LDPC Decoder Bit-Word Correction for Shorter Message Quantization

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Solution Overview

Problem

Practical implementations of LDPC decoders face limitations due to representing values with limited size bit-words, leading to suboptimal use of available bit-words in the decoding process, which affects the performance of the LDPC decoding process.

Innovation Solution

The method and apparatus improve LDPC decoding by applying corrections to bit-words, such as mapping to intermediate bit-words or using tables to generate shorter bit-words, allowing for better utilization of bit-words and enhancing the decoding process by determining messages based on sets of bit-words.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If shorter bit-words are used to represent messages in LDPC decoding, then resource requirements are reduced, but the performance of the decoding process deteriorates due to suboptimal use of available bit-words

Engineering Contradiction:
Improvebit-word lengthVSAvoiddecoding performance
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent applies parameter changes by transforming the representation of log-likelihood ratio values through correction operations. Instead of directly using the full precision bit-words, the system applies corrections that adjust the parameter representation to fit within shorter bit-word lengths while preserving decoding performance. This is achieved by modifying how message values are encoded and transmitted between processing elements.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces intermediary correction operations that act as mediators between the full precision log-likelihood ratios and the shorter bit-word representations. These correction operations serve as an intermediate step that transforms the data format, allowing efficient use of shorter bit-words without directly losing information. The correction mechanism bridges the gap between high-precision input and limited-precision output representations.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If full precision log-likelihood ratio values are used, then decoding accuracy is improved, but resource requirements and complexity increase

Engineering Contradiction:
Improvedecoding accuracyVSAvoidresource requirements
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system changes the parameters of message representation by applying corrections that transform full precision log-likelihood ratios into corrected values suitable for shorter bit-word storage. This parameter transformation maintains the essential information needed for accurate decoding while adapting the data to fit resource-constrained representations.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent extracts and separates the correction component from the full log-likelihood ratio values. By identifying and extracting the necessary correction operations, the system can work with reduced precision representations while compensating for the reduction through the extracted correction mechanism, thereby reducing resource requirements without sacrificing accuracy.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP4135205A1Apparatus and method for low density parity check code decoding
Publication Date: 2023.02.15 NOKIA SOLUTIONS & NETWORKS OY
  • EP4135205A1 patent drawingFigure 1
  • EP4135205A1 patent drawingFigure 2
  • EP4135205A1 patent drawingFigure 3

AI summary

Apparatus and method for low density parity check code decoding in a first processing device, wherein the method comprises - receiving a first bit-word of a first length related to a log-likelihood ratio of a bit of a signal; - obtaining a second bit-word of a second length that is shorter than the first length, wherein obtaining the second bit-word comprises applying a correction to the first bit-word; - determining a message (700) depending on a set of second bit-words (722-1, ..., 722-h), wherein the set of second bit-words (722-1, ..., 722-h) includes the second bit-word.