Partial Transport Block Retransmission via Code Block Group Segmentation
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Solution Overview
Problem
In wireless communication systems, particularly in LTE, when decoding fails, the entire transport block needs to be retransmitted even if only a single code block fails, leading to inefficient resource usage and increased data transmission requirements.
Innovation Solution
Implementing a method where hybrid automatic repeat request-acknowledgement (HARQ-ACK) information is transmitted using different resources based on the success or failure of code block groups, allowing for partial retransmission of only the failed code blocks instead of the entire transport block.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the entire transport block is retransmitted when decoding fails, then reliability of data transmission is improved, but resource usage efficiency deteriorates and data transmission requirements increase
Solution Approach 1:
The transport block is divided into multiple code block groups (CBGs), allowing selective retransmission of only the failed CBGs rather than the entire transport block. This segmentation enables granular error handling where individual CBGs can be identified and retransmitted independently, improving resource efficiency while maintaining reliability.
Solution Approach 2:
The failed code block groups are extracted and identified through HARQ-ACK information, allowing the system to isolate and retransmit only the specific failed portions. This extraction mechanism enables precise targeting of retransmission needs, avoiding unnecessary retransmission of successfully decoded data.
2Reliability
If the entire transport block is retransmitted when a single code block fails, then data integrity is ensured, but transmission overhead increases
Solution Approach 1:
The transport block is segmented into multiple code block groups, enabling identification and selective retransmission of only the failed segments. This reduces transmission overhead by avoiding retransmission of successfully decoded CBGs while ensuring data integrity through targeted retransmission of failed portions.
Solution Approach 2:
Instead of performing full retransmission of the entire transport block, the system performs partial retransmission of only the necessary failed CBGs. This partial action approach reduces transmission overhead while maintaining sufficient data integrity by addressing only the specific failures.
3Productivity
If code block group-based retransmission is implemented, then resource efficiency is improved, but system complexity increases due to additional HARQ-ACK resources and signaling
Solution Approach 1:
The HARQ-ACK information structure is designed to serve multiple functions: it can indicate ACK/NACK for the entire transport block or provide granular feedback for individual CBGs. This multi-functionality allows the same signaling mechanism to adapt to different retransmission scenarios, managing complexity while enabling efficient resource utilization.
Solution Approach 2:
The system dynamically selects between different HARQ-ACK feedback modes (full TB ACK/NACK or per-CBG feedback) based on channel conditions and retransmission needs. This dynamic adaptation allows the system to optimize resource efficiency while managing complexity by using detailed CBG-level feedback only when necessary.
Data Source
AI summary
The present disclosure relates to a communication technique for combining IoT technology with a 5G communication system for supporting a higher data transmission rate than 4G communication systems and to a system therefor. The present disclosure may be applied to intelligent services, such as smart homes, smart buildings, smart cities, smart cars or connected cars, healthcare, digital education, retail businesses, and security-and safety-related services on the basis of 5G communication technology and IoT-related technology. Disclosed are a method and apparatus for retransmitting only the code block, in a transport block, requiring retransmission and not the entire transport block if retransmission of the initially transmitted transport block is necessary.