Channel State Information Reporting Using Kronecker Product Codebooks
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Solution Overview
Problem
Existing methods for reporting channel state information in wireless communication systems, particularly when using two-dimensional array antenna elements and a codebook denoted by a Kronecker product of horizontal and vertical antenna precoding matrices, are inefficient.
Innovation Solution
The proposed solution involves a method for efficiently reporting channel state information using a codebook based on the Kronecker product of horizontal and vertical antenna precoding matrices, specifically designed for two-dimensional array antenna elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional channel state reporting methods are used with 2D array antenna elements and Kronecker product codebooks, then system compatibility is maintained, but reporting efficiency is insufficient
Solution Approach 1:
The patent segments the channel state information reporting into multiple independent components: wideband CSI reporting for overall channel conditions and subband CSI reporting for frequency-selective optimization. This segmentation allows parallel processing and reduces the total reporting time while maintaining accuracy, directly addressing the efficiency-time tradeoff in conventional methods
Solution Approach 2:
The patent introduces a new dimension to CSI reporting by implementing multi-resolution reporting structures that operate at different frequency granularities (wideband and subband levels). This dimensional approach enables the system to capture channel variations across different frequency ranges simultaneously, improving reporting efficiency without sacrificing detail
2Measurement precision
If detailed channel state information is reported for all antenna elements, then measurement precision is improved, but feedback overhead increases
Solution Approach 1:
The patent extracts and reports only the most significant channel state information components separately: wideband CSI captures the dominant spatial characteristics while subband CSI captures frequency-selective variations. This extraction approach reduces feedback overhead by eliminating redundant information while maintaining measurement precision through the complementary nature of the two reporting layers
Solution Approach 2:
The patent changes the reporting parameters by implementing different resolution levels for different frequency bands. Wideband reporting uses coarse granularity for overall channel characteristics, while subband reporting uses fine granularity for frequency-selective optimization. This parameter variation reduces total feedback overhead while preserving measurement precision where needed
Data Source
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AI summary
According to one embodiment of the present invention, a method for reporting a channel state of a downlink channel transmitted through two-dimensionally arranged Nt number of antenna ports is carried out by a terminal, wherein the method comprises the steps of: configuring each of the Nt number of antenna ports to be mapped to all antenna elements belonging to a specific antenna element group, and each antenna port of an antenna port group corresponding to a reference signal (RS), which is transmitted in the same OFDM symbol, to be mapped to different antenna element groups from each other, and receiving a channel state information (CSI)-RS configuration for reporting a channel state for the antenna port group; and calculating channel state information on a downlink channel through a CSI-RS received using the received CSI-RS configuration, and reporting, to a serving cell, the calculated channel state information, wherein the reported channel state information can contain a precoding matrix for selecting an antenna port group and a precoding matrix to be applied to the selected antenna port group.