Precoding Matrix Indicator for 3D Beam Control
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Solution Overview
Problem
Existing MIMO systems, particularly in LTE R8-R11, face challenges in effectively controlling beam shape and orientation in both horizontal and perpendicular directions due to limitations in precoding matrix feedback from user equipment to base stations.
Innovation Solution
A method and apparatus for determining a precoding matrix indicator that involves user equipment selecting a precoding matrix satisfying specific conditions, such as being a product of a diagonal matrix and a constant modulus matrix, to enable precise control of beam shape and orientation, and sending this indicator to the base station for accurate beamforming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional precoding matrices are used in existing LTE systems, then system compatibility is maintained, but beam shape and orientation control in both horizontal and perpendicular directions is insufficient
Solution Approach 1:
The precoding matrix is segmented into multiple independent components: a first precoding matrix for horizontal direction control and a second precoding matrix for perpendicular direction control. This segmentation allows each matrix to independently optimize beam characteristics in its respective dimension, thereby achieving comprehensive three-dimensional beam control while maintaining manageable complexity through modular structure
Solution Approach 2:
The invention extends the precoding control from traditional two-dimensional (horizontal only) to three-dimensional space by introducing a second precoding matrix that operates in the perpendicular direction. This dimensional extension enables independent control of beam orientation and shape in both horizontal and vertical planes, significantly enhancing adaptability without proportionally increasing complexity
2Measurement precision
If more degrees of freedom are utilized in active antenna systems, then beam control precision is improved, but system complexity increases
Solution Approach 1:
Different precoding matrices are applied to different spatial dimensions with specialized structures optimized for their respective control objectives. The first precoding matrix is designed specifically for horizontal beamforming with appropriate degrees of freedom, while the second precoding matrix is designed for vertical beamforming. This local optimization allows each component to achieve high precision in its specific domain without requiring the entire system to handle all complexity
Solution Approach 2:
The system dynamically selects and combines different precoding matrices based on channel conditions and service requirements. The UE can independently determine the first and second precoding matrices from respective codebooks, allowing flexible adaptation to varying beam control needs while maintaining system manageability through standardized selection procedures
3Manufacturing precision
If conventional CSI feedback mechanisms are used, then feedback overhead is limited, but beamforming accuracy in three-dimensional space is insufficient
Solution Approach 1:
The CSI feedback is segmented into separate components corresponding to horizontal and perpendicular directions. The UE independently determines a first precoding matrix indicator from a first codebook and a second precoding matrix indicator from a second codebook, allowing each feedback component to focus on optimizing beam characteristics in its specific dimension. This segmented feedback approach improves beamforming accuracy by providing direction-specific optimization while managing feedback volume through efficient codebook-based representation
Data Source
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AI summary
The present invention provides a method and an apparatus for determining a precoding matrix indicator, user equipment, and a base station. The method includes: determining a precoding matrix indicator PMI, where the PMI corresponds to a precoding matrix w, and the precoding matrix w satisfies a first condition, a second condition, or a third condition; and sending the PMI to a base station. Embodiments of the present invention further provide a corresponding apparatus, and the corresponding user equipment and base station. Technical solutions provided in the embodiments of the present invention can effectively control a beam, especially a beam shape and a beam orientation, in a horizontal direction and a perpendicular direction.