Optical Wireless Receiver Gain Control for Saturation Avoidance

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Solution Overview

Problem

Existing optical wireless communication systems face issues with receiver saturation due to varying distances between devices, leading to sub-optimal reception performance, especially in industrial environments where conventional gain control methods based solely on received signal strength fail to maximize data rate.

Innovation Solution

An advanced automatic gain control scheme that adjusts gain settings based on both received signal strength and data rate changes, using a power detector and digital baseband module to optimize performance in saturation regions by reducing gain when signal strength exceeds a threshold and data rate decreases.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional gain control based solely on received signal strength is used, then the system is simple to operate, but receiver saturation occurs leading to sub-optimal data rate performance

Engineering Contradiction:
Improvedata rateVSAvoidgain control complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent implements a feedback mechanism where the measured data rate is fed back to the gain controller, which then adjusts the receiver gain accordingly. This closed-loop control ensures that the receiver operates at optimal gain settings by continuously monitoring performance metrics and making real-time adjustments, thereby maximizing data rate while avoiding saturation.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The gain control system transitions from a static, signal-strength-only approach to a dynamic control mechanism that adapts based on both signal strength and measured data rate. This dynamic adjustment allows the system to respond to changing channel conditions and optimize performance in real-time, resolving the contradiction between simplicity and performance.

Inventive Principle:
Principle #15Dynamics

2Reliability

If receiver gain is increased to capture weak signals, then signal reception improves, but saturation occurs in high signal strength conditions reducing data rate

Engineering Contradiction:
Improvesignal reception reliabilityVSAvoiddata rate
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The system employs dynamic gain control that adjusts the receiver gain based on real-time measurements of both signal strength and data rate. When signal strength is high, the system reduces gain to prevent saturation and maintain optimal data rate performance. When signal strength is low, gain is increased to ensure reliable reception, thus dynamically balancing reliability and productivity.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the operating parameters of the receiver by adjusting gain settings based on multiple measured parameters (signal strength and data rate) rather than a single parameter. This multi-parameter-based parameter adjustment allows the system to navigate the trade-off between reliable signal reception and avoiding saturation, optimizing data rate across varying channel conditions.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If gain is reduced to avoid saturation, then data rate performance improves in high signal conditions, but signal reception becomes unreliable in low signal conditions

Engineering Contradiction:
Improvedata rateVSAvoidsignal reception reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The dynamic gain control system continuously monitors both signal strength and data rate to determine the appropriate gain setting. In high signal conditions, it reduces gain to prevent saturation and maximize data rate. In low signal conditions, it increases gain to ensure reliable reception. This dynamic adaptation resolves the contradiction by making gain adjustments context-dependent rather than fixed.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system adjusts the receiver gain parameter based on changes in operating conditions, specifically transitioning between high-gain and low-gain states depending on the measured signal strength and data rate performance. This parameter adaptation ensures that the receiver maintains optimal performance across the full range of signal conditions, balancing reliability and productivity.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach allows for maximizing data rate and avoiding receiver saturation by dynamically adjusting gain, ensuring optimal operation even in high signal strength conditions, thereby improving system performance and throughput.

Implementation Method 1

an optical receiver configured to receive a signal

Methodology Applied
Scientific EffectPhotoelectric Effect: Photoelectric Effect

Implementation Method 2

a power detector configured to detect a signal strength of the received signal

Methodology Applied
Scientific EffectPhotoelectric Effect: Photoelectric Effect

Data Source

PatentEP4315659B1Method and apparatus for avoiding saturation in optical wireless point-to-point systems
Publication Date: 2025.07.16 SIGNIFY HOLDING BV
  • EP4315659B1 patent drawingFigure 1~2
  • EP4315659B1 patent drawingFigure 3~4
  • EP4315659B1 patent drawingFigure 5

AI summary

An apparatus (200) in a point-to-point optical wireless communication system, the apparatus comprises an optical receiver (210) configured to receive a signal; a power detector (202) configured to detect a signal strength of the received signal; a digital baseband module (203) configured to demodulate the received signal and measure a data rate of the received signal; and a controller (204) configured to derive a gain setting adjustment according to a change of the measured data rate when the detected signal strength is above a certain threshold.