CSI Reporting Control via DCI Trigger Fields
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In future radio communication systems like LTE Rel. 14, LTE Rel. 15, and 5G, controlling aperiodic CSI reporting on both uplink shared and control channels is challenging, as existing systems assume CSI reporting is controlled using a PUSCH specified by a UL grant, which does not specify a resource for the uplink control channel, making it difficult to employ CSI reporting control methods without modifications.
Innovation Solution
The solution involves using downlink control information not related to data scheduling to control CSI reporting, including a CSI trigger field in DCI for scheduling UL or DL data, allowing flexible configuration of CSI reporting timing and resources, and distinguishing between CSI trigger DCI and data scheduling DCI using identification fields, payload sizes, and detection conditions to independently manage CSI reporting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If existing LTE systems use UL grant to control A-CSI reporting on PUSCH, then CSI reporting control is straightforward, but it cannot specify resources for uplink control channel (PUCCH) and lacks flexibility for future systems
Solution Approach 1:
The downlink control information (DCI) format is designed to serve multiple functions: it can indicate both data scheduling information and A-CSI reporting triggers, and can specify resources for both PUSCH and PUCCH channels. This multi-functionality allows the same control mechanism to handle diverse CSI reporting scenarios without requiring separate control procedures.
Solution Approach 2:
The DCI structure is segmented into distinct fields: one part indicates the trigger for A-CSI reporting, another part specifies the uplink channel type (PUSCH or PUCCH), and additional parts allocate specific resources. This segmentation allows flexible combination of control functions while maintaining clear interpretation at the receiver.
2Manufacturing precision
If separate DCI is used for CSI trigger and data scheduling, then resource allocation is precise, but control overhead increases
Solution Approach 1:
The invention merges the CSI trigger indication and data scheduling information into a single DCI message. The DCI contains both the trigger bit for A-CSI reporting and the resource allocation fields for uplink data, allowing simultaneous control of both functions in one transmission, thereby reducing control overhead while maintaining precise resource allocation.
Solution Approach 2:
The DCI structure includes optional fields that are only activated when needed. For example, PUCCH resource specification fields are included only when PUCCH-based CSI reporting is required, otherwise the same DCI format can be used with simpler resource allocation, reducing average overhead while maintaining precision when needed.
Data Source
Figure 6
Figure 7
Figure 8A~8B
AI summary
To appropriately control CSI reporting even in a case of performing CSI reporting by employing a method different from ones for existing LTE systems, one aspect of a user terminal of the present invention includes a transmitting section that transmits channel state information, and a control section that controls transmission of the channel state information by using certain downlink control information indicating trigger and/or activation of channel state information without scheduling data.