Reduced Precoding Matrix for Beam Selection Complexity
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Solution Overview
Problem
The existing methods for determining an optimum precoding choice in CSI reporting are computationally expensive due to the large size of the expanded precoding matrices, which complicates the selection process at user equipment (UE) in wireless communication systems.
Innovation Solution
The proposed solution simplifies the precoding matrix by defining a reduced precoding matrix that corresponds to a single centred beam per polarisation plane, reducing the complexity of calculations and minimizing accuracy reduction, while maintaining high correlation with the original cluster of beams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an expanded precoding matrix with multiple beams per polarisation plane is used, then the accuracy of CSI reporting is improved, but the computational complexity at the UE increases significantly
Solution Approach 1:
The patent divides the precoding matrix selection process into two stages: first selecting a cluster index from a reduced set of beam clusters, then selecting a beam index within the chosen cluster. This segmentation reduces the computational burden at UE by breaking down the large-scale matrix selection into smaller, manageable steps while maintaining accurate CSI reporting capability.
Solution Approach 2:
The patent introduces an intermediary reduced precoding matrix that acts as a bridge between the full expanded precoding matrix and the final selection process. This reduced matrix contains a subset of beams from each cluster and serves as a simplified representation that reduces computational complexity while preserving the essential characteristics needed for accurate CSI reporting.
2Device complexity
If a reduced precoding matrix with a single beam per polarisation plane is used, then the computational complexity is reduced, but the accuracy of CSI reporting may be degraded
Solution Approach 1:
The patent segments the beam selection process into cluster-level selection and beam-level selection. The reduced precoding matrix is used for cluster selection, while the full expanded precoding matrix is used for final beam selection within the chosen cluster. This two-stage segmentation allows the system to benefit from the computational simplicity of the reduced matrix while ultimately achieving accurate CSI reporting through the full matrix.
Solution Approach 2:
The patent performs preliminary action by using the reduced precoding matrix to identify the optimal beam cluster before proceeding to the final beam selection. This preliminary step narrows down the search space significantly, allowing the system to achieve accurate CSI reporting with reduced computational effort in the initial phase.
Data Source
AI summary
A method at user equipment ‘UE’, the method comprising: determining one or more radio channel estimates from received signals; selecting a precoding index fulfilling an optimization criterion based on the one or more radio channel estimates and a reduced precoding matrix, wherein the reduced precoding matrix comprises properties of a single beam for each of one or more polarization planes, and the reduced precoding matrix corresponds to an expanded precoding matrix comprising properties of a plurality of beams for each of one or more polarization planes; and transmitting a precoding matrix indicator ‘PMI’ based on the selected precoding index.