CBG-Based HARQ Feedback Compression for Multi-Band NR Overhead
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In wireless communication systems using multiple frequency bands, particularly in unlicensed spectrum, the existing HARQ feedback mechanisms result in high overhead and latency due to the scaling of feedback with the number of code block groups (CBGs) and the need for individual acknowledgement (ACK/NACK) for each CBG, which is not suitable for low-latency and high-reliability services.
Innovation Solution
Implementing a feedback mechanism that compresses HARQ feedback by predicting successful or unsuccessful receipt of CBGs based on interference patterns and channel availability, using lossy or lossless compression techniques, and transmitting early feedback for CBGs affected by interference, thereby reducing the number of bits required for feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If HARQ feedback is provided for all TBS sizes including small TBS values, then reliability of data transmission is improved, but uplink overhead increases due to additional PUCCH resources required
Solution Approach 1:
The patent changes the parameter of HARQ feedback provision from universal (all TBS sizes) to selective (only TBS sizes above threshold). Specifically, when TBS is below a configured threshold, HARQ feedback is not provided, reducing PUCCH resource requirements while maintaining reliability for larger transmissions where feedback is most beneficial
Solution Approach 2:
The patent extracts HARQ feedback for small TBS values from the universal feedback mechanism. By identifying and removing feedback requirements for TBS sizes below the threshold, the system reduces uplink overhead while preserving feedback for larger TBS values where it provides the most value
2Quantity of substance
If HARQ-ACK feedback is bundled for small TBS values, then uplink overhead is reduced, but reliability of data transmission deteriorates due to loss of individual ACK/NACK information
Solution Approach 1:
The patent changes the parameter of feedback provision from bundled (for all small TBS) to selective (only for TBS above threshold). This parameter change ensures that individual ACK/NACK information is preserved for transmissions where TBS exceeds the threshold, maintaining reliability while reducing overhead for smaller transmissions where feedback is omitted
3Adaptability or versatility
If PUCCH resources are allocated for every possible TBS size, then coverage of HARQ feedback is improved, but resource utilization efficiency decreases due to wasted resources for small TBS
Solution Approach 1:
The patent changes the parameter of PUCCH resource allocation from universal (all TBS sizes) to threshold-based (TBS above configured threshold). This ensures PUCCH resources are allocated and utilized only when necessary, improving resource utilization efficiency while maintaining feedback coverage for transmissions where it provides value
Solution Approach 2:
The patent extracts unnecessary PUCCH resource allocations for small TBS values by introducing a threshold. Resources are removed from the allocation plan for TBS below the threshold, eliminating waste while preserving resources for larger TBS values where HARQ feedback is provisioned
Data Source
Figure 1(a)~1(b)
Figure 2
Figure 3
AI summary
An apparatus for a wireless communication system uses a plurality of frequency bands for a communication with one or more network entities, e.g., one or more user devices or one or more base stations, in the wireless communication system. The apparatus receives from a transmitter or the one or more network entities a transport block, TB, the TB being split into a plurality of code block groups, CBGs, each CBG including one or more code blocks, CBs, and being confined to one of the plurality of frequency bands. The apparatus provides or predicts a feedback for each of the CBGs indicating one or more of a successful receipt of the CBG, a non-successful receipt of the CBG, no need for redundancy for the CBG and a need for some redundancy for the CBG, amount of additional redundancy needed, e.g., a hybrid automatic repeat request, HARQ, feedback. The apparatus compresses the feedbacks and/or the predicted feedbacks for each of the CBGs into a compressed feedback based on an interference pattern on one or more of the frequency bands which is detectable at the apparatus and the transmitter or the one or more network entities, e.g. Listen-before-Talk, LBT, failure, and to transmit to the one or more of the network entities the compressed feedback.