Matrix-Based Decoding for Lower Field Multiplication Load

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Solution Overview

Problem

Conventional error correcting coding techniques have high processing amounts, particularly in the field multiplication performed during the decoding process.

Innovation Solution

A decoding apparatus that reduces processing amounts by generating a ϕ-th order vector and an inverse matrix, allowing for efficient computation of plaintext elements through vector conversion and inverse matrix multiplication, utilizing a specific matrix structure and polynomial operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional Reed-Solomon decoding is performed using the full inverse matrix A′−1, then complete plaintext recovery is achieved, but the processing amount of field multiplication becomes excessively high

Engineering Contradiction:
Improveplaintext recovery completenessVSAvoiddecoding processing speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent extracts only the necessary φ rows (corresponding to parity shares) from the full inverse matrix A′−1 to form a reduced inverse matrix. This extraction eliminates unnecessary computational operations while preserving the capability to recover the missing φ plaintext elements, directly reducing field multiplication processing amount without compromising decryption completeness

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent segments the decoding process into two distinct phases: (1) recovering φ missing plaintext elements using only φ rows of the inverse matrix multiplied by φ parity shares, and (2) obtaining the remaining k-φ plaintext elements directly from k-φ available data shares. This segmentation avoids redundant computations and optimizes the overall decoding efficiency

Inventive Principle:
Principle #1Segmentation

2Manufacturing precision

If the full inverse matrix A′−1 is used for decoding, then all plaintext elements can be computed, but the computational complexity and processing time increase

Engineering Contradiction:
Improveplaintext element accuracyVSAvoiddecoding computation time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent applies partial action by computing only what is necessary: φ rows of the inverse matrix are sufficient to recover φ missing plaintext elements. The remaining k-φ plaintext elements are obtained directly from available data shares without requiring matrix multiplication, thus achieving complete plaintext recovery with reduced computational effort and time

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentUS10511330B2Decoding apparatus, decoding method and program
Publication Date: 2019.12.17 NIPPON TELEGRAPH & TELEPHONE CORP
  • US10511330B2 patent drawing
  • US10511330B2 patent drawing

AI summary

To reduce the processing amount of a field multiplication. a denotes a k-th order vector whose elements are a0, . . . , ak−1 (a0, . . . , ak−1∈GF(xq)). A denotes an n-by-k matrix formed by vertically connecting a identity matrix and a Vandermonde matrix. b denotes an n-th order vector obtained by multiplying the vector a and the matrix A whose elements are b0, . . . , bn−1 (b0, . . . , bn−1∈GF(xq)). A vector conversion part 11 generates a ϕ-th order vector b′ using ϕ elements bp0, . . . , bpϕ−1 of the vector b. An inverse matrix generation part 12 generates a ϕ-by-ϕ inverse matrix A′−1. A plaintext computation part 13 computes elements ae0, . . . , aeϕ−1 of the vector a by multiplying the vector b′ and the inverse matrix A′−1.