CSI Reporting Reducing Reference Signal Overhead

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Solution Overview

Problem

As the number of antenna ports increases in LTE systems, the reference signal resource overheads in CSI processes become significant, particularly between non-beamforming and beamforming CSI-RS resources, affecting spectrum efficiency.

Innovation Solution

The method involves using a terminal to determine and report precoding matrix indicators (PMIs) for a non-beamforming reference signal resource, which are then used by the base station to determine PMIs for a beamforming resource, reducing resource overheads by leveraging a lower-dimensional PMI to improve beamforming accuracy and system performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the number of antenna ports is increased to improve spectrum efficiency, then the reference signal resource overheads in CSI processes increase

Engineering Contradiction:
Improvespectrum efficiencyVSAvoidreference signal resource overheads
Core Design Contradiction:
ProductivityVSQuantity of substance

Solution Approach 1:

The patent segments the PMI reporting into two parts: first PMIs for non-beamforming reference signal resources and second PMIs for beamforming reference signal resources. This segmentation allows the system to use lower-dimensional first PMIs to indicate non-beamforming resources, reducing the overall PMI dimension and reference signal overhead while maintaining support for multiple antenna ports

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the parameter dimension of PMI by introducing a reduced-dimensional first PMI for non-beamforming resources. Instead of using full-dimensional PMIs for all resources, the system uses lower-dimensional first PMIs that require fewer bits for reporting, thereby reducing reference signal resource overheads while maintaining the ability to support increased antenna ports

Inventive Principle:
Principle #35Parameter changes

2Quantity of substance

If the dimension of PMI is reduced to decrease reporting overhead, then the beamforming accuracy may be compromised

Engineering Contradiction:
ImprovePMI reporting overheadVSAvoidbeamforming accuracy
Core Design Contradiction:
Quantity of substanceVSMeasurement precision

Solution Approach 1:

The patent segments PMI reporting into first PMIs (lower dimension) for non-beamforming resources and second PMIs (higher dimension) for beamforming resources. This segmentation allows the system to use only lower-dimensional information where sufficient while reserving higher-dimensional second PMIs specifically for beamforming operations where precision is critical

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first PMIs serve as an intermediary that provides sufficient information for non-beamforming resource indication without requiring full beamforming precision. The base station uses these first PMIs to determine appropriate second PMIs for beamforming, creating a two-stage process that optimizes both overhead reduction and accuracy maintenance

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3451565B1Channel state information reporting method, reading method, and related apparatus
Publication Date: 2025.01.08 HUAWEI TECH CO LTD
  • EP3451565B1 patent drawingFigure 1~2
  • EP3451565B1 patent drawingFigure 3A
  • EP3451565B1 patent drawingFigure 3B

AI summary

The present invention discloses a channel state information reporting method, including: determining, by a terminal, R first precoding matrix indicators PMIs of M first reference signal resources, and determining a channel quality indicator CQI based on the R first PMIs, where M and R are integers greater than or equal to 1; and reporting, by the terminal, channel state information, where the channel state information includes the R first PMIs and N CQIs, or the channel state information includes the R first PMIs and one CQI, the R first PMIs are used by a base station to determine P second PMIs according to a first operational criterion, a dimension of the second PMI is greater than a dimension of the first PMI, and P and N are integers greater than or equal to 1. Embodiments of the present invention further provide a channel state information reading method a related device. In the embodiments of the present invention, reference signal resource overheads in a CSI process can be reduced.