Massive MIMO Channel State Information Feedback Overhead Reduction
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Solution Overview
Problem
In wireless communication systems supporting massive multiple input multiple output (MIMO), existing methods face challenges in efficiently transmitting channel state information (CSI) due to the complexity of managing multiple antennas and feedback overhead, particularly in systems with a large number of transmit antennas.
Innovation Solution
The method involves a user equipment (UE) receiving CSI configuration information and transmitting CSI along with identification information of partial channels, which can correspond to specific columns or rows of an antenna array, associated with single or dual codebooks, and adjusting feedback frequencies based on identification information, with identification information only transmitted with wideband precoding matrix indicators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If all channel state information for all antennas is transmitted, then channel estimation accuracy is improved, but feedback overhead increases
Solution Approach 1:
The patent divides the complete channel state information into multiple CSI parts, where each part corresponds to a subset of antennas (e.g., first column, second column, first row, second row of the antenna array). The UE transmits only the selected CSI part corresponding to the serving beam, rather than all channel state information for all antennas, thereby reducing feedback overhead while maintaining sufficient channel estimation accuracy for the active beam.
2Measurement precision
If identification information is transmitted with every CSI report, then beam identification accuracy is improved, but feedback overhead increases
Solution Approach 1:
The patent transmits identification information only when necessary, specifically when the CSI is wideband PMI. The base station pre-configures the UE with CSI part indicators that implicitly identify the serving beam, so that identification information is only explicitly transmitted when needed for wideband precoding, reducing redundant feedback overhead while maintaining beam identification accuracy.
3Speed
If feedback frequency is increased for all channels, then channel state update speed is improved, but signaling overhead increases
Solution Approach 1:
The patent applies different feedback frequencies to different CSI parts based on their specific requirements. The base station can configure the UE to report selected CSI parts at appropriate intervals, allowing faster update rates for critical channel information while maintaining lower overhead for less dynamic parameters, thereby optimizing the balance between channel state update speed and signaling overhead.
Data Source
AI summary
A method for a terminal transmitting channel state information (CSI) in a wireless access system that supports massive multiple-input multiple-output (MIMO) according to one embodiment of the present invention may comprise the steps of: receiving CSI configuration information for reporting CSI; and transmitting CSI and identification information with respect to the partial channel corresponding to the CSI of the full channel according to the massive MIMO, on the basis of the CSI configuration information.