Code Block Group Feedback for Targeted Data Retransmission

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Solution Overview

Problem

Existing data transmission methods result in wasteful network resource usage due to retransmitting entire Transport Blocks (TBs) even when only one Code Block (CB) is in error, despite all CBs being correct.

Innovation Solution

Implement a mechanism where the receiving terminal determines erroneous Code Block Groups (CBGs) and feeds back specific acknowledgement (ACK/NACK) for each CBG, allowing the transmitting terminal to retransmit only the affected CBGs, thereby optimizing data retransmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the transmitting terminal retransmits the entire TB upon receiving a NACK, then the data can be received correctly by the receiving terminal, but network resources are wasted due to retransmitting all CBs even when only one CB is in error

Engineering Contradiction:
Improvedata reception correctnessVSAvoidnetwork resource waste
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent divides the TB into multiple CBGs (Code Block Groups) and implements separate HARQ processes for each CBG. When an error occurs in a specific CBG, only that CBG is retransmitted rather than retransmitting the entire TB. This segmentation allows selective retransmission of only the erroneous portions, reducing network resource waste while maintaining data reception correctness.

Inventive Principle:
Principle #1Segmentation

2Reliability

If the transmitting terminal retransmits the entire TB upon receiving a NACK, then all erroneous CBs can be corrected, but the retransmission overhead increases significantly

Engineering Contradiction:
Improveerror correction capabilityVSAvoidretransmission overhead
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The TB is segmented into multiple CBGs, each with its own HARQ process identifier. This allows the receiving terminal to identify which specific CBG contains errors and feedback NACK only for that CBG. The transmitting terminal then retransmits only the erroneous CBG, reducing retransmission overhead and time compared to retransmitting the entire TB.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different HARQ process parameters (such as redundancy version RV) are applied to different CBGs based on their specific error conditions. This local quality approach allows optimized retransmission of each CBG individually, improving error correction efficiency while minimizing overall retransmission time.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3745628B1Method, device, and system for transmitting data
Publication Date: 2025.09.24 BEIJING XIAOMI MOBILE SOFTWARE CO LTD
  • EP3745628B1 patent drawingFigure 1~2
  • EP3745628B1 patent drawingFigure 3
  • EP3745628B1 patent drawingFigure 4

AI summary

The present disclosure relates to a method, device, and system for transmitting data, and belongs to the technical field of communications. The method comprises: receiving a transport block (TB) transmitted by a transmitting terminal, wherein the TB comprises a plurality of code blocks (CBs); determining an erroneous CB in the TB, and determining, according to a preset affiliation between CBs and code block groups (CBGs), whether each CBG comprises an erroneous CB, wherein any CB corresponds to m CBGs in the affiliation, and m is a preset positive integer; for each CBG, if the CBG comprises an erroneous CB, determining that feedback information corresponding to the CBG is a negative acknowledgement NACK, and if the CBG does not comprise an erroneous CB, determining that the feedback information corresponding to the CBG is a positive acknowledgement ACK; and transmitting the feedback information corresponding to each CBG to the transmitting terminal. The present disclosure can reduce waste of network resources.