Polar Code Puncturing Selection for Lower HARQ Frame Error

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Solution Overview

Problem

Random puncturing in Hybrid Automatic Repeat Request (HARQ) for Polar codes leads to poor transmission performance due to high frame error rates, reducing the quality of the Polar code.

Innovation Solution

A method to determine multiple candidate sets of puncturing locations for Polar codes, calculating the sum of error probabilities for each set, and selecting the set with the minimum upper bound of frame error rate for rate matching, thereby improving transmission performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If random puncturing is used in HARQ for Polar codes, then the puncturing process is simple and fast, but the frame error rate is high and transmission performance is poor

Engineering Contradiction:
Improvepuncturing processing speedVSAvoidframe error rate
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent pre-calculates and stores optimal puncturing location sets for different code rates before actual transmission. These pre-computed puncturing patterns are stored in a lookup table, allowing the system to quickly select the appropriate puncturing configuration without performing real-time error probability calculations, thus maintaining high processing speed while achieving low frame error rates through optimized puncturing locations

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the puncturing location parameters based on code rate requirements. Instead of random puncturing, the system selects from pre-determined puncturing location sets that are optimized for specific code rates. This parameter optimization ensures that the most reliable bit channels are preserved for transmission while discarding less critical bits, thereby reducing frame error rate without significantly increasing computational complexity

Inventive Principle:
Principle #35Parameter changes

2Reliability

If optimal puncturing locations are selected by calculating error probabilities, then the frame error rate is reduced and transmission performance is improved, but the calculation complexity and processing time increase

Engineering Contradiction:
Improveframe error rateVSAvoidcalculation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent performs the complex error probability calculations and optimal puncturing location selection in advance, before actual data transmission. The results are stored in a pre-computed lookup table that maps code rates to optimal puncturing location sets. During real-time operation, the system only needs to perform simple table lookups based on the current code rate, avoiding the need for complex real-time calculations while still achieving optimal puncturing performance

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent creates pre-computed copies of optimal puncturing configurations for different code rates. Instead of recalculating optimal puncturing locations for each transmission, the system uses copied, pre-determined puncturing patterns from the lookup table. This copying approach maintains the reliability benefits of optimized puncturing while dramatically reducing the computational complexity and processing time required during actual transmission operations

Inventive Principle:
Principle #26Copying

Data Source

PatentEP3057255B1Rate matching method and apparatus for polar codes, and wireless communication device
Publication Date: 2018.08.22 HUAWEI TECH CO LTD
  • EP3057255B1 patent drawingFigure 1~2
  • EP3057255B1 patent drawingFigure 3
  • EP3057255B1 patent drawingFigure 4

AI summary

Provided are a rate matching method and apparatus for Polar codes, and a wireless communication device. The method comprises: with respect to Polar codes output by an encoder, determining a plurality of types of punching position sets to be selected, punching positions indicated by any two punching position sets being not completely identical to each other; for each type of punching position set, determining the sum of error probabilities of all bit channels for transmitting information bits of the Polar codes when the punching position set is applied, the sum of the error probabilities being called the upper limit of frame error ratios corresponding to the punching position set; and from the plurality of types of punching position sets to be selected, selecting a punching position set corresponding to the minimum upper limit of the frame error ratios as a selected punching position set, and according to p punching positions indicated in the selected punching position set, conducting rate matching. The present invention increases the HARQ transmission performance of Polar codes.