Methods and apparatus for use in reducing residual phase error in OFDM communication signals

1. An apparatus comprising:

a residual phase error estimator configured to estimate a residual phase error at least partially based on a plurality of phases of a first channel-compensated received signal and a plurality of phases of a sliced version of the first channel-compensated received signal and configured to correct a channel estimate at least partially based on the residual phase error estimate, to thereby generate a corrected channel estimate; and

a channel compensator configured to generate a second channel-compensated received signal at least partially based on a received signal and the corrected channel estimate.

2. The apparatus, as recited in claim 1 , further comprising:

a channel estimator configured to generate a channel estimate at least partially based on the received signal; and

a first channel compensator configured to generate the first channel-compensated signal at least partially based on the received signal and the channel estimate.

3. The apparatus, as recited in claim 2 , wherein the channel estimate is generated using a pilot tone symbol received in an OFDM communication signal and a previously known pilot tone symbol.

4. The apparatus, as recited in claim 1 , wherein the residual phase error estimator comprises:

a first phase calculator configured to determine the plurality of phases of the first channel-compensated signal;

a slicer configured to generate the sliced version of the first channel-compensated received signal;

a second phase calculator configured to determine the plurality of phases of the sliced version of the first channel-compensated received signal; and

an error calculator configured to generate a residual phase error at least partially based on the plurality of phases of the first channel-compensated received signal and the plurality of phases of the sliced version of the first channel-compensated received signal.

5. The apparatus, as recited in claim 4 , wherein the error calculator comprises:

a difference calculator configured to generate a plurality of phase differences corresponding to differences between corresponding phases of the plurality of phases of the first channel-compensated received signal and the plurality of phases of the sliced version of the first channel-compensated received signal;

a maximum value remover configured to identify a subset of the plurality of phase differences and to omit from the subset one or more of the largest magnitudes of the plurality of phase differences; and

an averager configured to generate an average phase difference based on the subset of the plurality of phase differences.

6. A method for use in orthogonal frequency division multiplexed (OFDM) communications, the method comprising:

estimating a residual phase error at least partially based on a plurality of phases of a first channel-compensated received signal and a plurality of phases of a sliced version of the first channel-compensated received signal to thereby generate a residual phase error estimate; and

generating a second channel-compensated received signal at least partially based on the received signal and a corrected channel estimate, the corrected channel estimate being at least partially based on the residual phase error estimate.

7. The method, as recited in claim 6 , further comprising:

generating a channel estimate; and

generating a first compensated received signal at least partially based on the received signal and the channel estimate to thereby generate the first channel-compensated received signal.

8. The method, as recited in claim 7 , wherein the channel estimate is generated using a pilot tone symbol received in an OFDM communication signal and a previously known pilot tone symbol.

9. The method, as recited in claim 6 , wherein the estimating the residual phase error comprises:

determining the plurality of phases of the first channel-compensated received signal;

generating the sliced version of the first channel-compensated received signal;

determining the plurality of phases of the sliced version of the channel-compensated received signal; and

generating the residual phase error estimate at least partially based on the plurality of phases of the first channel-compensated received signal and the plurality of phases of the sliced version of the first channel-compensated received signal.

10. The method, as recited in claim 6 , wherein the generating the residual phase error estimate comprises:

calculating a plurality of phase differences corresponding to differences between corresponding phases of the plurality of phases of the first channel-compensated received signal and the plurality of phases of the sliced version of the first channel-compensated received signal;

identifying a subset of the plurality of phase differences and omitting from the subset one or more of the largest magnitudes of the plurality of phase differences; and

generating an average phase difference based on the subset of the plurality of phase differences.

11. An apparatus comprising:

means for estimating residual phase error due to channel estimation, wherein the means for estimating comprises:

means for generating a residual phase error at least partially based on a plurality of phases of a channel-compensated received signal and a plurality of phases of a sliced version of the channel-compensated received signal; and

means for compensating a received constellation signal based on the estimated residual phase error due to channel estimation.

12. The method, as recited in claim 11 , wherein the means for estimating comprises:

means for determining a plurality of phases of the channel-compensated received signal;

means for generating the sliced version of the channel-compensated received signal; and

means for determining the plurality of phases of the sliced version of the channel-compensated received signal.