Polar Code Interleaving with Congruential Mapping for Lower Frame Errors

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Traditional HARQ technologies using random puncturing for polar codes result in high frame error rates and poor performance, necessitating an improvement in Hybrid Automatic Repeat Request (HARQ) efficiency.

Innovation Solution

A rate matching method for polar codes that employs a congruential sequence to achieve more uniform bit structures, reducing frame error rates and enhancing HARQ performance through interleaving and mapping functions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional random puncturing is used for polar code HARQ, then the implementation is simple, but the frame error rate is high and HARQ performance is poor

Engineering Contradiction:
ImproveHARQ performanceVSAvoidinterleaving structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent pre-generates a congruential sequence and stores it in memory before HARQ operation. This preliminary preparation allows the system to quickly access and apply the optimal interleaving pattern during rate matching without real-time computation, thereby improving HARQ performance while maintaining implementation simplicity

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the interleaving parameter from random selection to a structured congruential sequence defined by the formula i = (a*i_prev + c) mod N. By changing the mathematical structure of the interleaving pattern while keeping the code length N flexible, the system achieves better error distribution and HARQ performance without significantly increasing complexity

Inventive Principle:
Principle #35Parameter changes

2Quantity of substance

If code length N is increased for polar code, then coding capacity increases, but the complexity of rate matching and interleaving increases

Engineering Contradiction:
Improvecode lengthVSAvoidrate matching complexity
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The patent designs a universal congruential sequence-based interleaving method that works for any code length N. The same mathematical framework and algorithm structure can handle different code lengths (e.g., 512, 1024, 2048 bits) without requiring separate optimization, making the rate matching process scalable and manageable despite increasing code length

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The congruential sequence automatically adapts to different code lengths through the modular arithmetic operation mod N. The sequence self-adjusts its period and pattern based on the code length parameter, eliminating the need for manual reconfiguration or complex adaptive algorithms when code length changes

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3079290B1Method and apparatus for rate matching of polar code
Publication Date: 2019.04.10 HUAWEI TECH CO LTD
  • EP3079290B1 patent drawingFigure 1~2
  • EP3079290B1 patent drawingFigure 3
  • EP3079290B1 patent drawingFigure 4a

AI summary

A rate matching method for a polar code is provided, where the method includes: acquiring a congruential sequence according to a code length of a target polar code; performing sorting processing on the congruential sequence according to a preset rule, to acquire a reference sequence; determining a mapping function according to the congruential sequence and the reference sequence; and interleaving the target polar code according to the mapping function, to generate interleaved output bits. The congruential sequence is determined based on the code length of the polar code, and interleaving of the target polar code is implemented by using the congruential sequence, which can enable a sequence of bits obtained after the interleaving to have a more uniform structure, can reduce a frame error rate and improve HARQ performance, thereby improving reliability of communication; can be applicable to rate matching processes of polar codes of various code lengths, and has good commonality and practicality.