Adaptive CRC Check Bit Length for Variable Code Rates
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Solution Overview
Problem
Existing CRC encoding schemes in the NR system are inflexible, as they support only one check bit length, leading to suboptimal communication performance due to inability to adapt the check bit length to varying code lengths and rates, resulting in increased block error rates and signal-to-noise requirements.
Innovation Solution
A method and apparatus that dynamically determine the check bit length based on code length and rate information using a correspondence table and CRC polynomial, allowing flexible selection of check bits to optimize communication performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If one CRC polynomial supports only one check bit length, then the encoding scheme is simple, but the adaptability to different code lengths and rates is poor
Solution Approach 1:
The patent applies dynamics by making the check bit length variable rather than fixed. The CRC encoding scheme dynamically selects the check bit length based on the code length and code rate of the input data, allowing the system to adapt to different communication conditions while maintaining a relatively simple encoding structure.
Solution Approach 2:
The patent changes the parameter of check bit length from a fixed value to a variable that depends on code length and code rate. By establishing a correspondence relationship between these parameters, the system can flexibly adjust the check bit length to optimize communication performance for different data characteristics.
2Reliability
If check bit length is fixed, then the encoding process is straightforward, but communication performance is reduced due to inability to optimize for different code lengths and rates
Solution Approach 1:
The patent applies preliminary action by pre-establishing a correspondence table that maps code length and code rate combinations to optimal check bit lengths. This pre-computed mapping allows the system to quickly determine the appropriate check bit length without complex real-time calculations, thereby improving communication performance while maintaining ease of operation.
Solution Approach 2:
The patent introduces a correspondence table as an intermediary between the input data characteristics (code length and rate) and the CRC encoding process. This intermediary structure simplifies the selection of check bit length by providing a direct lookup mechanism, avoiding complex decision-making while optimizing communication performance.
3Reliability
If a single CRC polynomial is used, then the implementation is simple, but the error detection capability is suboptimal for varying code parameters
Solution Approach 1:
The patent changes the parameter of CRC polynomial from a single fixed polynomial to a set of polynomials selected based on code length and code rate. By establishing a correspondence between these parameters and appropriate polynomials, the system optimizes error detection capability for different communication scenarios while managing polynomial selection complexity through pre-defined mappings.
Data Source
AI summary
A cyclic redundancy check bit determination method and system, the method including obtaining an information bit, determining, based on a first correspondence, that a check bit length is L, where L is a natural number, and where the first correspondence includes a correspondence among code length information of to-be-transmitted data including the information bit, length information of the information bit, and the check bit length, and determining a first check bit based on a first cyclic redundancy check (CRC) polynomial, where a length of the first check bit is the check bit length L, where a highest power of terms in the first CRC polynomial is Lmax, where Lmax is a positive integer, and where Lmax is greater than or equal to L.