Distributed CRC Polar Codes Without Gaussian Elimination Overhead

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Solution Overview

Problem

Existing methods for generating CRC matrices for polar codes in communication systems require complex Gaussian elimination, leading to significant computing overhead, especially when the information block size changes.

Innovation Solution

A method to determine a cyclic redundancy check (CRC) generator sequence that enables early termination of polar encoded sequences by distributing CRC bits within the control information values, using a selected part of the CRC generator sequence, and polar encoding the combined sequence.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If Gaussian elimination methods are used to transform the CRC generator matrix to an upper triangle like matrix, then the CRC distribution performance is improved, but the computing complexity overhead increases significantly

Engineering Contradiction:
ImproveCRC distribution performanceVSAvoidcomputing complexity overhead
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-computing and storing the transformation matrices (Q and P) and interleaving patterns for different information block sizes before actual communication occurs. These pre-computed structures are stored in memory and directly applied during encoding, eliminating the need for real-time Gaussian elimination and significantly reducing computing complexity while maintaining optimal CRC distribution.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If row and column swapping is performed to obtain an upper triangle like matrix, then each CRC bit can be placed after the bits on which it depends, but the processing time increases

Engineering Contradiction:
ImproveCRC bit positioningVSAvoidprocessing time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent resolves this time-consuming operation by pre-computing the row and column permutation patterns (stored as matrices Q and P) for all possible information block sizes. These permutation patterns are stored in memory and directly applied during encoding without performing actual row and column swapping operations in real-time, thus maintaining optimal CRC bit positioning while minimizing processing time.

Inventive Principle:
Principle #10Preliminary action

3Adaptability or versatility

If the CRC generator matrix is regenerated for each information block size, then the CRC distribution adapts to different payload sizes, but the energy consumption increases

Engineering Contradiction:
ImproveCRC distribution adaptationVSAvoidenergy consumption
Core Design Contradiction:
Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The patent addresses energy consumption by pre-computing and storing the CRC generator matrix transformations and interleaving patterns for all supported information block sizes before communication begins. During actual encoding, the system simply retrieves and applies the pre-computed structures corresponding to the current payload size, avoiding repeated regeneration of matrices and significantly reducing energy consumption while maintaining full adaptability to different payload sizes.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3619811B1Distributed CRC polar codes
Publication Date: 2025.06.04 NOKIA TECHNOLOGIES OY
  • EP3619811B1 patent drawingFigure 1
  • EP3619811B1 patent drawingFigure 2~3
  • EP3619811B1 patent drawingFigure 4

AI summary

A method comprising: determining a cyclic redundancy check (CRC) generator sequence defining a one to one mapping between a sequence of control information values and cyclic redundancy check (CRC) sequence values; and determining a combined sequence, the combined sequence formed by distributing the cyclic redundancy check (CRC) value sequence within the sequence of control information values, wherein the distributing the cyclic redundancy check (CRC) value sequence within the sequence of control information values is based on a selected part of the cyclic redundancy check (CRC) generator sequence.