Polar Code Rate Matching with Circular Buffer for Flexible Code Lengths

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Solution Overview

Problem

Polar code hardware exhibits high complexity due to its intricate encoding process, particularly in hybrid automatic repeat request mechanisms, making it challenging to transmit bit sequences of varying lengths effectively.

Innovation Solution

A rate matching method and device for Polar codes that utilize a circular buffer to selectively process and transmit bit sequences by applying predefined rules, including one-to-one mapping interleaving functions and BRO interleaving, to simplify the encoding process and reduce hardware complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If different hardware modules are used to implement rate matching for different code lengths and code rates, then the Polar code can transmit bit sequences of any length, but the hardware complexity increases significantly

Engineering Contradiction:
Improvecapability to transmit bit sequences of any lengthVSAvoidPolar code hardware complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements a universal rate matching structure that can handle different code lengths and code rates using the same hardware module. The circular buffer and rate matching module are designed to be configurable rather than dedicated to specific code parameters, allowing one module to serve multiple functions across different transmission scenarios.

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

Solution Approach 2:

The patent introduces dynamic configuration capabilities where the rate matching parameters (such as buffer size, starting positions, and selection patterns) can be adjusted based on the required code length and code rate. This dynamic adaptability eliminates the need for multiple fixed hardware modules while maintaining support for various transmission requirements.

Inventive Principle:
Principle #15Dynamics

2Ease of manufacture

If a recursive encoder structure is used for Polar codes, then the encoding process can be systematically implemented, but the encoding process becomes intricate and complex

Engineering Contradiction:
Improvesystematic implementation of encoding processVSAvoidencoding process complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent divides the encoding process into distinct functional segments: information bit insertion, frozen bit insertion, parity bit generation, and rate matching. Each segment is handled by a dedicated functional module, which simplifies the overall process by breaking down the complex recursive encoding into manageable, independent stages that can be implemented and controlled separately.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3567734B1Method and apparatus for processing rate matching of polar codes
Publication Date: 2024.08.07 ZTE CORP
  • EP3567734B1 patent drawingFigure 1a
  • EP3567734B1 patent drawingFigure 1b
  • EP3567734B1 patent drawingFigure 2~3

AI summary

Provided is a rate matching method and device for a Polar code. The method includes: concatenating K information bits and (N-K) frozen bits to generate a bit sequence of N bits, and encoding the bit sequence of N bits by means of a Polar code encoder with a generator matrix of size N×N to generate an initial bit sequence {S0,S1,...,SN-1} of N bits, where K and N are both positive integers and K is less than or equal to N; dividing a circular buffer into q parts, selecting bits from the initial bit sequence {S0,S1,...,SN-1} in a non-repeated manner, and writing the bits into the q parts of the circular buffer according to a predefined rule, where q=1, 2, 3 or 4; and sequentially selecting a bit sequence of a specified length from a predefined starting position in a bit sequence in the circular buffer and taking the bit sequence of the specified length as a bit sequence to be transmitted.