Polar Code Bit Allocation With CRC-PC Hybrid Outer Coding
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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 and decoding performance by allocating bits based on subchannel reliability and quasi-periodic features of channel polarization.
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 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 to coexist in the same polar coding system.
Solution Approach 2:
The outer code structure serves multiple functions simultaneously: CRC bits detect errors in received data, PC bits enable early termination by providing check constraints during incremental decoding, and the combined structure maintains compatibility with polar encoding. This multi-functionality resolves the contradiction by making the outer code system capable of both error detection and early termination.
2Ease of manufacture
If CRC bit is placed at end of information bits, then error detection is simplified, but encoding optimization capability is reduced
Solution Approach 1:
The outer code is segmented into distinct functional components: CRC bits for error detection and PC bits for encoding optimization. This segmentation allows each component to perform its specialized function independently while working together as a unified outer code structure, resolving the contradiction between simplicity and adaptability.
Solution Approach 2:
Different portions of the outer code have different qualities and functions. CRC bits are positioned to provide error detection with simple parity checks, while PC bits are distributed among information bits to provide encoding optimization capabilities. This local differentiation allows each part to excel at its specific function while contributing to overall system performance.
3Ease of operation
If PC polar scheme is used, then early termination capability is improved, but construction complexity increases
Solution Approach 1:
Instead of implementing the full complex PC polar construction, the patent applies partial PC functionality by distributing only sufficient PC bits among information bits to enable early termination. This partial application reduces construction complexity while maintaining the essential early termination capability, resolving the contradiction between functionality and complexity.
4Ease of operation
If first path decoding result is output by default, then decoding process is simplified, but decoding reliability deteriorates
Solution Approach 1:
The patent implements feedback mechanisms where PC bits provide check constraints that verify decoding results. Instead of simply outputting the first path result, the system uses PC check constraints to validate decoding outcomes and provide feedback for error correction, thereby improving reliability while maintaining relatively simple decoding processes.
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.