scholarly journals Li-Pos: A Light Positioning Framework Leveraging OFDM for Visible Light Communication

Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4310
Author(s):  
Jianbin Wu ◽  
Sami Ahmed Haider ◽  
Muhammad Irshad ◽  
Jehangir Arshad ◽  
Sohail M. Noman ◽  
...  
Keyword(s):  
Visible Light ◽  
Light Source ◽  
Orthogonal Frequency Division Multiplexing ◽  
Pulse Width Modulation ◽  
Light Emitting Diode ◽  
Area Under The Curve ◽  
Visible Light Communication ◽  
Delay Spread ◽  
Entire Area ◽  
Receiver Plane

The design of solid-state lighting is vital, as numerous metrics are involved in their exact positioning, and as it is utilized in various processes, ranging from intelligent buildings to the internet of things (IoT). This work aims to determine the power and delay spread from the light source to the receiver plane. The positions of the light source and receiver were used for power estimation. We focus on analog orthogonal frequency-division multiplexing (OFDM) in visible light communication (VLC) and assess the area under the curve (AUC). The proposed system was designed using modulation techniques (i.e., quadrature amplitude modulation; QAM) for visible light communication (VLC) and pulse-width modulation (PWM) for dimming sources. For the positioning and spreading of brightness, the proof-of-concept was weighted equally over the entire area. Therefore, the receiver plane was analyzed, in order to measure the power of each light-emitting diode (LED) in a given area, using the delayed mean square error (MSE). A framework was applied for the placement of LEDs, using full-width at half-maximum (FWHM) parameters with varying distances. Then, the received power was confirmed. The results show that the AUC using DRMS values for LEDs significantly increased (by 30%) when the number of source LEDs was changed from four to three. These results confirm that our system, associated with the simple linear lateration estimator, can achieve better energy consumption.

scholarly journals Study of the Performance of Deep Learning-Based Channel Equalization for Indoor Visible Light Communication Systems

Photonics ◽  
2021 ◽  
Vol 8 (10) ◽  
pp. 453
Author(s):  
Pu Miao ◽  
Weibang Yin ◽  
Hui Peng ◽  
Yu Yao
Keyword(s):  
Deep Learning ◽  
Visible Light ◽  
Communication Systems ◽  
Orthogonal Frequency Division Multiplexing ◽  
Light Emitting Diode ◽  
Visible Light Communication ◽  
Channel Equalization ◽  
Training Data ◽  
Traditional System ◽  
Ber Performance

The inherent impairments of visible light communication (VLC) in terms of nonlinearity of light-emitting diode (LED) and the optical multipath restrict bit error rate (BER) performance. In this paper, a model-driven deep learning (DL) equalization scheme is proposed to deal with the severe channel impairments. By imitating the block-by-block signal processing block in orthogonal frequency division multiplexing (OFDM) communication, the proposed scheme employs two subnets to replace the signal demodulation module in traditional system for learning the channel nonlinearity and the symbol de-mapping relationship from the training data. In addition, the conventional solution and algorithm are also incorporated into the system architecture to accelerate the convergence speed. After an efficient training, the distorted symbols can be implicitly equalized into the binary bits directly. The results demonstrate that the proposed scheme can address the overall channel impairments efficiently and can recover the original symbols with better BER performance. Moreover, it can still work robustly when the system is complicated by serious distortions and interference, which demonstrates the superiority and validity of the proposed scheme in channel equalization.

Quantitative analysis of the stacked autoencoder method in MIMO-ACO-OFDM VLC systems

2020 ◽  
pp. 147715352092620
Author(s):  
LL Hao ◽  
CD Li ◽  
DY Wang
Keyword(s):  
Visible Light ◽  
Bit Error Rate ◽  
Error Rate ◽  
Communication System ◽  
Orthogonal Frequency Division Multiplexing ◽  
Visible Light Communication ◽  
Delay Spread ◽  
Rate Performance ◽  
Stacked Autoencoder ◽  
Minimum Mean Squared Error

In this paper, a stacked autoencoder network is utilised to realise the signal constellation and transceivers adapted to the dimmable indoor visible light communication system in order to acquire lower symbol error probability. Its decoder parts function as denoising and the equaliser for the proposed multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) visible light communication system which can compensate the non-linear transfer function and the crosstalk between multiple LED data streams. The bit error rate performance as well as the influence of LED spatial intervals on root mean square delay spread, impulse response and bit rate have been analysed considering multipath reflections of the indoor MIMO-VLC system. The numerical results show that the a stacked autoencoder technique performs better in bit error rate reduction compared with state-of-art the zero forcing and minimum mean squared error algorithm. The experiment also shows, when the semi-angle at half power of LEDs and the field of view of Photodetectors become small, better performance can be achieved at the centre of the room, which can be explained by strong beam converge and the decreased multipath interference. Moreover, enlarging the separation between LEDs leads to improved bit error rate performance and reduced channel correlation of channel matrix, which need to be optimally chosen in practice.

scholarly journals Hybrid modulation schemes for data transmission improvement of indoor visible light communication system

2018 ◽  
Vol 7 (4) ◽  
pp. 2822 ◽  
Author(s):  
Abdelhalim Zekry ◽  
Christena Ghandour ◽  
Nazmi A. Mohammed ◽  
S El-Rabaie
Keyword(s):  
Visible Light ◽  
Data Transmission ◽  
Orthogonal Frequency Division Multiplexing ◽  
Pulse Width Modulation ◽  
Mathematical Formulation ◽  
Visible Light Communication ◽  
Pulse Position Modulation ◽  
Dimming Control ◽  
Efficient Data ◽  
Modulation Schemes

This work enhances the bit rate characteristics, receiver sensitivity and power requirements of multicarrier modulation schemes (MCM) for visible light communication (VLC) dimming control system at bit error rate (BER) less than 10-3. This study develops the mathematical formulation for merging pulse position modulation (PPM) and overlapping pulse position modulation (OPPM) with M-ary quadrature amplitude modulation DC-Biased optical orthogonal frequency division multiplexing (M-QAM DCO OFDM), which can achieve efficient data transmission while maintaining communication quality. These schemes are then compared with the conventional merging (i.e M-QAM DCO OFDM with pulse width modulation (PWM)). Relating to the recent advances in the field, the additional comparative study is established with the latest merging platform (i.e. M-QAM DCO OFDM with multiple pulse position modulation (MPPM)). 

scholarly journals A Novel Transceiver Model for Polar Transform Optical (PTO-) OFDM for Visible Light Communication (VLC) Based on Peak to Average Power Ratio Reduction using Precoding

2020 ◽  
Vol 9 (10) ◽  
pp. 307-315
Keyword(s):  
Visible Light ◽  
Power Efficiency ◽  
Orthogonal Frequency Division Multiplexing ◽  
Light Emitting Diode ◽  
Average Power ◽  
Visible Light Communication ◽  
Intensity Modulation ◽  
Power Ratio ◽  
Positive Real ◽  
High Data

Indoor visible light communication (VLC) has the potential of providing high data rates for short-range wireless communication with a relative spatial elevated security in contrast to a radiofrequency wireless one. To support that high data stream, Orthogonal Frequency Division Multiplexing (OFDM) is used; however, due to the limited operational bandwidth of the commercial white light-emitting diode (LED), signal processing techniques are used to increase the efficiency of the OFDM and to adapt OFDM to VLC systems. As a major concern, the intensity modulation direct detection necessary for VLC requires positive real signal, this is dealt with by imposing Hermitian pre-possessing or Cartesian to polar conversion post-processing to the OFDM. The use of the Cartesian to polar converter allows the transmission of complex OFDM symbols through the intensity modulation channel. A polar transform optical (PTO-) OFDM presented here as an improvement and simplification of previous polar optical OFDM schemes gives an efficient transceiver architecture. Nevertheless, both OFDM transmission techniques for Visible optical links, similar to radiofrequency (RF), suffer greatly from irregular excessive Peak-to-Average power ratio (PAPR). Higher PAPR reduces the power efficiency of the On-Off Keying (OOK) based on pulse amplitude modulation (PAM). Furthermore, it also is recommendable to reduce the PAPR for conformity with eye safety. A precoding technique is proposed to reduce the PAPR of intensity-modulated for direct detectability of the OFDM signal destined for the wireless optical link using Cartesian-to-Polar conversion. Based on the enhanced processing at the front ends and using MATLAB simulation, it is proven that the presented model can improve the link parameters including the bit error rate (BER) and signal to noise ratio (SNR) and bandwidth efficient compared to Hermitian modified ones.

scholarly journals The Detection and Recognition of RGB-LED-ID Based on Visible Light Communication using Convolutional Neural Network

2019 ◽  
Vol 9 (7) ◽  
pp. 1400 ◽  
Author(s):  
Weipeng Guan ◽  
Jingyi Li ◽  
Shangsheng Wen ◽  
Xinjie Zhang ◽  
Yufeng Ye ◽  
...  
Keyword(s):  
Neural Network ◽  
Visible Light ◽  
Pulse Width Modulation ◽  
Light Emitting Diode ◽  
Complementary Metal Oxide Semiconductor ◽  
Visible Light Communication ◽  
Image Sensor ◽  
Oxide Semiconductor ◽  
Light Emitting ◽  
Modulation And Demodulation

In this paper, an online to offline (O2O) method based on visible light communication (VLC) is proposed, which is different from the traditional VLC with modulation and demodulation. It is a new VLC with modulation and recognition. We use RGB light emitting diode (RGB-LED) as the transmitter, and use Pulse Width Modulation (PWM) to modulate the signal to make it flicker at high frequency. Therefore, several features are created. At the receiver, the complementary metal-oxide-semiconductor (CMOS) image sensor is applied to our system to capture LED images with stripes. A convolution neural network (CNN) is then introduced in our system as a classifier. By offline training for the classifiers and online recognition of LED-ID, the scheme proposed could improve the speed of LED-ID (the unique identification of each different LED) identification and improve the robustness of the system. This is the first application of CNN in the field of VLC.

scholarly journals Deep Learning-Assisted Index Estimator for Generalized LED Index Modulation OFDM in Visible Light Communication

Photonics ◽  
2021 ◽  
Vol 8 (5) ◽  
pp. 168
Author(s):  
Manh Le-Tran ◽  
Sunghwan Kim
Keyword(s):  
Deep Learning ◽  
Visible Light ◽  
Error Rate ◽  
Orthogonal Frequency Division Multiplexing ◽  
Light Emitting Diode ◽  
Visible Light Communication ◽  
Ofdm System ◽  
Signal Demodulation ◽  
Index Estimation ◽  
Index Modulation

In this letter, we present the first attempt of active light-emitting diode (LED) indexes estimating for the generalized LED index modulation optical orthogonal frequency-division multiplexing (GLIM-OFDM) in visible light communication (VLC) system by using deep learning (DL). Instead of directly estimating the transmitted binary bit sequence with DL, the active LEDs at the transmitter are estimated to maintain acceptable complexity and improve the performance gain compared with those of previously proposed receivers. Particularly, a novel DL-based estimator termed index estimator-based deep neural network (IE-DNN) is proposed, which can employ three different DNN structures with fully connected layers (FCL) or convolution layers (CL) to recover the indexes of active LEDs in a GLIM-OFDM system. By using the received signal dataset generated in simulations, the IE-DNN is first trained offline to minimize the index error rate (IER); subsequently, the trained model is deployed for the active LED index estimation and signal demodulation of the GLIM-OFDM system. The simulation results show that the IE-DNN significantly improves the IER and bit error rate (BER) compared with those of conventional detectors with acceptable run time.

scholarly journals Experimental Investigation of Zadoff-Chu Matrix Precoding for Visible Light Communication System with OFDM Modulation

2018 ◽  
Vol 2018 ◽  
pp. 1-6
Author(s):  
Xinyue Guo ◽  
Yang Guo ◽  
Shuangshuang Li
Keyword(s):  
Visible Light ◽  
Orthogonal Frequency Division Multiplexing ◽  
High Speed ◽  
Forward Error Correction ◽  
Signal To Noise Ratio ◽  
Light Emitting Diode ◽  
Average Power ◽  
Visible Light Communication ◽  
Potential Candidate ◽  
Ofdm Modulation

Light-emitting diode- (LED-) based visible light communication (VLC) has become a potential candidate for next generation high-speed indoor wireless communication. Due to the limited modulation bandwidth of the LED, orthogonal frequency division multiplexing (OFDM) modulation is particularly preferred in the VLC system to overcome the ISI, which suffers from the high peak-to-average power ratio (PAPR) and leads to severe performance loss. In this paper, we propose and experimentally demonstrate a novel Zadoff-Chu matrix (ZCM) precoding scheme, which can not only reduce the PAPR, but also provide uniform signal-to-noise ratio (SNR) profile. The theoretical analysis and simulation show that the proposed scheme achieves better PAPR performance compared with the traditional precoding schemes. The experimental demonstration further validates the bit error rate (BER) performance improvement, where the measured BERs are all below the 7% pre-forward error correction (pre-FEC) limit of 3.8 × 10−3 when the transmitted data rate is 50 Mb/s.

An approach to ensure joint illumination & communication performance of a forward error corrected indoor visible light communication (VLC) system in presence of ambient light interference

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Sourish Chatterjee ◽  
Biswanath Roy
Keyword(s):  
Visible Light ◽  
Bit Error Rate ◽  
Error Rate ◽  
Light Emitting Diode ◽  
Visible Light Communication ◽  
Ambient Light ◽  
Ambient Illumination ◽  
Communication Performance ◽  
Light Interference ◽  
Forward Error

AbstractIn recent time of looming radio frequency (RF) spectrum crisis, visible light communication using lighting infrastructure emerged as a potential alternative at an indoor environment. This paper addresses the setback associated with ambient light interference in an indoor Visible Light Communication (VLC) system to ensure joint communication and illumination performance inside an office room. A novel VLC architecture with suitable white light emitting diode (WLED) luminaire arrangement is presented to minimize the dispersion of signal to interference plus noise ratio (SINR) across the room. Luminaires are categorized in two groups viz. data transmitting illuminants and illuminants for lighting purpose. The first group is dedicated to transmit data as well as serves the purpose of illumination. The other set creates only ambient illumination to achieve quality lighting attributes. The proposed forward error corrected receiver configuration discards the ambient light noise originated by the illuminants that serve the ambient illumination. Tail biting convolutional encoder and viterbi decoder are used at the encoding section of the transmitter and decoding section of the receiver respectively to improve bit error rate. Results obtained through MATLAB simulation shows better average bit error rate (BER) in the order of 10−8 measured at uniformly distributed 25 grid points over the working plane. At the same time achieved average horizontal illuminance with good uniformity comply with ISO recommendation.

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