Codebook Subset Selection for MIMO Feedback Overhead
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Solution Overview
Problem
In MIMO communication systems, the increase in the number of antennas leads to a larger channel matrix dimension, resulting in exponential feedback overhead and increased terminal complexity due to the need for high quantization accuracy, with current solutions failing to effectively manage signaling overhead when the codebook is large.
Innovation Solution
A method and system for acquiring a codebook that involves generating a codebook subset by determining a signaling indication method and using CSS signaling to select and notify the subset, reducing signaling overhead by optimizing the relationship between CSS signaling bits and codewords.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a large codebook is used to maintain quantization accuracy in MIMO systems with increased antennas, then the quantization efficiency is improved, but the signaling overhead increases exponentially
Solution Approach 1:
The patent segments the large codebook into multiple codebook subsets, each corresponding to specific channel conditions or antenna configurations. Instead of feedback all codewords individually, the system selects and feeds back only the relevant subset, dramatically reducing signaling overhead while preserving quantization accuracy for the actual channel state.
Solution Approach 2:
The patent applies partial action by selecting only the necessary portion of the codebook (relevant subset) rather than using the entire codebook for all channel conditions. This partial feedback approach provides sufficient quantization accuracy for current channel conditions without the excessive signaling overhead of complete codebook feedback.
2Adaptability or versatility
If each codeword in the codebook corresponds to one bit for selection, then the codebook selection flexibility is improved, but the signaling overhead increases significantly when the codebook is large
Solution Approach 1:
The patent segments the codebook selection process into two stages: first selecting a codebook subset based on channel conditions, then selecting specific codewords within that subset. This hierarchical segmentation reduces the total number of bits needed while maintaining selection flexibility, as the subset selection captures the majority of channel variability.
Solution Approach 2:
The patent introduces a new dimension to codebook selection by organizing codewords into hierarchical groups or subsets based on channel characteristics. This dimensional organization allows indirect selection through subset indicators, reducing the direct bit requirement from linear codebook size to logarithmic scale while preserving adaptability.
3Measurement precision
If the codebook dimension increases to match larger antenna arrays, then the channel representation accuracy is improved, but the terminal complexity increases significantly
Solution Approach 1:
The patent segments the large-dimensional codebook into smaller manageable subsets, allowing the terminal to work with reduced complexity data structures. The terminal only needs to process and compare codewords within the relevant subset rather than the entire large codebook, significantly reducing computational complexity while maintaining channel representation accuracy.
Solution Approach 2:
The patent applies partial action by having the terminal process only the necessary portion of the codebook (the relevant subset) rather than the complete large-dimensional codebook. This partial processing maintains sufficient channel representation accuracy for current conditions while dramatically reducing terminal computational complexity and memory requirements.
Data Source
AI summary
Provided are a method, apparatus and system for acquiring a codebook, the method including: generating, by a base station, a codebook corresponding to Nt ports and r layers transmission according to a first preset condition, the codebook being for feeding back a preceding matrix, the first preset condition being a common set condition between the base station and a terminal, Nt being a port number, and r being a transmission layer number; determining, by the base station, a signaling indication method for selecting a codebook subset corresponding to the codebook according to a second preset condition; and acquiring, by the base station, Codebook Subset Selection (CSS) signaling for selecting the codebook subset correspondingly according to the signaling indication method, and notifying the selected codebook subset to a terminal through the CSS signaling.