Reed-Muller Soft Decision Decoding with Optimal Decomposition

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Solution Overview

Problem

High-speed communication networks, such as optical networks, face challenges in achieving coding gains while maintaining low encoding and decoding complexity, particularly in decoding soft information from receive signals.

Innovation Solution

The method involves performing soft decision decoding of Euclidean space Reed-Muller codes using maximum likelihood and maximum a posteriori decoders, with optimal decomposition variables determined through log-likelihood ratio calculations and Plotkin decomposition, enabling efficient decoding of higher order Reed-Muller codes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If soft decision decoding is used to improve decoding performance and coding gain, then decoding accuracy is improved, but decoding complexity increases

Engineering Contradiction:
Improvedecoding accuracyVSAvoiddecoding complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The decoding process is segmented into multiple stages: syndrome calculation, error pattern identification, and soft decision refinement. Each stage processes only the necessary information for that specific task, breaking down the complex soft decision decoding into manageable segments that reduce overall computational burden while maintaining accuracy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies partial soft decision processing by performing full soft decision decoding only on critical portions of the data where error correction is most needed, while using simpler hard decision methods for less critical portions. This selective approach achieves sufficient decoding accuracy without the full computational cost of complete soft decision decoding.

Inventive Principle:
Principle #16Partial or excessive action

2Reliability

If higher order Reed-Muller codes are used to achieve coding gain close to Shannon limit, then error correction performance is improved, but encoding and decoding complexity increases

Engineering Contradiction:
Improveerror correction performanceVSAvoidencoding and decoding complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Higher order Reed-Muller codes are decomposed into multiple lower order subcodes through systematic segmentation. The encoding and decoding processes are divided into separate stages, each handling a specific subset of the code structure. This segmentation allows complex higher order codes to be processed using simpler, repeated applications of lower order decoding algorithms, reducing overall complexity while maintaining the coding gain benefits.

Inventive Principle:
Principle #1Segmentation

3Reliability

If complex error correcting codes are used to provide coding gain, then reliability is improved, but latency increases due to additional decoding processing

Engineering Contradiction:
Improvecoding gainVSAvoiddecoding latency
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

Syndrome calculations and error pattern pre-identification are performed as preliminary actions before the main soft decision decoding process. By pre-computing these intermediate results, the patent reduces the processing time required during the critical decoding path, thereby reducing overall latency while maintaining the reliability benefits of complex error correcting codes.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS8245116B2Method for performing soft decision decoding of Euclidean space Reed-Muller codes
Publication Date: 2012.08.14 MITSUBISHI ELECTRIC RESEARCH LABORATORIES INC
  • US8245116B2 patent drawing
  • US8245116B2 patent drawing
  • US8245116B2 patent drawing

AI summary

Soft decision decoding of a codeword of a Reed-Muller (RM) code byselecting an optimal decomposition variable i using a likelihood calculation. A code RM(r, m) is expressed as {(u, uv)|uεRM(r, m−1) and vεRM(r−1, m−1)}, where uv denotes a component-wise multiplication of u and v, and (u, uv)=(r1, r2). A receive codeword is separated into r1=u and r2=uv based on the optimal decomposition variable, and r2 is decoded according to the optimal decomposition variable, using a RM(r−1, m−1) decoder to obtain a decoded v and a first set of decoded bits. The decoded v is combined with r1 using (r1+r2v)/2, and(r1+r2v)/2 is decoded using a RM(r, m−1) decoder to obtain a decoded u and a second set of decoded bits.