Aperiodic CSI Reporting via PUCCH Trigger Mechanisms
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Solution Overview
Problem
Current wireless communication systems face inefficiencies in reporting aperiodic channel state information (CSI) due to limitations in uplink resources and timing, particularly when A-CSI reporting is requested without available uplink data, leading to delayed CSI feedback and impaired downlink channel-dependent scheduling.
Innovation Solution
A method and apparatus for a user equipment (UE) to receive a feedback configuration and CSI trigger for reporting aperiodic CSI feedback using a physical uplink control channel (PUCCH), where the CSI trigger can include either a dedicated downlink control indicator (DCI) or a group common DCI, enabling the UE to determine channel condition information and report it efficiently using PUCCH resources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If aperiodic CSI reporting is requested without available uplink data, then CSI feedback timing is delayed, but using PUCCH resources enables timely CSI reporting
Solution Approach 1:
The PUCCH resource is configured to serve multiple functions: it can carry both uplink data and aperiodic CSI feedback. When uplink data is unavailable, the same PUCCH resource is utilized for CSI reporting, eliminating resource availability constraints and ensuring timely feedback delivery.
2Measurement precision
If dedicated DCI is used for A-CSI triggering, then CSI reporting accuracy is improved, but signaling overhead increases
Solution Approach 1:
The CSI triggering function is merged into the uplink grant DCI structure. The same DCI that schedules uplink data transmission also contains the A-CSI triggering indication, eliminating the need for separate dedicated DCI and reducing signaling overhead while maintaining precise CSI triggering capability.
3Reliability
If PUCCH resources are configured for A-CSI reporting, then CSI feedback reliability is improved, but uplink resource complexity increases
Solution Approach 1:
The PUCCH resource for A-CSI reporting is pre-configured and semi-statically allocated before actual CSI reporting occurs. This preliminary configuration simplifies the resource management complexity during dynamic operation while ensuring reliable, interference-coordinated CSI feedback transmission.
Data Source
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AI summary
Reporting aperiodic channel state information (A-CSI) via a physical uplink control channel (PUCCH) is disclosed. A UE receives a configuration to report aperiodic channel state information (A-CSI) using physical uplink control channel (PUCCH). The UE can report lightweight A-CSI via short/long PUCCH or may report heavy A-CSI via short/long PUCCH. The UE receives a trigger signal for PUCCH-based A-CSI reporting either by a dedicated downlink grant or by a group common DCI. When triggered via a DCI-based trigger, the PUCCH resource can be either a resource used for HARQ-ACK feedback, e.g., short PUCCH; or a semi-static configured PUCCH resource, e.g., either short PUCCH or long PUCCH. When triggered via a group common DCI-based trigger, the PUCCH resource can be either semi-statically configured, or dynamically indicated.