CSI Codebook Parameter Configuration for Coherent Joint Transmission
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Solution Overview
Problem
In 5G wireless communication systems operating at sub-1GHz frequencies, supporting a large number of CSI-RS antenna ports is challenging due to the larger antenna form factor size required, limiting spectral efficiency and MU-MIMO spatial multiplexing gains, which can be addressed by distributing antenna ports across multiple locations for coherent joint transmission.
Innovation Solution
The proposed solution involves configuring codebook parameters for CSI reports using multiple tables to optimize feedback overhead in multi-TRP coherent joint transmission scenarios, specifically extending existing codebook parameter configurations and mapping components to achieve a good performance-and-overhead trade-off, allowing for efficient CSI reporting across distributed antenna ports.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If antenna ports are distributed across multiple locations for coherent joint transmission, then spectral efficiency and MU-MIMO spatial multiplexing gains are improved, but CSI reporting overhead increases
Solution Approach 1:
The codebook parameters are segmented into multiple tables (first table for {α1, . . . , αNTRP} combinations, second table for (M,β) values, third table for linking). This segmentation allows the CSI reporting to be structured in a way that reduces overhead while maintaining the ability to support distributed antenna ports for coherent joint transmission.
Solution Approach 2:
The codebook parameters are pre-configured and pre-mapped across the multiple tables before actual CSI reporting occurs. The relationships between parameters are established in advance through the third table that links the first and second tables, enabling efficient reporting without increasing overhead during operation.
2Productivity
If codebook parameters are configured using multiple tables with mapped components, then performance-and-overhead trade-off is optimized, but device complexity increases
Solution Approach 1:
The multi-table codebook parameter configuration serves multiple functions: the first table stores {α1, . . . , αNTRP} combinations related to vector counts per TRP group, the second table stores (M,β) pairs related to coefficient counts and vector dimensions, and the third table provides linking between them. This universal structure handles both single-TRP and multi-TRP scenarios while optimizing the performance-overhead trade-off.
Data Source
AI summary
Apparatuses and methods for channel state information (CSI) codebook parameters for coherent joint-transmission. A method performed by a user equipment (UE) includes receiving information about a CSI report. The information indicates codebook parameters NL≥1 combinations of values of {α1, . . . , αN<sub2>TRP</sub2>} from a first table and a value of (M,β) from a second table. {α1, . . . , αN<sub2>TRP</sub2>} is related to a number of a first set of vectors associated with each of NTRP groups of ports, where αr≤1 for r=1, . . . , NTRP, β is a parameter related to a maximum number of coefficients, and M is a parameter related to a second set of vectors. The method further includes determining the CSI report based on the information and transmitting the CSI report. The codebook parameters are configured based on a third table that links the first and second tables.