Polar Code Encoding with CRC-PC Checks for Early Termination
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Solution Overview
Problem
Current polar coding schemes, such as CA-Polar and PC-Polar, face limitations in early termination capability and encoding optimization, leading to poor performance in decoding reliability and complexity, especially at high signal-to-noise ratios.
Innovation Solution
The proposed method involves performing both cyclic redundancy check (CRC) and parity check encoding before polar encoding, and using CRC-aided PC polar encoding to improve error detection capability, allowing for double encoding and double checks on the encoding side and decoding side, respectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If CRC code is used as outer code in CA-Polar scheme, then error detection capability is improved, but early termination capability during decoding is lost and encoding optimization space is reduced
Solution Approach 1:
The patent combines CRC code and PC code into a hybrid outer code structure. The CRC bits provide error detection capability while the PC bits are distributed among information bits to enable early termination during decoding. This merging allows both error detection and early termination capabilities to coexist in the same polar coding system.
Solution Approach 2:
The hybrid outer code structure serves multiple functions simultaneously: CRC bits provide error detection, PC bits enable early termination, and the combined structure maintains compatibility with polar encoding. This multi-functionality resolves the contradiction by making the outer code structure capable of both error detection and early termination.
2Reliability
If CRC bit is placed on subchannel with highest reliability, then error detection is improved, but encoding optimization space is reduced
Solution Approach 1:
The patent applies different qualities to different parts of the code structure: CRC bits are placed on high-reliability subchannels for error detection, while PC bits are distributed among information bits on various subchannels to provide early termination capability. This local differentiation allows each part to optimize for its specific function while maintaining overall system performance.
3Ease of operation
If PC code is used as outer code in PC-Polar scheme, then early termination capability is improved, but construction complexity increases and decoding reliability decreases
Solution Approach 1:
The patent segments the outer code into distinct CRC and PC components with different functions. The CRC portion handles error detection while the PC portion provides early termination. This segmentation reduces construction complexity by clearly defining the roles of each component rather than using a monolithic PC code structure.
4Device complexity
If only single encoding (CRC or PC) is performed, then device complexity is reduced, but decoding performance and transmission reliability are poor
Solution Approach 1:
The patent uses a composite outer code structure combining CRC and PC codes, analogous to composite materials in engineering. This hybrid structure leverages the error detection strength of CRC and the early termination strength of PC to achieve superior decoding performance that neither code could provide alone, while maintaining manageable complexity through structured integration.
Data Source
AI summary
Embodiments of this application disclose encoding and decoding methods and apparatus related to the communications. One of the methods includes: obtaining, based on polar code rate matching, a subchannel corresponding to a punctured bit or a shortened bit; determine subchannels corresponding to an information bit and a check frozen bit that are different from the subchannel corresponding to the punctured bit or the shortened bit; determining that a subchannel corresponding to a frozen bit that is different from the subchannels corresponding to the information bit and the check frozen bit and the subchannel corresponding to the punctured bit or the shortened bit; performing, according to the subchannels corresponding to the information bit and the check frozen bit and the subchannel corresponding to the frozen bit, parity check encoding and polar encoding based on the information bit to obtain encoded information; and sending the encoded information.