Precoder Codebook Filtering by Far-Field Radiation Patterns
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Solution Overview
Problem
Existing reciprocity-assisted codebook-based beamforming algorithms select beams based on received power without considering interference, leading to excessive sidelobes that degrade overall cell throughput due to interference with neighboring cells.
Innovation Solution
Modify the precoder codebook by excluding beamformers with radiation patterns that have sidelobes exceeding a certain threshold or causing excessive interference, using far-field analysis to determine suitable beams for downlink transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If beamformers are selected based on received power maximization without interference constraints, then the signal strength for the intended receiver is improved, but excessive sidelobes are generated that cause interference to neighboring cells and degrade overall cell throughput
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing radiation pattern information and sidelobe levels for all candidate beamformers in an offline manner before actual beam selection. This pre-computed information is then used during online beam selection to quickly identify and exclude beamformers with excessive sidelobes, enabling interference-aware beam selection without real-time complexity
Solution Approach 2:
The patent extracts and removes beamformers with excessive sidelobes from the codebook based on pre-calculated radiation pattern information. By identifying beamformers whose sidelobes exceed a threshold and excluding them from the selectable beamformer set, the system eliminates the source of interference to neighboring cells while maintaining beamformers that provide good signal strength with acceptable sidelobe levels
2Object-affected harmful factors
If a comprehensive interference constraint is applied during beam selection, then interference to neighboring cells is reduced, but the complexity of the beam selection algorithm increases
Solution Approach 1:
The patent reduces online algorithmic complexity by performing all interference-related calculations offline. Radiation patterns, sidelobe levels, and beamformer evaluations are pre-computed and stored in tables before runtime. During actual beam selection, the system simply compares pre-computed values against thresholds and selects from pre-filtered candidates, transforming a complex real-time optimization problem into a simple lookup and comparison operation
Solution Approach 2:
The patent uses pre-computed radiation pattern data and beamformer evaluation results as disposable information structures that are calculated once offline and then reused multiple times during online operations. This approach replaces complex real-time calculations with simple references to pre-computed data, significantly reducing the computational burden during actual beam selection while maintaining comprehensive interference constraints
Data Source
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AI summary
A method, system and apparatus for downlink precoder codebook modification. The precoder codebook having a plurality of beamformers. The method including determining a radiation pattern for each of the plurality of beamformers, determining whether the determined radiation pattern for each of the plurality of beamformers satisfies a design criterion and excluding from the codebook the beamformers that have determined radiation patterns that meet the design criterion. The system and apparatus having one or more processors and memory storing instructions that, when executed by the one or more processors, cause the system and apparatus to perform the method.