Adaptive Satellite Demodulation for Priority-Based Message Delay

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Solution Overview

Problem

Existing satellite communication systems for Low Earth Orbital (LEO) constellations face challenges in providing real-time service while optimizing for power consumption, memory requirements, and bandwidth, especially when communicating with low-power small terminals in environments with high interference.

Innovation Solution

An adaptive demodulation system that prioritizes on-board demodulation of high-priority messages for short-delay transmission and delegates lower-priority message demodulation to ground stations, utilizing high-gain antenna arrays efficiently to communicate with small terminals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If on-board demodulation is performed for all messages, then real-time service is ensured, but on-board processing power and power consumption increase significantly

Engineering Contradiction:
Improvemessage delivery delayVSAvoidon-board processing power
Core Design Contradiction:
Loss of timeVSPower

Solution Approach 1:

The patent segments messages into high-priority and low-priority categories. High-priority messages undergo on-board demodulation for real-time delivery, while low-priority messages are stored as raw samples and processed later on the ground. This segmentation resolves the contradiction by applying different processing strategies to different message types, ensuring real-time service for critical messages without overloading on-board processing power.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements dynamic adaptive demodulation where the satellite adjusts its processing behavior based on buffer status, power availability, and message priority. The demodulation threshold is dynamically adjusted to optimize the balance between real-time service and power consumption, allowing the system to adapt to varying operational conditions rather than using a fixed processing strategy.

Inventive Principle:
Principle #15Dynamics

2Loss of time

If on-board memory is increased to store all received samples, then delay-tolerant service is improved, but satellite mass and cost increase

Engineering Contradiction:
Improvemessage storage capabilityVSAvoidsatellite mass
Core Design Contradiction:
Loss of timeVSWeight of moving object

Solution Approach 1:

The patent segments stored data into processed messages and raw samples. Only essential high-priority messages are retained on-board after demodulation, while low-priority messages are discarded after ground processing. This reduces the memory burden and satellite mass while maintaining delay-tolerant service capability for non-critical communications.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent treats raw signal samples as temporary, disposable data that can be discarded after ground processing. Instead of permanently storing all samples, the system processes them transiently on the ground and discards them after extraction, reducing long-term storage requirements and satellite mass.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Productivity

If high-gain antenna arrays are used to communicate with small terminals, then communication efficiency is improved, but on-board processing complexity and power consumption increase

Engineering Contradiction:
Improvecommunication efficiencyVSAvoidon-board processing complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent segments the communication task into two phases: on-board signal acquisition using high-gain antenna arrays, and offline demodulation processing on the ground. This segmentation allows the satellite to use sophisticated antenna arrays for efficient signal capture without burdening on-board processing resources, resolving the contradiction between communication efficiency and processing complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces ground stations as intermediaries that perform the complex demodulation processing. The satellite's high-gain antenna arrays efficiently capture signals from small terminals, then transfer raw samples to ground stations for sophisticated processing. This intermediary approach enables the use of advanced antenna technology without increasing on-board processing complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Reliability

If the number of ground stations is increased to ensure real-time service, then message delivery reliability is improved, but system cost and complexity increase

Engineering Contradiction:
Improvereal-time service availabilityVSAvoidground segment complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments service requirements into real-time and delay-tolerant categories. Only high-priority messages requiring real-time delivery are routed through multiple ground stations, while low-priority messages can be handled by fewer ground stations with longer processing times. This segmentation reduces the overall number of ground stations needed while maintaining real-time service reliability for critical communications.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different service quality levels to different messages based on priority. High-priority messages receive premium real-time processing with multiple ground station involvement, while low-priority messages accept delayed processing with fewer ground stations. This local quality differentiation reduces overall system complexity while ensuring real-time reliability where needed.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP4068651B1Method for adaptive demodulation and satellite implementing such a method
Publication Date: 2025.08.13 EUTELSAT
  • EP4068651B1 patent drawingFigure 1A~1B
  • EP4068651B1 patent drawingFigure 2
  • EP4068651B1 patent drawingFigure 3

AI summary

An aspect of the invention concerns a method for processing a signal received from at least one terminal, said method being performed on-board by a satellite equipped with an antenna array comprising a plurality of element; said satellite comprising a memory and means for processing data contained in said memory; said method comprising: a step (2R1) of receiving, a low bit rate signal from at least one terminal; a step (2D1) of demodulating the low bit rate signal received from said terminal; a step (2E1) of extracting information from the demodulated low bit rate signal, said information containing data concerning a signal, said main signal, to be sent by said terminal; a step (2R2) of receiving, the main signal containing at least one message from at least one terminal; a step (2S1) of sampling the main signal received by each element of the antenna array; a step (2S2) of storing the sampled main signal in the satellite memory; when the satellite is in the range of a ground station, a step (2T1) of transmitting the stored samples to the ground station for further processing along with information extracted from the demodulated low bit rate signal and corresponding to said stored sample.