Precoded CSI-RS Antenna Port Allocation for Full-Dimension MIMO
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Solution Overview
Problem
Existing channel quality reporting processes in wireless communication systems do not adequately accommodate large two-dimensional array transmit antennas, leading to inefficiencies in channel state information reporting and feedback, particularly in full-dimension MIMO systems with multiple transmit antennas.
Innovation Solution
A method is introduced where a Base Station precodes CSI-RS antenna ports with a first precoding matrix, allowing User Equipment to determine a second precoding matrix based on received CSI-RS and signaled antenna port information, enabling efficient transmission and reception of data using a scalable and flexible CSI feedback scheme that reduces feedback overhead through dimensionality reduction and cumulative updates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing channel quality reporting processes are used, then the system maintains simplicity in implementation, but the system cannot adequately accommodate large two-dimensional array transmit antennas resulting in insufficient channel state information reporting accuracy
Solution Approach 1:
The CSI feedback process is segmented into multiple stages: first, the UE receives precoded CSI-RS from the BS; second, the UE determines channel quality based on this precoded reference signal; third, the UE reports only the necessary channel quality information rather than complete channel state. This segmentation allows accurate CSI reporting for large 2D antenna arrays while reducing feedback overhead and complexity.
Solution Approach 2:
The base station performs preliminary precoding of the CSI-RS before transmission to the UE. This preliminary action allows the UE to measure channel quality on already-precoded reference signals, which simplifies the UE's measurement process and enables accurate CSI reporting without requiring the UE to process raw multi-antenna signals directly.
2Loss of information
If traditional CSI reporting methods are used with large numbers of antenna elements, then the system maintains uniform treatment of all antennas, but the feedback overhead increases significantly
Solution Approach 1:
The invention extracts only the essential channel quality information from the complete channel state that the UE could potentially measure. Instead of reporting all channel state parameters for each antenna element in large 2D arrays, the system extracts and reports only the channel quality metrics that are necessary for downlink scheduling and precoding optimization, thereby reducing feedback overhead while maintaining adaptability to large antenna configurations.
Solution Approach 2:
The system changes the parameter being reported from complete channel state information to condensed channel quality information. By transforming the feedback parameter from detailed channel matrices to aggregated quality metrics, the system reduces feedback overhead significantly while still providing the BS with sufficient information to adapt to large antenna arrays through intelligent precoding.
3Productivity
If the UE determines precoding matrices based on received precoded CSI-RS, then the system achieves efficient CSI feedback with reduced overhead, but the UE requires advanced processing capabilities
Solution Approach 1:
The precoded CSI-RS acts as an intermediary that carries channel state information in a pre-processed form. Instead of requiring the UE to directly handle raw multi-antenna channel data and perform complex matrix operations, the precoded CSI-RS serves as an intermediate representation that simplifies the UE's processing task while still enabling efficient CSI feedback through the use of standard precoding techniques.
Data Source
AI summary
A base station includes a transceiver, and a processor configured to allocate at least one CSI-RS antenna port to a user equipment (UE), precode the at least one CSI-RS antenna port with a first precoding matrix, cause the transceiver to transmit the at least one CSI-RS antenna port precoded with the first precoding matrix through a channel to the UE, cause the transceiver to signal a number of the at least one antenna port to the UE, cause the transceiver to receive an index for a second precoding matrix from the UE, wherein the second precoding matrix is determined by the UE according to the at least one CSI-RS antenna port precoded with the first precoding matrix as received through the channel by the UE and the signaled number of the at least one antenna port, and precode transmission data with the first precoding matrix and the second precoding matrix.