Partial Reverse Concatenation for Tight Modulation Constraints
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Solution Overview
Problem
Conventional reverse concatenation schemes for data storage face challenges such as high implementation complexity, weakened modulation constraints, and inability to satisfy non-uniform constraints, particularly in product codes, which hinder their practical implementation in data storage systems like tape drives and optical storage.
Innovation Solution
The implementation of a partial reverse concatenated modulation code that applies a C2 encoding scheme followed by one or more modulation encoding schemes, and then a C1 encoding scheme, rather than completely reversing the order of error correction coding and modulation coding, simplifying the data flow architecture and maintaining tight modulation constraints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional reverse concatenation is applied to product codes, then modulation code rate improves, but implementation complexity increases significantly
Solution Approach 1:
The patent segments the encoding process into distinct C2 and C1 encoding stages with specific operational sequences. By dividing the monolithic reverse concatenation into manageable segments with defined interfaces, the implementation complexity is reduced while maintaining the code rate improvements.
Solution Approach 2:
The patent applies partial reverse concatenation by inverting only the necessary portions of the encoding sequence rather than completely reversing the conventional order. This selective inversion achieves the desired code rate improvement without requiring a complete architectural overhaul, thereby reducing implementation complexity.
2Reliability
If C2 symbol insertion is performed after modulation coding, then error correction capability is enhanced, but modulation constraints are weakened
Solution Approach 1:
The patent performs C2 encoding and symbol insertion before modulation coding rather than after. This preliminary action ensures that the modulation constraints are established on the original data structure, preventing weakening of constraints while still achieving enhanced error correction through C2 coding.
Solution Approach 2:
The patent changes the timing parameter of C2 symbol insertion from post-modulation to pre-modulation. This parameter change maintains the integrity of modulation constraints by ensuring they are applied to the unexpanded data structure, while C2 error correction capability is preserved through proper sequencing.
3Productivity
If complete reverse concatenation is implemented, then format efficiency improves, but backward compatibility is lost
Solution Approach 1:
The patent implements partial reverse concatenation rather than complete reverse concatenation. By applying the reverse ordering only to specific encoding stages (C2 then C1) while maintaining compatibility interfaces, the patent achieves format efficiency improvements without completely breaking backward compatibility with existing systems.
Data Source
AI summary
In one embodiment, a method includes writing data to a storage medium, via a write channel, by applying a partial reverse concatenated modulation code to the data prior to storing encoded data to the storage medium. The applying the partial reverse concatenated modulation code to the data includes application of a C2 encoding scheme to the data to produce C2-encoded data prior to application of one or more modulation encoding schemes to the C2-encoded data to produce modulated data, followed by application of a C1 encoding scheme to the modulated data subsequent to the application of the one or more modulation encoding schemes to produce the encoded data.