Phase-Locked Loop Optical Wireless Timing Synchronization

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Solution Overview

Problem

Optical communications systems face challenges such as the need for a line of sight between transmitters and receivers, potential interference from objects, and higher attenuation rates compared to radio frequency signals, which can disrupt wireless optical signal transmission.

Innovation Solution

A platform equipped with an optical transmitter, detector, sensor, and phase-locked loop circuit, where the processor unit coordinates the transmission of optical signals based on timing intervals indicated by the presence of secondary optical signals, ensuring non-overlapping transmissions and adapting to movement-induced changes in the field of view.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If wireless optical communication is used to avoid RF interference, then communication reliability is improved, but signal attenuation increases

Engineering Contradiction:

Improvecommunication reliabilityVSAvoidsignal attenuation

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The system uses periodic beacon signals to establish and maintain communication timing. The beacon transmitter sends periodic beacon optical signals that the receiver detects to synchronize transmission time intervals, enabling reliable communication despite attenuation by establishing precise periodic transmission windows

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The system implements feedback through the beacon signal mechanism where the receiver detects beacon signals and uses this information to determine precise transmission timing. This feedback loop allows the system to adapt to channel conditions and maintain reliable communication by synchronizing transmissions to optimal time intervals

Inventive Principle:

Principle #23Feedback

2Reliability

If line of sight is maintained for optical transmission, then transmission quality is improved, but system adaptability to movement decreases

Engineering Contradiction:

Improvetransmission qualityVSAvoidadaptability to movement

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The system performs preliminary synchronization by detecting beacon signals before actual data transmission. The receiver uses the beacon to establish the time interval and synchronize its transmitter in advance, ensuring that when data transmission occurs, the line of sight condition is maintained even if minor movements occur during the synchronized interval

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system dynamically adjusts transmission timing based on detected beacon signals. By continuously synchronizing to the beacon's time interval, the system adapts to relative movements between transmitter and receiver while maintaining line of sight during the synchronized transmission windows

Inventive Principle:

Principle #15Dynamics

3Reliability

If precise timing control is implemented, then interference reduction is improved, but device complexity increases

Engineering Contradiction:

Improveinterference reductionVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The beacon signal acts as an intermediary that mediates timing synchronization between transmitters and receivers. Instead of complex direct coordination between multiple transmitters, each transmitter independently synchronizes to the common beacon signal, simplifying the overall system while achieving precise timing control and interference reduction

Inventive Principle:

Principle #24Intermediary (Mediator)

4Measurement precision

If beacon signal detection is used for synchronization, then transmission timing precision is improved, but energy consumption increases

Engineering Contradiction:

Improvetransmission timing precisionVSAvoidenergy consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The system uses periodic beacon signals at optimized intervals rather than continuous transmission. The receiver detects these periodic beacons to synchronize timing, achieving precise transmission timing while consuming less energy compared to continuous synchronization signals or more frequent beacon intervals

Inventive Principle:

Principle #19Periodic action

Data Source

PatentUS8478126B1Phase lock loop for optical wireless network

Publication Date: 2013.07.02 THE BOEING CO

AI summary

An apparatus comprises a platform, an optical transmitter associated with the platform, an optical detector associated with the platform, a sensor associated with the platform, a phase-locked loop circuit, and a processor unit associated with the platform. The optical transmitter is configured to transmit first optical signals. The optical detector is configured to receive optical signals. The phase-locked loop circuit is configured to indicate a presence of second optical signals in the optical signals indicating a time interval to transmit information in the first optical signals. The processor unit is electrically connected to the optical detector, the optical transmitter, and the sensor. The processor unit is associated with the phase-locked loop circuit. The processor unit is configured to transmit the information in the first optical signals using the optical transmitter during the time interval.