Adjusted Min-Sum Decoding for Low-Complexity LDPC and Turbo Codes

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Solution Overview

Problem

Current decoding algorithms for LDPC and Turbo codes, such as BCJR and Sum-product decoders, are complex and not easily implementable, leading to degraded performance at lower rates, especially in high-speed applications like 5G wireless communication systems.

Innovation Solution

The implementation of an adjusted minimum-sum (AdjMS) algorithm that approximates update functions and determines magnitudes of outgoing log likelihood ratios (LLRs) for efficient decoding, allowing for a unified decoder that supports both LDPC and Turbo codes with high performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional decoding algorithms (BCJR, Sum-product) are used, then decoding accuracy is maintained, but implementation complexity increases and performance degrades at lower rates

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

Solution Approach 1:

The patent transforms the complex sum-product decoding algorithm into a simplified adjusted minimum-sum algorithm by changing the computational parameters from full summation to minimum-based operations. This parameter transformation maintains decoding accuracy while significantly reducing implementation complexity, especially for high-speed applications like 5G wireless communication systems

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs a simplified decoding approach that uses approximate computations instead of exact calculations, analogous to using cheaper, simpler components. The adjusted minimum-sum algorithm provides sufficient decoding performance with reduced computational resources, making it suitable for resource-constrained high-speed communication systems

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

2Reliability

If complex decoding algorithms are implemented, then decoding performance is maintained, but processing speed decreases

Engineering Contradiction:
Improvedecoding performanceVSAvoidprocessing speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent changes the computational parameters from complex summation operations to simpler minimum-based operations, enabling faster processing while maintaining acceptable decoding performance. This parameter transformation is crucial for achieving high-speed decoding in modern wireless communication systems

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The adjusted minimum-sum algorithm skips complex intermediate calculation steps required by traditional sum-product decoding, rushing through the essential computations more efficiently. This approach maintains decoding performance while significantly improving processing speed for high-rate LDPC code decoding

Inventive Principle:
Principle #21Skipping (Rushing through)

3Reliability

If traditional decoders are used for both LDPC and Turbo codes, then code-specific performance is optimized, but device complexity increases

Engineering Contradiction:
Improvecode-specific performanceVSAvoiddecoder complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent develops a unified adjusted minimum-sum decoding framework that can decode both LDPC and Turbo codes using the same algorithmic structure. This universal approach eliminates the need for separate complex decoders for different code types, reducing overall device complexity while maintaining code-specific performance through parameter adjustments

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

Data Source

PatentUS10419027B2Adjusted min-sum decoder
Publication Date: 2019.09.17 QUALCOMM INC
  • US10419027B2 patent drawing
  • US10419027B2 patent drawing
  • US10419027B2 patent drawing

AI summary

Certain aspects of the present disclosure generally relate to techniques for efficient, high-performance decoding of low-density parity check (LDPC) codes, for example, by using an adjusted minimum-sum (AdjMS) algorithm, which involves approximating an update function and determining magnitudes of outgoing log likelihood ratios (LLRs). Similar techniques may also be used for decoding turbo codes. Other aspects, embodiments, and features (such as encoding technique) are also claimed and described.