CSI Feedback Structure for Coherent Joint Transmission
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently transmitting CSI feedback messages for coherent joint transmission (CJT) in MIMO systems, particularly in FR1 and FR2, which affect coverage and throughput.
Innovation Solution
A user equipment (UE) and base station (BS) system that performs channel measurements using CSI-RS resources, selects a set of resources for joint transmission, and transmits a CSI feedback message including a single RI, CQI, and PMIs, with phase and amplitude adjustment factors to optimize precoding matrices for multiple TRPs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple TRPs are deployed for CJT to improve coverage and throughput, then wireless communication performance is improved, but CSI feedback message transmission becomes more complex
Solution Approach 1:
The patent segments the CSI feedback into separate components: RI (rank indicator), CQI (channel quality indicator), and PMI (precoding matrix indicator). Each component can be transmitted independently, allowing the system to manage complexity by handling feedback in discrete, manageable units rather than as a single complex message.
Solution Approach 2:
The patent introduces a new dimension to the feedback mechanism by associating multiple PMIs with different TRPs while maintaining a single RI and CQI. This allows the system to represent multiple transmission points through a structured dimensional expansion of the feedback message, organizing complexity through mathematical structure.
2Device complexity
If a single RI and CQI are used for multiple TRPs, then feedback message structure is simplified, but measurement precision requirements increase
Solution Approach 1:
The patent applies local quality by assigning different measurement and reporting requirements to different TRPs. While a single RI and CQI are used for all TRPs, each TRP has its own PMI that can be independently optimized. This allows the system to maintain simplified overall structure while ensuring each individual TRP receives precise local feedback through its dedicated PMI.
3Manufacturing precision
If multiple PMIs are associated with different TRPs, then precoding optimization is improved, but information transmission volume increases
Solution Approach 1:
The patent makes the RI and CQI universal by using a single pair of indicators for all TRPs, while the PMIs provide the TRP-specific precision. This multi-functional approach allows the same RI and CQI to serve multiple TRPs simultaneously, reducing redundant information transmission while maintaining precise precoding control through the TRP-specific PMIs.
Data Source
AI summary
The present application relates to methods and apparatuses for transmitting a channel state information (CSI) feedback message. An embodiment of the present disclosure provides a user equipment (UE), comprising: a transceiver configured to: receive a CSI report configuration message indicating a plurality of channel state information reference signal (CSI-RS) resources for channel measurement and at least one zero-power or non-zero power CSI-RS resource for interference measurement, wherein each CSI-RS resource of the plurality of CSI-RS resources is associated with a CSI-RS resource indicator (CRI) and an identical number of CSI-RS ports; and a processor coupled with the transceiver and configured to: perform a channel measurement procedure based on the CSI report configuration message; and select a set of CSI-RS resources from the plurality of CSI-RS resources for a joint transmission based on the channel measurement procedure; wherein the transceiver is further configured to: transmit a CSI feedback message after the channel measurement procedure is performed, wherein the CSI feedback message includes a single rank indicator (RI), a single channel quality indicator (CQI), and a set of precoding matrix indicators (PMIs), wherein each PMI of the set of PMIs is associated with a respective CSI-RS resource in the selected set of CSI-RS resources, and wherein the RI indicates a rank applied to each CSI-RS resource of the selected set of CSI-RS resources, and the CQI indicates a channel quality associated with all CSI-RS resources in the selected set of CSI-RS resources.