scholarly journals Experimental Characterization of RGB LED Transceiver in Low-Complexity LED-to-LED Link

Sensors ◽  
2020 ◽  
Vol 20 (20) ◽  
pp. 5754
Author(s):  
Mariam Galal ◽  
Wai Pang Ng ◽  
Richard Binns ◽  
Ahmed Abd El Aziz
Keyword(s):  
Matched Filter ◽  
Signal To Noise Ratio ◽  
Light Emitting Diode ◽  
Low Complexity ◽  
Light Emitting ◽  
Transmission Distance ◽  
Noise Characteristics ◽  
Data Rates ◽  
Photovoltaic Mode ◽  
Iot Devices

This paper proposes a low-complexity and energy-efficient light emitting diode (LED)-to-LED communication system for Internet of Things (IoT) devices with data rates up to 200 kbps over an error-free transmission distance up to 7 cm. The system is based on off-the-shelf red-green-blue (RGB) LEDs, of which the red sub-LED is employed as photodetector in photovoltaic mode while the green sub-LED is the transmitter. The LED photodetector is characterized in the terms of its noise characteristics and its response to the light intensity. The system performance is then analysed in terms of bandwidth, bit error rate (BER) and the signal to noise ratio (SNR). A matched filter is proposed, which optimises the performance and increases the error-free distance.

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 Reflectance-Based Organic Pulse Meter Sensor for Wireless Monitoring of Photoplethysmogram Signal

Biosensors ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 87 ◽  
Author(s):  
Fahed Elsamnah ◽  
Anubha Bilgaiyan ◽  
Muhamad Affiq ◽  
Chang-Hoon Shim ◽  
Hiroshi Ishidai ◽  
...  
Keyword(s):  
Power Consumption ◽  
Structural Design ◽  
Signal To Noise Ratio ◽  
Light Emitting Diode ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Wireless Monitoring ◽  
Organic Light ◽  
Reduced Power Consumption

This paper compares the structural design of two organic biosensors that minimize power consumption in wireless photoplethysmogram (PPG) waveform monitoring. Both devices were fabricated on the same substrate with a red organic light-emitting diode (OLED) and an organic photodiode (OPD). Both were designed with a circular OLED at the center of the device surrounded by OPD. One device had an OLED area of 0.06 cm2, while the other device had half the area. The gap distance between the OLED and OPD was 1.65 mm for the first device and 2 mm for the second. Both devices had an OPD area of 0.16 cm2. We compared the power consumption and signal-to-noise ratio (SNR) of both devices and evaluated the PPG signal, which was successfully collected from a fingertip. The reflectance-based organic pulse meter operated successfully and at a low power consumption of 8 µW at 18 dB SNR. The device sent the PPG waveforms, via Bluetooth low energy (BLE), to a PC host at a maximum rate of 256 kbps data throughput. In the end, the proposed reflectance-based organic pulse meter reduced power consumption and improved long-term PPG wireless monitoring.

scholarly journals Transmitter and receiver technologies for optical wireless

2020 ◽  
Vol 378 (2169) ◽  
pp. 20190182 ◽  
Author(s):  
Dominic O'Brien ◽  
Sujan Rajbhandari ◽  
Hyunchae Chun
Keyword(s):  
State Of The Art ◽  
Signal To Noise Ratio ◽  
Light Emitting Diode ◽  
High Capacity ◽  
Electrical Signal ◽  
Dominant Factor ◽  
Optical Wireless ◽  
Theme Issue ◽  
Future Directions ◽  
Light Emitting

Providing a reliable link, with sufficient signal-to-noise ratio (SNR) and bandwidth to deliver high-capacity communications is a critical challenge for optical wireless (OW) communications and understanding and jointly optimizing the performance of the transmitter and receiver subsystems is a key part of this. At the transmitter a source of light, either a laser or a light-emitting diode, must be modulated with the communications signal. The resulting emission must be directed, using optics or steering systems, as required for the particular application, and must be within any safety levels set by relevant standards. The receiver is the most critical part of any optical link, as its design is a dominant factor in determining the received SNR, which determines the capacity and ultimately the utility of the link. A receiver must collect, filter and concentrate signal radiation, then detect and amplify the resulting electrical signal. This review surveys the state-of–the-art transmitter and receiver technologies. Details of design constraints are discussed, and potential future directions discussed. This article is part of the theme issue ‘Optical wireless communication’.

scholarly journals Opportunities and Challenges to Implementation of LIFI

2020 ◽  
Author(s):  
Mohammad Abdullah ◽  
Sameed ul Hussan ◽  
Salman Safdar
Keyword(s):  
Light Emitting Diode ◽  
Visible Radiation ◽  
Light Emitting ◽  
Internet Connection ◽  
The World ◽  
Iot Devices ◽  
Data Transferring ◽  
Better Than ◽  
The Way

LIFI was first introduce by Professor Harald Haas on July 2011. Light fidelity (LI-FI) may be a technology which uses light as a medium to travel from one place to a different. It uses Light like Light Emitting Diode (LED) visible radiation Communication (VLC) for data Transferring and Internet connection. LIFI may be a technique which uses light as a medium because it uses light to travel it's 20 times faster than any WIFI within the world. during this paper we speak about things like what's LIFI and the way it's better then WIFI why we want LIFI and What changes did bring LIFI in our Future LIFI. How it'll make IOT devices far better than before The Technique to implement LIFI and also the problem we face of implementation of LIFI

scholarly journals Optical Camera Communications for IoT–Rolling-Shutter Based MIMO Scheme with Grouped LED Array Transmitter

Sensors ◽  
2020 ◽  
Vol 20 (12) ◽  
pp. 3361 ◽  
Author(s):  
Shivani Rajendra Teli ◽  
Vicente Matus ◽  
Stanislav Zvanovec ◽  
Rafael Perez-Jimenez ◽  
Stanislav Vitek ◽  
...  
Keyword(s):  
Signal To Noise Ratio ◽  
Light Emitting Diode ◽  
Multiple Input Multiple Output ◽  
Raspberry Pi ◽  
High Data ◽  
Data Throughput ◽  
Data Rates ◽  
Led Array ◽  
Communication Links ◽  
Input Multiple Output

In optical camera communications (OCC), the provision of both flicker-free illumination and high data rates are challenging issues, which can be addressed by utilizing the rolling-shutter (RS) property of the image sensors as the receiver (Rx). In this paper, we propose an RS-based multiple-input multiple-output OCC scheme for the Internet of things (IoT) application. A simplified design of multi-channel transmitter (Tx) using a 7.2 × 7.2 cm2 small 8 × 8 distributed light emitting diode (LED) array, based on grouping of LEDs, is proposed for flicker-free transmission. We carry out an experimental investigation of the indoor OCC system by employing a Raspberry Pi camera as the Rx, with RS capturing mode. Despite the small area of the display, flicker-free communication links within the range of 20–100 cm are established with data throughput of 960 to 120 bps sufficient for IoT. A method to extend link spans up to 1.8 m and the data throughput to 13.44 kbps using different configurations of multi-channel Tx is provided. The peak signal-to-noise ratio of ~14 and 16 dB and the rate of successfully received bits of 99.4 and 81% are measured for the shutter speeds of 200 and 800 µs for a link span of 1 m, respectively.

scholarly journals Ambient LED Light Noise Reduction Using Adaptive Differential Equalization in Li-Fi Wireless Link

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1060
Author(s):  
Yong-Yuk Won ◽  
Sang Min Yoon ◽  
Dongsun Seo
Keyword(s):  
Forward Error Correction ◽  
First Generation ◽  
Weighting Function ◽  
Signal To Noise Ratio ◽  
Light Emitting Diode ◽  
Light Sources ◽  
Ambient Light ◽  
Light Emitting ◽  
Reduction Efficiency ◽  
Forward Error

For Li-Fi wireless links based on a white light emitting diode, an adaptive differential equalization (ADE) technique that reduces various noises such as interference noise and shot one generated from ambient light sources is pro-posed. The ADE technique reduces noise by taking advantage of the fact that the derivative between adjacent sampling points of signal with digital waveform is very different from that of noise with the random analog waveform. Furthermore, a weighting function that reflects the Poisson characteristics of shot noise is applied to the ADE technique in order to maximize the reduction efficiency of ambient noise. The signal-to-noise ratio of input non-return-to-zero-on–off keying (NRZ-OOK) signal is improved by 7.5 dB at the first-generation forward error correction (FEC) threshold (the bit error rate (BER) of 8 × 10−5) using the optical wireless experimental link. In addition, it is confirmed that it is possible to maintain the transmission performance corresponding to the BER of 1 × 10−5 by using the proposed ADE technique, even when the intensity of the ambient light source increases by 6 dB.

scholarly journals Designing of an Indoor Visible Light Communication Transceiver for Data Transmission using White LED

2016 ◽  
Author(s):  
Ha Duyen Trung ◽  
Do Trong Tuan
Keyword(s):  
Visible Light ◽  
Signal To Noise Ratio ◽  
Light Emitting Diode ◽  
Image Transmission ◽  
Visible Light Communication ◽  
Symbol Error Rate ◽  
Data Rate ◽  
Full Duplex ◽  
Light Emitting ◽  
Environment Experiment

Abstract: In this paper, a prototype of full-duplex indoor  Visible  Light  Communication  (VLC) transceiver  is  designed  to  demonstrate  an  optical wireless  system  based  on  Universal  Serial  Bus (USB) port for data transmissions using white Light Emitting  Diode  (LED).  Based  on  VLC  technology, the  designed  system  consists  of  transmitters  and receivers can achieve data rate of 161.2 Kbps error free at the distance of 92 cm between two computers for  real-time  text  and  image  transmission  over indoor  environment.  Experiment  results  show  that for text transmission, symbol error rate (SER) does not  vary  data  rate  at  some  transmission  distances, whereas  for  image  transmission,  minimum  square error (MSE) and peak signal to noise ratio (PSNR) indicate  that  the  received  image  and  transmitted image were almost similar.

scholarly journals Light-Emitting Diode Degradation and Low-Frequency Noise Characteristics

2011 ◽  
Vol 119 (4) ◽  
pp. 514-520 ◽  
Author(s):  
B. Šaulys ◽  
J. Matukas ◽  
V. Palenskis ◽  
S. Pralgauskaitė ◽  
G. Kulikauskas
Keyword(s):  
Light Emitting Diode ◽  
Low Frequency ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Light Emitting ◽  
Noise Characteristics

scholarly journals Multi-Site Photoplethysmographic and Electrocardiographic System for Arterial Stiffness and Cardiovascular Status Assessment

Sensors ◽  
2019 ◽  
Vol 19 (24) ◽  
pp. 5570 ◽  
Author(s):  
David Perpetuini ◽  
Antonio Maria Chiarelli ◽  
Lidia Maddiona ◽  
Sergio Rinella ◽  
Francesco Bianco ◽  
...  
Keyword(s):  
Signal To Noise Ratio ◽  
Light Emitting Diode ◽  
Single Pulse ◽  
High Signal ◽  
Silicon Photomultiplier ◽  
Light Emitting ◽  
Status Assessment ◽  
Ecg Leads ◽  
Development And Validation

The development and validation of a system for multi-site photoplethysmography (PPG) and electrocardiography (ECG) is presented. The system could acquire signals from 8 PPG probes and 10 ECG leads. Each PPG probe was constituted of a light-emitting diode (LED) source at a wavelength of 940 nm and a silicon photomultiplier (SiPM) detector, located in a back-reflection recording configuration. In order to ensure proper optode-to-skin coupling, the probe was equipped with insufflating cuffs. The high number of PPG probes allowed us to simultaneously acquire signals from multiple body locations. The ECG provided a reference for single-pulse PPG evaluation and averaging, allowing the extraction of indices of cardiovascular status with a high signal-to-noise ratio. Firstly, the system was characterized on optical phantoms. Furthermore, in vivo validation was performed by estimating the brachial-ankle pulse wave velocity (baPWV), a metric associated with cardiovascular status. The validation was performed on healthy volunteers to assess the baPWV intra- and extra-operator repeatability and its association with age. Finally, the baPWV, evaluated via the developed instrumentation, was compared to that estimated with a commercial system used in clinical practice (Enverdis Vascular Explorer). The validation demonstrated the system’s reliability and its effectiveness in assessing the cardiovascular status in arterial ageing.

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