Optical Wireless Transmitter Adaptation for Nonlinear Channel Distortion

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Solution Overview

Problem

Optical wireless transmitters face challenges in achieving both high data rates and long range due to nonlinear distortion from optical emitters like LEDs and lasers, which are limited by bandwidth and signal power, necessitating a compromise in control levels.

Innovation Solution

Adaptive adjustment of the operating point and electronic signal source of optical wireless devices to compensate for nonlinear channel distortion by changing the control level, modulation, and gain to optimize data rate and range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the signal amplitude at the transmitter is reduced to reduce nonlinear distortion, then the data rate is improved, but the range or coverage of the optical wireless data connection is reduced

Engineering Contradiction:

Improvedata rateVSAvoidrange

Core Design Contradiction:

ProductivityVSLength of moving object

Solution Approach 1:

The patent applies dynamics by making the transmitter operating point adjustable and adaptive. The system dynamically switches between different operating points (e.g., first and second operating points with different signal amplitudes) based on channel conditions, allowing optimization of either data rate or range depending on the transmission scenario. This resolves the contradiction by enabling the system to adapt rather than being fixed at a single compromise point.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the operating parameters of the optical transmitter by switching between multiple predefined operating points, each with different signal amplitude characteristics. This allows the system to select parameters that optimize for either high data rate (lower amplitude) or long range (higher amplitude) based on the specific communication needs and channel conditions.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If a higher symbol rate is used to increase data rate, then the bandwidth requirement increases, but the optical emitter bandwidth is limited

Engineering Contradiction:

Improvedata rateVSAvoidbandwidth

Core Design Contradiction:

ProductivityVSSpeed

Solution Approach 1:

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

Enables consistent high data rates and extended range by dynamically adapting to channel conditions, reducing nonlinear distortions and optimizing signal power for varying distances.

Implementation Method 1

an optical signal source configured to convert the data signal into the optical wireless signal and transmit it

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentEP4057525B1Optical wireless device for transmitting a wireless optical signal

Publication Date: 2025.08.06 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV

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AI summary

An optical wireless device configured to transmit an optical wireless signal over an optical wireless channel comprises the following: an electronic signal source configured to provide a data signal and an optical signal source configured to convert the data signal into the optical wireless signal and transmit it. The optical wireless device is configured to receive channel information that includes information associated with a nonlinear channel distortion of the optical wireless channel and to adjust the output of the optical signal source by changing an operating state of the electronic signal source to match the nonlinear channel distortion and/or by changing an operating point of the optical signal source to match the nonlinear channel distortion.