Inter-Track Interference Cancellation in Magnetic Storage Read Channels
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
As storage media capacities increase, adjacent data tracks in magnetic storage devices become closer, leading to significant inter-track interference (ITI) that can cause data corruption and introduce system latency due to positioning errors, making it difficult to read data from desired tracks without interference from adjacent tracks.
Innovation Solution
A method is introduced where a read channel reads sectors from a desired track, decodes them using an iterative decoder, and if decoding fails, it estimates and cancels ITI from adjacent tracks by subtracting the estimated interference, providing updated sector data that is then re-decoded, thereby reducing interference and improving data recovery efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If data tracks are placed closer together to increase storage density, then storage capacity increases, but inter-track interference increases causing data corruption
Solution Approach 1:
The patent reads tracking marks from adjacent tracks and uses the information from these potentially interfering tracks to calculate and cancel ITI. The harmful interference signal is converted into useful information for cancellation, allowing the system to tolerate closer track spacing while maintaining data integrity
Solution Approach 2:
The system performs preliminary reading of tracking marks from adjacent tracks before attempting to read the desired track data. By pre-acquiring the interference pattern from adjacent tracks, the system can prepare the cancellation filter in advance, reducing the impact of ITI on the main data reading operation
2Measurement precision
If tracking marks are read from adjacent tracks to detect ITI, then ITI detection is enabled, but system latency increases due to seeking and waiting
Solution Approach 1:
The patent combines the reading of tracking marks from adjacent tracks with the reading of desired track data into a single integrated operation. By merging these previously separate operations, the system eliminates the need for separate seeking and waiting phases, significantly reducing system latency while maintaining ITI detection accuracy
Solution Approach 2:
The system continuously reads tracking marks from adjacent tracks as part of the normal data reading operation, rather than performing discrete intermittent readings. This continuous acquisition allows for real-time ITI cancellation without interrupting the data stream, maintaining both precision and speed
3Reliability
If iterative decoding is performed to correct ITI corrupted data, then data recovery is improved, but processing time increases
Solution Approach 1:
The patent applies ITI cancellation before the iterative decoding process by pre-calculating and subtracting the estimated interference from adjacent tracks. This preliminary cleanup of the signal reduces the burden on the iterative decoder, allowing it to converge faster and improving overall processing speed while maintaining high data recovery rates
Data Source
AI summary
Described embodiments provide a method of cancelling inter-track interference (ITI) from one or more sectors read from a desired track of a storage medium. A read channel reads sectors in a desired track of the storage medium. An iterative decoder of the read channel decodes the read sectors, and if the read sectors are incorrectly recovered from the storage medium, selected sectors of a first adjacent track are read. An ITI canceller of the read channel estimates ITI in the read sectors of the desired track corresponding to the selected sectors of the adjacent track and subtracts the estimated ITI of the adjacent track from the data for the sectors of the desired track, providing updated sector data. The ITI cancelled data is replayed to the iterative decoder, which decodes the ITI cancelled data and provides the decoded ITI cancelled data as output data of the read channel.