Multi-TRP CSI Codebook With Joint Indicators for CSI-RS Port Grouping
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Solution Overview
Problem
Existing 5G/NR communication systems face challenges in efficiently supporting multi-TRP operations due to limited CSI-RS ports and high reporting overhead, which affect spectral efficiency and performance in both high and low frequency bands.
Innovation Solution
A CSI codebook design is proposed for multi-TRP operations, incorporating spatial-domain basis components and joint indicators to enhance CSI measurement and reporting, particularly extending Rel-16/17 Type-II CSI codebooks to support coherent joint transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If existing 5G/NR communication systems use limited CSI-RS ports for multi-TRP operations, then device complexity is reduced, but measurement precision and spectral efficiency deteriorate
Solution Approach 1:
The patent segments the CSI-RS ports into multiple groups (first group, second group, third group) with different configurations. Each group has specific properties (e.g., number of ports, spacing, distribution) that are optimized for different measurement purposes. This segmentation allows the system to achieve detailed channel state information without requiring all ports to be configured uniformly, thus improving measurement precision while managing device complexity.
Solution Approach 2:
The patent applies local quality by configuring different CSI-RS port groups with different local properties tailored to specific measurement needs. For example, the first group may have different port spacing than the second group, and each group may be distributed differently across the antenna array. This localized optimization allows precise CSI measurement for specific spatial regions or TRPs without requiring uniform high-complexity configuration across all ports.
2Device complexity
If existing systems use limited CSI-RS ports, then device complexity is reduced, but spectral efficiency deteriorates
Solution Approach 1:
By segmenting CSI-RS ports into multiple groups with different configurations, the system can efficiently measure channels from multiple TRPs simultaneously. The segmentation allows parallel measurement of different spatial regions, increasing the effective use of available spectrum and improving spectral efficiency without requiring all ports to be actively configured for all measurements at once.
Solution Approach 2:
The patent employs preliminary action by pre-configuring multiple CSI-RS port groups with different properties before actual channel measurement. This allows the system to have ready-to-use measurement configurations for multiple TRPs, enabling efficient multi-TRP operations without dynamic reconfiguration during data transmission, thus improving spectral efficiency.
3Measurement precision
If more CSI-RS ports are configured for multi-TRP operations, then measurement precision improves, but reporting overhead increases
Solution Approach 1:
The patent extracts and processes CSI information from specific subsets of CSI-RS port groups rather than treating all ports uniformly. By identifying and measuring only the necessary port groups for each TRP configuration, the system reduces the amount of CSI data that needs to be reported. The extraction focuses on the most relevant spatial and channel information, minimizing reporting overhead while maintaining measurement precision for the active TRPs.
Solution Approach 2:
The patent applies partial action by configuring and measuring only the necessary portions of CSI-RS ports for each TRP scenario. Instead of uniformly configuring all ports for all possible TRPs, the system configures specific port groups (first, second, third groups) with different densities and distributions, measuring only what is needed for the current transmission scenario, thus reducing reporting overhead.
4Adaptability or versatility
If CSI-RS ports are distributed differently across frequency bands, then adaptability improves, but device complexity increases
Solution Approach 1:
The patent creates universality by designing a unified multi-group CSI-RS configuration framework that can be applied across different frequency bands (e.g., low band, mid band, high band). The same basic structure of multiple port groups with different properties can be adapted to various frequency bands by adjusting parameters like port spacing, number of groups, and distribution patterns. This universal framework enables frequency-band-flexible multi-TRP operations without requiring entirely different configuration systems for each band.
Data Source
AI summary
Apparatuses and methods for CSI codebook for multi-TRP. a method for operating a user equipment (UE) is provided. The method includes receiving a configuration about a channel state information (CSI) report. The configuration includes information about (i) N>1 groups of CSI reference signal (CSI-RS) ports and (ii) a codebook. The codebook includes a spatial-domain (SD) basis component. The SD basis component includes Lr basis vectors for each group r=1, . . . , N. The method further includes, based on the configuration, measuring the N groups of CSI-RS ports and identifying, based on the measurement, the SD basis component. The method further includes transmitting the CSI report. The Lr values for r=1, . . . , N are indicated by a joint indicator. The joint indicator is a function of the Lr values.