Partial Reverse Concatenation Coding for Tighter Modulation Constraints
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Solution Overview
Problem
Conventional reverse concatenation schemes for data storage face challenges such as high implementation complexity, weakening of modulation constraints, and inability to satisfy non-uniform constraints, particularly in product codes, which hinders their practical implementation in magnetic tape and optical storage systems.
Innovation Solution
The implementation of a partial reverse concatenation (PRC) scheme, where modulation coding (MC) is performed subsequent to C2 error correction coding (ECC) but prior to C1 encoding, simplifying the data flow architecture and allowing non-uniform modulation constraints to be satisfied, thereby achieving tighter modulation constraints and improved error rate performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional reverse concatenation is used for product codes, then modulation code rate is improved (0.9951 vs 0.9697), but implementation complexity increases significantly
Solution Approach 1:
The patent inverts the conventional encoding order by performing modulation coding before C1 ECC encoding, while still performing C2 ECC encoding first. This partial inversion maintains the benefits of reverse concatenation (higher code rate) while simplifying the architecture by avoiding complete reordering of existing data flow architectures
Solution Approach 2:
The patent applies partial reverse concatenation rather than complete reverse concatenation. By only reversing the order of C1 and MC encoding while keeping C2 encoding first, the system achieves most of the performance benefits with reduced implementation complexity and without requiring complete architectural overhaul
2Reliability
If C2 symbol insertion is performed after modulation coding, then error correction capability is improved, but modulation constraints are weakened (G=22 vs G=14)
Solution Approach 1:
The patent performs modulation coding before C1 ECC encoding, ensuring that modulation constraints are satisfied early in the encoding process. By establishing the modulation code structure beforehand, the system maintains tighter constraints (G=12) while still allowing C1 and C2 codes to provide error correction capability
3Productivity
If conventional reverse concatenation architecture is implemented, then code rate improvement is achieved, but backward compatibility becomes difficult to maintain
Solution Approach 1:
The patent implements partial reverse concatenation that modifies the encoding order minimally - only changing the relative order of C1 and MC encoding while preserving C2 encoding position. This partial modification achieves code rate improvement while maintaining compatibility with existing data flow architectures and backward compatibility
Data Source
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AI summary
In one embodiment, a data storage system includes a write channel for writing data to a storage medium, the write channel configured to utilize a partial reverse concatenated modulation code. The write channel includes logic adapted for encoding data sets using a C2 encoding scheme, logic adapted for adding a header to each subunit of the data sets, logic adapted for encoding the headers of the data sets with a first modulation encoding scheme, logic adapted for encoding data portions of the data sets with a second modulation encoding scheme, logic adapted for encoding portions of the one or more C2-encoded data sets using a C1 encoding scheme, logic adapted for combining the C1-encoded portions with the modulation-encoded headers of the C2-encoded data sets using a multiplexer, and logic adapted for writing the one or more combined C1- and C2-encoded data sets to data tracks.