Semi-Static Codebook Feedback Overhead Reduction in 5G NR
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Solution Overview
Problem
The semi-static codebook in 5G NR systems has significant redundancy, leading to resource wastage and reduced communication efficiency due to unnecessary feedback information generation, especially for semi-persistent scheduling (SPS) and grant-free PDSCHs.
Innovation Solution
A method where a terminal device or network device determines the need for feedback information based on actual detection of PDSCHs, generating a semi-static codebook only when data is successfully received, and optimizing feedback time units using a time domain offset K1, reducing redundant feedback and resource usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a semi-static codebook is generated for all candidate receiving positions, then feedback coverage is complete, but resource overhead increases and redundancy occurs
Solution Approach 1:
The patent extracts only the necessary feedback information by checking actual PDSCH detection results before generating codebook entries. Instead of including all candidate positions, it removes entries for positions where no PDSCH was detected, thereby reducing codebook size and redundancy while maintaining feedback reliability for actual transmissions.
Solution Approach 2:
The patent applies partial action by generating codebook entries only for detected PDSCHs rather than for all candidate positions. This selective approach avoids excessive feedback generation, reducing overhead while ensuring all actual transmissions are covered.
2Reliability
If feedback is sent for all candidate positions, then no transmission is missed, but communication efficiency decreases due to redundant feedback
Solution Approach 1:
The patent extracts only the essential feedback by eliminating redundant entries for undetected PDSCH positions. This reduces the amount of feedback data transmitted, improving communication efficiency while maintaining reliability for actual transmissions through selective inclusion of only necessary feedback entries.
3Reliability
If a large semi-static codebook is used, then all possible PDSCH positions are covered, but resource wastage increases
Solution Approach 1:
The patent removes redundant codebook entries corresponding to undetected PDSCH positions, thereby reducing resource waste. Feedback completeness is maintained for actual transmissions by selectively including only those positions where PDSCH was detected, eliminating unnecessary resource allocation for hypothetical transmissions.
Solution Approach 2:
The patent discards redundant codebook entries for positions where no PDSCH was transmitted, recovering resources that would otherwise be wasted. This selective discarding maintains feedback completeness for actual transmissions while eliminating resource waste associated with unnecessary feedback entries.
Data Source
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AI summary
This application provides a feedback information transmission method and an apparatus. The method includes: A terminal device receives indication information from a network device. The indication information indicates to generate a semi-static codebook. The terminal device detects a first physical downlink shared channel PDSCH at M candidate receiving positions in a first time unit. The first PDSCH is an SPS PDSCH or a grant-free PDSCH, and M is a positive integer. The terminal device determines, based on a detection result of the first PDSCH, whether to send first feedback information to the network device. The first feedback information includes acknowledgement ACK information or negative acknowledgement NACK information indicating whether the first PDSCH detected at the M candidate receiving positions is correctly decoded. According to the feedback information transmission method provided in this application, overheads of a semi-static codebook can be reduced, a waste of resources can be reduced, feedback reliability can be improved, and communication efficiency can be improved.