Shared-Basis Precoding Matrix Indicator Feedback for Multi-TRP Hypotheses
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Solution Overview
Problem
In multiple transmission and reception point (multi-TRP) systems, the overhead of channel state information (CSI) feedback, particularly precoding matrix indicator (PMI), increases due to the linear scaling with the number of antennas, making it challenging for user equipment (UE) to efficiently report CSI to the network.
Innovation Solution
A method and apparatus for UE to jointly report a common spatial domain basis matrix and coefficient matrices for multiple transmission hypotheses, reducing PMI feedback payload by sharing a common spatial domain basis matrix across all hypotheses and optimizing coefficient matrices for each hypothesis, thereby enhancing spectrum efficiency and coverage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the number of antennas is increased in multi-TRP systems, then the signal transmission and reception quality is improved, but the CSI feedback overhead increases linearly
Solution Approach 1:
The patent segments the PMI feedback into two parts: a common spatial domain basis matrix shared across multiple TRPs and hypothesis-specific coefficient matrices. This segmentation allows the common spatial characteristics to be reported once while only the varying coefficient information needs to be reported for each hypothesis, significantly reducing the overall feedback overhead while maintaining accurate channel state information for multiple TRPs
Solution Approach 2:
The common spatial domain basis matrix serves multiple functions simultaneously: it represents the spatial characteristics for all TRPs and all transmission hypotheses. This universal matrix structure allows the system to handle multiple TRPs without proportionally increasing feedback overhead, as the same spatial basis applies across different transmission scenarios
2Measurement precision
If separate PMI feedback is reported for each transmission hypothesis, then the accuracy of channel state information is improved, but the feedback payload size increases
Solution Approach 1:
The patent extracts the common spatial domain basis matrix from the full PMI feedback for each hypothesis and reports it separately. By taking out the redundant common information and reporting it once, the system maintains measurement precision for each hypothesis while significantly reducing the total feedback payload size
Solution Approach 2:
The patent merges the common spatial characteristics across all transmission hypotheses into a single common spatial domain basis matrix. This merging eliminates redundant information while preserving the essential channel state accuracy needed for each hypothesis, achieving both compression and precision
Data Source
AI summary
Aspects relate to reporting channel state information (CSI) for a plurality of multiple transmission and reception points (TRPs) in a communication system. Downlink (DL) channels received from multiple TRPs are measured and a plurality of transmission hypotheses based on the measured DL channels from the multiple TRPs. The CSI is transmitted to a network in the communication system and includes a precoding matrix indicator (PMI) having at least a spatial domain basis matrix that is common to all of the transmission hypotheses and at least one coefficient matrix that is based on the spatial domain basis matrix.