CSI-RS Resource Configuration for Intra-Cell CoMP Measurement

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Solution Overview

Problem

Intra-cell CoMP systems face challenges in accurately measuring Channel State Information (CSI) due to interference and high overhead in existing CSI-RS configurations, which limits the flexibility and accuracy of CoMP operations, especially in heterogeneous networks with multiple transmission points.

Innovation Solution

The proposed solution involves an enhanced CSI-RS resource configuration that allows sporadic separate measurements and simplified feedback reports, enabling the eNB to reuse PDSCH effectively while minimizing CSI-RS overhead and supporting joint transmission between transmission points with separate CSI-RS resources and a secondary pattern for expanded CSI measurements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional CSI-RS configurations are used in intra-cell CoMP systems, then measurement coverage is provided, but measurement accuracy deteriorates due to interference and overhead

Engineering Contradiction:
ImproveCSI measurement accuracyVSAvoidCSI-RS overhead
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent segments the CSI-RS resources into multiple separate configurations, each associated with specific transmission points. Instead of using a single unified CSI-RS configuration that causes interference, the system divides the measurement resources into distinct segments that can be measured separately, reducing mutual interference and improving measurement accuracy while maintaining manageable overhead levels.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements periodic CSI-RS measurements with different periodicities for different transmission points. By using periodic action with varying intervals, the system can reduce the overall measurement overhead while ensuring accurate measurements are taken at appropriate intervals, balancing the trade-off between measurement accuracy and resource consumption.

Inventive Principle:
Principle #19Periodic action

2Measurement precision

If separate CSI-RS resources are assigned to each transmission point, then measurement accuracy improves, but system complexity increases

Engineering Contradiction:
ImproveTransmission point measurement accuracyVSAvoidCSI-RS configuration complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent creates a universal CSI-RS configuration framework that can accommodate multiple transmission points with different characteristics. The configuration structure is designed to be multi-functional, handling both individual transmission point measurements and coordinated multi-point operations through a unified configuration approach, thereby reducing system complexity while maintaining measurement accuracy.

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

Solution Approach 2:

The patent utilizes parameter changes in the CSI-RS configuration to manage complexity. By dynamically adjusting configuration parameters such as resource allocation, periodicity, and association relationships between CSI-RS resources and transmission points, the system can adapt to different operational scenarios without requiring fundamentally different configuration structures, thus controlling complexity while preserving measurement accuracy.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If expanded CSI measurements are performed frequently, then CoMP operation flexibility improves, but overhead increases

Engineering Contradiction:
ImproveCoMP operation flexibilityVSAvoidCSI measurement overhead
Core Design Contradiction:
Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The patent implements dynamic CSI measurement strategies where the measurement frequency and scope are adjusted based on operational conditions. The system can dynamically switch between different measurement modes, performing expanded measurements only when CoMP operations require high flexibility, while using simplified measurements during stable conditions, thus achieving adaptability without consistently high overhead.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent applies local quality by performing expanded CSI measurements selectively for specific transmission points or specific user equipment based on local conditions, rather than uniformly for all points and users. This localized approach to expanded measurements provides necessary CoMP flexibility where needed while reducing overall overhead by avoiding unnecessary measurements in areas where full flexibility is not required.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP2789199B9Channel measurements supporting coordinated multi-point operation
Publication Date: 2019.11.06 NOKIA TECHNOLOGIES OY
  • EP2789199B9 patent drawingFigure 1A~2
  • EP2789199B9 patent drawingFigure 1B
  • EP2789199B9 patent drawingFigure 3

AI summary

An aspect of this invention is a definition of a set of reused channel state information reference signal (CSI-RS) resources among transmission points, which can be lower power nodes, for intra- cell coordinated multi-point (CoMP) operation. Separate CSI-RS resources are defined for each transmission point for sporadic separate measurements to be made by user equipment. The sporadic measurements may be implemented with low additional overhead, and are used for generating potentially simplified CSI feedback to an evolved NodeB that enables adapting shared channel reuse and also potentially making related channel quality indicator (CQI) compensation.