Codebook Determination for 2D Antenna Arrays
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Solution Overview
Problem
Existing codebooks designed for one-dimensional antenna arrays are not suitable for two-dimensional arrays, leading to degraded system performance in three-dimensional beamforming/precoding techniques, as they fail to accurately match the patterns and application scenarios of two-dimensional antenna arrays, resulting in excessive codebook configuration and storage overhead.
Innovation Solution
A method and device for determining a codebook by configuring a codebook determination parameter based on antenna array parameters, allowing the User Equipment (UE) to adapt the codebook to the base station's antenna array without excessive configuration or storage overhead, using sets of matrices and Kronecker product operations to determine the corresponding precoding matrices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If existing codebooks designed for one-dimensional antenna arrays are directly applied to two-dimensional antenna arrays, then implementation simplicity is maintained, but system performance is degraded due to mismatch with three-dimensional beamforming patterns
Solution Approach 1:
The patent segments the two-dimensional antenna array into two separate one-dimensional arrays (horizontal and vertical dimensions). The codebook is constructed by combining two separate one-dimensional DFT matrices through Kronecker product, where each dimension has its own independent codebook structure. This segmentation allows the system to handle two-dimensional beamforming using compositions of one-dimensional structures, resolving the contradiction by maintaining implementation simplicity while achieving three-dimensional beamforming capability.
Solution Approach 2:
The patent employs a nested structure where the two-dimensional codebook is formed by nesting one-dimensional codebook structures. Specifically, the 2D codebook matrices are constructed by nesting the horizontal DFT matrix and vertical DFT matrix through Kronecker product operation. This nested approach allows the complex two-dimensional codebook to be built from simpler one-dimensional components, maintaining ease of implementation while achieving the required system performance for three-dimensional beamforming.
2Adaptability or versatility
If a single codebook is designed to meet all possible patterns of two-dimensional antenna arrays, then versatility is improved, but codebook size and configuration overhead become excessively large
Solution Approach 1:
The patent achieves universality through a parametric codebook design where the same codebook construction methodology (Kronecker product of two 1D DFT matrices) can be applied to any two-dimensional antenna array configuration. The codebook structure is universal and adaptable to different antenna numbers and arrangements by simply changing the parameters (number of horizontal and vertical antennas), without requiring separate codebooks for each pattern. This resolves the contradiction by providing codebook universality with controlled size through parameterization rather than enumeration of all possible patterns.
Solution Approach 2:
The patent uses parameter changes to adapt the codebook to different two-dimensional antenna array patterns. The codebook construction parameters (dimensions of the two 1D DFT matrices) can be adjusted according to the specific antenna configuration. By changing these parameters, the same codebook structure serves multiple antenna patterns, achieving versatility without proportionally increasing codebook size. The codebook size scales with the antenna configuration parameters rather than with the number of possible patterns.
3Measurement precision
If codebook quantization is increased to improve channel state information accuracy, then measurement precision is improved, but overhead for codebook configuration and storage increases
Solution Approach 1:
The patent segments the channel state information representation into two separate one-dimensional directional information components (horizontal and vertical angles). Instead of using a single large-scale 2D codebook that would require high quantization precision, the system separately quantizes the horizontal and vertical beam directions using two 1D DFT-based codebooks. This segmentation reduces the configuration overhead while maintaining the precision needed to represent three-dimensional channel state information, as each 1D codebook can be more efficiently quantized than a comparable 2D codebook.
Data Source
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AI summary
The present disclosure provides methods and devices for determining a codebook, to configure for a UE a codebook determination parameter in accordance with an antenna array parameter and enable the UE to determine a corresponding codebook in accordance with the codebook determination parameter, thereby to enable the determined codebook to be adapted to an antenna array of a base station without any excessive codebook configuration and storage overhead. The method for determining a codebook includes steps of: configuring for a UE a codebook determination parameter in accordance with an antenna array parameter adopted by a base station; and transmitting the codebook determination parameter to the UE to instruct the UE to determine the codebook in accordance with the codebook determination parameter.