Multibeam Satellite Frequency Reuse With Adaptive Interference Avoidance

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Solution Overview

Problem

Current satellite communications systems face capacity limitations, particularly in serving multiple customers with broadband services, due to inherent design constraints and the need for efficient bandwidth distribution across coverage areas, despite advances in technology.

Innovation Solution

The method involves a multibeam satellite system that utilizes frequency re-use by establishing service beams with common uplink and downlink frequency channels, employing circular polarization combinations to maximize bandwidth efficiency and adaptively re-assigning frequency channels to avoid interference with primary spectrum license holders, while leveraging satellite-based amplifiers for efficient signal transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If frequency re-use is implemented in multibeam satellite system, then bandwidth efficiency is improved, but interference with primary spectrum license holders occurs

Engineering Contradiction:
Improvebandwidth efficiencyVSAvoidinterference
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The system performs preliminary monitoring of out-of-band frequency channels before assigning transmit frequencies to subscriber terminals. By detecting the presence of primary license holder signals in advance, the system can prevent interference by selecting alternative frequency channels, thus resolving the contradiction between efficient frequency re-use and interference avoidance

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements continuous monitoring of frequency channels and provides feedback to the central unit about detected signals. This feedback mechanism enables dynamic frequency channel re-assignment when primary license holder signals are detected, allowing the system to maintain high bandwidth efficiency while avoiding interference through real-time adjustments

Inventive Principle:
Principle #23Feedback

2Object-affected harmful factors

If adaptive frequency re-assignment is implemented, then interference is avoided, but system complexity increases

Engineering Contradiction:
Improveinterference avoidanceVSAvoidsystem complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

Subscriber terminals autonomously monitor out-of-band frequency channels and report detections to the central unit, performing self-service frequency channel assessment. This distributes the monitoring workload across multiple terminals rather than requiring complex centralized monitoring, reducing overall system complexity while maintaining effective interference avoidance

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system dynamically changes frequency channel parameters based on detected signal conditions. By adapting the transmit frequency channel assignment based on monitored spectrum usage, the system achieves interference avoidance through parameter adjustment rather than through complex structural changes, thereby managing system complexity

Inventive Principle:
Principle #35Parameter changes

3Quantity of substance

If multiple subscriber terminals share common frequency channels, then capacity is increased, but interference management becomes more difficult

Engineering Contradiction:
Improvenumber of served customersVSAvoidinterference management complexity
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The system segments the frequency channel monitoring and management functions by having each subscriber terminal independently monitor its assigned frequency channels and report to the central unit. This segmentation of monitoring responsibilities across multiple terminals simplifies the overall interference management architecture while enabling high capacity through shared frequency channels

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP2645597B2Improved spot beam satellite systems
Publication Date: 2024.03.06 VIASAT INC
  • EP2645597B2 patent drawingFigure 1A
  • EP2645597B2 patent drawingFigure 1B
  • EP2645597B2 patent drawingFigure 2A

AI summary

A method is presented for transmitting data in a satellite system having multiple spot beams comprising (1) sending a broadband signal in a forward direction from a gateway terminal to a communications satellite for relay to at least one subscriber terminal, (2) receiving the broadband signal at the communications satellite, wherein the communications satellite comprises a bent pipe repeater having a plurality of satellite-based transmission amplifiers, (3) using one of the plurality of satellite-based transmission amplifiers to amplify the broadband signal and no other broadband signal from the gateway terminal, to produce an amplified broadband signal, (4) sending the amplified broadband signal as one of a plurality of service spot beams to the at least one subscriber terminal, and (5) receiving and retrieving data from the amplified broadband signal at the at least one subscriber terminal.