Two-Level CRC Coding Using Distinct Generator Polynomials
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Solution Overview
Problem
The use of the same generator polynomials for CRC coders in wireless communication systems leads to undetected error events at both levels of CRC checking, resulting in incorrect data being accepted as correct.
Innovation Solution
Employing different generator polynomials for CRC encoding the transport block and segmented code blocks, ensuring that the first and second generator polynomials have distinct factors or no common factors, and potentially using reciprocal polynomials, to enhance error detection capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the same generator polynomial is used for both transport block CRC and code block CRC encoding, then the system complexity is reduced and ease of operation is improved, but error detection capability deteriorates due to undetected error events at both CRC checking levels
Solution Approach 1:
The patent applies local quality by assigning different generator polynomials to different levels of the CRC encoding hierarchy. Specifically, a first generator polynomial is used for transport block CRC encoding while a second generator polynomial is used for code block CRC encoding. This differentiation ensures that error patterns undetected by one polynomial are likely to be detected by the other, thereby improving overall error detection capability without significantly increasing system complexity
Solution Approach 2:
The patent implements parameter changes by modifying the generator polynomial parameter at different hierarchical levels of CRC encoding. By changing the generator polynomial from the first level (transport block) to the second level (code block), the system creates diverse error detection capabilities that complement each other, reducing the probability of undetected errors while maintaining operational simplicity
2Reliability
If different generator polynomials are used for CRC encoding transport block and segmented code blocks, then error detection capability is improved, but device complexity increases
Solution Approach 1:
The patent applies local quality by assigning different generator polynomials to different levels of the CRC encoding hierarchy. Specifically, a first generator polynomial is used for transport block CRC encoding while a second generator polynomial is used for code block CRC encoding. This differentiation ensures that error patterns undetected by one polynomial are likely to be detected by the other, thereby improving overall error detection capability without significantly increasing system complexity
Solution Approach 2:
The patent implements preliminary action by pre-defining and storing multiple generator polynomials in the system. The first generator polynomial is used for transport block CRC encoding while a second generator polynomial is used for code block CRC encoding. This pre-preparation allows the system to switch between different polynomials without real-time computation overhead, thereby improving error detection capability while minimizing the increase in device complexity
Data Source
AI summary
A wireless communication device 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 block 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.