Signal peak-to-average power ratio (PAR) reduction

1. A method of reducing a peak to average power ratio (PAR) of a signal comprising:

comparing an input signal with a compressed signal to generate an error signal indicating distortion between the input signal and the compressed signal;

filtering the error signal based on an in-band frequency range to generate an in-band error signal indicating in-band distortion of the compressed signal with respect to the input signal from which the compressed signal is generated;

filtering the error signal based on an out-of-band frequency range to generate an out-of-band error signal indicating out-of-band distortion of the compressed signal with respect to the input signal;

applying an in-band gain to the in-band error signal to generate an adjusted in-band error signal;

applying an out-of-band gain to the out-of-band error signal to generate an adjusted out-of-band error signal; and

combining the compressed signal with the adjusted in-band error signal and the adjusted out-of-band error signal to generate an output signal, the compressed signal being combined with the adjusted in-band error signal and the adjusted out-of-band error signal, and the in-band gain and the out-of-band gain being based on the output signal such that distortion of the output signal is reduced with respect to distortion of the compressed signal.

2. The method of claim 1 , further comprising adjusting the in-band gain based on an in-band distortion target.

3. The method of claim 1 , further comprising adjusting the out-of-band gain based on an out-of-band distortion target.

4. The method of claim 1 , further comprising adjusting the in-band gain, the out-of-band gain, or both the in-band gain and the out-of-band gain based on an optimization scheme.

5. The method of claim 1 , further comprising clipping an amplitude of the input signal to generate the compressed signal.

6. The method of claim 1 , further comprising determining in-band distortion of the output signal based on an error vector magnitude (EVM) of the output signal with respect to the input signal and adjusting the in-band gain, the out-of-band gain, or both the in-band gain and the out-of-band gain based on the EVM.

7. The method of claim 1 , further comprising determining out-of-band distortion of the output signal based on an adjacent channel leakage ratio (ACLR) of the output signal and adjusting the in-band gain, the out-of-band gain, or both the in-band gain and the out-of-band gain based on the ACLR.

8. The method of claim 1 , further comprising filtering the error signal with a low-pass filter to generate the in-band error signal.

9. The method of claim 1 , further comprising filtering the error signal with a high-pass filter to generate the out-of-band error signal.

10. A system of reducing a peak-to-average power ratio (PAR) of a signal comprising:

an error detection module, comprising:

a comparator configured to compare an input signal with a compressed signal to generate an error signal indicating distortion between the input signal and the compressed signal;

an in-band filter configured to filter the error signal based on an in-band frequency range to generate an in-band error signal indicating in-band distortion of the compressed signal with respect to the input signal from which the compressed signal is generated; and

an out-of-band filter configured to filter the error signal based on an out-of-band frequency range to generate an out-of-band error signal indicating out-of-band distortion of the compressed signal with respect to the input signal;

an in-band gain unit configured to apply an in-band gain to the in-band error signal to generate an adjusted in-band error signal;

an out-of-band gain unit configured to apply an out-of-band gain to the out-of-band error signal to generate an adjusted out-of-band error signal; and

a combining module configured to combine the compressed signal with the adjusted in-band error signal and the adjusted out-of-band error signal to generate an output signal, the combining module configured to combine the compressed signal with the adjusted in-band error signal and the adjusted out-of-band error signal, the in-band gain unit configured to apply the in-band gain based on the output signal, and the out-of-band gain unit configured to apply the out-of-band gain based on the output signal such that distortion of the output signal is reduced with respect to distortion of the compressed signal.

11. The system of claim 10 , further comprising an adaptation module configured to adjust the in-band gain based on an in-band distortion target.

12. The system of claim 10 , further comprising an adaptation module configured to adjust the out-of-band gain based on an out-of-band distortion target.

13. The system of claim 10 , further comprising an adaptation module configured to adjust the in-band gain based on an optimization scheme.

14. The system of claim 10 , further comprising an adaptation module configured to adjust the out-of-band gain based on an optimization scheme.

15. The system of claim 10 , further comprising a compressing module configured to clip an amplitude of the input signal to generate the compressed signal.

16. The system of claim 10 , further comprising an adaptation module configured to determine in-band distortion of the output signal based on an error vector magnitude (EVM) of the output signal with respect to the input signal and configured to adjust the in-band gain, the out-of-band gain, or both the in-band gain and the out-of-band gain based on the EVM.

17. The system of claim 10 , further comprising an adaptation module configured to determine out-of-band distortion of the output signal based on an adjacent channel leakage ratio (ACLR) of the output signal and configured to adjust the in-band gain, the out-of-band gain, or both the in-band gain and the out-of-band gain based on the ACLR.

18. The system of claim 10 , wherein the in-band filter includes a low-pass filter and the out-of-band filter includes a high-pass filter.