CSI-RS Resource Indication via Physical Layer Signaling
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Solution Overview
Problem
Current CSI-RS-based measurement and feedback schemes, particularly the beamformed scheme, face high overheads when the number of UEs increases, necessitating a reduction in CSI-RS overheads without compromising system performance.
Innovation Solution
Implementing a method where an eNB configures and indicates CSI-RS resources using physical layer signaling or MAC signaling, allowing flexible configuration and real-time adjustment of CSI-RS resources based on UE service demands, reducing overheads by enabling only necessary CSI-RS usage for data transmission requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a beamformed CSI-RS scheme is adopted for each UE, then CSI measurement accuracy and feedback performance are improved, but CSI-RS overheads increase significantly when the number of UEs increases
Solution Approach 1:
The patent merges multiple UE-specific beamformed CSI-RS resources into a single cell-specific non-precoded CSI-RS resource. Instead of configuring separate beamformed CSI-RS for each UE, the network configures one common non-precoded CSI-RS that all UEs can use for channel measurement, thereby reducing overhead while maintaining measurement accuracy through codebook-based precoding selection.
Solution Approach 2:
The cell-specific non-precoded CSI-RS serves multiple functions: it provides channel measurement for all UEs in the cell simultaneously, replaces the need for multiple UE-specific beamformed CSI-RS resources, and enables both wide coverage and accurate CSI feedback through the combination of non-precoded transmission and codebook-based precoding selection.
2Quantity of substance
If cell-specific non-precoded CSI-RS is used, then CSI-RS overheads are reduced, but CSI measurement accuracy and feedback performance deteriorate
Solution Approach 1:
The patent introduces dynamic precoding selection where UEs can choose different precoding matrices from a codebook based on channel conditions. The network dynamically adjusts the precoding configuration through higher-layer signaling, allowing the system to adapt to changing channel states and maintain measurement accuracy while using a single non-precoded CSI-RS resource.
Solution Approach 2:
The patent changes the precoding parameter from UE-specific beamforming vectors to codebook-based precoding matrices. By allowing UEs to select precoding matrices from a predefined codebook based on channel quality, the system maintains measurement accuracy without requiring multiple UE-specific beamformed CSI-RS resources, thus reducing overhead.
3Reliability
If UE-specific beamformed CSI-RS is configured for all UEs, then individualized CSI measurement performance is improved, but system resource consumption increases
Solution Approach 1:
The patent extracts the essential channel measurement function from multiple UE-specific beamformed CSI-RS resources and concentrates it into a single cell-specific non-precoded CSI-RS resource. By separating the channel measurement function from the precoding function, the system reduces resource consumption while maintaining individualized CSI feedback performance through codebook-based precoding selection.
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AI summary
Disclosed are a method, device, and system for indicating a channel state information reference signal (CSI-RS) resource. A base station can configure one or more channel state information reference signal (CSI-RS) resources for a plurality of terminals within a cell covered by the base station, and can indicate a CSI-RS resource that can be used by each terminal in the plurality of terminal and belongs to the one or more CSI-RS resources, thereby enabling each terminal to perform measurement and feedback of channel state information according to the CSI-RS resource indicated by the base station by using a physical layer signal or a media access layer signal. In the present scheme, CSI-RS configuration of terminals can be quickly and flexibly changed by introducing a physical layer signal or a media access layer signal, thereby reducing overheads of CSI-RS without affecting system performance.