Polar Code Rate Matching Through Reliability-Aware Puncturing
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Solution Overview
Problem
Existing rate matching methods for polar codes, such as puncturing or shortening, result in performance loss when the mother code has a large number of information bits, as they directly reduce the code length, leading to inefficiencies in communication systems.
Innovation Solution
A method and apparatus for rate matching in polar codes that involve determining specific bit positions for puncturing or shortening based on thresholds and reliability criteria, such as P1 to-be-punctured bit positions corresponding to polarization channels 0 to P T1 -1, P T1 to 3N/8-1, or N/2 to 5N/8-1, where P T1 ≤ N/4, to optimize the encoded bit length without recalculating reliability, thereby reducing performance loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If direct puncturing or shortening is applied to a mother code with a large quantity of information bits, then the code length is reduced to match target length, but performance loss occurs
Solution Approach 1:
The invention segments the puncturing process into two stages: first puncturing frozen bits (reliable bits) to reduce code length, then puncturing information bits if further reduction is needed. This segmentation avoids directly puncturing information bits first, thereby reducing performance loss while achieving the target code length.
Solution Approach 2:
The invention performs preliminary puncturing of frozen bits before puncturing information bits. By removing frozen bits first (which are less critical for performance), the system prepares the code in advance to minimize performance degradation when information bits are subsequently punctured to achieve the target length.
2Adaptability or versatility
If the mother code length is reduced through puncturing to achieve target code length, then rate matching is achieved, but performance loss occurs due to direct information bit puncturing
Solution Approach 1:
The invention segments the code into frozen bits and information bits, and further segments the puncturing process into two phases: first puncturing frozen bits, then puncturing information bits. This segmentation enables flexible code length adaptation while preserving decoding performance by protecting information bits until necessary.
Solution Approach 2:
The invention applies different puncturing strategies to different parts of the code: frozen bits are punctured first (local action on less critical bits), and information bits are punctured only if needed (local action on critical bits). This local quality approach maintains overall code performance while achieving the required code length flexibility.
Data Source
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AI summary
Embodiments of the present invention provide a rate matching method and an apparatus, to avoid a performance loss in a puncturing/shortening process. The method includes: performing, by a sending apparatus, encoding by using a polar code polar to obtain a first encoded sequence whose length is N, where a sequence number of a polarization channel may range from 0 to N-1; determining, by the sending apparatus, P1 to-be-punctured bit positions, and performing puncturing at the P1 bit positions in the first encoded sequence to obtain rate-matched encoded bits, where the P1 to-be-punctured bit positions are bit positions corresponding to polarization channels 0 to PT1-1, PT1 to 3N/8-1, and/or N/2 to 5N/8-1, PT1 is a threshold of a quantity of to-be-punctured bit positions, and PT1 ≤ N/4; and sending the rate-matched encoded bits.