Polar Code Check-Bit Ordering for More Accurate Survivor Paths
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Solution Overview
Problem
The decoding performance of Polar codes is poor when the code length is small or medium, leading to decreased user experience due to reduced decoding quality in communication systems using successive-cancellation decoding methods.
Innovation Solution
An encoding method that adjusts check bits to specific positions based on sorting values derived from their relation to information bits, followed by a second-level encoding process, and a decoding method that decodes bits in sequence using a second-level decoding algorithm to output survivor paths, improving decoding performance and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If SC decoding method is used for Polar codes, then encoding complexity is low and Shannon capacity is achieved, but decoding performance is poor when code length is small or medium
Solution Approach 1:
The patent segments the decoding process into multiple stages: initial SC decoding to generate survivor paths, followed by check bit verification to filter invalid paths, and iterative refinement. This segmentation allows the system to maintain low encoding complexity while improving decoding performance by systematically eliminating incorrect survivor paths through check bit validation.
Solution Approach 2:
The patent performs preliminary SC decoding to generate a set of survivor paths before applying check bit verification. By preparing multiple candidate paths in advance and then validating them against check bits, the system avoids the need for complex decoding algorithms while still achieving reliable decoding for small and medium code lengths.
2Ease of manufacture
If check bits are appended at the end of information bits, then encoding is simple, but decoding accuracy is reduced due to poor survivor path accuracy
Solution Approach 1:
The patent performs preliminary SC decoding to generate multiple survivor paths before validating them with check bits. This preliminary action creates a candidate set that can be systematically filtered, improving decoding accuracy without complicating the encoding process.
Solution Approach 2:
The patent uses check bits to provide feedback on the validity of survivor paths. By verifying survivor paths against check bits and eliminating invalid ones, the system creates a feedback mechanism that progressively refines decoding accuracy while maintaining encoding simplicity.
3Reliability
If multiple survivor paths are maintained during decoding, then decoding reliability is improved, but computation complexity increases due to unnecessary paths
Solution Approach 1:
The patent implements feedback through check bit verification at each decoding stage. By checking survivor paths against check bits and eliminating invalid paths, the system provides feedback that reduces the number of paths that need to be tracked, thereby reducing computation complexity while maintaining reliability.
Solution Approach 2:
The patent discards invalid survivor paths that fail check bit verification while retaining valid paths for further processing. This selective discarding eliminates unnecessary computation on invalid paths while preserving the reliability benefits of maintaining multiple candidate paths.
Data Source
AI summary
Embodiments of the present invention provide an encoding/decoding method, apparatus, and system. The present invention is used to improve the decoding performance and improve accuracy of a survivor path. The method includes: encoding information bits to obtain a first-level encoded code word; obtaining a sorting value of each check bit of the first-level encoded code word, and adjusting each check bit to a corresponding position according to the sorting value of each check bit, where the sorting value refers to a value of S when the check bit is related to first S information bits of the information bits in the first-level encoded code word, and S is a non-zero integer; and performing second-level encoding on the first-level encoded code word after positions of the check bits are adjusted, thereby obtaining a second-level encoded code word. The present invention is applicable to various communication systems.