Coarse phase estimation for highly-spectrally-efficient communications
Methods and systems are provided for coarse phase estimation for highly-spectrally efficient communications. An example method may include, equalizing, in a receiver, a received inter-symbol correlated (ISC) signal to generate an equalized ISC signal. A phase adjustment signal may be generated based on an ISC feedback signal. The ISC feedback signal may be generated using a sequence estimation process and a non-linearity model. A phase of the equalized ISC signal may be adjusted using the generated phase adjustment signal, to generate a phase adjusted partial response signal. The phase adjustment signal may be generated based on a phase difference between the equalized ISC signal and the partial response feedback signal.
1. A method, comprising:
in a receiver:
equalizing a received inter-symbol correlated (ISC) signal to generate an equalized ISC signal;
generating a phase adjustment signal based on an ISC feedback signal, said ISC feedback signal generated using a sequence estimation process and a non-linearity model; and
adjusting a phase of said equalized ISC signal using said generated phase adjustment signal, to generate a phase adjusted ISC signal.
2. The method according to claim 1 , comprising generating said phase adjustment signal based on a phase difference between said equalized ISC signal and said ISC feedback signal.
3. The method according to claim 1 , wherein said non-linearity model is a model of non-linearity experienced by said ISC signal prior to said equalizing.
4. The method according to claim 1 , wherein said non-linearity model is a model of non-linearity of a front-end of a transmitter that transmitted said received ISC signal.
5. The method according to claim 1 , wherein said generating of said phase adjustment signal comprises:
generating a phase error signal corresponding to a phase difference between a rotated version of said ISC feedback signal and said equalized ISC signal.
6. The method according to claim 5 , comprising rotating said ISC feedback signal based on said phase error signal, to generate said rotated version of said ISC feedback signal.
7. The method according to claim 5 , comprising filtering using at least one feedback loop, said phase error signal to generate said phase adjustment signal.
8. The method according to claim 7 , comprising dynamically adjusting parameters that control bandwidth and/or gain of said at least one feedback loop.
9. The method according to claim 1 , wherein the received ISC signal is a partial response signal generated via a partial response filter.
10. A system, comprising:
circuitry that includes an equalization circuit, a phase adjustment circuit, a sequence estimation circuit, a non-linearity modeling circuit, and a carrier recovery circuit, wherein:
said circuitry is operable to equalize a received inter-symbol correlated (ISC) signal to generate an equalized ISC signal;
said circuitry is operable to generate a phase adjustment signal based on an ISC feedback signal, said ISC feedback signal generated using a sequence estimation process and said non-linearity modeling circuit; and
said circuitry is operable to adjust a phase of said equalized ISC signal using said generated phase adjustment signal, to generate a phase adjusted ISC signal.
11. The system according to claim 10 , wherein said circuitry is operable to generate said phase adjustment signal based on a phase difference between said equalized ISC signal and said ISC feedback signal.
12. The method according to claim 1 , wherein said non-linearity model is a model of non-linearity experienced by said ISC signal en route to said equalizer.
13. The method according to claim 1 , wherein said non-linearity model is a model of non-linearity of a front-end of a transmitter that transmitted said received ISC signal.
14. The method according to claim 1 , wherein said non-linearity model is a model of non-linearity of a front-end of said receiver.
15. The system according to claim 10 , wherein said circuitry is operable to generate said ISC feedback signal by processing said ISC signal with said non-linearity modeling circuit.
16. The system according to claim 10 , wherein during said generating of said phase adjustment signal, said circuitry is operable to generate a phase error signal corresponding to a phase difference between a rotated version of said ISC feedback signal and said equalized ISC signal.
17. The system according to claim 16 , wherein said circuitry is operable to rotate said ISC feedback signal based on said phase error signal, to generate said rotated version of said ISC feedback signal.
18. The system according to claim 16 , wherein the received ISC signal is a partial response signal generated via a partial response filter.
19. A receiver, comprising:
a sequence estimation circuit;
a non-linearity modeling circuit; and
a carrier recovery circuit that operates based on a ISC feedback signal, wherein:
said ISC feedback signal comprises a ISC signal generated by said sequence estimation circuit and processed by said non-linearity modeling circuit.
20. The receiver of claim 19 , comprising:
an equalizer circuit; and
a phase adjustment circuit, wherein:
an output of said equalizer circuit is input to said carrier recovery circuit and to said phase adjustment circuit;
an output of said carrier recovery circuit is input to said phase adjustment circuit; and
an output of said phase adjustment circuit is a phase adjusted version of said output of said equalizer circuit.