CSI Feedback Subband Selection for Overhead Reduction
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Solution Overview
Problem
Current CSI feedback systems face significant overhead due to the need to report Relative Power Indicator (RPI) and Phase Indicator (PI) for each subband in linear combination codebook-based feedback, which affects system performance.
Innovation Solution
The method involves selecting and reporting RPI and/or PI for a subset of subbands rather than all subbands, leveraging the correlation between amplitude and phase information across subbands to reduce feedback overhead while maintaining CSI feedback performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If RPI and PI are reported for all subbands in linear combination codebook-based feedback, then CSI feedback performance is improved, but feedback overhead increases significantly
Solution Approach 1:
The patent segments the feedback information by dividing subbands into different groups (first subbands and second subbands). For first subbands, both RPI and PI are reported, while for second subbands, only PMI is reported. This segmentation allows the system to maintain high CSI feedback performance for critical subbands while reducing overall feedback overhead by excluding redundant RPI and PI information from less critical subbands.
Solution Approach 2:
The patent extracts and removes the RPI and PI information from the feedback for certain subbands (second subbands), keeping only the essential PMI. This extraction principle reduces feedback overhead by eliminating redundant information that can be inferred or is less critical, while maintaining sufficient CSI feedback performance through the retained PMI and the selective inclusion of RPI and PI for first subbands.
2Productivity
If feedback overhead is reduced by reporting RPI and PI for only a subset of subbands, then system performance improves, but CSI feedback performance may be compromised
Solution Approach 1:
The patent applies local quality by differentiating the feedback reporting strategy for different subbands. First subbands, which are likely more critical or have higher variance, receive full feedback (RPI and PI), while second subbands use reduced feedback (PMI only). This localized approach ensures that CSI feedback performance is maintained where needed most, while system performance improves overall through reduced feedback overhead in less critical areas.
Data Source
AI summary
A method and apparatus for channel state information feedback and a storage medium are provided according to the present disclosure. The method includes: performing by a terminal channel measurement according to a reference signal; selecting M subbands from K subbands of a CSI reporting band, and reporting to a base station the M subbands' Relative Power Indicator (RPI) and Phase Indicator (PI) of a weighted coefficient associated with a precoding codebook index, where M and K are integers greater than or equal to 1, M<K; each subband is a set of R resource blocks RB, where R is an integer greater than or equal to 1.