scholarly journals Noise-Adaptive Visible Light Communications Receiver for Automotive Applications: A Step Toward Self-Awareness

Sensors ◽  
2020 ◽  
Vol 20 (13) ◽  
pp. 3764 ◽  
Author(s):  
Alin-Mihai Căilean ◽  
Mihai Dimian ◽  
Valentin Popa
Keyword(s):  
Visible Light ◽  
Traffic Safety ◽  
Resource Sharing ◽  
Visible Light Communication ◽  
Processing Technique ◽  
Open Loop ◽  
Visible Light Communications ◽  
Automotive Applications ◽  
Signal Processing Technique ◽  
Signal Treatment

Visible light communications are considered as a promising solution for inter-vehicle communications, which in turn can significantly enhance the traffic safety and efficiency. However, the vehicular visible light communications (VLC) channel is highly dynamic, very unpredictable, and subject to many noise sources. Enhancing VLC systems with self-aware capabilities would maximize the communication performances and efficiency, whatever the environmental conditions. Within this context, this letter proposes a novel signal to noise ratio (SNR)-adaptive visible light communication receiver architecture aimed for automotive applications. The novelty of this letter comes from an open loop signal processing technique in which the signal treatment complexity is established based on a real-time SNR analysis. So, the receiver evaluates the SNR, and based on this assessment, it reconfigures its structural design in order to ensure a proper signal treatment, while providing an optimal tradeoff between communication performances and computational resources usage. This approach based on software reconfiguration has the potential to provide the system with enhanced flexibility and enables its usage in resource sharing application. As far as we know, this approach has not been considered in vehicular VLC systems. The performances of the proposed architecture are demonstrated by simulations, which confirm the SNR-adaptive capacity and the optimized performances.

scholarly journals An ANN-Based Adaptive Predistorter for LED Nonlinearity in Indoor Visible Light Communications

Electronics ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 948
Author(s):  
Jenn-Kaie Lain ◽  
Yan-He Chen
Keyword(s):  
Visible Light ◽  
Light Emitting Diode ◽  
Optical Power ◽  
Visible Light Communication ◽  
Universal Function ◽  
Visible Light Communications ◽  
Least Mean Square ◽  
Training Sequences ◽  
Led Nonlinearity ◽  
Electrical Source

By modulating the optical power of the light-emitting diode (LED) in accordance with the electrical source and using a photodetector to convert the corresponding optical variation back into electrical signals, visible light communication (VLC) has been developed to achieve lighting and communications simultaneously, and is now considered one of the promising technologies for handling the continuing increases in data demands, especially indoors, for next generation wireless broadband systems. During the process of electrical-to-optical conversion using LEDs in VLC, however, signal distortion occurs due to LED nonlinearity, resulting in VLC system performance degradation. Artificial neural networks (ANNs) are thought to be capable of achieving universal function approximation, which was the motivation for introducing ANN predistortion to compensate for LED nonlinearity in this paper. Without using additional training sequences, the related parameters in the proposed ANN predistorter can be adaptively updated, using a feedback replica of the original electrical source, to track the LED time-variant characteristics due to temperature variation and aging. Computer simulations and experimental implementation were carried out to evaluate and validate the performance of the proposed ANN predistorter against existing adaptive predistorter schemes, such as the normalized least mean square predistorter and the Chebyshev polynomial predistorter.

scholarly journals Polymer colour converter with very high modulation bandwidth for visible light communications

2017 ◽  
Vol 5 (35) ◽  
pp. 8916-8920 ◽  
Author(s):  
D. A. Vithanage ◽  
A. L. Kanibolotsky ◽  
S. Rajbhandari ◽  
P. P. Manousiadis ◽  
M. T. Sajjad ◽  
...  
Keyword(s):  
Visible Light ◽  
High Speed ◽  
Visible Light Communication ◽  
Modulation Bandwidth ◽  
Visible Light Communications ◽  
Semiconducting Polymer ◽  
High Modulation ◽  
Very High

We report the synthesis, photophysics and application of a novel semiconducting polymer as a colour converter for high speed visible light communication.

scholarly journals Experimental Demonstration of Special-Shaped 32-Quadrature Amplitude Modulation Constellations for Visible Light Communications

2018 ◽  
Vol 2018 ◽  
pp. 1-7
Author(s):  
Xinyue Guo ◽  
Shuangshuang Li ◽  
Yang Guo
Keyword(s):  
Visible Light ◽  
Amplitude Modulation ◽  
High Speed ◽  
Light Emitting Diode ◽  
Rapid Development ◽  
Average Power ◽  
Visible Light Communication ◽  
Quadrature Amplitude Modulation ◽  
Visible Light Communications ◽  
Transmission Distance

With the rapid development of light-emitting diode, visible light communication (VLC) has become a candidate technology for the next generation of high-speed indoor wireless communication. In this paper, we investigate the performance of the 32-quadrature amplitude modulation (32-QAM) constellation shaping schemes for the first time, where two special circular constellations, named Circular (4, 11, 17) and Circular (1, 5, 11, 15), and a triangular constellation are proposed based on the Shannon’s criterion. Theoretical analysis indicates that the triangular constellation scheme has the largest minimum Euclidian distance while the Circular (4, 11, 17) scheme achieves the lowest peak-to-average power ratio (PAPR). Experimental results show that the bit error rate performance is finally decided by the value of PAPR in the VLC system due to the serious nonlinearity of the LED, where the Circular (4, 11, 17) scheme always performs best under the 7% preforward error correction threshold of 3.8 × 10−3 with 62.5Mb/s transmission data rate and 1-meter transmission distance.

Researching the Information of Transmission Technology Based on Traffic Lights

2014 ◽  
Vol 644-650 ◽  
pp. 4538-4541
Author(s):  
Qiang Li ◽  
Xin Rui Zhang
Keyword(s):  
Visible Light ◽  
Image Recognition ◽  
Communication Technology ◽  
High Speed ◽  
Visible Light Communication ◽  
Qr Code ◽  
Visible Light Communications ◽  
Traffic Light ◽  
Traffic Lights ◽  
Very High

This design is based on Visible Light Communication Technology, to achieve outdoor visible light communications and image recognition etc. through traffic lights. It will play a role on promoting the utilization of traffic lights. The system uses a LED dot matrix to imitate the traffic light, loading QR Code information on the LED dot matrix and then transporting it in a very high-speed flashing. In receiving terminal, first, webcam OV7670 collects information which from the LED dot matrix, then conveys the picture to FPGA, which is the processor. FPGA will handle the picture by gray scale processing, medium filtering and binary processing at last. Thus, the picture from the LED dot matrix will change to ‘0’ and ‘1’ in binary area. Secondly, as there’s a relationship between LED dot matrix and webcam pixels, we can count how many pixels represent one LED. Finally, we can decode the QR Code based on its own style, and display the final result on the TFT screen.

Image-sensor-based visible light communication for automotive applications

2014 ◽  
Vol 52 (7) ◽  
pp. 88-97 ◽  
Author(s):  
Takaya Yamazato ◽  
Isamu Takai ◽  
Hiraku Okada ◽  
Toshiaki Fujii ◽  
Tomohiro Yendo ◽  
...  
Keyword(s):  
Visible Light ◽  
Visible Light Communication ◽  
Image Sensor ◽  
Automotive Applications

scholarly journals Channel modelling for indoor visible light communications

2020 ◽  
Vol 378 (2169) ◽  
pp. 20190187 ◽  
Author(s):  
Farshad Miramirkhani ◽  
Murat Uysal
Keyword(s):  
Wireless Communication ◽  
Visible Light ◽  
Visible Light Communication ◽  
Visible Light Communications ◽  
Channel Models ◽  
Channel Modelling ◽  
Advantages And Disadvantages ◽  
Optical Propagation ◽  
Modelling Studies ◽  
Comprehensive Survey

Visible light communication (VLC) allows the dual use of light-emitting diodes (LEDs) for wireless communication purposes in addition to their primary purpose of illumination. As in any other communication system, realistic channel modelling is a key for VLC system design, analysis and testing. In this paper, we present a comprehensive survey of indoor VLC channel models. In order to set the background, we start with an overview of infrared (IR) channel modelling, which has received much attention in the past, and highlight the differences between visible and IR optical bands. In the light of these, we present a comparative discussion of existing VLC channel modelling studies and point out the relevant advantages and disadvantages. Then, we provide a detailed description of a site-specific channel modelling approach based on non-sequential ray tracing that precisely captures the optical propagation characteristics of a given indoor environment. We further present channel models for representative deployment scenarios developed through this approach that were adopted by the Institute of Electrical and Electronics Engineering (IEEE) as reference channel models. Finally, we consider mobile VLC scenarios and investigate the effect of receiver location and rotation for a mobile indoor user. This article is part of the theme issue ‘Optical wireless communication’.

scholarly journals Carrierless amplitude and phase modulation in wireless visible light communication systems

2020 ◽  
Vol 378 (2169) ◽  
pp. 20190181 ◽  
Author(s):  
N. Bamiedakis ◽  
R. V. Penty ◽  
I. H. White
Keyword(s):  
Visible Light ◽  
Communication Systems ◽  
High Speed ◽  
Low Cost ◽  
Visible Light Communication ◽  
Practical Implementation ◽  
Visible Light Communications ◽  
Modulation Formats ◽  
Spectrally Efficient ◽  
Basic Features

Visible light communications (VLCs) have attracted considerable interest in recent years owing to the potential to simultaneously achieve data transmission and illumination using low-cost light-emitting diodes (LEDs). However, the high-speed capability of such links is typically limited by the low bandwidth of LEDs. As a result, spectrally efficient advanced modulation formats have been considered for use in VLC links in order to mitigate this issue and enable higher data rates. Carrierless amplitude and phase (CAP) modulation is one such spectrally efficient scheme that has attracted significant interest in recent years owing to its good potential and practical implementation. In this paper, we introduce the basic features of CAP modulation and review its use in the context of indoor VLC systems. We describe some of its attributes and inherent limitations, present related advances aiming to improve its performance and potential and report on recent experimental demonstrations of LED-based VLC links employing CAP modulation. This article is part of the theme issue ‘Optical wireless communication’.

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