LED Optical Modulation for Noise-Resistant Authentication
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Solution Overview
Problem
Existing wireless network security methods, such as audible conveyance of shared secrets, face interference issues in noisy indoor environments, making it difficult to establish secure communication channels between devices without line of sight.
Innovation Solution
The use of light emitting diodes (LEDs) to modulate and convey network-associated secrets optically, which can be sensed by camera-equipped devices, providing a noise-resistant and line-of-sight-dependent method for secure authentication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If audible tones are used to convey device secrets, then authentication can be performed without visual UI interaction, but noise interference from indoor environments prevents reliable communication
Solution Approach 1:
The patent replaces the acoustic signal transmission system with an optical system. Instead of using audible tones that are susceptible to noise interference, the invention uses light from LED displays to convey authentication secrets. The optical system is detected by the camera sensor of the enrolling device, eliminating the reliability issues associated with acoustic transmission in noisy indoor environments.
2Reliability
If optical modulation of LED lighting is used to convey secrets, then noise resistance is significantly improved, but data transmission rate must exceed camera frame rate to achieve high-speed communication
Solution Approach 1:
The patent employs periodic modulation of the LED light intensity at frequencies synchronized with the camera's frame rate. By modulating the light in periodic on-off patterns that correspond to the camera's capture intervals, the system can reliably encode multiple bits of data per frame cycle. This periodic action allows the optical communication to achieve data rates exceeding the basic frame rate while maintaining noise resistance.
3Reliability
If devices are placed in close proximity for audible secret sharing, then signal-to-noise ratio improves, but line-of-sight requirement limits spatial flexibility
Solution Approach 1:
The patent makes the optical communication system universally adaptable to various spatial arrangements by using the device's existing camera and display components. The system can function whether devices are close or far apart, at different angles, or with varying line-of-sight conditions, as long as the optical signal can be detected. This multi-functional approach to spatial adaptability eliminates the need for close proximity placement while maintaining reliable communication.
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 reliable and high-speed optical data communication, allowing devices to establish secure connections even in noisy environments and maintaining security within a controlled space, with data rates exceeding camera frame rates.
Implementation Method 1
light emitting diodes (LEDs) to modulate and convey network-associated secrets optically
Implementation Method 2
the cameras of network-connected smartphones are used to sense the optical modulation
Data Source
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AI summary
Digital data is optically broadcast through an environment by controllably switching the brightness or chrominance of LED solid state lamps, or of other illumination sources (e.g., television screens and backlit computer displays). This optical data channel is useful to convey cryptographic key data by which devices within the environment can authenticate themselves to a secure network. In some embodiments, the optical modulation is sensed by the camera of a smartphone. The row data output by the smartphone's camera sensor is processed to extract the modulated data signal. In some monochrome embodiments, data communication speeds far in excess of the camera's frame rate (e.g., 30/second), or even the camera's row rate (e.g., 14,400/second) are achieved. Still greater rates can be achieved by conveying different data in different chrominance channels. A great number of other features and arrangements are also detailed.