3D MIMO Rank Search Range Optimization
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Solution Overview
Problem
Current wireless communication systems face challenges in efficiently generating and reporting channel state information for three-dimensional multiple input multiple output (MIMO) in wireless communication systems, particularly in configuring optimal precoders and ranks for 3D beamforming, which increases computational complexity and can lead to transmission errors due to mismatched layer feedback.
Innovation Solution
A method is introduced where a user equipment (UE) receives pilot signals from a base station, selects ranks for vertical and horizontal channels, configures a rank search range for a three-dimensional channel, and selects a precoder corresponding to the rank within this range, setting the larger rank value as a lower limit and the product of ranks as an upper limit, or the maximally implementable rank as an upper limit, to efficiently generate and report channel state information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the UE selects optimal precoders and ranks for 3D beamforming, then the accuracy of channel state information feedback is improved, but the computational complexity increases
Solution Approach 1:
The patent segments the 3D MIMO channel into two independent 2D channels (horizontal and vertical), allowing separate rank selection for each dimension. This segmentation reduces the computational complexity of finding the optimal 3D precoder while maintaining feedback accuracy, as the UE can independently optimize horizontal and vertical ranks without exhaustively searching the entire 3D precoder space.
Solution Approach 2:
The patent introduces a new dimension to the problem by considering both horizontal and vertical ranks separately. Instead of searching for optimal precoders in the traditional 2D space, the system extends the search to 3D MIMO space by defining a rank search range based on the product of horizontal and vertical ranks, enabling more accurate channel state information feedback through dimensional decomposition.
2Measurement precision
If the UE configures a wide rank search range for 3D channel, then the accuracy of precoder selection is improved, but the processing time and complexity increase
Solution Approach 1:
The patent applies preliminary action by first determining the horizontal and vertical ranks separately before configuring the rank search range for 3D MIMO. This preliminary rank selection narrows down the search space, allowing the UE to efficiently identify the optimal 3D precoder within a constrained rank search range, thereby reducing processing time while maintaining selection accuracy.
Solution Approach 2:
The patent changes the parameters used for precoder selection by introducing separate horizontal and vertical rank parameters. Instead of using a single rank value, the system defines a rank search range based on the product of horizontal and vertical ranks, which optimizes the search efficiency and reduces processing time while improving precoder selection accuracy through parameter decomposition.
3Device complexity
If the system uses traditional 2D MIMO methods for 3D beamforming, then the device complexity is reduced, but transmission errors increase due to mismatched layer feedback
Solution Approach 1:
The patent segments the 3D MIMO transmission into independent horizontal and vertical 2D channels, each with its own rank selection. This segmentation allows the system to use familiar 2D MIMO methods for each dimension while avoiding the layer mismatch problems of traditional 3D approaches, thereby maintaining low device complexity while improving transmission reliability through independent optimization of each dimension.
4Measurement precision
If the UE performs exhaustive search for optimal 3D precoders, then the channel state information accuracy is maximized, but the computational complexity becomes prohibitive
Solution Approach 1:
The patent resolves this contradiction by segmenting the exhaustive search problem into two separate 2D searches (horizontal and vertical). Instead of exhaustively searching all possible 3D precoders, the UE independently searches for optimal horizontal and vertical precoders, then combines them to form the 3D precoder. This segmentation reduces computational complexity from exponential to polynomial while maintaining channel state information accuracy.
Solution Approach 2:
The patent applies dimensionality change by transforming the 3D precoder optimization problem into a product of two 2D problems. By defining the rank search range as the product of horizontal and vertical ranks, the system enables efficient search in the 3D space without exhaustive enumeration, achieving optimal channel state information accuracy with manageable computational complexity through dimensional decomposition.
Data Source
AI summary
Disclosed in the present application is a method by which a terminal generates channel state information for multi-antenna-based beamforming in a wireless communication system. Specifically, the method comprises the steps of: receiving a first pilot signal and a second pilot signal from a base station; selecting a first rank on the basis of the first pilot signal and selecting a second rank on the basis of the second pilot signal; setting a rank search range for a three-dimensional channel on the basis of the first rank and the second rank; and selecting a rank for the three-dimensional channel within the rank search range and a precoder corresponding to the rank for the three-dimensional channel.