Coherent Optical Intersatellite Links for Low-Hop Express Mesh Routing
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Solution Overview
Problem
Existing satellite networking technologies suffer from excessive latency and power consumption due to zigzag routing paths and numerous hops in mesh-grid topologies, leading to inefficient use of modems and increased network load.
Innovation Solution
Implementing an Express-Mesh topology with coherent optical modems that directly connect sources and destinations in a straight line of sight, reducing the number of hops and streamlining physical paths, while using coherent optical modems with programmable modulation formats to adapt to link reach and capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If legacy mesh-grid topology routing by closest proximity is used, then satellite connectivity coverage is achieved, but latency increases due to excessive hops and zigzag paths
Solution Approach 1:
The patent implements dynamic topology adaptation where satellites switch between mesh-grid and express-mesh topologies based on real-time traffic demands and orbital positions. The routing protocol dynamically selects optimal paths by considering both connectivity requirements and latency optimization, allowing the network to transition between rigid mesh routing and flexible express routing depending on current conditions.
Solution Approach 2:
The patent segments the satellite network into two distinct routing modes: mesh-grid topology for general connectivity and express-mesh topology for latency-sensitive traffic. This segmentation allows different types of traffic to be routed through different topological structures, optimizing both coverage and latency performance simultaneously.
2Reliability
If legacy mesh-grid topology with multiple hops is used, then network coverage is maintained, but power consumption increases due to more actively involved modems
Solution Approach 1:
The system dynamically adjusts the number of active modems based on traffic demands. Satellites activate additional modems only when express-mesh routing is required for latency-sensitive traffic, while maintaining mesh-grid routing for general traffic to conserve power. This dynamic modem activation reduces overall power consumption while maintaining network coverage.
Solution Approach 2:
Instead of keeping all modems active continuously, the patent employs partial action by activating modems only when needed for express routing. This selective modem activation reduces the total number of actively involved modems and their associated power consumption while maintaining sufficient network coverage through the mesh-grid topology for non-critical traffic.
3Loss of time
If express-mesh topology with direct connections is implemented, then latency is reduced by minimizing hops, but network complexity increases due to traffic demand-based topology selection
Solution Approach 1:
The routing protocol implements self-service by automatically selecting between mesh-grid and express-mesh topologies based on predefined criteria such as traffic demand and orbital geometry. The system autonomously determines optimal routing paths without requiring manual configuration or complex centralized control, reducing operational complexity while maintaining low latency performance.
Solution Approach 2:
The patent changes topological parameters dynamically based on traffic demand and satellite positions. The routing protocol adjusts connectivity parameters to switch between mesh-grid and express-mesh modes, optimizing latency for sensitive traffic while maintaining simplicity for general traffic. This parameter-based adaptation manages complexity through standardized transition rules.
4Productivity
If coherent optical modems with programmable modulation formats are used, then link capacity and reach are optimized, but device complexity increases
Solution Approach 1:
The patent employs parameter changes by configuring modulation formats and transmission parameters based on link distance and traffic requirements. The coherent optical modems automatically adjust their operating parameters to optimize capacity and reach for each specific link, reducing the need for manual configuration and managing device complexity through automated parameter adaptation.
Solution Approach 2:
The coherent optical modems are designed with multi-functionality to handle various modulation formats and link conditions through a single unified device. This universality reduces device complexity by eliminating the need for multiple specialized modems while maintaining optimized performance across different link capacities and distances.
Data Source
AI summary
A satellite system is disclosed including a plurality of optical modems with digital signal processing circuitry supporting programmable modulation formats. A processor assigns subsets of the modems to establish inter-satellite links and ground links, and selects modulation formats based on link performance requirements such as connection distance and bandwidth demand. The system enables an express mesh inter-satellite topology, providing direct optical links among satellites positioned according to ground traffic sources and sinks, thereby reducing the number of hops, network latency, and power consumption. The processor may further adjust forward error correction coding, transmitted optical power, and wavelength allocation to optimize link performance. Satellites may dynamically reassign modems, power down unused modems, and operate in Low Earth Orbit (LEO) or Medium Earth Orbit (MEO). The disclosed methods and architectures allow efficient, low-latency satellite networking through coherent optical communications adaptable to evolving traffic patterns and environmental conditions.