Polar Code Rate Matching Across Code Rate Thresholds
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Solution Overview
Problem
Existing polar code rate matching methods in 5G communications face complexity and performance issues due to the need for flexible code length configuration and high complexity in calculating or storing sequences for different code rates and channel conditions, particularly in supporting a wide range of code lengths with low complexity.
Innovation Solution
A method and apparatus for polar code rate matching that dynamically selects between puncturing and shortening manners based on code rate thresholds and information bit thresholds, allowing for flexible rate matching by determining the appropriate manner through comparisons of code rates and thresholds to maintain performance across various encoding parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If real-time calculation is used to determine locations of information bits, then performance of the polar code is improved, but complexity at transmit end and receive end is greatly increased
Solution Approach 1:
The patent pre-calculates and stores the locations of information bits in a table during system design, so that during actual encoding and decoding operations, the device can directly query the pre-stored table without performing complex real-time calculations. This preliminary preparation resolves the contradiction by shifting computational burden from runtime to design time.
Solution Approach 2:
The patent creates a simplified copy of the complex calculation results by storing only the essential information (locations of information bits) in a lookup table, rather than storing or computing the full construction algorithm. This copying approach maintains performance while dramatically reducing computational complexity during operation.
2Reliability
If table storage is used to store constructed sequence, then performance of the polar code is improved, but complexity in storing the constructed sequence is significantly high
Solution Approach 1:
The patent extracts only the essential information from the full constructed sequence - specifically, just the locations of information bits are stored in the table, while other details are omitted. This extraction reduces the storage burden significantly while maintaining the performance benefits of having pre-calculated information.
Solution Approach 2:
The patent uses a simplified, lightweight table structure that stores minimal information compared to the full constructed sequence. This disposable-like simplified structure can be easily stored and queried without requiring significant memory resources, resolving the storage complexity issue.
3Device complexity
If puncturing manner is used for rate matching, then complexity is reduced, but the puncturing manner is applicable only to a low code rate
Solution Approach 1:
The patent dynamically selects between puncturing and shortening methods based on the code rate. For low code rates, puncturing is used; for medium and high code rates, shortening is used. This dynamic adaptation allows the system to maintain low complexity while being applicable across a wide range of code rates, resolving the contradiction between simplicity and versatility.
4Reliability
If shortening manner is used for rate matching, then a constant constructed sequence and a fixed puncturing rule may be used to obtain relatively stable performance, but this solution is applicable only to code rates within a specific range
Solution Approach 1:
The patent implements a dynamic selection mechanism that chooses between puncturing and shortening methods based on the code rate. For medium and high code rates, shortening is used to maintain stable performance; for low code rates, puncturing is used. This dynamic approach extends the applicability of the constant constructed sequence concept to a broader range of code rates while maintaining stability where applicable.
Data Source
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AI summary
This application provides a polar code rate matching method and apparatus. The method includes: obtaining, by a communications device, to-be-encoded information or to-be-decoded information; determining, by the communications device, a code rate R; determining, by the communications device, a to-be-used rate matching manner based on the code rate, a code rate threshold, a quantity of information bits, and an information bit threshold, or determining, by the communications device, a to-be-used rate matching manner based on the code rate, a code rate threshold, a target code length, and a target code length threshold, or determining, by the communications device, a to-be-used rate matching manner based on the code rate and two code rate thresholds, where the rate matching manner is a puncturing manner or a shortening manner; and rate matching, by the communications device based on the determined rate matching manner, a polar code of the to-be-encoded information, or rate dematching a polar code of the to-be-decoded information. In this way, a puncturing or shortening manner can be flexibly selected, so that performance is relatively good under different encoding parameters, and a performance loss is avoided in a puncturing or shortening process.