Satellite Spot Beam Overlap for Pointing Error Tolerance
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Solution Overview
Problem
Satellite communication systems face challenges in achieving high directivity and spectral reuse while maintaining tolerance to pointing errors, especially as the number of cells increases, leading to reduced antenna directivity and potential signal degradation.
Innovation Solution
A system comprising a controller and a multiple beam transceiver with an antenna and antenna feed array, configured to generate and radiate spot beams with overlapping patterns, providing a cell spot beam and adjacent spot beams that overlap symmetrically, thereby increasing pointing error tolerance and spectral reuse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the number of cells is increased to improve spectral reuse, then frequency band reuse increases, but antenna directivity decreases and spot beam width must be narrowed
Solution Approach 1:
The patent divides a single cell into multiple sub-cells, each served by a separate spot beam. This segmentation allows the service area to be covered by more cells (improving spectral reuse) while each spot beam maintains adequate directivity for its smaller sub-cell area. The controller manages multiple spot beams to serve different sub-cells independently.
Solution Approach 2:
The patent introduces a new dimension of cell organization by creating overlapping spot beam patterns that extend beyond traditional hexagonal cell boundaries. Adjacent spot beams overlap symmetrically to provide coverage in distal regions, effectively adding a spatial dimension to cell structure that allows higher spectral reuse while maintaining directivity.
2Reliability
If antenna directivity is increased to improve signal quality, then received signal quality improves, but tolerance for pointing error decreases
Solution Approach 1:
The patent applies different beam characteristics to different spatial regions. Central regions of cells receive high-directivity spot beams for optimal signal quality, while distal regions near cell boundaries receive overlapping spot beams from adjacent cells. This local differentiation allows high directivity where needed while providing pointing error tolerance through redundancy at boundaries.
Solution Approach 2:
The patent pre-configures overlapping spot beam patterns to provide coverage redundancy before pointing errors occur. The symmetric overlap of adjacent spot beams creates a cushion effect where users near cell boundaries are covered by multiple beams, compensating for potential pointing errors in advance.
3Stability of the object's composition
If spot beam width is narrowed to match smaller cell area, then coverage uniformity improves, but power is wasted and signal quality degrades
Solution Approach 1:
The patent merges adjacent spot beams to create overlapping coverage patterns. By combining the coverage areas of multiple spot beams, the system achieves uniform coverage across cell boundaries without requiring each individual beam to be narrowly focused. This merging allows broader beams that are more power-efficient while maintaining coverage uniformity through the combined pattern.
4Stability of the object's composition
If structural modifications or robust control are applied to achieve desired pointing accuracy, then pointing stability improves, but system complexity and cost increase
Solution Approach 1:
The patent creates multiple copies of spot beam patterns with symmetric overlap. Instead of modifying the physical satellite structure or control systems to improve pointing accuracy, the system uses software-controlled beamforming to generate redundant overlapping beams. This copying approach provides pointing error tolerance through redundancy rather than through complex hardware modifications.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enhances pointing error tolerance and spectral reuse, allowing for higher directivity antennas and improved edge-of-cell signal quality without significant complexity increases, compared to conventional hexagonal cell systems.
Implementation Method 1
The antenna feed array is configured to feed the antenna a beamformed downlink antenna feed signal, the beamformed downlink antenna feed signal being configured to radiate from the antenna as a plurality of spot beams
Data Source
Figure 1~2B
Figure 3A~3C
Figure 4~5
AI summary
Systems and methods are disclosed, and one includes receiving a configuration specification data, including a cell floorplan data identifying a plurality of rectangular cells, and indicating a cell width and a cell length of each, in combination with determining, based at least in part on the configuration specification data, a spot beam pattern that provides a plurality of rectangular cell coverage regions, having the cell length and width.