Multi-TRP CSI Codebook Configuration for Coherent Joint Transmission
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Solution Overview
Problem
Current wireless communication systems lack an efficient method for multi-TRP coherent joint transmission (CJT) CSI feedback, particularly in non-coherent joint transmission scenarios, leading to increased signaling overhead and inefficiencies in multi-antenna systems.
Innovation Solution
A codebook structure is designed for multi-TRP CJT CSI feedback, incorporating spatial and frequency basis selection matrices and combination coefficients to reduce overhead, allowing UEs to efficiently report preferred precoders to multiple TRPs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional CSI feedback methods are used for multi-TRP coherent joint transmission, then CSI reporting can be performed, but signaling overhead increases and efficiency decreases
Solution Approach 1:
The codebook is segmented into multiple codebook groups, each associated with a specific TRP. The UE selects one codebook group per TRP, allowing independent optimization for each transmission point. This segmentation enables efficient multi-TRP CJT CSI feedback by dividing the overall codebook selection into manageable per-TRP selections, reducing the complexity and overhead of reporting while maintaining accurate CSI for each TRP.
2Adaptability or versatility
If multi-TRP coherent joint transmission is implemented without optimized codebook structure, then transmission diversity is achieved, but system complexity increases
Solution Approach 1:
The codebook configuration is made dynamic and adaptable to different multi-TRP scenarios. The codebook structure supports flexible association between codebook groups and TRPs, allowing the system to adapt to varying numbers of TRPs and different transmission configurations. This dynamic codebook design enables the system to handle diverse multi-TRP scenarios without requiring separate complex configurations for each case.
3Measurement precision
If detailed CSI feedback is reported for each TRP, then transmission accuracy improves, but feedback overhead increases
Solution Approach 1:
The feedback mechanism merges the selection of codebook groups with the CSI reporting process. Instead of reporting separate detailed CSI parameters for each TRP, the UE reports codebook group indices that implicitly convey the preferred precoding information for each TRP. This merging of codebook selection and CSI feedback reduces the volume of feedback data while preserving the essential transmission accuracy information needed for multi-TRP CJT.
Data Source
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AI summary
Apparatus and methods are provided for port selection codebook configuration when a user equipment (UE) receives communicates with a plurality of transmission and reception points (TRPs). For multiple TRP (multi-TRP) coherent joint transmission (CJT) channel state information (CSI) reporting, a codebook is provided with a codebook structure by (I) or (II) in which t is a TRP index corresponding to a particular TRP, T is a total number of TRPs, (III) are Type II CSI codebooks reported for TRPs corresponding to index t, and (IV) are linear combination coefficients applied to each codebook for different TRPs. (V) for a spatial basis selection matrix (VI) a combination coefficient matrix (VII) and a frequency basis selection matrix (VIII).