scholarly journals Design and Implementation of a Monitoring System using Optical Camera Communication for a Smart Factory

2019 ◽  
Vol 9 (23) ◽  
pp. 5103 ◽  
Author(s):  
Nguyen Cong Hoan ◽  
Nguyen Van Hoa ◽  
Vu Thanh Luan ◽  
Yeong Min Jang
Keyword(s):  
Visible Light ◽  
Monitoring System ◽  
Low Cost ◽  
Visible Light Communication ◽  
Modulation Scheme ◽  
Light Emitting ◽  
Hospital Patients ◽  
Effects On Children ◽  
The Time Domain ◽  
Optical Camera Communication

Wireless technologies that are based on radio frequencies are currently widely used, with numerous applications around the world. However, they pose some disadvantages to human health. High frequencies can have potentially harmful effects on children, hospital patients, and even healthy people if the signal power exceeds the permitted standard. Conversely, the use of visible light for data transmission is a trend that presents new options, including optical wireless communication, optical camera communication, and visible light communication. This paper proposes a modulation scheme based on on-off keying in the time domain, which is applied to a monitoring system using optical camera communication. This scheme has various compatible supports for the global-shutter camera and rolling-shutter camera, which are popular commercially available cameras. Furthermore, this scheme facilitates a low-cost monitoring system. By using small light-emitting diodes (LEDs) and controlling the exposure time in a single camera, the camera, as a receiver, can simultaneously detect signals from up to 10 sensor devices in different positions at a maximum distance of up to 50 m, with a low error rate.

scholarly journals Design and Implementation of a Multi-Colour Visible Light Communication System Based on a Light-to-Frequency Receiver

Photonics ◽  
2019 ◽  
Vol 6 (2) ◽  
pp. 42 ◽  
Author(s):  
Roger Alexander Martínez-Ciro ◽  
Francisco Eugenio López-Giraldo ◽  
Andrés Felipe Betancur-Perez ◽  
Jose Martín Luna-Rivera
Keyword(s):  
Visible Light ◽  
Signal To Noise Ratio ◽  
Low Cost ◽  
Visible Light Communication ◽  
Pso Algorithm ◽  
Low Complexity ◽  
Symbol Error Rate ◽  
Modulation Scheme ◽  
Analog To Digital ◽  
Constellation Design

Colour-shift keying (CSK) is a visible light communication (VLC) modulation scheme used in the existing IEEE 802.15.7 standard. In CSK, information is transmitted by changing the light intensities of the RGB LEDs. In this work, a low-complexity VLC system is proposed using CSK modulation and a novel receiver based on a light-to-frequency (LTF) converter. At the receiver, CSK symbols are interpreted and decoded in terms of frequencies, which are processed by a counter module of a generic microcontroller, thus avoiding the use of analog-to-digital converters (ADCs), which results in a low-cost VLC system. The main contributions of this work are summarized in the following key points: (1) A low-complexity receiver for CSK modulation is introduced; (2) A particle swarm optimization (PSO) algorithm for CSK constellation design is suggested considering the restrictions of the LTF based receiver; (3) Experimental and theoretical validation is perfomed for the proposed multi-colour VLC system. The results show that this system can provide a transmission speed of 100 kbps using a 4-CSK-LTF constellation for a symbol error rate (SER) of 10 − 4 and a signal to noise ratio (SNR) around 35 dB. These results suggest that the analysed system could find applications on those scenarios where low transmission speeds and ease of deployment are the goals.

scholarly journals Design and Implementation of 2D MIMO-Based Optical Camera Communication Using a Light-Emitting Diode Array for Long-Range Monitoring System

Sensors ◽  
2021 ◽  
Vol 21 (9) ◽  
pp. 3023
Author(s):  
Huy Nguyen ◽  
Vanhoa Nguyen ◽  
Conghoan Nguyen ◽  
Van Bui ◽  
Yeongmin Jang
Keyword(s):  
Wireless Communication ◽  
Visible Light ◽  
Channel Coding ◽  
Communication Systems ◽  
Light Emitting Diode ◽  
Focal Length ◽  
Modulation Scheme ◽  
Light Emitting ◽  
Led Array ◽  
Optical Camera Communication

Wireless technologies that use radio frequency (RF) waveforms are common in wireless communication systems, such as the mobile communication, satellite system, and Internet of Things (IoT) systems. It is more advantageous than wired communication because of the ease of installation. However, it can negatively impact human health if high frequencies are used to transmit data. Therefore, researchers are exploring the potential of optical wireless communication as an alternative, which uses the visible light bandwidth instead of RF waveforms. Three possibilities are being investigated: visible light communication, light fidelity, and optical camera communication. In this paper, we propose a multiple-input multiple-output modulation scheme using a light-emitting diode (LED) array, which is applicable to the IoT system, based on on–off keying modulation in the time domain. This scheme is compatible with the two popular types of camera in the market, rolling shutter cameras and global shutter cameras, as well as the closed-circuit television camera, which is used in factories, buildings, etc. Despite the small size of the LED array, implementing this scheme with 10 links in different positions at a communication distance of 20 m is possible for efficient performance (low error rate) by controlling the exposure time, shutter speed, focal length, channel coding and applying the matched filter.

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