CJT Codebook Grouping for Localized Multi-TRP CSI Feedback
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Solution Overview
Problem
Existing wireless communication systems face challenges in managing channel state information (CSI) feedback overhead and intercarrier interference in multi-TRP deployments, particularly in distributed TRP scenarios where TRPs are spatially distanced and uncalibrated, leading to inefficient coherent transmission.
Innovation Solution
Implementing a coherent joint transmission (CJT) codebook for localized multi-TRP deployments, where UEs generate CSI reports based on a common precoding index for spatially co-located TRPs, minimizing feedback overhead by stacking precoding matrix parameters for physically co-located TRPs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate precoding indices are used for each TRP in distributed multi-TRP deployments, then transmission reliability can be maintained, but CSI feedback overhead increases significantly
Solution Approach 1:
The patent combines multiple TRPs into TRP groups where co-located TRPs share a common precoding index. This merging approach reduces the number of independent CSI reports needed, thereby reducing feedback overhead while maintaining transmission reliability through joint transmission across the grouped TRPs.
Solution Approach 2:
The patent segments TRPs into distinct groups based on their physical co-location relationships. By dividing the set of TRPs into manageable groups (with each group having a common precoding index) and allowing different groups to have different indices, the system reduces overall feedback overhead compared to treating each TRP independently.
2Area of stationary object
If distributed TRP deployments are used to expand coverage area, then network coverage is improved, but intercarrier interference increases due to uncalibrated TRPs
Solution Approach 1:
The patent introduces a spatial dimension-based grouping criterion for TRPs, where co-located TRPs are grouped together. This spatial organization allows the system to manage interference by ensuring that TRPs within the same group (and thus same location) are properly calibrated together, while still allowing distributed deployment across different locations to expand coverage.
3Productivity
If coherent joint transmission is implemented across all TRPs, then throughput is improved, but system complexity increases due to calibration requirements
Solution Approach 1:
The patent segments the calibration process by applying it at the TRP group level rather than individually for each TRP. TRPs within the same group share a common precoding index and can be calibrated together, reducing the overall calibration complexity while still enabling coherent joint transmission within each group to improve throughput.
Data Source
AI summary
Aspects of the present disclosure provide techniques for utilizing coherent joint transmission (CJT) codebook for localized multi-TRP deployment that minimizes overhead requirements needed for reporting channel feedback information. To this end, the UEs may generate CSI report based on CJT codebook that indicates a common precoding index for a spatial domain matrix for TRPs that are physically co-located. In some examples, the UE may provide a precoding matrix that is based on combination of parameters such as spatial domain matrix, spanning coefficients, and frequency domain matrix. Each of the precoding matrix parameters may be stacked corresponding to the number of TRPs that are localized in physical co-location in order to minimize the amount of information that the UE may need to report.