Galois Field Arithmetic Circuitry for Memory Error Correction

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Solution Overview

Problem

As the number of error-correctable bits increases in memory systems using error correction codes like BCH codes, the number of required multiplications in Galois fields increases, leading to a scaling issue in arithmetic circuitry for error locator polynomial calculations.

Innovation Solution

An arithmetic circuitry is configured to efficiently calculate multiplications by using a connected tensor obtained from a set of tensors, optimizing the AND and XOR operations to reduce the circuit scale, allowing for common calculations of syndrome multiplications in error locator polynomial coefficient calculations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the number of error-correctable bits increases, then the error correction capability improves, but the number of required Galois field multiplications increases leading to larger circuit scale

Engineering Contradiction:
Improveerror correction capabilityVSAvoidcircuit scale
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the Galois field multiplication operation into distinct computational stages: syndrome calculation, error locator polynomial coefficient calculation, and error position determination. By dividing the multiplication tasks across these segments and identifying redundant operations within each segment, the circuit can reuse computation results rather than performing duplicate multiplications, thus reducing the overall circuit scale while maintaining error correction capability for a higher number of bits

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent creates a universal arithmetic circuit that performs multiple functions: it calculates syndromes, computes error locator polynomial coefficients, and determines error positions. This multi-functional circuit design allows the same hardware resources to be reused across different stages of the error correction process, reducing the need for separate dedicated circuits for each function and thereby suppressing the increase in circuit scale as error correction capability increases

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If the number of error-correctable bits increases, then the error correction capability improves, but the transistor count in the arithmetic circuitry increases

Engineering Contradiction:
Improveerror correction capabilityVSAvoidtransistor count
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent merges the arithmetic operations for syndrome calculation, error locator polynomial coefficient calculation, and error position determination into a single integrated arithmetic circuit. By combining these previously separate functions into one unified circuit structure, the patent reduces the total transistor count compared to having separate circuits for each function, while still providing error correction for an increased number of bits

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If more Galois field multiplications are performed, then the error correction accuracy improves, but the operational efficiency decreases due to larger circuit scale

Engineering Contradiction:
Improveerror correction accuracyVSAvoidoperational efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent performs preliminary calculation of syndromes and error locator polynomial coefficients using optimized arithmetic operations before the actual error position determination. By preparing these intermediate results in advance with reduced computational redundancy, the circuit maintains high error correction accuracy while improving overall operational efficiency, as the subsequent error position calculation can proceed with pre-computed values rather than performing redundant multiplications

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS20240184532A1Arithmetic circuitry, memory system, and control method
Publication Date: 2024.06.06 KIOXIA CORP
  • US20240184532A1 patent drawing
  • US20240184532A1 patent drawing
  • US20240184532A1 patent drawing

AI summary

According to one embodiment, an arithmetic circuitry is configured to: calculate an AND value that is a result of an AND operation of elements a and b of a Galois field; and calculate, for each of a plurality of mutually different sets of (u, v), a {circumflex over ( )} (2u)×b {circumflex over ( )} (2v), which is a product of a 2u-th power of a and a 2v-th power of b, from an XOR operation based on the AND value and a connected tensor obtained by collecting a plurality of tensors different for each set.