Multibeam Satellite Receiver for Nonlinear Co-Channel Interference

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Solution Overview

Problem

Multibeam satellite systems with aggressive frequency reuse experience severe nonlinear co-channel interference (CCI) due to high-power amplifier saturation, degrading spectral and power efficiency without proper distortion compensation.

Innovation Solution

A low-complexity receiver employing a divide-and-conquer (DAC) strategy decomposes interfering sources into smaller sets based on intensity, using a Volterra series for nonlinear distortion modeling and successive interference cancellation (SIC) with soft-in soft-out (SISO) information exchange.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If aggressive frequency reuse is employed in multibeam satellite systems, then spectral efficiency is improved, but co-channel interference severity increases

Engineering Contradiction:

Improvespectral efficiencyVSAvoidco-channel interference

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The receiver segments the composite signal into multiple individual beam signals using separate correlation processors, each dedicated to detecting a specific beam signal. This segmentation allows independent processing and interference mitigation for each beam, enabling aggressive frequency reuse while managing co-channel interference effectively.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary signal processing chain between the received composite signal and the final detection output. This includes correlation processors that compute correlation values between the composite signal and local replica signals, followed by decision devices that interpret these correlation values. This intermediary processing structure enables sophisticated interference mitigation while maintaining spectral efficiency.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Use of energy by moving object

If HPAs are operated close to saturation to achieve high power efficiency, then power efficiency is improved, but nonlinear distortion increases

Engineering Contradiction:

Improvepower efficiencyVSAvoidnonlinear distortion

Core Design Contradiction:

Use of energy by moving objectVSObject-generated harmful factors

Solution Approach 1:

The patent replaces traditional linear signal processing methods with a nonlinear correlation-based detection approach. The correlation processors inherently handle nonlinear distortions by comparing the received signal with local replica signals, effectively compensating for HPA nonlinearities without requiring linear HPA operation, thus maintaining power efficiency while reducing distortion impact.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The decision devices provide feedback by making detection decisions based on correlation values, which are then used to refine the signal interpretation. This feedback mechanism allows the system to adapt to nonlinear distortions and make accurate decisions even when HPAs operate close to saturation, maintaining both power efficiency and signal quality.

Inventive Principle:

Principle #23Feedback

3Device complexity

If prior art linear distortion assumptions are used, then device complexity is reduced, but performance degrades under nonlinear conditions

Engineering Contradiction:

Improvereceiver complexityVSAvoidsystem performance

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The receiver is segmented into multiple independent correlation processors, each handling a specific beam signal. This segmentation allows the system to implement sophisticated nonlinear distortion compensation without requiring a single complex processing unit, thereby maintaining manageable device complexity while improving reliability under nonlinear conditions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent changes the fundamental processing parameter from linear correlation (prior art) to nonlinear correlation that accounts for HPA saturation effects. By modifying the correlation process to inherently handle nonlinearities, the system achieves improved performance without proportionally increasing device complexity, as the same correlation structure is used but with enhanced processing capabilities.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12526073B2Iterative mitigation of nonlinear co-channel interference in high-efficiency multibeam satellite systems

Publication Date: 2026.01.13 HUGHES NETWORK SYST

AI summary

A communications apparatus to resolve a composite signal including an induced nonlinear distortion, a desired signal and interferer signals, wherein the desired signal includes desired symbols and the interferer signals include interferer symbols using N frameworks, each framework including a detector to partition the desired symbols and the interferer symbols based on an interference severity into a dominant group and a non-dominant group, and to generate A Posteriori Probabilities (APP) of the desired symbols and the interferer symbols, wherein the detector of each of the N frameworks generates the APP based on a feedback of the APP from each of the N frameworks, and the detector reduces the induced nonlinear distortion of the desired signal using a nonlinear mathematical model such as Volterra series.