Optical Wireless Link Masking for Range-Limited Security
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Solution Overview
Problem
Optical wireless communication systems face challenges in securing data transmission outdoors due to the potential for unauthorized capture and demodulation of optical signals beyond intended ranges, especially in scenarios where optical beams are emitted into free space.
Innovation Solution
The system employs an optical data signal accompanied by a masking or jamming signal with a substantially identical wavelength component, controlling the overlap of coverage areas to maintain a signal-to-noise ratio below a threshold, thereby preventing demodulation beyond a certain distance, using transmitters like LEDs or laser diodes, and adjusting beam angles, power, and placement to ensure secure communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If optical beams are emitted into free space for outdoor communication, then communication range and availability are improved, but security is worsened due to potential unauthorized capture beyond intended range
Solution Approach 1:
The patent introduces a masking signal as an intermediary element that occupies the same optical spectrum as the data signal. This masking signal acts as a mediator that prevents unauthorized devices from capturing and demodulating the data signal beyond the intended communication range, while allowing legitimate receivers within the designated area to successfully receive the data.
Solution Approach 2:
The patent employs parameter changes by adjusting the signal-to-noise ratio through the introduction of the masking signal. By controlling the power levels and spectral characteristics of the masking signal, the system maintains the data signal above the detection threshold for legitimate receivers within the intended range while pushing the effective signal level below the detection threshold for unauthorized receivers beyond that range.
2Object-affected harmful factors
If masking signal with identical wavelength is introduced to secure the link, then security is improved, but signal-to-noise ratio deteriorates for legitimate receivers at the boundary
Solution Approach 1:
The patent applies local quality by creating different signal conditions in different spatial regions. Within the intended communication area, the data signal maintains sufficient signal-to-noise ratio for reliable reception. Beyond the intended area, the masking signal dominates the optical spectrum, creating a different local quality that prevents unauthorized reception. The system thus provides different signal characteristics depending on the receiver's location.
Solution Approach 2:
The patent uses partial action by introducing the masking signal only in the spectral region where security is needed, rather than uniformly across all frequencies. The masking signal is strategically positioned to overlap with the data signal only in the unauthorized reception zone, while allowing the data signal to remain strong for legitimate receivers within the intended range.
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
The solution effectively secures optical wireless communication by ensuring only intended devices within a defined range can demodulate the data signal, enhancing security and reducing the risk of eavesdropping.
Implementation Method 1
an optical data signal is emitted together with scrambling/jamming/masking signals
Implementation Method 2
the optical masking signal comprising a wavelength component substantially identical to a wavelength component of the optical data signal
Data Source
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Figure 3
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AI summary
An optical wireless communication device (200) comprising: a data transmitter (201) configured to transmit an optical data signal; a masking transmitter (202) configured to transmit an optical masking signal; wherein the optical masking signal comprising a wavelength component substantially identical to a wavelength component of the optical data signal; the device (200) configured to set a certain distance (d) by controlling at least one of the data transmitter (201) and the masking transmitter (202), such that a coverage area (210) of the optical data signal is overlapped with a coverage area (220) of the optical masking signal to a certain extent at the certain distance (), keeping a signal to noise ratio of the optical data signal below a threshold and complicating a recovery of the optical data signal by another device located at and beyond that certain distance (d).