User Terminal ACK Control for Code Block Group Retransmission
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Solution Overview
Problem
Existing technologies fail to efficiently address the challenges of efficient retransmission control in future radio communication systems, particularly in 5G and NR systems, where transport block sizes (TBS) larger than in LTE systems are expected, leading to increased code blocks and inefficient retransmission control, which degrades throughput.
Innovation Solution
A user terminal with a receiving section that receives a downlink signal comprising multiple code blocks and controls receipt confirmation information transmission based on downlink control information (DCI) for scheduling, allowing retransmission control in units smaller than transport blocks, such as code blocks or code block groups, to improve efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If retransmission control is performed in a transport block unit in existing LTE systems, then device complexity is reduced and ease of operation is maintained, but performance degrades when the number of code blocks per transport block increases in future high-speed communication systems
Solution Approach 1:
The patent segments the transport block into smaller code block groups (CBGs) as the unit for retransmission control. Instead of treating the entire transport block as a single unit, the system divides it into multiple CBGs, allowing selective retransmission of only the erroneous groups. This segmentation enables finer-grained error handling, improving reliability while maintaining manageable complexity through organized group management.
2Productivity
If the transport block size is increased to support high-speed communication in future systems, then data rate and capacity are improved, but the number of code blocks increases leading to performance degradation in retransmission control
Solution Approach 1:
The patent applies segmentation by dividing large transport blocks into multiple code block groups. This allows the system to handle larger data rates while maintaining effective retransmission control by managing smaller, organized units rather than treating the entire large block as one unit, thus preventing performance degradation.
Solution Approach 2:
The patent changes the parameter of retransmission control granularity from transport block level to code block group level. This parameter change enables the system to adapt to larger transport block sizes required for high-speed communication while maintaining effective error handling through finer-grained control units.
3Measurement precision
If receipt confirmation information is transmitted for each code block to improve error detection accuracy, then measurement precision is improved, but device complexity and overhead increase
Solution Approach 1:
The patent merges multiple code blocks into code block groups, and transmits receipt confirmation information at the group level rather than for each individual code block. This merging approach maintains adequate error detection accuracy while significantly reducing the complexity and overhead associated with managing individual code block acknowledgments.
Solution Approach 2:
The patent applies partial action by providing receipt confirmation at the code block group level rather than for every individual code block. This partial approach achieves sufficient error detection precision for practical purposes while avoiding the excessive complexity that would result from tracking each code block separately.
Data Source
AI summary
To properly perform retransmission control in future radio communication systems, a user terminal according to one aspect of the present invention is provided with a receiving section that receives a downlink (DL) signal comprised of a transport block including a plurality of code blocks, and a control section that controls transmission of receipt confirmation information to the DL signal, where even in the case where transmission of the receipt confirmation information for each code block is configured, the control section controls transmission of the receipt confirmation information for each transport block, based on downlink control information (DCI) for scheduling the DL signal or payload of an uplink (UL) signal.