Geographic Multipath Routing for Intermittent Ad Hoc Links

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Solution Overview

Problem

Existing routing protocols in dynamic networks with intermittent connectivity, such as flying ad-hoc networks, face challenges in maintaining efficient data transmission due to frequent disconnections and reliance on probabilistic forwarders, which may not be effective in environments like commercial or military aircraft and satellite constellations.

Innovation Solution

A multipath geographic routing protocol that combines opportunistic and source-based forwarding mechanisms, utilizing geolocation and path quality metrics to ensure data packets are transmitted via multiple routes, with a local content store to enhance fault tolerance and reduce network traffic.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If probabilistic forwarding mechanisms are used in dynamic networks, then routing decisions can be made with local knowledge, but the effectiveness deteriorates in environments with intermittent connectivity such as flying ad-hoc networks

Engineering Contradiction:

Improverouting decision makingVSAvoidpacket delivery effectiveness

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent segments the routing process into two distinct phases: interest packet forwarding using geographic routing protocols that exploit location information, and data packet forwarding using source routing protocols that follow pre-determined paths. This segmentation allows each phase to use the most appropriate forwarding mechanism for its specific requirements, resolving the contradiction between ease of operation and reliability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary action by first forwarding interest packets to discover valid routes through the network before actual data transmission occurs. The interest packets explore the network topology and identify reliable paths in advance, so when data packets need to be transmitted, the pre-discovered routes can be used, ensuring reliability even in intermittent connectivity environments.

Inventive Principle:

Principle #10Preliminary action

2Productivity

If unicast routing strategies are used to find the shortest path towards destination, then routing efficiency is improved, but the local optimum problem occurs where intermediate nodes have no neighbor with progress toward destination

Engineering Contradiction:

Improverouting efficiencyVSAvoidpacket delivery success

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent inverts the traditional routing approach by first sending interest packets from the consumer to the producer to discover valid routes, rather than directly forwarding data packets from producer to consumer. This inversion allows the network to adapt to dynamic conditions and identify actual viable paths, avoiding the local optimum problem where unicast routing gets stuck at intermediate nodes without progress toward the destination.

Inventive Principle:

Principle #13The other way round (Inversion)

3Ease of operation

If geographic routing protocols are used to exploit location information, then routing decisions are simplified, but the requirement for accurate destination location information becomes difficult to maintain

Engineering Contradiction:

Improverouting decision simplicityVSAvoiddestination location accuracy

Core Design Contradiction:

Ease of operationVSLoss of information

Solution Approach 1:

The patent performs preliminary location information gathering by forwarding interest packets that carry and update location information along the discovered route. This preliminary action ensures that when data packets need to be forwarded, accurate location information is already available in the routing tables of intermediate nodes, eliminating the need for continuous location updates and maintaining routing simplicity.

Inventive Principle:

Principle #10Preliminary action

4Reliability

If multiple paths are used for packet replication, then delivery probability is increased, but network congestion and resource usage increase

Engineering Contradiction:

Improvepacket delivery probabilityVSAvoidnetwork resource consumption

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent applies partial action by using packet replication selectively rather than universally. Interest packets are replicated to discover multiple paths, but actual data packets are forwarded only along the pre-discovered valid routes. This partial replication approach increases delivery probability by having backup paths available while avoiding excessive resource consumption by not flooding the network with redundant data packets along all possible paths.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentEP4109973B1Multipath geographic routing protocol

Publication Date: 2026.01.28 AIRBUS (SAS)

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AI summary

Systems and methods for routing data packets in mobile ad-hoc networks are described. An interest packet is sent from a data consumer to a data producer via multiple intermediate routing devices. The interest packet is transmitted from one routing device to the next routing device based on the geographic position of the routing devices and the interest message carries information about the links and network nodes it passes when being transmitted. The data packet is transmitted from the data producer to the data consumer the same path in the reverse order. In case one of the intermediate nodes is not available anymore, due to the mobile nature of the ad-hoc network, an opportunistic forwarding strategy is applied.