LDPC Error Correction Circuit With Degree-Based Decoding Rules

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Solution Overview

Problem

Low density parity check (LDPC) error correction methods face high complexity and an increased error floor due to approximation, which limits their effectiveness in improving signal-to-noise ratio (SNR) versus bit-error rate (BER) performance.

Innovation Solution

An error correction circuit and method that includes a memory for storing decoding parameters and a processing circuit to determine graph-degrees of variable nodes, adjust decoding parameters based on error rates, and output corrected data by iteratively performing LDPC decoding with adaptive decoding rules, thereby reducing the error floor and improving BER with increasing SNR.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If LDPC method is used for error correction, then error correction capability is improved, but calculation complexity increases

Engineering Contradiction:
Improveerror correction capabilityVSAvoidcalculation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the variable nodes into different groups based on their graph-degree values (e.g., degree-3, degree-4, degree-5 variable nodes). Each group is decoded using tailored decoding rules optimized for its specific degree characteristics. This segmentation allows the system to apply simpler, more efficient decoding operations to each subgroup rather than using a single complex decoding algorithm for all nodes, thereby reducing overall calculation complexity while maintaining error correction capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different decoding rules to different variable nodes based on their local graph-degree properties. Specifically, degree-3 variable nodes use one decoding rule, degree-4 variable nodes use another rule, and degree-5 variable nodes use a third rule. This local quality approach ensures that each node is processed with the most appropriate algorithm for its characteristics, optimizing the balance between correction effectiveness and computational efficiency for each local region of the code graph.

Inventive Principle:
Principle #3Local quality

2Device complexity

If approximation is applied to reduce LDPC complexity, then calculation complexity decreases, but error floor increases

Engineering Contradiction:
Improvecalculation complexityVSAvoiderror floor
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent changes the decoding parameters (decoding rules) based on the graph-degree parameter of variable nodes. Instead of using a fixed approximation for all nodes, the system selects from multiple decoding rules depending on the degree of each variable node. This parameter adaptation allows the system to maintain higher accuracy for nodes where it is critical (reducing error floor) while still applying simplified rules where appropriate (controlling complexity).

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If uniform decoding rule is applied to all variable nodes, then device complexity decreases, but error correction performance deteriorates

Engineering Contradiction:
Improvedecoding rule complexityVSAvoiderror correction performance
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent applies different decoding rules to different variable nodes based on their local graph-degree properties. Specifically, degree-3 variable nodes use one decoding rule, degree-4 variable nodes use another rule, and degree-5 variable nodes use a third rule. This local quality approach ensures that each node is processed with the most appropriate algorithm for its characteristics, optimizing the balance between correction effectiveness and computational efficiency for each local region of the code graph.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent segments the variable nodes into different groups based on their graph-degree values (e.g., degree-3, degree-4, degree-5 variable nodes). Each group is decoded using tailored decoding rules optimized for its specific degree characteristics. This segmentation allows the system to apply simpler, more efficient decoding operations to each subgroup rather than using a single complex decoding algorithm for all nodes, thereby reducing overall calculation complexity while maintaining error correction capability.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentUS11175985B2Error correction circuit and method for operating the same
Publication Date: 2021.11.16 SAMSUNG ELECTRONICS CO LTD
  • US11175985B2 patent drawing
  • US11175985B2 patent drawing
  • US11175985B2 patent drawing

AI summary

An error correction circuit includes a memory that stores at least one decoding parameter, a low density parity check (LDPC) decoder that includes a first variable node storing one bit of the data, receives the at least one decoding parameter from the memory, decides a degree of the first variable node based on the at least one decoding parameter, and decides a decoding rule necessary for decoding of the one bit based on the degree of the first variable node, and an adaptive decoding controller that outputs corrected data based on a decoding result of the LDPC decoder.