Enhancement for amplify-and-forward relay

1. A method of wireless communication at a relay, comprising:

receiving a signal from a source, wherein the signal comprises reference signal (RS) and data;

applying Fast Fourier Transform (FFT) to the signal to generate RS symbols including the RS and data symbols including the data;

determining to equalize the signal based on a first carrier frequency offset and a second carrier frequency offset being aligned in direction, the first carrier frequency offset being between the source and the relay, the second carrier frequency offset being between the relay and a destination;

equalizing the signal based on the RS and the data, wherein the RS is used for equalization based on the RS symbols including the RS being input to an RS extraction module, the data is used for equalization without the data symbols including the data being input to the RS extraction module, and equalizing the signal includes equalizing the data symbols and the RS symbols;

amplifying the equalized signal; and

transmitting the amplified signal to the destination.

2. The method of claim 1 , further comprising:

receiving a configuration of the RS from the source.

3. The method of claim 1 , wherein said equalizing the signal comprises:

estimating a channel or a phase based on the RS.

4. The method of claim 1 , wherein said equalizing the signal further comprises:

equalizing tone symbols based on the RS; and

applying Inverse FFT (IFFT) to the equalized tone symbols.

5. The method of claim 1 , wherein said equalizing the signal further comprises:

applying Inverse Discrete Fourier Transform (IDFT) to a subset of tone symbols to extract RS samples;

estimating a phase drift based on the RS samples; and

phase-compensating the signal based on the estimated phase drift.

6. The method of claim 1 , wherein said equalizing the signal comprises:

filtering the signal by an analysis filter bank based on a Discrete Fourier Transform (DFT) matrix;

adjusting the filtered signal by weights based on the RS; and

synthesizing the adjusted filtered signal by a synthesis filter bank based on an Inverse DFT matrix corresponding to the analysis filter bank.

7. The method of claim 1 , wherein the signal is equalized without demodulation or decoding of the data.

8. A relay, comprising:

a receiver configured to receive a signal from a source, wherein the signal comprises reference signal (RS) and data;

a module configured to apply a Fast Fourier Transform (FFT) to the signal to generate RS symbols including the RS and data symbols including the data;

a scheme selector configured to determine to equalize the signal based on a first carrier frequency offset and a second carrier frequency offset being aligned in direction, the first carrier frequency offset being between the source and the relay, the second carrier frequency offset being between the relay and a destination;

an equalizer configured to equalize the signal based on the RS and the data, wherein the RS is used for equalization based on the RS symbols including the RS being input to an RS extraction module, the data is used for equalization without the data symbols including the data being input to the RS extraction module, and to equalize the signal, the equalizer is configured to equalize the data symbols and the RS symbols;

an amplifier configured to amplify the equalized signal; and

a transmitter configured to transmit the amplified signal to the destination.

9. The relay of claim 8 , wherein the receiver is further configured to:

receive a configuration of the RS from the source.

10. The relay of claim 8 , wherein the equalizer is configured to:

estimate a channel or a phase based on the RS.

11. The relay of claim 8 , wherein the equalizer is further configured to:

equalize tone symbols based on the RS; and

apply Inverse FFT (IFFT) to the equalized tone symbols.

12. The relay of claim 8 , wherein the equalizer is further configured to:

apply Inverse Discrete Fourier Transform (IDFT) to a subset of tone symbols to extract RS samples;

estimate a phase drift based on the RS samples; and

phase-compensate the signal based on the estimated phase drift.

13. The relay of claim 8 , wherein the equalizer is configured to:

filter the signal by an analysis filter bank based on a Discrete Fourier Transform (DFT) matrix;

adjust the filtered signal by weights based on the RS; and

synthesize the adjusted filtered signal by a synthesis filter bank based on an Inverse DFT matrix corresponding to the analysis filter bank.

14. The relay of claim 8 , wherein the signal is equalized without demodulation or decoding of the data.

15. An apparatus for wireless communication, comprising:

means for receiving a signal from a source, wherein the signal comprises reference signal (RS) and data;

means for applying Fast Fourier Transform (FFT) to the signal to generate RS symbols including the RS and data symbols including the data;

means for determining to equalize the signal based on a first carrier frequency offset and a second carrier frequency offset being aligned in direction, the first carrier frequency offset being between the source and a relay, the second carrier frequency offset being between the relay and a destination;

means for equalizing the signal based on the RS and the data, wherein the RS is used for equalization based on the RS symbols including the RS being input to an RS extraction module, the data is used for equalization without the data symbols including the data being input to the RS extraction module, and the means for equalizing the signal is configured to equalize the data symbols and the RS symbols;

means for amplifying the equalized signal; and

means for transmitting the amplified signal to the destination.

16. The apparatus of claim 15 , further comprising:

means for receiving a configuration of the RS from the source.

17. The apparatus of claim 15 , wherein the means for equalizing the signal is further configured to:

estimate a channel or a phase based on the RS.

18. The apparatus of claim 15 , wherein the means for equalizing the signal is further configured to:

equalize tone symbols based on the RS; and

apply Inverse FFT (IFFT) to the equalized tone symbols.

19. The apparatus of claim 15 , wherein the means for equalizing the signal is further configured to:

apply Inverse Discrete Fourier Transform (IDFT) to a subset of tone symbols to extract RS samples;

estimate a phase drift based on the RS samples; and

phase-compensate the signal based on the estimated phase drift.

20. The apparatus of claim 15 , wherein the means for equalizing the signal is further configured to:

filter the signal by an analysis filter bank based on a Discrete Fourier Transform (DFT) matrix;

adjust the filtered signal by weights based on the RS; and

synthesize the adjusted filtered signal by a synthesis filter bank based on an Inverse DFT matrix corresponding to the analysis filter bank.

21. A non-transitory computer-readable medium having instructions stored thereon, the instructions comprising code executable for a relay to:

receive a signal from a source, wherein the signal comprises reference signal (RS) and data;

apply Fast Fourier Transform (FFT) to the signal to generate RS symbols including the RS and data symbols including the data;

determine to equalize the signal based on a first carrier frequency offset and a second carrier frequency offset being aligned in direction, the first carrier frequency offset being between the source and the relay, the second carrier frequency offset being between the relay and a destination;

equalize the signal based on the RS and the data, wherein the RS is used for equalization based on the RS symbols including the RS being input to an RS extraction module, the data is used for equalization without the data symbols including the data being input to the RS extraction module, and to equalize the signal, the code executable for the relay is to equalize the data symbols and the RS symbols;

amplify the equalized signal; and

transmit the amplified signal to the destination.