Aperiodic CSI Feedback Scheme for Multi-Carrier LTE-A Systems

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Solution Overview

Problem

Current LTE-A systems face challenges in efficiently managing aperiodic CSI feedback, particularly with multi-carrier configurations, leading to significant feedback overhead and incomplete CSI reporting due to rigid feedback mechanisms that do not adapt well to varying carrier configurations and channel quality differences.

Innovation Solution

A method is introduced where a base station configures a UE with a CSI feedback scheme that includes a joint feedback scheme for all activated DL CCs, a first independent feedback scheme for DL CCs with UL grants, and a second independent feedback scheme for DL CCs with system-level paired linking relationships, allowing flexible aperiodic CSI reporting based on carrier configuration conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If a joint feedback scheme is used for all activated DL CCs, then comprehensive CSI reporting is achieved, but feedback overhead increases significantly

Engineering Contradiction:
ImproveCSI reporting completenessVSAvoidfeedback overhead
Core Design Contradiction:
Loss of informationVSQuantity of substance

Solution Approach 1:

The patent segments the feedback scheme into multiple types (joint feedback scheme, first independent feedback scheme, second independent feedback scheme) that can be selectively applied to different downlink component carriers based on their paired linking relationships with uplink carriers. This segmentation allows the system to report CSI comprehensively for carriers requiring it while avoiding redundant feedback for carriers that don't need it, thus reducing overall feedback overhead while maintaining reporting completeness.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If independent feedback schemes are used for each DL CC, then feedback flexibility is improved, but device complexity increases

Engineering Contradiction:
Improvefeedback flexibilityVSAvoidfeedback scheme complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent creates a universal feedback mechanism where a single uplink grant can trigger CSI feedback for multiple downlink component carriers simultaneously. The base station configures multiple feedback schemes that share common structures and procedures, allowing the system to adapt to different carrier configurations without requiring entirely separate feedback mechanisms for each carrier. This multi-functionality reduces device complexity while maintaining feedback flexibility.

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

3Ease of manufacture

If rigid feedback mechanisms are used, then implementation simplicity is maintained, but adaptability to varying carrier configurations deteriorates

Engineering Contradiction:
Improveimplementation simplicityVSAvoidcarrier configuration adaptability
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent introduces dynamic adaptability by allowing the base station to configure different feedback schemes (joint, first independent, second independent) based on the specific paired linking relationships between uplink and downlink component carriers. The system can dynamically select which feedback scheme to apply to each carrier pair, enabling simple implementation for straightforward configurations while adapting to complex multi-carrier scenarios when needed.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP2897317B1Indication method, base station, and system for CSI feedback
Publication Date: 2016.06.22 CHINA ACAD OF TELECOMM TECH
  • EP2897317B1 patent drawingFigure 1
  • EP2897317B1 patent drawingFigure 2~3
  • EP2897317B1 patent drawingFigure 4A~4B

AI summary

The present invention relates to the technical field of wireless communications. Provided are an indication method, a base station, and a system for channel state information (CSI) feedback. The indication method comprises: the base station allocating to a user equipment (UE) a CSI feedback method (S701); by means of allocation signaling, the base station transmitting to the UE the CSI feedback method allocated, instructing the CSI feedback method to be employed by the UE when making an aperiodic CSI report (S702). The feedback method comprises: the UE receiving the allocation instruction transmitted by the base station, acquiring the CSI feedback method allocated for the UE by the base station; when the UE confirms the triggering of an aperiodic CSI report, using the CSI feedback method allocated therefor by the base station. In the present invention, the base station can perform the selection of the appropriate aperiodic CSI feedback method on on the basis of the status of carrier allocation, thereby optimizing the CSI feedback mechanism, and improving system design flexibility.