Polar Code Rate Matching Using Grouped Puncturing And Shortening
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Solution Overview
Problem
Polar codes require rate matching to achieve any target code length, but existing methods are complex and inefficient, especially when recalculating polar channel reliability for shortening patterns, leading to performance instability and high construction complexity.
Innovation Solution
A group-based puncturing/shortening rate matching method that divides encoded bits into equal-length groups, determines puncturing/shortening positions based on a specific pattern, and uses a block interleaver for efficient rate matching, reducing complexity and improving performance by selectively deleting bits and placing frozen bits on polar channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If existing rate matching methods are used for polar codes, then any target code length can be achieved, but the construction complexity increases and performance stability deteriorates due to recalculating polar channel reliability
Solution Approach 1:
The patent segments the encoded bit sequence into multiple groups (first group, second group, third group, etc.) and applies different puncturing/shortening strategies to each group based on their positions. This segmentation allows the system to achieve different code lengths without recalculating polar channel reliability, as the grouping and selection rules are predetermined based on the mother code length and target code length relationships.
2Adaptability or versatility
If existing rate matching methods are used for polar codes, then any target code length can be achieved, but performance stability worsens due to recalculating polar channel reliability
Solution Approach 1:
The patent performs preliminary actions by pre-defining the grouping structure and puncturing/shortening rules based on the mother code length before actual encoding. The encoded bit sequence is divided into groups with predetermined sizes and positions, and the selection of which groups to puncture or shorten is determined in advance based on the target code length. This preliminary structuring eliminates the need for recalculating polar channel reliability during rate matching, thereby maintaining performance stability.
3Device complexity
If group-based puncturing/shortening is implemented, then construction complexity is reduced, but implementation complexity increases due to dividing bits into groups and determining patterns
Solution Approach 1:
The patent changes parameters by establishing clear mathematical relationships between the mother code length N, the number of groups, and the size of each group. The grouping structure is defined by parameters such as the first number (determining first group size), second number (determining second group size), and third number (determining third group size). These parameter-based definitions simplify implementation by providing deterministic rules rather than requiring complex algorithms, making the grouping and pattern determination straightforward to implement.
Data Source
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AI summary
This application discloses a rate matching method. The method includes: obtaining an encoded bit sequence, where the encoded bit sequence includes g equal-length groups, a quantity of encoded bits in each group is N/g, N is a mother code length of a polar code, N is an integral power of 2, g is an integer greater than or equal to 4 and less than N, and g is an integral power of 2; determining, based on the groups, a position of a bit that needs to be punctured/shortened in the encoded bit sequence; and obtaining an encoded bit in the encoded bit sequence except the bit that needs to be punctured/shortened, to obtain an encoded bit sequence obtained after rate matching. Group-based puncturing/shortening rate matching is easy to implement, thereby improving polar code performance.