Scheduled Forwarding Tables for Orbital Line-of-Sight Occlusions
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Solution Overview
Problem
Existing IP service systems face challenges with long round trip times and interruptions to line of sight connectivity due to orbital mechanics, leading to unstable network connectivity and frequent routing reconvergence in space-ground networks.
Innovation Solution
A Lunar and Interplanetary communication system utilizing a Software-Defined Networking (SDN) system with a dynamic forwarding table that schedules packet paths based on orbital locations and line of sight occlusions, incorporating a centralized SDN system to pre-calculate reachability calendars and generate time-based rolling forwarding tables to minimize occlusion times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional IP service systems are used in space-ground networks, then basic communication functionality is provided, but line of sight connectivity is frequently interrupted due to orbital mechanics causing unstable network connectivity
Solution Approach 1:
The system performs preliminary actions by pre-calculating reachability calendars that predict future line of sight occlusions based on orbital mechanics. The SDN controller proactively determines when connectivity will be disrupted and schedules packet forwarding paths in advance to avoid these occlusions, rather than reacting to disruptions after they occur. This preliminary planning ensures stable network connectivity despite the inherently unstable line of sight conditions in space-ground networks.
2Reliability
If dynamic routing adjustments are made to handle occlusions, then connectivity is maintained, but frequent routing reconvergence increases system complexity and processing overhead
Solution Approach 1:
The SDN controller acts as an intermediary that centralizes the complexity of handling orbital mechanics and line of sight occlusions. Instead of individual network devices independently detecting and reacting to connectivity disruptions (which would cause frequent routing reconvergence), the SDN controller receives orbital information, calculates reachability calendars, and distributes scheduled forwarding paths to network devices. This intermediary approach maintains communication reliability while reducing system complexity at the network device level.
3Reliability
If store-and-forward techniques are used to handle occlusions, then packet delivery is ensured, but resource usage increases and communication efficiency decreases
Solution Approach 1:
The system applies preliminary action by pre-scheduling packet forwarding paths based on predicted line of sight availability. The SDN controller determines optimal forwarding paths before occlusions occur, allowing packets to be transmitted efficiently during periods when direct connectivity is available. This approach reduces the need for store-and-forward techniques, thereby decreasing network resource consumption and improving communication efficiency while maintaining packet delivery reliability.
Data Source
AI summary
Disclosed herein are systems, methods, and computer-readable media for network communication within a Lunar and Interplanetary communication system. In one aspect, a length of time of line of sight occlusion associated with an object is determined based on a position of the object within its orbit. A dynamic forwarding table is generated that schedules packet paths among nodes within the network based on the length of time of the line of sight occlusion. A packet path for a packet is determined based on the dynamic forwarding table, where the packet path is based on minimizing the length of time of the line of sight occlusion associated with the object.