Multi-Level Parity Sectors for LDPC Codeword Recovery
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Solution Overview
Problem
Existing data storage systems face inefficiencies in decoding codewords due to reliance on Viterbi-type detectors, which can increase signal noise, whereas using parity sectors for updating reliability metrics is more effective in compensating for signal noise sources.
Innovation Solution
Emphasizing the use of parity sectors over Viterbi-type detectors for updating reliability metrics during decoding, particularly through iterative processing and generating multiple parity sectors across data segments to optimize codeword recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Viterbi-type detectors are used for decoding codewords, then decoding can be performed, but signal noise increases and decoding performance deteriorates
Solution Approach 1:
The patent extracts the harmful Viterbi-type detection step from the decoding process and replaces it with parity sector-based updating. By removing the Viterbi detector component that introduces signal noise, the system achieves better decoding performance without the harmful noise effect.
Solution Approach 2:
The patent introduces parity sectors as an intermediary mechanism to update reliability metrics instead of using Viterbi-type detectors. The parity sectors serve as a mediator that provides noise-free reliability updates by comparing expected and actual codeword values, thereby avoiding the signal noise introduced by Viterbi detection.
2Reliability
If multiple parity sectors are generated and processed iteratively, then codeword recovery rate improves, but processing time and computational complexity increase
Solution Approach 1:
The patent performs preliminary actions by pre-calculating and storing multiple parity sectors before the actual decoding process. These parity sectors are prepared in advance and can be quickly applied during decoding without requiring complex real-time calculations, thus improving recovery rate while minimizing additional processing time.
Solution Approach 2:
The patent implements a dynamic iterative processing approach where the number of parity sector applications and iteration depth can be adjusted based on the actual decoding needs. The system dynamically adapts the processing intensity - applying more parity sectors only when necessary to recover difficult codewords, thereby balancing recovery rate improvement with processing time constraints.
Data Source
AI summary
A data storage device is disclosed wherein a first plurality of codewords are generated each comprising a plurality of symbols, and a first parity sector is generated over the first plurality of codewords. A second plurality of codewords are generated each comprising a plurality of symbols, and a second parity sector is generated over the second plurality of codewords. A third parity sector is generated over a first subset of the first plurality of codewords and a first subset of the second plurality of codewords, and a fourth parity sector is generated over a second subset of the first plurality of codewords and a second subset of the second plurality of codewords. When processing of a first codeword fails, the first codeword and the first parity sector are processed using a LDPC type decoder, and the first codeword and the third parity sector are processed using the LDPC type decoder.