HARQ Feedback Segmentation for 5G CBG Error Reporting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In 5G wireless communication systems, the existing HARQ feedback mechanisms face challenges in efficiently conveying error information for code block groups (CBGs) during multi-PDSCH scheduling with a single DCI, leading to increased delay and overhead, particularly in extreme broadband and low-latency applications like XR, where retransmitting entire transport blocks is not optimal.
Innovation Solution
The method involves determining the size of HARQ ACK/NACK feedback based on the number of incorrectly received transport blocks, with separate PUCCH resources for TB-based and CBG-based feedback, and applying multi-level coding principles to compress the feedback size, ensuring that the second report for CBG errors is only transmitted when within a predefined cap or bundled to prevent excessive size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If HARQ feedback includes detailed CBG error information for all transport blocks, then error correction reliability is improved, but feedback overhead increases
Solution Approach 1:
The feedback is segmented into two parts: a first report containing TB-level ACK/NACK information, and a second report containing CBG-level error information only for incorrectly received TBs. This segmentation allows the system to maintain high reliability by providing detailed CBG error information when needed, while reducing overhead by only transmitting the second report when necessary (i.e., when TBs are incorrectly received).
Solution Approach 2:
Instead of transmitting complete CBG error information for all TBs unconditionally, the patent applies partial action by only transmitting the second report with CBG error information when TBs are actually incorrectly received. This reduces unnecessary feedback overhead while maintaining reliability for the cases that actually require error correction.
2Reliability
If HARQ feedback transmits complete error information for all transport blocks and code block groups, then error correction reliability is improved, but transmission delay increases
Solution Approach 1:
The feedback mechanism is divided into two sequential reports: the first report provides immediate TB-level acknowledgment, and the second report provides detailed CBG-level error information only when needed. This segmentation reduces transmission delay by allowing the receiver to quickly identify correctly received TBs without waiting for complete detailed error information, while still maintaining reliability through the subsequent detailed error report when errors are detected.
Solution Approach 2:
The patent transmits detailed CBG error information partially, only when TBs are incorrectly received. This approach reduces transmission delay by avoiding unnecessary transmission of complete error information for correctly received TBs, while maintaining error correction reliability for the actual error cases.
3Measurement precision
If separate PUCCH resources are allocated for TB-based and CBG-based feedback, then feedback precision is improved, but device complexity increases
Solution Approach 1:
The patent segments feedback resources into separate PUCCH resources for TB-based feedback and CBG-based feedback. This segmentation improves feedback precision by allowing independent optimization and management of different feedback types, while the complexity is managed through clear separation of concerns and standardized resource allocation procedures.
Solution Approach 2:
The PUCCH resources are designed to handle multiple feedback types (TB-level and CBG-level) through a unified framework. The same PUCCH resource can carry different types of feedback information depending on the transmission scenario, reducing overall system complexity while maintaining precision for each feedback type.
Data Source
AI summary
Systems, methods, apparatuses, and computer program products for feedback per code block group (CBG). A method may include receiving from a network element, at least one transport block including at least one coding block group. The method may also include determining which of the at least one transport block and the at least one coding block group was correctly or incorrectly received. The method may further include transmitting, based on the determination, a first report which identifies transport blocks of the at least one transport block that was correctly received and incorrectly received. In addition, the method may include, upon determining that at least one of the transport blocks was received incorrectly, transmitting a second report identifying coding block groups of the at least one coding block group that was incorrectly received from the transport blocks that were incorrectly received.