Codebook Subset Constraint Parameters for Wireless Signaling Overhead Reduction
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Solution Overview
Problem
In wireless communication systems, especially with 2D antenna arrays, the conventional method of constraining a codebook subset to reduce implementation complexity and overhead is inefficient due to the large number of possible precoding matrices, leading to excessive system resource occupation.
Innovation Solution
A method and device for constraining a codebook subset by determining and transmitting codebook subset constraint parameters to a UE, which indicate available matrices based on antenna array configuration, application scenarios, uplink signal measurements, or feedback information, allowing for the selection of active precoding matrices to reduce the number of matrices in the codebook.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a conventional bitmap method is used to indicate each precoding matrix availability, then the codebook subset can be constrained, but a large number of system resources are occupied due to the huge number of precoding matrices (4096 or more)
Solution Approach 1:
The codebook is segmented into multiple codebook groups, where each group contains a subset of precoding matrices. Instead of using a single large bitmap to indicate availability of all precoding matrices, the system divides the indication into multiple smaller bitmaps corresponding to different codebook groups. This segmentation reduces the signaling overhead for each individual bitmap while maintaining the ability to constrain the overall codebook subset.
Solution Approach 2:
The patent introduces a new dimension of organization by grouping precoding matrices into codebook groups. This dimensional change transforms the flat, exhaustive bitmap approach into a hierarchical structure where availability is indicated at the group level rather than individual matrix level, significantly reducing the number of bits required for signaling.
2Measurement precision
If a large codebook is designed to match all possible 2D antenna array configurations and application scenarios, then the CSI feedback accuracy is improved, but the uplink feedback overhead and implementation complexity at UE side increase
Solution Approach 1:
The large codebook is segmented into multiple codebook groups, each tailored to specific antenna array configurations or application scenarios. The UE can select from multiple codebook groups based on the actual deployment scenario, maintaining high CSI feedback accuracy for the selected group while avoiding the overhead of processing all matrices in a single large codebook.
Solution Approach 2:
The system dynamically selects which codebook group to use based on the antenna array configuration and application scenario. This dynamic selection allows the codebook size and composition to adapt to the specific situation, optimizing the balance between feedback accuracy and overhead for each scenario rather than using a fixed large codebook for all cases.
Data Source
AI summary
The embodiments of the present disclosure provide a method and a device for constraining a codebook subset. The method includes steps of: determining codebook subset constraint parameters for all or parts of matrix sets for constructing a codebook respectively, each codebook subset constraint parameter indicating an available matrix in a corresponding matrix set; and transmitting the determined codebook subset constraint parameters to a UE. The number of the matrices in each matrix set for constructing the codebook is far less than the number of precoding matrices in the codebook.