User Terminal CBG Retransmission for Transport Block Efficiency
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Solution Overview
Problem
Existing LTE systems face inefficiencies in retransmission control due to TB segmentation, leading to performance declines when errors concentrate in part of the code blocks, especially in future systems with increased CBs, as they control retransmissions in TB units rather than CB groups.
Innovation Solution
The method involves forming CBGs based on the maximum number of CBGs per TB or CBs per CBG, determined by higher layer signaling, and sending retransmission control information on a per CBG basis, with proper mapping to time/frequency resources to minimize latency and error rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If retransmission control is performed in TB units, then control simplicity is maintained, but transmission efficiency deteriorates when errors concentrate in part of the code blocks
Solution Approach 1:
The patent segments the transport block into multiple code block groups (CBGs) for independent retransmission control. Each CBG can be individually acknowledged and retransmitted, allowing selective retransmission of only error-prone portions rather than the entire TB, thus improving transmission efficiency while maintaining control simplicity through standardized CBG-level protocols
2Productivity
If code block segmentation is increased for future systems, then data rate capacity is improved, but performance decline increases when errors concentrate in code blocks
Solution Approach 1:
The patent divides segmented code blocks into smaller code block groups (CBGs) that can be independently managed. This finer segmentation allows the system to handle increased code block counts in future systems while maintaining performance stability through selective retransmission of only failed CBGs rather than all code blocks
Solution Approach 2:
The patent applies different handling strategies to different CBGs based on their individual error status. Successful CBGs are not retransmitted while failed CBGs are selectively retransmitted, allowing the system to optimize performance for each local segment rather than applying uniform retransmission to all code blocks
Data Source
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AI summary
The present invention is designed to properly form CBGs that are each formed with one or more CBs within a TB. According to one aspect of the present invention, a user terminal has a transmitting/receiving section that transmits and/or receives a transport block (TB), including code block groups (CBGs) that are each formed with one or more code blocks (CBs), and a control section that determines one or more CBs that form each CBG based on a maximum number of CBGs per TB or a maximum number of CBs per CBG.