Satellite Messaging Proxy for Secure Off-Grid Low-Bandwidth Routing

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Solution Overview

Problem

Existing wireless networks face limitations in data transmission speed and bandwidth, particularly when user equipment devices transition from terrestrial to non-terrestrial networks, leading to increased latency and security risks, especially in off-grid scenarios.

Innovation Solution

Implementing a non-terrestrial network (NTN) with a constellation of communications satellites and a terrestrial network, utilizing an inter-working function (IWF) server to route messages between user equipment devices, ensuring secure and efficient data transmission by encrypting and compressing data, and using an IWF to act as a proxy, masking the off-grid status of the device.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a UE device transitions from terrestrial network to non-terrestrial network (NTN), then coverage and connectivity are improved, but data transmission speed and bandwidth deteriorate

Engineering Contradiction:
Improvenetwork coverageVSAvoiddata transmission speed
Core Design Contradiction:
Adaptability or versatilityVSSpeed

Solution Approach 1:

The system segments data transmission into two paths: control signaling and small data packets through NTN, and bulk data transmission through terrestrial networks when available. This segmentation allows the device to maintain connectivity via satellite while leveraging terrestrial networks for high-speed data when in range, thus resolving the contradiction between coverage and transmission speed.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary mechanism where the UE device buffers data locally and transmits it through NTN only when necessary, rather than continuously attempting high-bandwidth connections. This intermediary buffering approach allows the system to maintain connectivity adaptability while managing bandwidth constraints of NTN.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If data is transmitted over NTN with limited bandwidth, then connectivity is maintained, but transmission time and latency increase

Engineering Contradiction:
ImproveconnectivityVSAvoidtransmission latency
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system performs preliminary actions by pre-establishing data buffers and encryption keys before NTN transmission is needed. Data is prepared and buffered in advance, and security credentials are pre-configured, so that when NTN transmission becomes necessary, the actual data transfer can occur more efficiently with reduced processing latency.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements periodic transmission opportunities where the UE device attempts to connect to terrestrial networks at regular intervals. When terrestrial connectivity is available, bulk data is transmitted quickly; when unavailable, the system switches to periodic NTN transmission for essential data, thus managing latency through structured periodic attempts rather than continuous high-latency transmission.

Inventive Principle:
Principle #19Periodic action

3Reliability

If encryption keys are stored on the UE device for security, then user privacy is protected, but security risks increase when the device is off-grid

Engineering Contradiction:
Improveuser privacyVSAvoidsecurity risks
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent extracts the critical security function from the UE device by separating key storage and decryption operations. Encryption keys are stored securely in the UE device, but decryption of incoming data and verification of outgoing data occur through the server infrastructure when the device is off-grid. This extraction reduces security risks by preventing the UE device from holding all security credentials locally while maintaining user privacy protection.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The server acts as an intermediary security layer between the UE device and the network. When the device is off-grid, the server handles key management, data encryption, and decryption operations, mediating security functions remotely. This intermediary approach maintains user privacy through encryption while reducing security risks by preventing the UE device from being a single point of failure for key storage.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Ease of operation

If the UE device appears connected to the terrestrial network while off-grid, then communication routing is simplified, but network resource consumption increases

Engineering Contradiction:
Improvecommunication routingVSAvoidnetwork resource consumption
Core Design Contradiction:
Ease of operationVSLoss of energy

Solution Approach 1:

The system creates a virtual copy of the connected state through the server infrastructure. When the UE device is off-grid, the server maintains a virtual representation of the device's connectivity state, allowing messages to be routed as if the device were actually connected. This copying approach simplifies communication routing without requiring the physical UE device to consume network resources, as the virtual copy handles routing decisions server-side.

Inventive Principle:
Principle #26Copying

Data Source

PatentEP4661458A1Communications system with low-bandwidth messaging
Publication Date: 2025.12.10 APPLE INC
  • EP4661458A1 patent drawingFigure 1
  • EP4661458A1 patent drawingFigure 2~3
  • EP4661458A1 patent drawingFigure 4

AI summary

A communications system (38) may include a satellite constellation and a terrestrial network (34) that convey text messages between first and second user equipment (UE) devices (10). The terrestrial network (34) may include a core network (20), an inter-working function (IWF) server (18), and carrier networks (22). The IWF server (18) may distribute keys and the first UE device (10) may transmit provisioning data to the core network (20) while the first UE device is on-grid. When the first UE device goes off-grid, the first UE device may transmit an escrow key (106) to the core network (20) for use in decrypting a device public key (110) from the provisioning data. The core network (20) may transmit the device public key (110) and other information to the IWF (18) for use in routing messages via the NTN. The core network (20) may use the handles to enforce an allow list that filters traffic to the first UE device over the NTN.