HARQ Feedback Signalling for Selective Code Block Retransmission

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Solution Overview

Problem

Current HARQ mechanisms in wireless communications are inefficient in handling large transport block sizes, leading to unnecessary retransmissions of entire blocks due to single-bit feedback, which increases resource usage and processing complexity.

Innovation Solution

Implementing a multi-bit feedback mechanism that provides detailed information on the state of individual code blocks, allowing for targeted retransmissions of only failed blocks, thereby reducing the retransmission channel usage and optimizing resource allocation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If single-bit feedback is used in HARQ mechanisms, then the feedback mechanism is simple, but retransmission efficiency deteriorates due to unnecessary retransmissions of entire blocks

Engineering Contradiction:
Improvefeedback mechanism complexityVSAvoidretransmission efficiency
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The patent segments the transport block into multiple code blocks and provides separate feedback for each code block. Instead of using a single-bit feedback for the entire transport block, the system generates individual feedback bits for each code block based on its decoding status, enabling selective retransmission of only failed code blocks rather than retransmitting the entire block.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from a single-bit feedback dimension to a multi-bit feedback dimension by introducing feedback at the code block level. This dimensional expansion allows the system to provide detailed information about the status of individual code blocks, enabling more precise control over retransmissions and improving overall system efficiency.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Productivity

If multi-bit feedback mechanism is implemented to provide detailed code block state information, then retransmission efficiency is improved, but device complexity increases

Engineering Contradiction:
Improveretransmission efficiencyVSAvoidfeedback mechanism complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent segments the feedback mechanism into individual feedback bits corresponding to each code block. This segmentation allows the system to provide detailed status information for each code block while maintaining a structured and manageable feedback format that can be efficiently processed by both transmitter and receiver.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements a dynamic feedback mechanism where the number of feedback bits is determined by the number of code blocks in the transport block. The feedback mechanism adapts to different transport block sizes and configurations, providing multi-bit feedback only when necessary and maintaining flexibility in handling various transmission scenarios.

Inventive Principle:
Principle #15Dynamics

3Loss of energy

If targeted retransmission of failed code blocks is enabled, then resource allocation is optimized, but processing complexity increases due to individual code block identification

Engineering Contradiction:
Improveresource usageVSAvoidprocessing complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent segments the transport block into multiple independently identifiable code blocks, each with its own feedback bit. This segmentation enables the receiver to identify which specific code blocks failed decoding and allows the transmitter to retransmit only those specific code blocks, avoiding the waste of retransmitting successfully decoded portions of the transport block.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements a detailed feedback mechanism where each code block's decoding status is reported individually to the transmitter. This feedback information enables the transmitter to make informed decisions about selective retransmission, optimizing resource allocation by transmitting only the necessary code blocks that require retransmission.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3476068B1Enhanced feedback signalling
Publication Date: 2023.10.04 NOKIA TECHNOLOGIES OY
  • EP3476068B1 patent drawingFigure 1
  • EP3476068B1 patent drawingFigure 2
  • EP3476068B1 patent drawingFigure 3

AI summary

A method comprises detecting (205), in a first communications apparatus, the number of failed code blocks in a transport block transmitted (204) to the first apparatus from a second apparatus and a corresponding feedback size indicator. The feedback size in dicator is received (203) in the first apparatus from the second apparatus e.g. via con trol channel signalling (202). Alternatively, the feedback size indicator is received in the transport block. The first apparatus selects (205) the format of a HARQ feedback message to be generated based on the feedback size indicator, and generates (205) the feedback message based on the number of failed code blocks in the transport block. The generated feedback message is of the selected format and indicates the failed code blocks in the transport block. The first apparatus transmits (206) the generated feed back message to the second apparatus.