Deep-Learning Optical Communication for Single-LED C-OOK and OFDM
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Solution Overview
Problem
Existing visible light communication technologies face challenges in transmitting high-speed and low-speed data simultaneously, and existing digital optical signal transmission technologies are limited in multiplexing different types of information.
Innovation Solution
A hybrid waveform combining Camera On-Off Keying (C-OOK) and Orthogonal Frequency Division Multiplexing (OFDM) modulation schemes, integrated with a code-division multiple access (CDMA) system, utilizes deep learning to accurately decode optical signals, enabling simultaneous transmission and reception of high-speed and low-speed data using a single LED.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If M-FSK scheme is used for visible light communication, then communication function is added to LED light, but difficulty in transmitting high-speed data occurs
Solution Approach 1:
The patent segments the data transmission into two distinct channels: OOK modulation for low-speed data and OFDM modulation for high-speed data. This segmentation allows each channel to be optimized for its specific speed requirement, resolving the contradiction between adding communication function and achieving high-speed transmission.
Solution Approach 2:
The patent merges OOK modulated signals and OFDM modulated signals into a single optical waveform that can be transmitted simultaneously through one LED. This combining enables the system to transmit both low-speed and high-speed data over the same physical channel, achieving high data transmission speed while maintaining communication versatility.
2Adaptability or versatility
If FSK modulation is used, then information can be transmitted, but limitation of FSK-modulating only the same information occurs
Solution Approach 1:
The patent segments the information transmission into different types: low-speed data transmitted via OOK modulation and high-speed data transmitted via OFDM modulation. This segmentation enables the system to handle different information types with appropriate modulation schemes, enhancing adaptability without excessive complexity.
Solution Approach 2:
The patent creates a universal modulation system where a single LED can transmit multiple types of information (low-speed and high-speed data) simultaneously using different modulation techniques. This multi-functionality allows the system to adapt to various information transmission requirements without requiring separate dedicated channels.
3Productivity
If hybrid waveform with C-OOK and OFDM is used, then simultaneous transmission of high-speed and low-speed data is enabled, but decoding accuracy requirement increases
Solution Approach 1:
The patent incorporates preamble sequences in the OFDM modulated signals as a preliminary action to enable accurate signal detection and synchronization. The preambles allow the receiver to initially lock onto the signal structure before decoding the actual data, thereby maintaining high decoding accuracy even with the complex hybrid waveform containing both C-OOK and OFDM signals.
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 system allows for accurate decoding of both C-OOK and OFDM signals, improving data throughput and enabling communication with multiple users at a lower cost compared to conventional systems.
Implementation Method 1
a single LED
Implementation Method 2
Visible light communication (VLC) technology, which is a wireless communication technology that adds a communication function to wavelengths of visible light emitted from the LED lamp
Implementation Method 3
obtaining an image of an optical signal from a light source of an optical communication transmission device using a high-resolution camera
Data Source
AI summary
An optical communication method using deep learning in a code-division multiple access (CDMA) scheme may include obtaining an image of an optical signal from a light source and applying a first model trained to identify a location of the light source to detect the light source in the image. The method may also include detecting a preamble of an on-off keying (OOK) modulated signal from a pulse signal generated based on the identified light source using a second model trained to detect preambles in received signals, to decode the OOK modulated signal for a first user device by applying a first pseudo-random noise (PN) code. The method may further include determining a start position of an orthogonal frequency division multiplexing (OFDM) frame in an OFDM modulated signal from the pulse signal, to decode the OFDM modulated signal by applying a first Walsh code.