Inter-track interference cancelation for shingled magnetic recording
Inter-track interference cancelation is disclosed, including: receiving an input sequence of samples associated with a track on magnetic storage; using a processor to generate inter-track interference (ITI) data associated with a first side track including by performing a correlation between the input sequence of samples and a sequence of data associated with the first side track.
1. A method, comprising:
receiving an input sequence of samples associated with a track on magnetic storage;
using a processor to generate inter-track interference (ITI) data associated with a first side track including by performing a correlation between the input sequence of samples and a sequence of data associated with the first side track;
generating ITI data associated with a second side track, including by performing a correlation between the input sequence of samples and a sequence of data associated with the second side track;
removing the ITI data associated with the first side track and the ITI data associated with the second side track from the input sequence of samples;
determining that error correction processing, associated with the input sequence of samples with the ITI data associated with the first side track and the ITI data associated with the second side track removed, has failed; and
generating a new position associated with a read-head based at least in part on a power value associated with the ITI data associated with the first side track and a power value associated with the ITI data associated with a second side track.
2. The method of claim 1 , wherein generating ITI data includes generating a set of correlation coefficients and selecting a subset of the set of correlation coefficients.
3. The method of claim 2 , wherein the selected subset of correlation coefficients is used to determine a relative phase offset between the track and the first side track.
4. The method of claim 2 , wherein the selected subset of correlation coefficients is used to determine a side track pulse-shape associated with the first side track.
5. The method of claim 2 , wherein selecting a subset of the set of correlation coefficients is based at least in part on a peak value associated with the set of correlation coefficients.
6. The method of claim 2 , wherein selecting a subset of the set of correlation coefficients is based at least in part on a maximum power value associated with the set of correlation coefficients.
7. The method of claim 2 , wherein selecting a subset of the set of correlation coefficients is based at least in part on a maximum absolute sum value associated with the set of correlation coefficients.
8. The method of claim 1 , further comprising determining whether a function associated with the set of correlation coefficients exceeds a set threshold, and in the event that the function exceeds the set threshold, removing the ITI data from the input sequence of samples and in the event that the function does not exceed the set threshold, not removing the ITI data from the input sequence of samples.
9. The method of claim 1 , wherein generating ITI data associated with the first side track includes independently generating ITI data for each of two or more fragments associated with the first side track.
10. The method of claim 9 , wherein each of the two or more fragments associated with the first side track are determined based on locations corresponding to a plurality of servo wedges.
11. The method of claim 9 , further comprising removing ITI data generated for each of the two or more fragments from the input sample of sequences.
12. A system, comprising:
a processor configured to:
receive an input sequence of samples associated with a track on magnetic storage;
generate inter-track interference (ITI) data associated with a first side track including by performing a correlation between the input sequence of samples and a sequence of data associated with the first side track;
generate ITI data associated with a second side track, including by performing a correlation between the input sequence of samples and a sequence of data associated with the second side track;
remove the ITI data associated with the first side track and the ITI data associated with the second side track from the input sequence of samples;
determine that error correction processing, associated with the input sequence of samples with the ITI data associated with the first side track and the ITI data associated with the second side track removed, has failed; and
generate a new position associated with a read-head based at least in part on a power value associated with the ITI data associated with the first side track and a power value associated with the ITI data associated with a second side track; and
a memory coupled with the processor and configured to provide the processor with instructions.
13. The system of claim 12 , wherein the processor is configured to generate ITI data, including by generating a set of correlation coefficients and selecting a subset of the set of correlation coefficients.
14. The system of claim 13 , wherein the selected subset of correlation coefficients is used to determine a relative phase offset between the track and the first side track.
15. The system of claim 13 , wherein the selected subset of correlation coefficients is used to determine a side track pulse-shape associated with the first side track.
16. The system of claim 13 , wherein the processor is configured to select a subset of the set of correlation coefficients based at least in part on a peak value associated with the set of correlation coefficients.
17. The system of claim 13 , wherein the processor is configured to select a subset of the set of correlation coefficients based at least in part on a maximum power value associated with the set of correlation coefficients.
18. The system of claim 12 , wherein the processor is further configured to determine whether a function associated with the set of correlation coefficients exceeds a set threshold, and in the event that the function exceeds the set threshold, to remove the ITI data from the input sequence of samples and in the event that the function does not exceed the set threshold, to not remove the ITI data from the input sequence of samples.
19. The system of claim 12 , wherein the processor is configured to generate ITI data associated with the first side track, including by independently generating ITI data for each of two or more fragments associated with the first side track.
20. The system of claim 19 , wherein the processor is further configured to remove ITI data generated for each of the two or more fragments from the input sample of sequences.
21. A computer program product, the computer program product being embodied in a non-transitory computer readable medium and comprising computer instructions for:
receiving an input sequence of samples associated with a track on magnetic storage;
generating inter-track interference (ITI) data associated with a first side track including by performing a correlation between the input sequence of samples and a sequence of data associated with the first side track;
generating ITI data associated with a second side track, including by performing a correlation between the input sequence of samples and a sequence of data associated with the second side track;
removing the ITI data associated with the first side track and the ITI data associated with the second side track from the input sequence of samples;
determining that error correction processing, associated with the input sequence of samples with the ITI data associated with the first side track and the ITI data associated with the second side track removed, has failed; and
generating a new position associated with a read-head based at least in part on a power value associated with the ITI data associated with the first side track and a power value associated with the ITI data associated with a second side track.
22. The computer program product of claim 21 , wherein the computer instructions for generating ITI data include computer instructions for generating a set of correlation coefficients and selecting a subset of the set of correlation coefficients.
23. The computer program product of claim 22 , wherein the selected subset of correlation coefficients is used to determine a relative phase offset between the track and the first side track.
24. The computer program product of claim 22 , wherein the selected subset of correlation coefficients is used to determine a side track pulse-shape associated with the first side track.
25. The computer program product of claim 21 further comprising computer instructions for determining whether a function associated with the set of correlation coefficients exceeds a set threshold, and in the event that the function exceeds the set threshold, removing the ITI data from the input sequence of samples and in the event that the function does not exceed the set threshold, not removing the ITI data from the input sequence of samples.
26. The computer program product of claim 21 , wherein the computer instructions for generating ITI data associated with the first side track include computer instructions for independently generating ITI data for each of two or more fragments associated with the first side track.
27. The computer program product of claim 26 further comprising computer instructions for removing ITI data generated for each of the two or more fragments from the input sample of sequences.