Multi-Layer CRC Coding for Undetected Error Reduction

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Solution Overview

Problem

The use of the same generator polynomials for CRC coding in both transport blocks and segmented code blocks leads to undetected error events, which can result in incorrect data being accepted as correct by the receiver, reducing the effectiveness of two-level CRC error detection in wireless communication systems.

Innovation Solution

Employing different generator polynomials for CRC encoding the transport block and the segmented code blocks, ensuring that the first and second generator polynomials have distinct characteristics, such as different factors or sets of polynomial coefficients, to improve error detection capabilities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the same generator polynomial is used for CRC encoding at both transport block level and code block level, then the implementation complexity is reduced, but undetected error events increase

Engineering Contradiction:
ImproveCRC encoding complexityVSAvoiderror detection capability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent applies different generator polynomials at different levels of the CRC encoding hierarchy. Specifically, a first generator polynomial is used for transport block level CRC encoding, while a second generator polynomial is used for code block level CRC encoding. This local differentiation of polynomial characteristics enhances error detection capability without significantly increasing overall system complexity.

Inventive Principle:
Principle #3Local quality

2Reliability

If different generator polynomials are used for CRC encoding at transport block level and code block level, then error detection capability is improved, but implementation complexity increases

Engineering Contradiction:
Improveerror detection capabilityVSAvoidCRC encoding complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent changes the polynomial parameter characteristics between different CRC encoding levels. By selecting generator polynomials with different factors or coefficient sets for transport block level versus code block level encoding, the system optimizes error detection for various error patterns while managing implementation complexity through systematic parameter selection.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2181505B1Multi-layer cyclic redundancy check code in wireless communication system
Publication Date: 2019.05.22 GOOGLE TECHNOLOGY HOLDINGS LLC
  • EP2181505B1 patent drawingFigure 1
  • EP2181505B1 patent drawingFigure 2
  • EP2181505B1 patent drawingFigure 3

AI summary

A wireless communication device (200) including a first CRC coder that generates a first block of CRC parity bits on a transport block and associates the first block of CRC parity bits with the transport block, a segmenting entity that segments the transport blocks into multiple code blocks after associating, and a second coder that generates a second block of CRC parity bits on each code block and associates a second block of CRC parity bits with each code block. The first and second blocks of CRC parity bits are based on first and second generator polynomials. In one embodiment, the first and second generator polynomials are different. In another embodiment, the generator polynomials are the same and the transport block is interleaved before segmenting or the code block are interleaved before encoding with the second block of CRC parity bits.