Optical Timestamp Synchronization for Indoor Wireless Clocks
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Solution Overview
Problem
Existing wireless time synchronization methods, particularly RF-based approaches, face challenges in indoor environments due to degradation of GPS signals, high implementation costs, interference, and bandwidth requirements, leading to synchronization errors and disruptions in machine production lines.
Innovation Solution
Utilizing optical wireless signals, specifically encoded using a color-based optical coding scheme, to transmit timestamps for time synchronization between a master and slave device, enabling synchronization without the limitations of RF-based systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GPS-based time synchronization is used, then time reference accuracy is improved, but indoor deployment becomes impractical due to signal degradation
Solution Approach 1:
The patent introduces an optical wireless communication system as an intermediary between the master node and slave nodes for time synchronization. Instead of relying on GPS signals that cannot penetrate buildings, the system uses optical signals (visible light, infrared, or ultraviolet) transmitted through the indoor environment to carry timing information, thereby enabling accurate time synchronization in indoor deployments where GPS is unavailable
Solution Approach 2:
The patent replaces the radio frequency (RF) based GPS reception system with an optical-based time distribution system. By substituting RF signals with optical signals for time synchronization purposes, the system overcomes the fundamental limitation of GPS signal blockage in indoor environments while maintaining synchronization accuracy
2Stability of the object's composition
If atomic clock solutions are provided in MNO infrastructure, then time reference stability is improved, but implementation cost becomes prohibitively high for indoor industrial deployments
Solution Approach 1:
The patent employs commercially available oscillators and timing components in the master node instead of expensive atomic clocks. The system achieves sufficient time reference stability for industrial applications using these lower-cost components, making the solution economically viable for indoor industrial deployments while maintaining the required synchronization performance
Solution Approach 2:
The patent changes the operational parameters of the timing system by using optical communication with high precision timestamping capabilities. This allows the system to achieve the required time reference stability through careful parameter optimization of conventional components rather than relying on expensive atomic clock hardware
3Ease of operation
If RF-based time synchronization is used, then wireless time distribution is achieved, but synchronization accuracy is degraded due to propagation delay estimation errors and interference
Solution Approach 1:
The patent substitutes RF-based wireless time distribution with optical wireless time distribution. Optical signals provide superior propagation characteristics in indoor environments, with less susceptibility to multipath effects and interference, thereby significantly improving synchronization accuracy while maintaining wireless operation
Solution Approach 2:
The patent implements periodic exchange of synchronization messages (Sync, Delay_Req, Delay_Resp) between master and slave nodes using optical signals. This periodic communication pattern allows for continuous refinement of timing offsets and propagation delay measurements, enhancing synchronization accuracy through repeated measurements and corrections
4Reliability
If time synchronization is performed separately from information transfer using licensed RF spectrum, then timing distribution is achieved, but bandwidth requirements and interference increase
Solution Approach 1:
The patent merges time synchronization communication with data communication by using the same optical wireless channel for both purposes. Timestamps and synchronization messages are transmitted alongside data traffic in the same optical communication link, eliminating the need for separate dedicated bandwidth for timing distribution and reducing overall resource consumption
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
Achieves robust and resource-efficient time synchronization with high accuracy, minimizing interference and cost, suitable for indoor industrial applications.
Implementation Method 1
transmitting, using optical wireless signals, a timestamp representative of a clock time of the master device to the slave device. The timestamp is encoded using a color-based optical coding scheme
Data Source
AI summary
A technique for performing time synchronization between a master device and a slave device is disclosed. A method implementation of the technique is performed by the master device and comprises transmitting, using optical wireless signals, a timestamp representative of a clock time of the master device to the slave device, wherein the timestamp is encoded using a color-based optical coding scheme and is to be used by the slave device to set a clock time of the slave device in accordance with the timestamp to thereby synchronize the clock time of the slave device with the clock time of the master device.