Iterative MAP Decoding Stopping Using State Metric Signatures

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Solution Overview

Problem

Conventional turbo decoding methods require a large number of iterations to achieve high accuracy, leading to increased power consumption and decoding delay, and existing stopping methods either require significant memory or complex calculations.

Innovation Solution

A low-complexity method using state metric signatures to determine the stopping index during iterative MAP decoding, reducing the number of iterations and memory requirements, and implemented in a chip to save power and reduce chip area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the number of iterations is increased to improve decoding accuracy, then the decoding performance approaches Shannon's channel capacity limit, but the power consumption and decoding delay increase

Engineering Contradiction:
Improvedecoding accuracyVSAvoidpower consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent implements dynamic iteration stopping by introducing a stopping criterion that monitors the evolution of extrinsic information across iterations. The decoding process adaptively terminates when convergence is detected, rather than executing a fixed number of iterations. This dynamic approach allows the system to stop early when accuracy requirements are met, reducing power consumption while maintaining decoding performance.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent employs feedback mechanisms by comparing extrinsic information from successive iterations to determine convergence. The stopping criterion uses feedback from the decoding process itself (the change in extrinsic information) to make decisions about continuing or terminating iterations. This feedback-driven approach optimizes the trade-off between decoding accuracy and power consumption.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If the number of iterations is increased to improve decoding accuracy, then the decoding performance approaches Shannon's channel capacity limit, but the decoding delay increases

Engineering Contradiction:
Improvedecoding accuracyVSAvoiddecoding delay
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent implements dynamic iteration stopping by introducing a stopping criterion that monitors the evolution of extrinsic information across iterations. The decoding process adaptively terminates when convergence is detected, rather than executing a fixed number of iterations. This dynamic approach allows the system to stop early when accuracy requirements are met, reducing decoding delay while maintaining decoding performance.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent employs feedback mechanisms by comparing extrinsic information from successive iterations to determine convergence. The stopping criterion uses feedback from the decoding process itself (the change in extrinsic information) to make decisions about continuing or terminating iterations. This feedback-driven approach optimizes the trade-off between decoding accuracy and decoding delay.

Inventive Principle:
Principle #23Feedback

3Use of energy by moving object

If existing stopping methods are used to reduce the number of iterations, then power consumption and decoding delay are reduced, but large memory and complicated calculations are required

Engineering Contradiction:
Improvepower consumptionVSAvoidmemory requirement
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent extracts only the essential information needed for stopping decisions - specifically, the extrinsic information from the current and previous iterations. Rather than using complex metrics that require large memory buffers, the method extracts and compares only the necessary decoding parameters. This extraction approach reduces memory requirements while maintaining the ability to make informed stopping decisions.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent employs simple, lightweight stopping criteria that do not require complex data structures or large memory allocations. The method uses basic comparisons of extrinsic information values, which are computationally inexpensive and require minimal memory. This approach replaces complex, memory-intensive stopping methods with simpler, more efficient alternatives.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Data Source

PatentUS8984377B2Stopping methods for iterative signal processing
Publication Date: 2015.03.17 NATIONAL KAOHSIUNG UNIVERSITY OF SCIENCE & TECHNOLOGY
  • US8984377B2 patent drawing
  • US8984377B2 patent drawing
  • US8984377B2 patent drawing

AI summary

A stopping method for an iterative signal processing includes a first step of receiving the state signatures generated by the iterative signal processing. A next step includes accumulating the state signatures into a stopping index variable. A next step includes stopping iterative decoding when the stopping index variable is less than a predetermined threshold.