HARQ-ACK Feedback Bit Restriction in Wireless Systems
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Solution Overview
Problem
In wireless communication systems, particularly in 5G networks, there is a challenge in efficiently transmitting HARQ-ACK feedback information for uplink signals when the number of bits required exceeds the available bitmap size, leading to inefficiencies in resource consumption and increased retransmissions.
Innovation Solution
A method and apparatus that restrict the number of bits used for HARQ-ACK feedback by comparing the required bitmap size with the available size, allowing for reduced bit transmission and employing bundling or padding to optimize feedback within the limited bit capacity, specifically in codeblock group (CBG)-based HARQ-ACK feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If HARQ-ACK feedback is transmitted using a bitmap for each codeblock group (CBG), then decoding accuracy is improved, but the number of bits required exceeds the available bitmap size
Solution Approach 1:
The patent segments the feedback mechanism by dividing CBGs into different feedback types (first type with individual CBGACK/NACK bits, second type with bundled ACK/NACK bits). This segmentation allows the system to provide detailed feedback for some CBGs while using compressed feedback for others, resolving the contradiction between detailed decoding accuracy and bitmap size constraints.
Solution Approach 2:
The patent changes the feedback parameter structure by introducing different feedback modes for different CBG types. Instead of using a uniform bitmap for all CBGs, the system dynamically adjusts the feedback representation based on CBG type, enabling both high accuracy for critical CBGs and efficient compression for others within the same bitmap.
2Loss of energy
If the number of bits for HARQ-ACK feedback is restricted to fit available bitmap size, then resource consumption is optimized, but the number of retransmissions increases
Solution Approach 1:
By segmenting CBGs into different types with different feedback strategies, the system optimizes resource consumption for the second type CBGs using bundled feedback while maintaining reliability for first type CBGs using individual CBGACK/NACK bits. This selective approach reduces overall retransmissions while fitting within bitmap constraints.
Solution Approach 2:
The patent introduces an intermediary classification mechanism that categorizes CBGs into different types based on their feedback requirements. This intermediary layer enables the system to apply appropriate feedback compression selectively, reducing resource consumption without compromising the reliability of critical data transmissions.
3Measurement precision
If individual CBGACK/NACK bits are transmitted for each CBG, then feedback precision is improved, but device complexity increases
Solution Approach 1:
The patent segments the feedback processing into two distinct paths: one for first type CBGs requiring individual CBGACK/NACK bit generation and another for second type CBGs using bundled feedback. This segmentation allows the system to maintain high feedback precision where needed while reducing processing complexity through bundling for other CBGs.
Solution Approach 2:
Instead of applying individual CBG-level feedback to all CBGs (excessive action), the patent applies this precise feedback mechanism only to first type CBGs where it is most beneficial (partial action). For second type CBGs, the system uses simpler bundled feedback, thereby reducing overall device complexity while maintaining necessary feedback precision.
Data Source
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AI summary
A method of performing, by a base station, communication in a wireless communication system is provided. The method includes obtaining feedback configuration information of a hybrid automatic repeat request (HARQ) process for performing a feedback, in a unit of code block group (CBG), on a result of decoding, comparing a size of a bitmap required for the feedback in the unit of CBG with a size of an available bitmap of the base station, and transmitting feedback information in which a number of bits are restricted according to a preset method, when the size of the bitmap required for the feedback is greater than the size of the available bitmap.