Optical Feeder Link Routing for Satellite Beam Capacity Balance
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Solution Overview
Problem
Satellite communication systems face challenges in achieving high capacity with a limited number of satellite access nodes (SANs) due to issues such as oversubscribed and undersubscribed spot beams, increased feeder link bandwidth needs, and atmospheric attenuation of optical signals, which affect the reliability of optical feeder links.
Innovation Solution
Implementing optical feeder links with flexible routing and diversity techniques, using binary modulated optical signals, RF modulated optical signals, and complex modulation schemes to enhance bandwidth efficiency and reliability, while reducing the number of SANs and mitigating atmospheric interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of spot beams is increased to provide high capacity, then system capacity is improved, but the number of oversubscribed and undersubscribed spot beams increases, reducing reliability
Solution Approach 1:
The patent implements dynamic routing that allows optical signals to be flexibly directed to different spot beams based on real-time subscription conditions. This dynamic adaptation enables the system to balance load across spot beams, preventing oversubscription and undersubscription issues while maintaining high capacity through multiple spot beams.
Solution Approach 2:
The system changes the routing parameters of optical signals dynamically based on spot beam subscription status. By adjusting which optical signals are routed to which spot beams, the system can optimize capacity utilization and maintain reliability even with a large number of spot beams.
2Productivity
If feeder link bandwidth is increased to support high capacity, then system capacity is improved, but bandwidth available for user links is reduced
Solution Approach 1:
The patent replaces traditional radio frequency feeder links with optical feeder links. This substitution provides vastly superior bandwidth for feeder connections, enabling high system capacity without consuming RF spectrum that would be needed for user links. The optical domain offers essentially unlimited bandwidth compared to RF constraints.
3Ease of manufacture
If the number of SANs is reduced to lower costs, then system cost is improved, but the ability to provide high capacity is reduced
Solution Approach 1:
The patent makes each SAN universal by implementing flexible optical routing that allows a single SAN to serve multiple spot beams dynamically. This multi-functionality enables fewer SANs to provide high capacity by adapting their service scope based on demand, eliminating the need for dedicated SANs for each spot beam.
Solution Approach 2:
The system implements dynamic routing that allows SANs to adapt their capacity allocation in real-time. This dynamic capability enables a smaller number of SANs to flexibly meet varying capacity demands across different spot beams, maintaining high system capacity while reducing the total number of SANs required.
4Productivity
If optical feeder links are used to increase bandwidth efficiency, then bandwidth efficiency is improved, but atmospheric attenuation reduces signal reliability
Solution Approach 1:
The patent introduces diversity routing as an intermediary mechanism to mitigate atmospheric attenuation. By providing multiple alternative routing paths for optical signals, the system can switch to alternative paths when atmospheric conditions degrade signal quality, maintaining reliability while preserving the bandwidth efficiency of optical links.
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
Enhances system capacity and reduces costs by optimizing feeder link bandwidth, improving signal reliability through flexible routing and diversity, and enabling efficient use of RF spectrum.
Implementation Method 1
The optical transmitter modulates beam element signals to a composite optical signal. In one embodiment, the modulated composite optical signal is a binary modulated signal.
Implementation Method 2
In another embodiment, the modulated composite optical signal is an RF modulated signal.
Implementation Method 3
In yet another embodiment, the modulated composite optical signal is a signal modulated using a complex modulation scheme.
Implementation Method 4
An optical receiver in the satellite receives the modulated composite optical signal and converts the modulated composite optical signal to a composite signal.
Data Source
AI summary
Broadband satellite communications systems using optical feeder links are disclosed. Various optical modulation schemes are disclosed that can provide improved capacity for fixed spot beam, on board beamforming, and ground-based beamforming broadband satellite systems.