PDSCH and DMRS-Based CSI Reporting With Lower Feedback Delay
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Solution Overview
Problem
Conventional CSI reporting techniques in wireless communication systems face limitations in feedback delay and overhead, particularly with aperiodic CSI reporting, and the use of CSI-RS contributes to channel overhead.
Innovation Solution
UE initiated CSI reporting and downlink grant based CSI reporting utilize PDSCH and DMRS as measurement resources, allowing for flexible CSI reporting and reducing delay by calculating CQI based on the slot of PDSCH and DMRS reception, and using dedicated uplink resources after a CSI timeline.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If CSI-RS is used for channel measurement, then channel state information can be obtained, but downlink signal overhead increases
Solution Approach 1:
The PDSCH and DMRS, originally designed for data transmission and demodulation respectively, are made to serve dual purposes by enabling CSI measurement functionality. This allows the same downlink signals to provide both their primary functions and channel state information, eliminating the need for separate CSI-RS resources.
Solution Approach 2:
The patent combines the CSI measurement function with the existing PDSCH and DMRS signals. Instead of using separate CSI-RS resources, the measurement capabilities are merged into the data transmission path, allowing channel quality assessment to be performed using the same resources already allocated for user data.
2Reliability
If aperiodic CSI is triggered by network failures, then feedback can be obtained, but feedback delay increases
Solution Approach 1:
The UE performs channel measurements continuously on PDSCH/DMRS and maintains ready-to-report CSI information. When the network triggers a CSI report or when failure detection occurs, the UE can immediately provide feedback without requiring additional measurement time, thus reducing feedback delay while maintaining reliability.
Solution Approach 2:
The patent establishes a feedback mechanism where the UE continuously monitors PDSCH/DMRS and can rapidly report CSI when triggered. This continuous monitoring and rapid feedback capability ensures that reliability is maintained while minimizing the time delay between failure detection and feedback provision.
3Measurement precision
If conventional CSI reporting is used, then channel state information is provided, but flexibility in scheduling is reduced
Solution Approach 1:
The patent introduces dynamic CSI reporting where the UE can autonomously initiate CSI reports based on detected channel conditions. This dynamic approach allows the system to adapt scheduling decisions in real-time based on current channel state, providing both measurement precision and scheduling flexibility that conventional static reporting cannot achieve.
Solution Approach 2:
The UE is empowered to autonomously determine when to report CSI based on its own channel measurements of PDSCH/DMRS. This self-service capability allows the UE to proactively provide channel state information when it detects favorable conditions, giving the network greater flexibility in scheduling without requiring constant network-initiated triggering.
Data Source
AI summary
This disclosure provides systems, methods and apparatus, including computer programs encoded on computer storage media, for transmitting a channel state information (CSI) report from a user equipment (UE). The CSI report may be a UE initiated CSI report or may be based on a downlink grant. The UE may determine to transmit the CSI report based on measurement using a physical downlink control channel (PDSCH) and/or a demodulation reference signal (DMRS). The UE may determine a reference resource for CSI feedback. The UE may calculate a channel quality indicator (CQI) based on the reference resource. The UE may transmit the CQI in the CSI report on an uplink resource.