ML-Based Iterative Decoder Prediction for Convergence Latency

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Solution Overview

Problem

Existing LDPC and turbo-code decoders lack deterministic convergence, failing to meet quality-of-service (QoS) and 'Fast-Fail' mode requirements due to variable convergence times, which are not uniform or predictable, leading to inefficiencies and potential timeouts.

Innovation Solution

A system utilizing machine learning classifiers to predict decoder success and latency by analyzing syndrome weights and error patterns, allowing for optimization of decoder parameters such as LLRs, bit-flipping thresholds, and clock frequency adjustments to ensure consistent convergence within predetermined thresholds.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If iterative decoding is used for LDPC and turbo-codes, then capacity-approaching correction capability is achieved, but convergence time becomes non-deterministic and variable

Engineering Contradiction:
Improvecorrection capabilityVSAvoidconvergence time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by training a machine learning classifier beforehand on a dataset of codeword features and their corresponding decoding outcomes. This pre-trained classifier then quickly predicts the convergence behavior of new codewords before actual decoding begins, enabling the system to prepare appropriate responses in advance rather than waiting for decoding to complete.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces a machine learning classifier as an intermediary between the input codeword and the decoding process. This classifier analyzes features of the codeword and predicts decoding outcomes, serving as a mediator that provides advance information about convergence behavior without being part of the actual decoding algorithm itself.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If decoder runs for many iterations to ensure convergence, then correction accuracy improves, but latency increases and QoS requirements are not met

Engineering Contradiction:
Improvecorrection accuracyVSAvoidlatency
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system performs preliminary classification of codewords based on their features before committing to full decoding iterations. By predicting the likely outcome in advance, the system can make informed decisions about resource allocation and timing, preventing unnecessary long wait times while ensuring accurate correction when needed.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback by using the classifier's predictions to inform subsequent decoding decisions. The predicted outcomes provide feedback about expected convergence behavior, allowing the system to adjust its approach based on this advance information rather than blindly executing fixed iteration counts.

Inventive Principle:
Principle #23Feedback

3Loss of time

If decoder stops after few iterations for fast processing, then latency decreases, but convergence reliability drops and decoding may fail

Engineering Contradiction:
ImprovelatencyVSAvoidconvergence reliability
Core Design Contradiction:
Loss of timeVSReliability

Solution Approach 1:

The classifier performs preliminary assessment of each codeword's likely decoding behavior before the actual decoding begins. This advance knowledge allows the system to set appropriate iteration limits and expectations without compromising reliability, as the short processing time is paired with predictive information about the outcome.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses the classifier's predictions to self-regulate its decoding process. By knowing in advance whether a codeword is likely to converge quickly or fail, the system can autonomously make decisions about resource allocation and timing without external intervention, optimizing both speed and reliability based on the codeword's own characteristics.

Inventive Principle:
Principle #25Self-service

4Reliability

If uniform convergence time is enforced for all codewords, then QoS requirements are met, but some codewords may be forced to run unnecessary iterations increasing power consumption

Engineering Contradiction:
ImproveQoS complianceVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies local quality by treating different codewords differently based on their individual characteristics and predicted outcomes. Instead of applying a uniform iteration limit to all codewords, the system uses the classifier's predictions to tailor the decoding process to each specific codeword's needs, allocating resources locally rather than uniformly.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system changes parameters dynamically based on classifier predictions. Rather than maintaining fixed decoding parameters for all cases, the patent adjusts decoding behavior according to the predicted outcome for each codeword, optimizing the balance between QoS compliance and power consumption by adapting parameters to local conditions.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS11088712B2Iterative decoder performance prediction using machine learning
Publication Date: 2021.08.10 SANDISK TECHNOLOGIES LLC
  • US11088712B2 patent drawing
  • US11088712B2 patent drawing
  • US11088712B2 patent drawing

AI summary

An illustrative embodiment of this disclosure is an apparatus, including a memory, a processor in communication with the memory, and a decoder. The processor is configured to train a classifier, calculate one or more features of a codeword, predict an outcome of decoding the codeword with the decoder, and determine, using the classifier, whether the outcome satisfies a predetermined threshold. In some embodiments, based on the outcome, the processor selects a set of decoder parameters to improve decoder performance.