Polar Code Interleaver Layout for Lower BLER in 64-QAM

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Solution Overview

Problem

Existing wireless communication networks face challenges in achieving optimal performance for polar codes, particularly under Additive White Gaussian Noise (AWGN), due to insufficient Signal-to-Noise Ratio (SNR) and Block Error Rate (BLER) with traditional interleaver designs for higher-order modulation schemes like 16-QAM or 64-QAM.

Innovation Solution

A new interleaver design utilizing a right isosceles triangle-shaped or trapezoid-shaped matrix with varying columns between rows, where the number of columns in each row decreases, and the inclusion of null values to create a trapezoid shape, is introduced to improve the interleaving process for polar codes, reducing complexity and latency while maintaining performance comparable to random interleavers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional interleaver designs are used for polar codes, then the structure is simple, but the SNR performance is insufficient and BLER is high for higher-order modulation schemes

Engineering Contradiction:
ImproveSNR and BLER performanceVSAvoidinterleaver structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies asymmetry by designing an interleaver with unequal column lengths across rows, where the first row has more columns than subsequent rows. This asymmetric structure creates better bit dispersion patterns that improve SNR and BLER performance for higher-order modulation schemes like 16-QAM and 64-QAM, while maintaining manageable structural complexity through a systematic design approach.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent transitions from traditional rectangular interleaver structures to a two-dimensional triangular arrangement where rows have varying column counts. This dimensional reorganization creates a more effective interleaving pattern that spreads bits across different rows and columns, improving error correction performance without proportionally increasing structural complexity.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If complex interleaver designs are used to improve SNR and reduce BLER, then reliability improves, but computational complexity and latency increase

Engineering Contradiction:
ImproveSNR and BLER performanceVSAvoidcomputational efficiency and latency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent segments the code block into multiple rows with varying column counts, creating a structured interleaving pattern. This segmentation approach improves reliability by better distributing error-prone bits while maintaining computational efficiency through a systematic, rule-based interleaving process that avoids the high complexity of random interleaving methods.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the structural parameters of the interleaver by varying column lengths across rows rather than using uniform dimensions. This parameter variation optimizes the interleaving effect for higher-order modulations while keeping the overall structure manageable, achieving better SNR and BLER performance without proportionally increasing computational complexity.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If uniform column-length interleavers are used, then the structure is regular and simple, but performance for higher-order modulation schemes deteriorates

Engineering Contradiction:
Improveinterleaver implementation simplicityVSAvoidperformance for 16-QAM and 64-QAM
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent deliberately introduces asymmetry by designing rows with different column lengths, where the first row contains more columns than subsequent rows. This asymmetric design significantly improves performance for higher-order modulation schemes like 16-QAM and 64-QAM by creating more effective bit dispersion patterns, while the systematic construction method keeps implementation complexity reasonable.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent implements a dynamic interleaver structure where the number of columns varies by row rather than maintaining a static uniform structure. This dynamic approach adapts the interleaving pattern to better suit the requirements of higher-order modulations, improving reliability while maintaining ease of implementation through clear structural rules.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4135228A1An efficient interleaver design for polar codes
Publication Date: 2023.02.15 QUALCOMM INC
  • EP4135228A1 patent drawingFigure 1
  • EP4135228A1 patent drawingFigure 2
  • EP4135228A1 patent drawingFigure 3

AI summary

Aspects of the disclosure relate to wireless communication devices configured to encode information blocks to produce code blocks and interleave the code blocks utilizing an interleaver including a plurality of rows and a plurality of columns, where the number of columns of the interleaver varies between the rows. In some examples, the interleaver includes a right isosceles triangle-shaped matrix of rows and columns. In other examples, the interleaver includes a trapezoid-shaped matrix of rows and columns.