SRS-Assisted CSI Reporting for Selective SD Beam and FD Vector Feedback
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently reporting large-scale parameters (LSPs) associated with angles and delays, leading to high feedback overhead and UE complexity due to the need for frequent reporting of small-scale parameters (SSPs) and LSPs at the same rate.
Innovation Solution
A method is introduced to utilize sounding reference signals (SRS) for network-triggered CSI reporting, allowing selective reporting of SD beams and FD vectors based on DL/UL reciprocity, reducing the need for simultaneous reporting of both W1,l and Wf,l by using DCI bits for explicit or implicit triggering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If LSPs are reported at the same rate as SSPs, then measurement precision is improved, but feedback overhead increases
Solution Approach 1:
The patent implements dynamic triggering mechanisms where the reporting of LSPs is adaptively controlled based on channel conditions. The network can trigger LSP reporting only when necessary using DCI formats, rather than requiring periodic reporting at fixed intervals. This dynamic approach maintains measurement precision when channel conditions warrant it while significantly reducing feedback overhead during stable conditions.
Solution Approach 2:
The patent changes the reporting parameter structure by separating LSP reporting from SSP reporting timelines. Different reporting configurations can be applied where LSPs are reported with different periodicity and triggering conditions compared to SSPs. This parameter separation allows the system to optimize feedback quantity independently for each parameter type, reducing overall overhead while maintaining necessary precision.
2Measurement precision
If LSPs are reported frequently, then channel state information accuracy is improved, but UE complexity increases
Solution Approach 1:
The patent implements periodic reporting structures where LSPs are reported at configured intervals rather than continuously. The network configures reporting periodicity and triggers based on periodic CSI-RS measurements, allowing the UE to process and report LSPs only at scheduled times when measurement accuracy is sufficient, thereby reducing processing complexity while maintaining accuracy requirements.
Solution Approach 2:
The patent uses preliminary channel measurements through periodic CSI-RS transmissions before triggering LSP reporting. The UE performs measurements in advance on downlink reference signals, and the network triggers reporting only when measurements indicate changed channel conditions. This preliminary measurement approach ensures accuracy is maintained while UE complexity is reduced by avoiding unnecessary reporting processing.
3Measurement precision
If network triggers CSI reporting explicitly, then reporting accuracy is improved, but signaling overhead increases
Solution Approach 1:
The patent introduces periodic CSI-RS measurements as an intermediary mechanism between channel conditions and LSP reporting triggers. Rather than direct explicit triggering for every report, the system uses pre-configured periodic measurements that automatically indicate when channel changes warrant reporting. This intermediary approach maintains reporting accuracy while reducing the need for frequent explicit DCI triggering signals.
Solution Approach 2:
The patent makes DCI formats multi-functional by enabling them to trigger both SSP and LSP reporting through unified mechanisms. A single DCI format can configure triggering conditions that apply to multiple reporting types simultaneously, reducing the need for separate signaling for different reporting functions and thereby reducing overall signaling overhead while maintaining accurate triggering.
Data Source
AI summary
A method of channel state information (CSI) reporting is disclosed that includes determining, with a user equipment (UE), whether CSI to be reported includes a matrix based on network (NW) triggering and performing, with the UE, CSI reporting based on the determination. The CSI reporting may be periodic, semi-persistent, or aperiodic CSI reporting. The matrix may be W1,l, Wf,l, or both. The NW triggering may be explicitly performed using one or more downlink control information (DCI) bits. The NW triggering may be implicitly performed based on a location of DCI detected by the UE. In other aspects, a user equipment is also disclosed.