scholarly journals Polarization Differential Visible Light Communication: Theory and Experimental Evaluation

Sensors ◽  
2020 ◽  
Vol 20 (19) ◽  
pp. 5661
Author(s):  
Jorik De Bruycker ◽  
Willem Raes ◽  
Stanislav Zvánovec ◽  
Nobby Stevens
Keyword(s):  
Visible Light ◽  
Communication Theory ◽  
Rotation Angle ◽  
Signal To Noise Ratio ◽  
Visible Light Communication ◽  
Signal Quality ◽  
Polarization Direction ◽  
Signal To Noise ◽  
Research Attention ◽  
Analytical Expression

Visible Light Communication (VLC) has received substantial research attention in the last decade. The vast majority of VLC focuses on the modulation of the transmitted light intensity. In this work, however, the intensity is kept constant while the polarization direction is deployed as a carrier of information. Demodulation is realized by using a differential receiver pair equipped with mutually orthogonal polarizers. An analytical expression to evaluate the Signal-to-Noise Ratio (SNR) as a function of the rotation angle of the receiver is derived. It is demonstrated that the signal quality can deteriorate heavily with receiver orientation when using a single differential receiver pair. A way to overcome this drawback using two receiver pairs is described. The analytical expression is experimentally verified through measurements with two different receiver setups. This work demonstrates the potential of polarization-based modulation in the field of VLC, where receiver rotation robustness has been achieved by means of a dedicated quadrant photodiode receiver.

scholarly journals A Full-Duplex LED-to-LED Visible Light Communication System

Electronics ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 1713
Author(s):  
Hyunwoo Jung ◽  
Sung-Man Kim
Keyword(s):  
Visible Light ◽  
Bit Error Rate ◽  
Error Rate ◽  
Signal To Noise Ratio ◽  
Light Emitting Diode ◽  
Visible Light Communication ◽  
Full Duplex ◽  
Signal To Noise ◽  
Light Emitting ◽  
Half Duplex

We experimentally demonstrated full-duplex light-emitting diode (LED)-to-LED visible light communication (VLC) using LEDs as the transmitter and receiver. Firstly, we investigated the performance dependency on the wavelengths of the LED transmitter and receiver by measuring the rise time and signal-to-noise ratio (SNR). Through the investigation, we were able to choose the optimal LED color set for LED-to-LED VLC using Shannon’s channel capacity law. The bit error rate (BER) results of full-duplex and half-duplex LED-to-LED VLC systems with the optimal LED sets are shown to compare the performance. Furthermore, we discuss major distortions and signal losses in the full-duplex LED-to-LED VLC system.

scholarly journals An Optimization of the Signal-to-Noise Ratio Distribution of an Indoor Visible Light Communication System Based on the Conventional Layout Model

2020 ◽  
Vol 12 (21) ◽  
pp. 9006
Author(s):  
Xiangyang Zhang ◽  
Nan Zhao ◽  
Fadi Al-Turjman ◽  
Muhammad Bilal Khan ◽  
Xiaodong Yang
Keyword(s):  
Visible Light ◽  
Communication System ◽  
Signal To Noise Ratio ◽  
Visible Light Communication ◽  
Optimal Layout ◽  
Signal To Noise ◽  
Ratio Distribution ◽  
Channel Quality ◽  
Reflected Light ◽  
Noise Ratio

For an actual visible light communication system, it is necessary to consider the uniformity of indoor illumination. Most of the existing optimization schemes, however, do not consider the effect of the first reflected light, and do not conform to the practical application conventions, which increases the actual cost and the complexity of system construction. In this paper, considering the first reflected light and based on the conventional layout model and the classic indoor visible light communication model, a scheme using the parameter Q to determine the optimal layout of channel quality is proposed. We determined the layout, and then carried out a simulation. For comparison, the normal layout and the optimal layout of illumination were also simulated. The simulation results show that the illuminance distributions of the three layouts meet the standards of the International Organization for Standardization. The optimal layout of channel quality in the signal-to-noise ratio distribution, maximum delay spread distribution, and impulse response is obviously better than the optimal layout of illumination. In particular, the effective area percentage of the optimal layout of channel quality is increased by 0.32% and 6.08% to 88.80% as compared with the normal layout’s 88.48% and the optimal layout of illumination’s 82.72%. However, compared with the normal layout, the advantages are not very prominent.

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.

The reduction of statistical noise in airborne radiometric data

1976 ◽  
Vol 13 (10) ◽  
pp. 1351-1357 ◽  
Author(s):  
J. Tammenmaa ◽  
R. L. Grasty ◽  
M. Peltoniemi
Keyword(s):  
Energy Spectrum ◽  
Point Source ◽  
Signal To Noise Ratio ◽  
Measurement Time ◽  
Signal To Noise ◽  
Analytical Expression ◽  
Noise Ratio ◽  
Radiometric Data ◽  
Statistical Noise

An analytical expression for the Fourier energy spectrum of a radioactive point source is found to satisfactorily define that part of the spectrum in which all radiometric features are located. It is shown that the decreased signal-to-noise ratio arising from a shorter measurement time can be regained by the application of a suitable filter, resulting in better ground resolution and less distortion of radiometric anomalies.

scholarly journals Performance evaluation of optical attocells configuration in an indoor visible light communication

2019 ◽  
Vol 14 (2) ◽  
pp. 668 ◽  
Author(s):  
M.S. M. Gismalla ◽  
M.F. L. Abdullah
Keyword(s):  
Visible Light ◽  
Power Distribution ◽  
Signal To Noise Ratio ◽  
Low Cost ◽  
Data Communication ◽  
Visible Light Communication ◽  
Base Stations ◽  
Configuration Model ◽  
Received Power ◽  
Small Base

Visible light communication VLC is deemed as futuristic technology applied for both illumination and data communication due to the low-cost energy consumption, long life expectancy, huge bandwidth, and high security compared to radio frequency RF. Uncovered area, minimum signal-to-noise ratio (SNR) and received power results from the non-uniform distribution of small base stations (i.e. Optical attocells) in the room. In this paper, the researchers propose a new LEDs distribution of five optical attocells configuration model in order to optimize the received power distribution and SNR at the center of the room for indoor VLC system. The optical attocells configuration in terms of received power to fill the uncovered area at the center of the room has been investigated. The simulation results showed that the proposed attocells configuration saved 24.9% of the transmitted power. Besides that, the whole room was covered uniformly.  As a result, the received power and SNR are improved.

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