Recursive Polar Code Bit Allocation to Mitigate SNR Spikes

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Solution Overview

Problem

Existing wireless communication systems using fractally enhanced kernel polar codes experience performance loss due to spikes in achievable signal-to-noise ratio (SNR) curves, particularly when puncturing a large number of bits to achieve specified code block sizes.

Innovation Solution

Implementing adjusted fractally enhanced kernel polar codes by recursively splitting the codeword into sub-blocks, allocating information bits based on mutual information metrics, and removing additional information bits to improve channel capacity and reduce SNR spikes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If fractally enhanced kernel polar codes are used with large number of punctured bits, then code block size can be achieved, but performance loss occurs due to SNR spikes

Engineering Contradiction:
Improvecode block sizeVSAvoidperformance
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent divides the codeword into multiple sub-blocks and processes each sub-block separately with its own information bit allocation. This segmentation allows the system to handle large code block sizes through puncturing while maintaining performance by optimizing the information bit distribution across sub-blocks, thereby resolving the contradiction between achieving large code block sizes and maintaining reliability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different information bit allocation strategies to different sub-blocks based on their specific characteristics. By recursively allocating information bits to sub-blocks and then to individual bit channels within each sub-block, the system optimizes local quality of each segment, which prevents SNR spikes and maintains overall performance when large numbers of bits are punctured.

Inventive Principle:
Principle #3Local quality

2Reliability

If information bits are allocated based on recursive mutual information calculation, then bit channel allocation is optimized, but computational complexity increases

Engineering Contradiction:
Improvebit channel allocationVSAvoidcomputational complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent reduces computational complexity by dividing the large-scale mutual information calculation into smaller sub-blocks. Each sub-block undergoes recursive mutual information calculation independently, which significantly reduces the overall computational burden while still achieving optimized bit channel allocation. This segmentation approach resolves the contradiction between optimization and complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs mutual information calculation recursively on sub-blocks rather than on the entire codeword at once. This partial action approach applies the complex calculation only where necessary (in the recursive sub-block allocation) rather than uniformly across all bits, reducing overall computational complexity while maintaining allocation optimization.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP3724999B1Polar code construction with recursive mutual information based bit channel allocation followed by removal of bit channels
Publication Date: 2025.04.16 QUALCOMM INC
  • EP3724999B1 patent drawingFigure 1
  • EP3724999B1 patent drawingFigure 2
  • EP3724999B1 patent drawingFigure 3

AI summary

Methods, systems, and devices for wireless communications are described. In some systems, wireless devices may implement adjusted fractally enhanced kernel polar coding. An encoder may receive a number of information bits and a block size for transmission, and may append an additional number of information bits to the information bits for transmission. The encoder may perform a recursive bit allocation process to allocate the aggregate set of information bits between a set of sub-blocks based on mutual information metrics. To obtain the correct number of information bits and block size, the encoder may remove a number of information bits equal to the number of appended additional bits (e.g., from a first half of the sub-blocks), assign the remaining information bits to bit channels in each sub-block, and block puncture a set of bits (e.g., from the first half). The resulting codeword may mitigate occurrences of achievable signal-to-noise ratio (SNR) spikes.