Channel State Information Reporting Using Linear Codeword Combination
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Solution Overview
Problem
Current wireless communication systems face challenges in efficiently transmitting and receiving channel state information in multi-antenna systems, particularly in 2D AAS and 3D-MIMO systems, which affects multi-user performance and increases feedback overhead.
Innovation Solution
A method for user equipment (UE) to report channel state information by receiving a CSI-RS from a base station, using a codebook to generate a precoding matrix through a linear combination of codewords with applied power and phase coefficients, reducing feedback overhead and improving beam accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a codebook with multiple codewords is used to generate precoding matrices in multi-antenna systems, then multi-user transmission performance is improved, but channel state information feedback overhead increases
Solution Approach 1:
The codebook is segmented into multiple groups where each group contains codewords with specific properties. The UE selects one group based on channel conditions and reports only the group index rather than individual codeword selections, reducing feedback overhead while maintaining multi-user performance
Solution Approach 2:
Instead of reporting complete channel state information for all antenna elements, the system uses partial feedback by reporting precoding matrix indicators (PMI) that reference pre-defined matrices in the codebook, providing sufficient information for multi-user scheduling without exhaustive feedback
2Measurement precision
If a linear combination of codewords with power coefficients is used to generate precoding matrices, then beam accuracy is improved, but device complexity increases
Solution Approach 1:
Precoding matrices involving linear combinations of codewords are pre-calculated and stored in the codebook at both transmitter and receiver sides. The UE performs simple lookup and selection of pre-computed matrices rather than performing complex real-time linear combination calculations, reducing processing complexity while maintaining beam accuracy
Solution Approach 2:
The system changes the parameter representation from individual codeword weights to codebook indices. By quantizing the continuous space of possible linear combinations into discrete codebook entries, the system achieves practical implementation with reduced complexity while preserving essential beamforming accuracy
Data Source
AI summary
Disclosed are a method for transmitting and receiving channel state information in a multi-antenna wireless communication system, and an apparatus therefor. Particularly, a method by which user equipment (UE) reports channel state information in a two-dimensional multi-antenna wireless communication system comprises the steps of: receiving, from a base station, a channel state information reference signal (CSI-RS) through a multi-antenna port; and reporting the channel state information to the base station, wherein a plurality of codewords, which are used for generating a pre-coding matrix selected by the UE in a codebook for reporting the channel state information, are specified by the channel state information and, after power coefficients are applied to each of the plurality of codewords, the pre-coding matrix can be generated based on a linear combination of the plurality of codewords to which the power coefficients are applied.