CSI Determination for CoMP Using Segmented Subframe Reference Signals

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Solution Overview

Problem

Current wireless communication systems face challenges in efficiently determining channel state information (CSI) from multiple nodes, particularly in coordinated multi-point (CoMP) transmission scenarios, where reference signals from different nodes may overlap or coincide, leading to complexities in channel estimation and data transmission optimization.

Innovation Solution

The method involves a user equipment (UE) receiving reference signals from multiple nodes, determining CSI for different subframes, and reporting these to select appropriate nodes for data transmission, allowing for coordinated data reception from one or more nodes based on the CSI, even when reference signals coincide or overlap in certain subframes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If reference signals from multiple nodes are transmitted in overlapping subframes, then coordinated multi-point transmission capability is improved, but channel estimation complexity and interference increase

Engineering Contradiction:
ImproveCoMP transmission capabilityVSAvoidChannel estimation complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the channel estimation process by determining CSI separately for different subframe types (first subframes with both reference signals, second subframes with only second reference signal, third subframes with only first reference signal). This segmentation allows the UE to handle overlapping reference signals in a structured manner, reducing estimation complexity while maintaining CoMP capability

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The network configures the UE with CSI reporting settings in advance, specifying which reference signals to use for CSI determination in different subframe types. This preliminary configuration enables the UE to prepare appropriate estimation strategies before receiving actual reference signals, reducing real-time processing complexity

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If separate CSI determination is performed for different subframes, then transmission optimization accuracy is improved, but signaling overhead and processing requirements increase

Engineering Contradiction:
ImproveCSI determination accuracyVSAvoidSignaling overhead
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent establishes universal CSI reporting mechanisms that work across different subframe types. The same CSI reporting framework is used whether the UE determines CSI from one reference signal or multiple reference signals, reducing the need for separate signaling protocols and minimizing overhead

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The network dynamically adjusts CSI reporting parameters based on subframe type and active reference signals. By changing reporting parameters adaptively rather than maintaining fixed reporting requirements, the system achieves precise CSI determination while optimizing signaling overhead based on actual transmission conditions

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2720425B1Method and apparatus for determining and using channel state information
Publication Date: 2020.03.18 QUALCOMM INC
  • EP2720425B1 patent drawingFigure 1
  • EP2720425B1 patent drawingFigure 2
  • EP2720425B1 patent drawingFigure 3

AI summary

Techniques for receiving reference signals from multiple nodes and determining channel state information (CSI) for the nodes are disclosed. A user equipment (UE) may determine and report CSI for the multiple nodes to support data transmission to the UE. The nodes may transmit reference signals based on different configurations. The configuration for each node may indicate when, where, and how the node transmits its reference signal. The UE may determine CSI for different nodes and/or different combinations of nodes based on the reference signals transmitted by these nodes as well as an indication of which subframes to use to determine each CSI reported by the UE. The UE may report different CSIs for different subframes and may receive data transmission sent by a single node or a combination of nodes based on the reported CSIs.