scholarly journals Characterization of Light-To-Frequency Converter for Visible Light Communication Systems

Electronics ◽  
2018 ◽  
Vol 7 (9) ◽  
pp. 165 ◽  
Author(s):  
Roger Martínez Ciro ◽  
Francisco López Giraldo ◽  
Andrés Betancur Perez ◽  
Martín Luna Rivera
Keyword(s):  
Visible Light ◽  
Communication Systems ◽  
Signal To Noise Ratio ◽  
Frequency Converter ◽  
Optical Power ◽  
Visible Light Communication ◽  
Periodic Signal ◽  
Maximum Output ◽  
Analog To Digital ◽  
Modulation Format

PIN (positive intrinsic negative) photodiodes and analog-to-digital converters (ADC) are commonly used on visible light communication (VLC) receivers in order to retrieve the data on detected signals. In this paper, a visible light communication receiver based on a light to frequency converter (LTF) is proposed. We characterized the LTF and derived an equation for signal-to-noise ratio (SNR) estimation in terms of its input optical power, and the frequency of the output periodic signal. The experiments show that the periodic signal of the LTF converter has a maximum output frequency of 600 kHz at a distance of 6.2 cm. In this setup, measured SNR reached 18.75 dB, while the lowest obtained SNR with 1.1 m length was roughly −35.1 dB. The results obtained suggest that a bit rate of 150 kbps can be achieved with an on-off keying (OOK) modulation format. We analyzed the results and discuss the advantages and limitations of the LTF converter for optical wireless communication purposes.

scholarly journals Energy-Efficient Optimization Design for the Multi-Color LED Based Visible Light Communication Systems under Illumination Constraints

2018 ◽  
Vol 9 (1) ◽  
pp. 1 ◽  
Author(s):  
Yu Zuo ◽  
Jian Zhang
Keyword(s):  
Energy Consumption ◽  
Visible Light ◽  
Power Allocation ◽  
Communication Systems ◽  
Optimization Design ◽  
Optical Power ◽  
Visible Light Communication ◽  
Visible Light Communications ◽  
Allocation Scheme ◽  
High Modulation

Visible light communications (VLCs) utilizing multi-color light-emitting diodes (LEDs) can achieve a high modulation bandwidth and high-quality illumination compared with phosphor-converted LEDs, which have attracted much attention. However, the spectrum overlapping of different colors may cause the crosstalk problem, which should be considered in the practical multi-color LED-based VLC systems. Due to the ever-increasing energy consumption, the interest in an energy-saving communication technique has further increased. In this paper, in order to maximize energy efficiency, an optimization problem of the optical power allocation scheme is formulated for the multi-color LED-based VLC systems under the necessary communication requirements and illumination constraints with luminance, chromaticity, and signal to interference plus noise ratio (SINR) constraints. Simulation results indicate that the proposed optimal power allocation scheme can reduce energy consumption while satisfying the illumination and communication requirements.

scholarly journals On the Achievable Information Rate of Probabilistic Shaping QAM Order and Source Entropy in Visible Light Communication Systems

2020 ◽  
Vol 10 (12) ◽  
pp. 4299 ◽  
Author(s):  
Peng Zou ◽  
Fangchen Hu ◽  
Yiheng Zhao ◽  
Nan Chi
Keyword(s):  
Visible Light ◽  
Communication Systems ◽  
Signal To Noise Ratio ◽  
Visible Light Communication ◽  
Spectrum Efficiency ◽  
Information Rate ◽  
Computation Complexity ◽  
Signal To Noise ◽  
First Time ◽  
The Relationship

Probabilistic shaping (PS) is a powerful tool that can realize a flexible data rate and high spectrum efficiency. However, the performance of PS is closely related to the quadrature amplitude modulation (QAM) order, source entropy (SE), normalized generalized mutual information (NGMI), and achievable information rate (AIR). In this paper, we investigated the relationship between PS QAM order, SE, NGMI, and AIR performance for the first time in the visible light communication (VLC) system. Under a specific signal-to-noise ratio (SNR), the PS QAM order and SE in this paper can realize a high AIR at a preset NGMI threshold with the lowest computation complexity, which is just 0.1 bit smaller than the highest AIR. Simulation and experimental results show that the NGMI fluctuates between only ±0.005 of the preset NGMI threshold, which proves that the scheme proposed in this paper is feasible.

scholarly journals Advanced Modulation Format of Probabilistic Shaping Bit Loading for 450-nm GaN Laser Diode based Visible Light Communication

Sensors ◽  
2020 ◽  
Vol 20 (21) ◽  
pp. 6143
Author(s):  
Guoqiang Li ◽  
Fangchen Hu ◽  
Peng Zou ◽  
Chaofan Wang ◽  
Gong-Ru Lin ◽  
...  
Keyword(s):  
Visible Light ◽  
Laser Diode ◽  
High Speed ◽  
Signal To Noise Ratio ◽  
Visible Light Communication ◽  
System Capacity ◽  
High Data ◽  
Modulation Format ◽  
Bit Loading ◽  
Power Loading

Visible light communication is an emerging high-speed optical wireless communication technology that can be a candidate to alleviate pressure on conventional radio frequency-based technology. In this paper, for the first time, the advanced modulation format of probabilistic shaping (PS) bit loading is investigated in a high data rate visible light communication system based on a 450-nm Gallium Nitride laser diode. The characteristic of the system is discussed and PS bit loading discrete multi-tone modulation helps to raise the spectral efficiency and improve the system performance. Higher entropy can be achieved in the same signal-to-noise ratio (SNR) and modulation bandwidth limitation, comparing to bit and power loading. With PS bit loading, an available information rate (AIR) of 10.23 Gbps is successfully achieved at the signal bandwidth of 1.5 GHz in a 1.2 m free space transmission with normalized generalized mutual information above 0.92. And higher AIR can be anticipated with an entropy-loading strategy that fixes the channel characteristic. Experimental results validate that a PS bit loading scheme has the potential to increase the system capacity.

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.

Research of LED Emission Cross-Section on Light Communication Systems

2014 ◽  
Vol 602-605 ◽  
pp. 3039-3042
Author(s):  
Wei Min Qi ◽  
Jie Xiao
Keyword(s):  
Visible Light ◽  
Cross Section ◽  
Power Distribution ◽  
Communication Systems ◽  
Emission Cross Section ◽  
Optical Power ◽  
Visible Light Communication ◽  
Communication Performance ◽  
Light Emitting ◽  
Communication Source

Visible light communication (VLC) is an optical wireless communication technology that uses visible light emitting diodes (LEDs) as a communication source. Since the LEDs are also used for illumination, the cross-section emission effects of the LEDs need to be analyzed as they apply to indoor VLC channels. In order to evaluate the illumination and communication performance according to the emission cross-section pattern, a simple LED model with a quasi-elliptic emission cross-section is proposed and compared to a circular LED model. The LEDs with a quasi-elliptic emission cross-section provide less fluctuation in the illumination and optical power distribution at the receiving plane. The four-transmitter VLC system is found to support at least at 30 and 33 Mb/s for circular and quasi-elliptic emission cross-section LEDs for the entire receiving plane, respectively.

scholarly journals Performance of Outdoor Lamp Implementation for Visible Light Communication under Ambient Environment

2018 ◽  
Author(s):  
Ronaldo Soritua Sitanggang ◽  
Denny Darlis ◽  
Karina Wahyu Noviyanti
Keyword(s):  
Light Intensity ◽  
Visible Light ◽  
Communication Systems ◽  
Optical Power ◽  
Visible Light Communication ◽  
Digital Data ◽  
Maximum Distance ◽  
Optimal Distance ◽  
Types Of Information ◽  
Incandescent Lamps

This article is preprint for ASAIS 2018 - Visible Light Communication is the name given to wireless communication systems that convey information by modulating visible light by the human eye. Interest in the field of VLC has grown rapidly along with the development of LEDs as a source of lighting. The motivation is clear: If the room is lit by an LED, why not use it further for the communication provider, along with the lighting facilities at the same time? At the sending side, VLC technology uses LED lighting lamps which are currently very popular to replace incandescent lamps and TL (Fluorescent Lamp) lamps. Visible light communication has many advantages, including security, speed, and convenience to be applied to users to send various types of information including digital data such as text and images. Several studies have been conducted previously regarding the application of information delivery systems using VLC such as sending voice, digital data, images, and video. However, it has not been clearly stated the influence of various lighting lamps used on the system mentioned above such as electrical and optical power used, the angle of transmission and optimal distance with the influence of environmental conditions that cause information transmission losses. Data that can be sent well use yard lighting with a maximum distance of 130 cm with 15 lx light intensity, street lighting with a maximum distance of 400 cm with 6 lx light intensity, and vehicle lights with a maximum distance of 270 cm with 12 lx light intensity.

OFFSET MODULATION FOR VISIBLE LIGHT COMMUNICATION SYSTEMS

2019 ◽  
Vol 78 (13) ◽  
pp. 1213-1222
Author(s):  
A. A. Abdulkafi ◽  
S. M. Hardan ◽  
M. K. Hussein ◽  
Ibrahim K. Sileh
Keyword(s):  
Visible Light ◽  
Communication Systems ◽  
Visible Light Communication
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