA) distortion for a transmitter branch of a multiple-input multiple-output (MIMO) configuration having multiple branches, the method comprising:

combining an original baseband input signal of a first MIMO transmitter branch with a crosstalk output signal generated from two or more signals (y 2 , y 3 , y 4 ) associated with two or more respective MIMO branches to produce a combined signal, wherein the two or more signals are used as input to, and processed by, a crosstalk model;

digitally pre-distorting the combined signal; and

processing the combined signal to generate an output signal in order to minimize error of the original baseband input signal caused by the crosstalk and/or PA distortion.

2. The method of claim 1 , wherein the combined signal is digitally pre-distorted before generating the output signal.

3. The method of claim 1 , wherein the original baseband input signal is digitally pre-distorted before combining with the crosstalk output signal.

4. The method of claim 1 , wherein the two or more signals are associated with output signals of the two or more respective MIMO branches.

5. The method of claim 1 , wherein processing the combined signal further comprises inputting the combined signal to a power amplifier (PA).

6. The method of claim 1 , wherein processing the combined signal further comprises:

up-converting the combined signal;

power amplifying the up-converted signal; and

down-converting the amplified signal.

7. The method of claim 6 , further comprising:

measuring an error energy of the down-converted signal and the original baseband input signal; and

when the error energy is minimized between the output signal and the original baseband input signal, saving weighting coefficients for the transmitter branch.

8. The method of claim 1 , further comprising, adapting weighting coefficients for signal processing on the current branch in response to error energy minimized.

9. A transmitter arrangement for cancelling crosstalk and correcting power amplifier (PA) distortion for a transmitter branch of a multiple-input multiple-output (MIMO) configuration having multiple branches, comprising:

an interface for receiving an original baseband signal of a first MIMO branch;

processing circuitry configured to combine the original baseband input signal of the first MIMO branch with a crosstalk output signal generated from two or more signals associated with two or more respective MIMO branches to produce a combined signal, wherein the two or more signals are used as input to, and processed by, a crosstalk model;

digitally pre-distorting the combined signal; and

the processing circuitry further configured to process the combined signal to generate an output signal in order to minimize error of the original baseband input signal caused by the crosstalk and/or PA distortion.

10. The transmitter arrangement of claim 9 , wherein the processing circuitry digitally pre-distorts the combined signal before generating the output signal.

11. The transmitter arrangement of claim 9 , wherein the processing circuitry digitally pre-distorts the original baseband input signal before combining with the crosstalk output signal.

12. The transmitter arrangement of claim 9 , wherein the two or more signals are associated with output signals of the two or more respective MIMO branches.

13. The transmitter arrangement of claim 9 , wherein the transmitter arrangement further comprises a power amplifier (PA), and

wherein the processing circuitry is further configured to input the combined signal to the PA.

14. The transmitter arrangement of claim 9 , wherein the processing circuitry is further configured to:

up-convert the combined signal;

power amplify the up-converted signal; and

down-convert the amplified signal.

15. The transmitter arrangement of claim 14 , wherein the processing circuitry is further configured to:

measure error energy of the down-converted signal and the original baseband input signal; and

when the error energy is minimized between the output signal and the original baseband input signal, save weighting coefficients for the transmitter branch.

16. The transmitter arrangement of claim 15 , wherein the processing circuitry is further configured to:

adapt the weighting coefficients for signal processing on the current branch in response to error energy minimization.

17. The transmitter arrangement of claim 9 , wherein the interface and processing circuitry are included in a wireless device.

18. The transmitter arrangement of claim 9 , wherein the interface and processing circuitry are included in a base station.

19. A non-transitory, tangible computer-readable memory having instructions that, when executed by processing circuitry, cause the processing circuitry to perform operations comprising:

combine an original baseband input signal of a first MIMO transmitter branch with a crosstalk output signal generated from two or more signals associated with two or more respective MIMO branches to generate a combined signal, the two or more signals being used as inputs to and processed by a crosstalk model;

digitally pre-distorting the combined signal; and

process the combined signal to generate an output signal in order to minimize error of the original baseband input signal caused by the crosstalk and/or PA distortion.

20. The non-transitory, tangible computer-readable memory of claim 19 , wherein the combined signal is digitally pre-distorted before generating the output signal.