Multitrack readback and multiuser detection for disk drives
View Patent ↗Techniques for reading data from a storage medium ( 150 ) having a high track density prone to adjacent track interference are disclosed. One or more sensing elements ( 120 ) are used to extract data stored on adjacent tracks. Multiuser detection ( 130 ) is then used to detect/decode a single track that is closely spaced to its neighboring tracks, resolve interference from adjacent tracks, or to simultaneously detect/decode multiple adjacent closely packed tracks.
1. A device for reading data from a storage medium having a high track density prone to adjacent track interference, the device comprising:
a data reader having one or more sensing elements adapted to read data from the storage medium, the read data including target track data as well as interference data from one or more adjacent tracks; and
a multiuser detection module adapted to jointly detect and decode the read data corresponding to multiple tracks, thereby separating the target track data from interfering track data.
2. The device of claim 1 wherein the data reader includes a single sensing element adapted to make multiple passes over the storage medium, one pass for each adjacent track included in a group of tracks.
3. The device of claim 2 wherein the group of tracks is three to five adjacent tracks.
4. The device of claim 1 wherein the data reader includes multiple sensing elements for simultaneously sensing multiple tracks, with one or more sensing elements per each adjacent track included in a group of tracks.
5. The device of claim 4 wherein the group of tracks is three to five adjacent tracks.
6. The device of claim 4 wherein the multiple sensing elements are proximate one another.
7. The device of claim 1 wherein the data reader includes an analog-to-digital converter for converting the read data into its digital equivalent, and a buffer for storing the digital data, thereby allowing digital data from a group of adjacent tracks to be provided to the multiuser detection module.
8. The device of claim 1 wherein the storage medium having a high track density prone to adjacent track interference is one of a data storage tape or disk.
9. The device of claim 1 wherein a track transfer function includes envelope information of a shape, amplitude and phase of each track of a group of adjacent tracks read by the one or more sensing elements, and the multiuser detection module is operatively coupled with a parameter estimation module adapted to identify the track transfer function associated with the group.
10. The device of claim 1 further comprising:
a data selector module adapted to receive separated and decoded track signals from the multiuser detection module, and to output requested data bits corresponding to at least one of a single track or multiple tracks.
11. The device of claim 1 wherein the device further includes a data writer and is capable of writing data to the storage medium.
12. The device of claim 1 wherein each of the one or more sensing elements is centered over at least one of a different radius on the storage medium or a different track on the storage medium or a different read line on the storage medium.
13. A method for reading data from a storage medium having a high track density prone to adjacent track interference, the method comprising:
reading data from the storage medium, the read data including target track data as well as interference data from one or more adjacent tracks; and
jointly detecting and decoding the read data corresponding to multiple tracks, thereby separating the target track data from interfering track data.
14. The method of claim 13 wherein reading data from the storage medium includes making multiple passes over the storage medium with a sensing element, one pass for each adjacent track included in a group of tracks.
15. The method of claim 14 wherein the group of tracks is at least three adjacent tracks.
16. The method of claim 13 wherein reading data from the storage medium includes simultaneously sensing multiple tracks, with one or more sensing elements per each adjacent track included in a group of tracks.
17. The method of claim 16 wherein the group of tracks is at least three adjacent tracks.
18. The method of claim 13 further comprising:
converting the read data into its digital equivalent; and
storing the digital data, thereby allowing digital data from a group of adjacent tracks to be provided to the multiuser detection module.
19. The method of claim 13 wherein a track transfer function includes envelope information of a shape, amplitude and phase of each track of a group of adjacent tracks read by one or more sensing elements, the method further comprising:
identifying the track transfer function associated with the group.
20. The method of claim 13 further comprising:
outputting requested data bits corresponding to at least one of a single track or multiple tracks.
21. The method of claim 13 wherein reading data from the storage medium further includes centering each of one or more sensing elements over at least one of a different radius on the storage medium or a different track on the storage medium or a different read line on the storage medium.
22. A device for reading data from a storage medium having a high track density prone to adjacent track interference, the device comprising:
one or more sensing elements adapted to read data from the storage medium, the read data including target track data as well as interference data from one or more adjacent tracks;
one or more positioning arms operatively coupled to the one or more sensing elements, and adapted to center each sensing element over at least one of a different radius on the storage medium or a different track on the storage medium or a different read line on the storage medium; and
a multiuser detection module adapted to jointly detect and decode the read data corresponding to multiple tracks, thereby separating the target track data from interfering track data.